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Doppler color flow mapping in the evaluation of prosthetic mitral and aortic valve function
Abstract
Doppler color flow mapping and color-guided conventional Doppler studies were performed on 119 patients with 126 prosthetic valves (mitral alone in 60, aortic alone in 52 and both mitral and aortic in 7 patients) within 2 weeks of the catheterization study or surgery, or both. The mean pressure gradients derived by color-guided continuous wave Doppler ultrasound correlated well with those obtained at catheterization for both the tissue and mechanical mitral and aortic prostheses (r = 0.85 to 0.87). For the effective prosthetic orifice areas, better correlation with catheterization results were obtained with the tissue mitral (r = 0.94) and tissue aortic (r = 0.87) prostheses than with the mechanical mitral (r = 0.79) and mechanical aortic (r = 0.76) prostheses. The maximal width of the color flow signals at their origin from the tissue mitral prostheses also correlated well with the effective prosthetic orifice area at catheterization (r = 0.81). Doppler color flow mapping identified prosthetic valvular regurgitation with a sensitivity and specificity of 89% and 100%, respectively, for the mitral and 92% and 83% for the aortic prostheses. There was complete agreement between the Doppler color flow mapping and angiographic grading of the severity of prosthetic valvular regurgitation in 90% of mitral and 73.5% of the aortic regurgitant prostheses with under- or overestimation by greater than 1 grade in only two cases. Valvular and paravalvular regurgitation was correctly categorized by Doppler color flow mapping in relation to the surgical findings in 94% of the mitral and 80.5% of the aortic prostheses.
... Colour Doppler mode occasionally allows small para-or intraprosthetic regurgitations from aortic prostheses to be identified [9]. ...
... Estimation of left ventricular ejection fraction (LVEF) by two-dimensional echocardiography is part of the routine investigation. The resting LVEF is the most important prognostic indicator in patients with chronic ischaemic heart disease and plays an important role in treatment decisions, including consideration for cardiac resynchronisation [8,9]. ...
... The assessment scheme we have used is similar to that used by Kapur and associates. 18 The degree of aortic regurgitation remained unchanged and clinically insignificant during follow-up ( Figure E2, A). There was no significant change in mitral regurgitation during follow-up ( Figure E2, B). ...
We performed the first human case of successful transapical transcatheter aortic valve implantation on a beating heart in October 2005, and therefore we have the longest follow-up on transapical aortic valve implantation in humans. We now report clinical and echocardiographic outcomes of transapical aortic valve implantation in 71 patients.
Between October 2005 and February 2009, 71 patients (44 female) underwent transcatheter transapical aortic valve implantation with either 23- or 26-mm Edwards Lifesciences transcatheter bioprostheses. All patients with symptomatic aortic stenosis were declined for conventional aortic valve replacement owing to unacceptable operative risks and were not candidates for transfemoral aortic valve implantation because of poor arterial access. Clinical and echocardiographic follow-ups were performed before discharge, at 1 and 6 months, and then yearly. The mean follow-up was 12.9 +/- 11.5 months with a total of 917.3 months of follow-up.
Mean age was 80.0 +/- 8.1 years and predicted operative mortality was 34.5% +/- 20.4% by logistic EuroSCORE and 12.1% +/- 7.7% by The Society of Thoracic Surgeons Risk Calculator. Valves were successfully implanted in all patients. Twelve patients died within 30 days (30-day mortality: 16.9% in all patients, 33% in the first 15 patients, and 12.5% in the remainder), and 10 patients died subsequently. Overall survival at 24 and 36 months was 66.3% +/- 6.4% and 58.0% +/- 9.5%, respectively. Among 59 patients who survived at least 30 days, 24- and 36-month survivals were 79.8% +/- 6.4% and 69.8% +/- 10.9%, respectively. Late valve-related complications were rare. New York Heart Association functional class improved significantly from preoperative 3.3 +/- 0.8 to 1.8 +/- 0.8 at 24 months. The aortic valve area and mean gradient remained stable at 24 months (1.6 +/- 0.3 cm(2) and 10.3 +/- 5.9 mm Hg, respectively).
Our outcome suggests that transapical transcatheter aortic valve implantation provides sustained clinical and hemodynamic benefits for up to 36 months in selected high-risk patients with symptomatic severe aortic stenosis.
... Today, thanks to the widespread use of echocardiography techniques, small and asymptomatic PVL are also often detected, as a result of the high sensitivity of color-flow mapping. [4][5][6] Little is known about the incidence of aortic PVLs detected in the short term after conventional aortic valve surgery. Furthermore, the natural course of these leaks has not yet been adequately studied. ...
Background:
Paravalvular leak (PVL) is a well-known complication after aortic valve replacement (AVR). Although some studies have described the incidence of postoperative aortic PVL, there are conflicting data about the predictive factors and a paucity of evidence regarding their time course and impact on survival.
Methods:
Data were collected from patients who underwent surgical AVR at Circolo Hospital in Varese, Italy from January 2014 to December 2017. A transthoracic echocardiogram (TTE) was performed in all patients before hospital discharge. Additionally, a second TTE was obtained during postoperative follow-up in subjects with early aortic PVL.
Results:
A total of 514 patients were enrolled in the study. At hospital discharge, aortic PVL was present in 60 patients (11.7%); the majority (78.3%) of the PVLs were mild. Multivariate logistic regression analysis identified smaller body surface area, female sex, and operating surgeon as the strongest predictors of early aortic PVL. Follow-up TTE was available for 50 patients (83.3%). Median time from the date of surgery to follow-up TTE was 2.2 years (0.4 to 4 years). Most aortic PVLs remained unchanged (50%) or disappeared (36%) over time. Only 2 patients (4%) had a progression of the leak. Overall, mortality was 8.4% (43 of 514). Survival was negatively affected by the presence of residual, mild to moderate, or moderate aortic PVL.
Conclusions:
Aortic PVL is not uncommon after standard AVR. Operating surgeon, smaller body surface area, and female sex are risk factors for the development of this complication. These leaks are usually mild and generally have a benign course. However, the presence of mild to moderate or more severe aortic PVL may influence postoperative survival.
... A more accurate technique to evaluate the hydrodynamic performance of the valve called the colour Doppler mapping technique was introduced by Kapur et al. (1989). This technique provides a reliable tool to assess the high flow velocity field. ...
... Now that transoesophageal echocardiography (TOE) is widely available, a different picture is emerging. 2 Small and asymptomatic paraprosthetic jets are often detected incidentally as a result of the high sensitivity of colour flow mapping, [3][4][5] mainly when it is used with TOE. 6 However, important clinical issues have not yet been adequately studied, such as the prevalence of these jets, their cause and time course, and their clinical consequences. Answers to these questions are clinically relevant for deciding which (if any) patients with small paraprosthetic jets, detected either incidentally or because of systematic study, need more careful follow up or even a repeat operation. ...
Objective
To assess the prevalence, mechanisms, and significance of paraprosthetic regurgitation detected incidentally by transoesophageal echocardiography (TOE) in patients after heart valve replacement.
Design
Prospective observational study.
Setting
Tertiary referral centre.
Patients
360 consecutive patients (mean (SD) age 65.8(9.5) years, 193 women) undergoing elective first ever valve replacement.
Methods
Postoperative and follow up TOE, and tests for haemolysis and anaemia.
Results
There were 243 aortic, 90 mitral, and 27 double valve replacements, using 316 mechanical and 44 tissue valves, giving 270 aortic and 117 mitral valves. One patient with severe paraprosthetic mitral regurgitation underwent immediate reoperation and was excluded from subsequent analyses. Paraprosthetic jets were detected around 16 (6%) of the aortic and 38 (32%) of the mitral valves (p < 0.05) at the postoperative study. Follow up TOE was available for 151 aortic and 67 mitral valves, 0.9 (0.5) years after operation. Paraprosthetic jets were present in 15 (10%) of the aortic and 10 (15%) of the mitral valves (NS). Two thirds of the aortic and a fifth of the mitral jets were new. Paraprosthetic jets were more common in aortic valves in a supra-annular (12 of 88, 14%) than in an intra-annular position (4 or 182, 2%; p < 0.005) and in mitral valves inserted with continuous (36 of 88, 41%) rather than interrupted sutures (2 of 28, 7%; p < 0.001). Lactate dehydrogenase concentration was higher in patients with paraprosthetic jets than in those without (752 (236) v 654 (208) IU/l, p < 0.001). Haemoglobin and haptoglobin concentrations were not different.
Conclusions
Small paraprosthetic leaks are common, are related to surgical factors, are not associated with increased subclinical haemolysis, and are benign during the first year after heart valve replacement.
... The sinuses of Valsalva (Fig. 3B), sinotubular junction ( Fig. 3B), and proximal ascending aorta (1 cm above the sinotubular junction) (Fig. 3B) were measured at end-diastole, also in the parasternal long-axis view. The degree of post-procedural AR was assessed semiquantitatively with color flow Doppler according to current guidelines and was considered significant if moderate or greater (13,14). Intraobserver and interobserver variability, agreement, and interstudy reproducibility. ...
The purpose of this study was to determine imaging predictors of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) and the agreement and reproducibility of cardiovascular magnetic resonance (CMR), cardiac computed tomography (CCT), and transthoracic echocardiography (TTE) in aortic root assessment.
The optimal imaging strategy for planning TAVI is unclear with a paucity of comparative multimodality imaging data. The association between aortic root morphology and outcomes after TAVI also remains incompletely understood.
A total of 202 consecutive patients assessed by CMR, CCT, and TTE for TAVI were studied. Agreement and variability among and within imaging modalities was assessed by Bland-Altman analysis. Postoperative AR was assessed by TTE.
Of the 202 patients undergoing TAVI assessment with both CMR and TTE, 133 also underwent CCT. Close agreement was observed between CMR and CCT in dimensions of the aortic annulus (bias, -0.4 mm; 95% limits of agreement: -5.7 to 5.0 mm), and similarly for sinus of Valsalva, sinotubular junction, and ascending aortic measures. Agreement between TTE-derived measures and either CMR or CCT was less precise. Intraobserver and interobserver variability were lowest with CMR. The presence and severity of AR after TAVI were associated with larger aortic valve annulus measurements by both CMR (p = 0.03) and CCT (p = 0.04) but not TTE-derived measures (p = 0.10). Neither CCT nor CMR measures of annulus eccentricity, however, predicted AR after TAVI (p = 0.33 and p = 0.78, respectively).
In patients undergoing imaging assessment for TAVI, the presence and severity of AR after TAVI were associated with larger aortic annulus measurements by both CMR and CCT, but not TTE. Both CMR and CCT provide highly reproducible information in the assessment of patients undergoing TAVI.
... The AR was classified as paravalvular, transvalvular, or both by using the assessment scheme used by Moss and colleagues 12 and Kapur and colleagues. 13 Calcification Score Index Corciu and colleagues 14 described and validated the calcification score index, a semiquantitative echocardiographic cardiovascular score using relatively simple transthoracic echocardiographic parameters (anterior mitral annular calcification, aortic valve sclerosis, and aortic root sclerosis) permitting better characterization of the risk of developing cardiovascular disease. We modified this score and added information on calcification of specific structures of the aortic root (ie, aortic annulus, sinotubular junction, and aortic valve commissures) that we considered potentially important to assess the risk of postoperative AR after TAVI ( Table 1). ...
Transcatheter aortic valve implantation is an emerging technique for the treatment of aortic valve stenosis in high-risk patients. Detailed knowledge of aortic root anatomy, including specific information on the extent of native cusp calcifications, is required. The aim of this study was to evaluate whether echocardiographic assessment of aortic stenosis using a calcification score is useful to predict outcomes of transcatheter aortic valve implantation in elderly high-risk patients.
Detailed preoperative digitalized transesophageal echocardiographic images were available from 103 patients treated by transapical transcatheter aortic valve implantation between February 2006 and February 2009. On the basis of a previously published study, an index score was developed to describe the extent of valve calcification ranging from 0 to 8 (normal to diffuse calcification).
The median age of patients was 82.2 ± 5.9 years. The mean logistic European System for Cardiac Operative Risk Evaluation was 33.0% ± 16.3%. Mild paravalvular leak was present in 43 patients (42.2%), and a moderate paravalvular leak was observed in 5 patients (4.9%). Severe regurgitation was not observed in any patient. Logistic regression analysis revealed that the transcatheter aortic valve implantation echocardiographic calcification score is associated with the presence of moderate paravalvular aortic regurgitation (odds ratio, 8.5; 95% confidence interval, 1.2-58.9; P = .0001) and overall moderate aortic regurgitation (odds ratio, 3.6; 95% confidence interval, 1.2-10.4; P = .0006).
Transesophageal echocardiography demonstrates detailed anatomic information of the calcification patterns of the aortic valve and root and thus plays an important role in the screening of patients undergoing transcatheter aortic valve implantation. The transcatheter aortic valve implantation echocardiographic calcification score allowed prediction of the risk of postoperative paravalvular and overall aortic regurgitation.
Doppler echocardiography is increasingly used not only to identify disease in native heart valves, but also to assess the function of prosthetic valves. The purpose of this paper is to provide a summary of the principles of Doppler echocardiography for the cardiac surgeon which will lead to a discussion of assessment of prosthetic valve function. Solid cardiac structure imaging is first discussed in both one-dimensional (M-mode) and two-dimensional (B-mode) modalities. Measurements of blood cell velocities by conventional spectral Doppler echocardiography are then discussed leading to two-dimensional flow imaging by color Doppler flow mapping. Assessment of prosthetic valve function is divided into two sections: normal prosthetic valve function and prosthetic valve dysfunction. Subtopics within each of these divisions are discussed in the context of conventional and color Doppler ultrasonography.
For the last 40 years, valve replacement with various substitutes in patients with severe valve dysfunction has been practiced, particularly in those with unrepairable valve deformation [1]. Valve Substitutes: Artificial valve substitutes are essentially of two types: mechanical and bioprostheses.
Die Mitralstenose ist einer der häufigsten isolierten Klappenfehler. Frauen erkranken etwa 2mal so oft wie Männer. Die Ursache dafür ist unbekannt. Die ersten klinischen Symptome des Vitiums treten meist zwischen dem 20. und 40. Lebensjahr auf. Frühere Manifestationen sind in den Zivilisationsländern selten, in Ländern wie Indien jedoch keine Ausnahme. Insgesamt scheint die Inzidenz der Mitralstenose wie auch anderer rheumatischer Klappenerkrankungen in den hoch entwickelten Zivilisationsländern parallel mit dem rheumatischen Fieber im Verlauf der letzten Dekaden abzunehmen (Clemmesen 1949), so daß nichtrheumatische Klappenfehler relativ mehr in den Vordergrund treten.
Complex intracardiac shunting, whether congenital or acquired often presents a difficult diagnostic challenge. The physical signs may be confusing or misleading, particularly in patients who have multiple sites where intracardiac shunting is occurring, and an accurate diagnosis cannot always be established despite cardiac catheterisation.
In den folgenden Kapiteln 45–49 sollen die Herzklappenfehler Mitralstenose, Mitralinsuffizienz, Aortenstenose, Aorteninsuffizienz, Tricuspidalstenose und Tricuspidalinsuffizienz abgehandelt werden. Mit Ausnahme der isolierten Aortenstenose sind diese Herzklappenfehler überwiegend als erworben anzunehmen. Als solche sind sie in über 90% der Fälle die Folge einer rheumatischen Karditis unter Mitbeteiligung des Klappenendokards. Aufgrund einer großen Verlaufsuntersuchung ist nach einem rheumatischen Fieber während der Kindheit in etwa 70% mit der einen oder anderen Form einer rheumatischen Herzerkrankung, zumeist einem Befall einer oder mehrerer Herzklappen zu rechnen (Bland u. Duckett
Jones 1951). In einer weiteren Verlaufsstudie über mehr als 20 Jahre entwickelt sich in mehr als 80% ein Ein- oder Mehr-Klappen-Fehler (Wilson u. Lim 1957). Am häufigsten, in etwa 35% (Wilson u. Lim 1957) bis zu 58% (Grosse-Brockhoff et al. 1960) war die Mitralklappe befallen. Ungefähr ein Viertel bis ein Drittel der Patienten mit einem Mitralvitium wies gleichzeitig einen Aortenklappenfehler auf. Hämodynamisch bedeutsame Tricuspidalfehler sind dagegen vergleichsweise selten und machen etwa 5% aller rheumatischen Klappenerkrankungen aus. Eine ausgesprochene Rarität stellt die rheumatische Erkrankung der Pulmonalklappe dar. Eine isolierte rheumatische Erkrankung der Tricuspidal- oder Pulmonalklappe konnte bisher nicht beobachtet werden (Hudson 1965).
Effective orifice area of 3 different designs of prosthetic valves implanted in the aortic position was determined by the continuity equation and the Gorlin formula using Doppler hemodynamic data. The orifice area by the two methods correlated well in the case of tilting disc prostheses (r = 0.75, P = 0.0001, n = 37, SEE = 0.17 cm(2)) but poorly in the case of bileaflet mechanical valves (r = 0.40, P = 0.17, n = 13) and ball-in-cage prostheses (r = 0.58, P = 0.06, n = 11). Estimation of prosthetic aortic valve area by the Gorlin formula is inappropriate in the latter two types of prostheses because of design-related variable empiric constant.
For the last 40 years, valve replacement with various substitutes in patients with severe valve dysfunction has been practiced, particularly in those with unrepairable valve deformation [1].
Valve Substitutes: Artificial valve substitutes are essentially of two types: mechanical and bioprostheses.
Objectives:
This study aims to evaluate the clinical outcome of fibrinolytic treatment of prosthetic valve thrombosis (PVT) with 'streptokinase' as a first line treatment for these cases.
Methods:
The study group was 20 consecutive patients (10 females) diagnosed with PVT. The protocol for streptokinase administration was either accelerated (intravenous infusion of 0.5 million IU over 30 minutes followed by 0.15 million IU/h) or conventional (intravenous infusion of 0.25 million IU over 30 minutes followed by 0.15 million IU/h). Success of fibrinolytic therapy was defined as complete restoration of valve function in the presence or absence of complications.
Results:
Eighteen patients (90%) had mitral PVT and two (10%) had aortic PVT. Thrombolytic therapy with streptokinase was successful in all but one case, with a total mortality of four cases (20%). In PVT episodes, before streptokinase therapy, the prosthetic valve areas (in all cases, mitral and aortic positions) were 0.82 ± 0.21, 0.83 ± 0.21, and 0.73 ± 0.18 cm²; and the peak and mean transvalvular gradients were 38.7 ± 16.7 and 25.4 ± 8.7, 34.1 ± 8.8 and 23.2 ± 5.4, and 80.0 ± 14.1 and 45.0 ± 7.1 mmHg, respectively. After streptokinase therapy, the prosthetic valve area and peak and mean transvalvular gradients improved significantly (for all cases, mitral and aortic positions: valve area 2.17 ± 0.58, 2.21 ± 0.61, and 1.85 ± 0.07 cm², peak gradient 18.7 ± 11.0, 16.4 ± 7.7, and 39.0 ± 18.4, and mean gradient 9.6 ± 7.1, 8.2 ± 5.3, and 22.0 ± 11.3 mmHg, respectively; paired t-test, P<0.001 for pre- versus post-streptokinase infusion for all variables).
Conclusion:
Fibrinolytic therapy using streptokinase was an effective therapeutic strategy for the management of PVT and is a reasonable alternative to surgery.
Background. There is the potential for left ventricular outflow obstruction when small aortic valve bioprostheses are employed in normal-sized or large adults. It has been hoped that bovine pericardial valves would improve hemodynamic performance in the smaller tissue valve sizes.
Surgical valve replacement is the most commonly performed for aortic stenosis. Randomized trials comparing stentless to stented bioprostheses for aortic valve replacement in elderly are scarce. The aim of our study was comparing and evaluating the early hemodynamic performances of Hancock™ stented and FreeStyle™ stentless xenograft aortic valves in aortic valve replacement in elderly patients.
The study involved 40 patients (27 females and 13 males) older than 75 years old. The study was done during the postoperative period. Aortic valve replacements of stented and stentless xenografts were performed to the patients in Group I and Group II, respectively. Investigations for the echocardiographic results were completed on the postoperative 8-10th days. Parameters for the evaluation of hemodynamics were peak pressure gradient, mean pressure gradient and effective orifice area. The parameters were calculated with Doppler echocardiography by using specific formulas.
Peak pressure gradients in patients with stented valves were significantly higher than in stentless valves [Stented valve group 32.45 ± 7.58 vs Stentless valve group 21.50 ± 4.77 mmHg] (p < 0.05). Mean pressure gradients were found to be significantly higher in stented group compared with stented group [Stented valve group 11.050 ± 3.2521 vs Stentless valve group 19.350 ± 6.6036 mmHg] (p < 0.05). The effective orifice area index of implanted valve was significantly greater in the stentless group, as well [Stentless valve group 2.5050 ± 0.6022 vs Stented valve group 1.3050 ± 0.3316 cm2] (p < 0.05).
In early postoperative period, effective orifice areas and pressure gradients were found higher in stentless valve group.
La sostituzione valvolare con protesi di vario tipo, in pazienti con disfunzione valvolare grave è stata praticata negli ultimi
40 anni, soprattutto in quei pazienti con deformazioni valvolari non correggibili [1]. Le protesi valvolari sono essenzialmente di due tipi: meccaniche e biologiche.
To assess resting hemodynamics of an unselected group of patients with prostheses or bioprostheses sized less-than-or-equal-to 21 mm implanted into the aortic valve position during a 7-year period, 46 of 50 eligible patients were examined by Doppler echocardiography. The valves were Carpentier-Edwards (CE) supraannular 21 mm (n = 8), Medtronic-Hall (MH) 20 mm (n = 8) and 21 mm (n = 21), and the rest (n = 9) were other valves with only 1 to 3 patients in each group. Gradients, valve areas and dimensionless obstruction indexes (ratio of subvalvular/ valvular velocities and velocity time integrals) were compared. By analysis of variance, gradients did not differ significantly between the CE supraannular 21 mm, the MH 20 and 21 mm prostheses (peak/mean 25 +/- 8/14 +/- 5, 31 +/- 13/16 +/- 6 and 25 +/- 10/13 +/- 5 mm Hg; p = not significant). Only 2 patients had a mean gradient >25 mm Hg. The valve area was slightly larger for the MH 21 mm group compared with the CE supraannular 21 mm group (1.34 +/- 0.15 vs 1.16 +/-0.14 cm2, p <0.05). The dimensionless obstruction indexes did not differ (CE supraannular 21 mm 0.36 +/- 0.07/0.40 +/- 0.07 (velocities/velocity time integrals), MH 20 mm 0.40 +/- 0.12/0.47 +/- 0.12, MH 21 mm 0.38 +/- 0.05/0.44 +/- 0.06; p = not significant). An inverse relation was demonstrated between the left ventricular outflow tract diameter and the subvalvular velocities (r = -0.60, p <0.001), thus emphasizing the necessity of making a correction for prevalvular velocities when applying the Bernoulli equation in calculating gradients across small aortic valve prostheses. It is concluded that acceptable resting hemodynamics are obtained with the CE supraannular 21 mm, the MH 20 and 21 mm prostheses in the narrow aortic root. The moderate obstruction caused by the prostheses is not likely to be a limiting factor for the hemodynamic capacity of these patients.
Transesophageal echocardiography is routinely used to guide percutaneous interventions involving the mitral valve. Mitral balloon valvuloplasty for rheumatic mitral valve stenosis (MS) was the first percutaneous intervention to gain wide acceptance. New techniques have been developed to treat degenerative and functional mitral regurgitation (MR) as well as paravalvular mitral leak (PVML). This review describes the use of echocardiography for transcatheter treatment of MS, MR, and PVML.
IntroductionProstheses In Aortic PositionMitral And Tricuspid ProsthesesConclusion
In order to determine the standard Doppler hemodynamic characteristics of the Bjork-Shiley monostrut aortic prosthesis and the value of the continuity equation to calculate the prosthetic valvular area, we performed Doppler echocardiographic study in 106 stable patients with this prosthesis and in 7 patients with suspicion of aortic Bjork-Shiley dysfunction. We measured maximum and mean Doppler gradients, prosthetic valvular area using the continuity equation, and degree of aortic regurgitation. The maximum and mean Doppler gradients in the 106 stable patients ranged from 9.5 to 51 mmHg (X̄= 28.9 ± 11 mmHg) and from 2 to 24 mmHg (X̄= 12.7 ± 5.2 mmHg), respectively. Maximum Doppler gradients > 45 mmHg and mean Doppler gradients > 20 mmHg occurred only in size 23 or smaller. No patient had a mean Doppler gradient > 25 mmHg. We found significant differences between sizes 25 and 27 (P < 0.01) and 21 and 25 (P < 0.01), but not between sizes 19, 21, and 23, or 23 and 25. There was significant difference in Doppler prosthetic valvular area between each valve size. The correlation coefficient between the prosthetic size and the echo-Doppler valvular area was 0.89 according to a lineal equation (SEE = 16). We could demonstrate mild aortic regurgitation in 25 cases (24%). The Doppler-derived prosthetic valvular area was < 0.38 cm2 in two patients with obstruction and > 2 cm2 in three patients with regurgitation alone. We conclude that high pressure gradients can be observed through the smallest sizes of the Bjork-Shiley monostrut aortic prostheses. Mild aortic regurgitation is a common finding. Our values are suggested as a reference for comparison in the case of suspected Bjork-Shiley valve dysfunction. The Doppler-derived prosthetic valvular area may be useful in patients with dysfunction of this prosthesis, especially to differentiate obstruction and regurgitation from regurgitation alone.
Doppler echocardiography is being used increasingly in the follow-up of patients with valvular heart prostheses because it provides unique hemodynamic information about flow through prosthetic valves. A baseline checkup about 3 months after implantation is now recommended. We therefore now supply eachpatient with an identity and follow-up card for each particular prosthesis.
The diagnosis and assessment of mitral regurgitation has been one of the main challenges for cardiac ultrasound. Imaging techniques (M-mode and two-dimensional echocardiography) provide direct morphologic and etiologic information of the evaluation of patients with suspected mitral regurgitation. The advent of cardiac Doppler increased tremendously the ability to evaluate mitral regurgitation noninvasively. Continuous-wave and pulsed Doppler have been found to be sensitive and specific in the detection of mitral regurgitation. The introduction of color flow Doppler simplified enormously the assessment of patients with suspected mitral regurgitation. The maximal regurgitant area and maximal regurgitant area corrected for left atrial size have become the most commonly used parameters to evaluate mitral regurgitation by color flow Doppler in the clinical setting. However, the color regurgitant jet area is highly dependent on anatomical, hemodynamic, and equipment factors. A new method, based on the proximal isovelocity surface area, is being evaluated and appears to be relatively independent of equipment factors. Transesophageal echocardiography has been shown to be exquisitely sensitive in the detection of mitral regurgitation. Quantitation of mitral regurgitation by trans-esophageal echocardiography is currently based on the maximal regurgitant area and this parameter appears to correlate closely with the angiographic degree of mitral regurgitation. Pulmonary venous flow analysis had been used in conjunction with color flow mapping for the evaluation of mitral regurgitation by transesophageal echocardiography. The presence of reversed systolic flow has been shown to be sensitive and specific for the diagnosis of severe mitral regurgitation. Patients with clinically difficult surface studies, flail mitral valve leaflets, and prosthetic mitral valve are best evaluated by the transesophageal approach with interrogation of pulmonary venous flow.
Abstract Aortic valve replacement with stentless porcine valve should provide superior hemodynamic results to stented porcine valve because the obstruction caused by the stent and the sewing ring is eliminated. In addition, the coronary sinuses of the recipient may allow for better dissipation of the mechanical stress to which the leaflets are subjected during diastole, thus enhancing durability of the heterograft.
Aortic valve replacement with stentless glutaraldehyde-fixed aortic porcine bioprosthesis was carried out successfully in six young sheep. These animals were hemodynamically evaluated at 3 to 6 months after operation and found to have no resting gradients or any degree of aortic regurgitation. Explantation of the aortic heterograft revealed that it was well healed in the aortic root and had no evidence of any calcification. A clinical trial has been initiated and the results in the first five humans who underwent aortic valve replacement with a stentless porcine aortic bioprosthesis have been satisfactory.
Eighty consecutive patients who underwent both left ventriculography and single-plane transesophageal echocardiography with Doppler color flow mapping were studied to compare the two techniques in the assessment of mitral regurgitation. Only the mosaic aspect of the regurgitant jet was included in the measurements. Values for inter- and intraobserver variability for the maximal regurgitant area measurements were 10 ± 9% and 9 ± 8%, respectively.The best correlation between angiography and Doppler color flow imaging was obtained with the maximal regurgitant area (r = 0.90). A maximal regurgitant area <3 cm2 predicted mild mitral regurgitation with a sensitivity of 96%, specificity of 100% and a predictive accuracy of 98%, whereas a maximal regurgitant area >6 cm2 predicted severe mitral regurgitation with a sensitivity of 91%, a specificity of 100% and a predictive accuracy of 98%. A strong, although inferior, correlation was found for the maximal regurgitant area/left atrial area ratio (r = 0.81). A ratio <20% predicted mild mitral regurgitation with 94% accuracy, whereas a ratio >35% predicted severe mitral regurgitation with 85% accuracy.Thus, single-plane transesophageal echocardiography with Doppler color flow mapping is an exquisitely sensitive technique for the diagnosis of mitral regurgitation. Minimal degrees of mitral regurgitation can be detected in approximately 62% of patients in whom no mitral regurgitation is detected by angiography. The mosaic maximal regurgitant area is a simple and easily obtainable Doppler echocardiographic index that provides an accurate estimation of mitral regurgitation severity.
The study investigated echocardiographic findings after 1 month in 22 patients who received a CoreValve prostheses to treat aortic valve stenosis. Particular attention was paid to the evaluation of valvular leaks and the left ventricular wall thickness. Echocardiograms were obtained prior to implantation, at discharge and 1 month later. The patients' mean age was 77 ± 4 years. At discharge, 16 patients (76%) had aortic regurgitation: 8 grade I and 8 grade II. At 1 month, only 13 (62%) presented with the condition: 10 grade I and 3 grade II, with 8 patients (38%) demonstrating a reduction of at least one grade (P < .005). The septal thickness decreased (from 14.2 ± 2 mm at baseline to 11 ± 2.4 mm at 1 month; P < .001), as did the posterior wall thickness (from 10.9 ± 2.4 mm at baseline to 8.3 ± 1.2 mm at 1 month; P < .001). In our patient series, the frequency and grade of residual aortic regurgitation after implantation of the CoreValve prosthesis decreased within 1 month, and favorable left ventricular remodeling was also observed.
The aim of this study was to assess prosthesis/annulus discongruence and its impact on the occurrence of significant aortic regurgitation (AR) immediately after transcatheter aortic valve implantation (TAVI).
Paravalvular AR might occur after TAVI, but its determinants remain unclear.
Comprehensive echocardiographic examinations were performed in 74 patients who underwent TAVI with a balloon expandable device. Congruence between annulus and device was appraised with the cover index: 100 x (prosthesis diameter - transesophageal echocardiography annulus diameter)/prosthesis diameter.
At baseline aortic valve area was 0.67 +/- 0.2 cm(2), and mean gradient was 50 +/- 15 mm Hg. The TAVI used transfemoral approach in 46 patients (62%) and transapical access in 28 (38%). Prosthesis size was 23 mm in 24 patients (34%) and 26 mm in 50 patients (66%). After TAVI, paravalvular AR was absent in 5 patients (7%), graded 1/4 in 53 (72%), 2/4 in 12 (16%), and 3/4 in 4 (5%). Occurrence of AR >or=2/4 was related to greater patient height, larger annulus, and smaller cover index (all p < 0.002) but not to ejection fraction, severity of stenosis, or prosthesis size. AR >or=2/4 was never observed in patients with aortic annulus <22 mm or with a cover index >8%. Significant improvements were observed from the first 20 cases (AR >or=2/4, 40%) to the last 54 (AR >or=2/4, 15%) (p = 0.02). In multivariate analysis, independent predictors of AR >/=2/4 were low cover index (odds ratio: 1.22; per confidence interval: 1.03 to 1.51 per 1% decrease, p = 0.02) and first versus last procedures (odds ratio: 2.24; 95% confidence interval: 1.07 to 5.22, p = 0.03).
Our study shows that the occurrence of AR >or=2/4 is related to prosthesis/annulus discongruence even after adjustment for experience. Hence, to minimize paravalvular AR, appropriate annular measurements and prosthesis sizing are critical.
This study was designed to investigate the usefulness and limitations of echocardiography in optimizing the outcome of percutaneous aortic valve implantation.
Percutaneous aortic valve implantation is an emerging technique that has the potential to revolutionize the treatment of aortic valve disease. To date, however, the technique has been limited by technical constraints. Precise positioning of the valve is essential to minimize the potential for paravalvular regurgitation or device migration. Initial experience with device placement utilized fluoroscopic guidance only.
Candidates for percutaneous aortic valve implantation were evaluated with transthoracic echocardiography (TTE) to assess aortic annular dimension and aortic valve hemodynamics. Fifty consecutive patients were deemed suitable for percutaneous aortic valve implantation. Seventy-four percent (37 of 50) of patients underwent transesophageal echocardiography (TEE) during the procedure.
Eighty-six percent (43 of 50) of patients had successful implantation, of which 77% (33 of 43) had TEE. Transthoracic echocardiography was used to determine annular dimension and was useful in guiding correct device sizing. Transesophageal echocardiography was able to successfully guide device implantation in 97% (33 of 34) of patients in whom the native valve was crossed with the percutaneous heart valve. Transesophageal echocardiography was used for the early detection of paravalvular aortic regurgitation (AR) and complemented fluoroscopy in the detection of complications. Additional balloon dilatation of the percutaneous heart valve was performed in 12 patients because of significant paravalvular AR, with 7 showing improvement in AR grade. After the procedure, early outcomes were evaluated using TTE. All patients in whom the device was successfully placed (43 of 50) had improvement in their aortic stenosis. Paravalvular AR, although present in many patients, is usually mild and has not emerged as a significant problem.
Echocardiography has an important role in case selection, in guiding device placement, and in detecting complications of percutaneous aortic valve implantation.
A 76-year-old man who underwent aortic valve replacement for severe calcific aortic stenosis developed a significant paravalvular leak. Because the risk of re-operation was felt too great, a percutaneous transcatheter obliteration of the defect using an Amplatzer vascular plug was undertaken, with an excellent clinical outcome.
Normal Doppler-derived data for new prosthetic designs are currently gathered after marketing. Therefore the cardiologist needing to assess a new valve may need to equate Doppler results with data gathered invasively during premarket testing. This invites error because catheterization and Doppler ultrasonography are not always directly comparable. This review discusses difficulties in defining normal prosthetic function and problems arising from the comparison of catheter and Doppler data. It concludes that (1) the hemodynamic formulas in current use have limitations when applied to normally functioning prosthetic valves, (2) patterns of normal regurgitation differ widely between different valve designs and may occasionally resemble paraprosthetic leaks, (3) there is a good case for reporting only raw Doppler data rather than derived pressure drop or effective orifice area, (4) a new prosthetic design should be tested in vivo with Doppler ultrasonography before marketing, and (5) nonprosthetic factors affecting Doppler data and flow information should always be given.
To assess the value and limitations of single-plane transesophageal echocardiography in the evaluation of prosthetic aortic valve function, 89 patients (69 mechanical and 20 bioprosthetic aortic valves) were studied by combined transthoracic and transesophageal 2-dimensional and color flow Doppler echocardiography. In the assessment of aortic regurgitation, the transthoracic and transe sophageal echocardiographic findings were concordant in 71 of 89 patients (80%). In 8 patients, the degree of aortic regurgitation was underestimated by the transthoracic approach; in each case the quality of the transthoracic echocardiogram was poor. In 10 patients, transesophageal echocardiography failed to detect trivial aortic regurgitation due to acoustic shadowing of the left ventricular outflow tract from a mechanical valve in the mitral valve position. Transesophageal echocardiography was superior to transthoracic echocardiography in diagnosing perivalvular abscess, subaortic perforation, valvular dehiscence, torn or thickened bioprosthetic aortic valve cusps, and in clearly distinguishing perivalvular from valvular aortic regurgitation. Transesophageal echocardiography correctly diagnosed bioprosthetic valve obstruction in 1 patient, but failed to diagnose mechanical valve obstruction in another.
Gradient echo nuclear magnetic resonance (NMR) imaging and transesophageal two-dimensional color Doppler echocardiography are flow-sensitive techniques that have been used in the diagnosis and grading of valvular regurgitation. To define the diagnostic value of gradient echo NMR imaging in the detection of regurgitant flow in cardiac valve prostheses and the differentiation of physiologic leakage flow from pathologic transvalvular or paravalvular leakage flow, 47 patients with 55 valve prostheses were examined. Color Doppler transesophageal echocardiography was used for comparison. Surgical confirmation of findings was obtained in 11 patients with 13 valve prostheses. Gradient echo NMR imaging showed regurgitant flow in 37 of 43 valves with a jet seen on transesophageal echocardiography and it detected physiologic leakage flow in 4 additional valves. There was 96% agreement between the two methods in distinguishing between physiologic and pathologic leakage flow. The methods differed on jet origin of pathologic leakage flow in six prostheses. The degree of regurgitation was graded by both NMR imaging and transesophageal echocardiography, according to the area of the regurgitant jet visualized; gradings were identical for 75% of valve prostheses. Quantification of jet length and area showed a good correlation between the two methods (r = 0.85 and r = 0.91, respectively). Gradient echo NMR imaging is a useful noninvasive technique for the detection, localization and estimation of regurgitant flow in cardiac valve prostheses. However, because transesophageal echocardiography is less time-consuming and less expensive, gradient echo NMR imaging is unlikely to displace transesophageal echocardiography and should be used only in the occasional patient who cannot be adequately imaged by echocardiography.
The Hatle formula was derived empirically in native mitral stenosis and may not be valid for normal prosthetic valves. Bileaflet mechanical prostheses open fully at low flows and have minimal interindividual variation in orifice area. In these valves effective area and measured manufacturer's area should be similar. We studied 60 patients aged 58 +/- 12 yr at a mean of 5 months after implantation with a CarboMedics prosthesis. There was a coexistent aortic prosthesis in 21. All diastolic measurements were averaged over 5 beats and stroke volume was calculated from the integral of the subaortic velocity trace and the cross-sectional area of the left ventricular outflow tract. For the whole group, area by the Hatle formula was 3.1 +/- 0.7 cm2 and measured area was 2.8 +/- 0.4 cm2. There was no significant correlation between these values (p = 0.329). Pressure half-time was more closely correlated with peak transmitral velocity (p = 0.012), RR interval (p = 0.015), diastolic time interval (p = 0.062) and stroke volume (p = 0.074). We conclude that the Hatle formula should not be applied to normal bileaflet mitral prostheses where pressure half-time reflects nonprosthetic factors more closely than orifice area.
To compare the effect of exercise on pressure half time in patients with mechanical or bioprosthetic mitral valves. A relative pressure half time (pressure half time as a percentage of RR interval) was used in an attempt to correct for the shortening of the diastolic time interval caused by the increase in heart rate during exercise and thus to uncover the effects of valve design on pressure half time during exercise.
Twenty clinically stable (New York Heart Association grade I-II) patients with mechanical (n = 12) or bioprosthetic (n = 8) mitral valves (median age 51) years. The median time since valve replacement was 42 months.
Continuous wave Doppler echocardiography from the apical view at rest and during moderate supine bicycle exercise (50 W).
During exercise the mean (SD) heart rate increased from 79 (12) to 101 (12) beats per minute (95% confidence interval (95% CI) of difference, 15 to 29/min) and the peak pressure gradient from 11 (5) to 18 (6) mm Hg (95% CI of difference 5 to 9 mm Hg). The pressure half time decreased from 114 (30) to 78 (26) ms (95% CI of difference (30-42 ms). There was no difference between the valve types. The relative pressure half time remained unchanged in patients with mechanical valves during exercise (13 (4) rest and 13 (5)% exercise, respectively) and decreased in patients with bioprostheses (17 (3) and 12 (3)%, respectively (95% CI of difference 2 to 8%, p = 0.025).
In patients with mechanical mitral valves the decrease in the pressure half time during exercise is probably mostly the result of the shortening of the diastolic time interval with increasing heart rate whereas in patients with bioprosthetic valves an increase in functional valve area may contribute to the shortening of pressure half time during exercise.
To evaluate normal regurgitant characteristics of St. Jude (SJ) and Medtronic-Hall (MH) mitral valves, four sizes (25-31 mm) of each were studied in a pulsatile flow model.
Regurgitant flow was measured by flowmeter at left ventricular pressures of 80, 130, and 180 mm Hg. Peak regurgitant flow rates ranged from 6.2 to 12.7 cm3/sec in SJ valves and from 7.9 to 17.5 cm3/sec in MH valves. Regurgitant orifice areas calculated from the Doppler continuity equation ranged from 1.6 to 2.0 mm2 in SJ valves and from 2.2 to 2.9 mm2 in MH valves. Regurgitant volumes across the closed valve at a left ventricular pressure of 130 mm Hg were normalized to an ejection time of 280 msec and ranged from 1.5 to 1.9 cm3 in SJ valves and from 2.1 to 2.8 cm3 in MH valves. Jets were imaged by color Doppler in six rotational planes, and jet size and morphology were compared with those of regurgitant jets from circular orifices with sizes comparable to the calculated prosthetic valve regurgitant orifices (1.1-3.1 mm2). SJ valves showed two converging jets from the pivot points, one central jet, and a variable number of peripheral jets. The mean color jet area derived from the six image planes ranged from 1.6 to 5.3 cm2. Aliasing occurred only close to the valve (maximal distance 0.5-2.0 cm). MH valves showed a large central jet with a maximal length of aliased flow between 2.0 and 5.5 cm. Depending on valve size, driving pressure, and image plane, one or two small peripheral jets were found. These jets did not show aliasing in any case. The mean color jet area ranged from 5.1 to 11.0 cm2. Jets originating from circular orifices of comparable size showed jet areas from 5.5 to 13.9 cm2 and aliasing distances from 3.3 to 7.3 cm. At similar regurgitant orifice areas, driving pressures, and regurgitant flows, the measured color areas and aliasing distances were smallest in SJ valves, larger in MH valves, and largest in simple circular orifices.
Large, complex regurgitant jets can be found in normal closed SJ and MH valves by color Doppler, although regurgitant flow volume is minimal. Jet size and velocity distribution differs markedly between SJ valves, MH valves, and circular orifices, even with comparable driving pressure, regurgitant orifice area, and regurgitant volume. The characteristic patterns of normal regurgitation must be recognized to avoid incorrect diagnoses of pathological regurgitation in SJ and MH prosthetic valves. MH valves should not be removed solely on the basis of a central regurgitant jet with a long aliasing distance. Peripheral jets in MH valves and all jets in SJ valves should be considered normal as long as no or only minimal aliasing is present. In contrast, peripheral jets with significant aliasing may represent strong evidence of pathological regurgitation.
To test the value of acceleration flow signals proximal to the leaking orifice in assessing the severity of prosthetic mitral valve regurgitation, 39 consecutive patients undergoing left ventriculography were examined by Doppler color flow imaging. Acceleration flow signals proximal to the regurgitant orifice were detected in 27 of the 31 patients who had prosthetic mitral regurgitation by left ventriculography (sensitivity 87%). All four patients without acceleration flow signals had mild prosthetic mitral regurgitation by angiography. No acceleration flow signals were detected in any patient without prosthetic regurgitation by left ventriculography (specificity 100%). Individual values of the maximal area of acceleration flow signals obtained from three orthogonal planes in seven patients with mild prosthetic mitral regurgitation by angiography ranged from 0 to 17 mm2 (mean 4 +/- 6). In 8 patients with moderate prosthetic mitral regurgitation by angiography, the maximal area of acceleration flow signals ranged from 21 to 58 mm2 (mean 33 +/- 15), whereas the maximal area of acceleration flow signals in 16 patients with severe prosthetic regurgitation ranged from 20 to 173 mm2 (mean 102 +/- 41). The maximal area of the acceleration flow signals from three planes correlated well with the angiographic grade of prosthetic mitral regurgitation. There was a significant difference in the maximal area of acceleration flow signals between mild and moderate (p less than 0.001), moderate and severe (p less than 0.001) and mild and severe (p less than 0.001) prosthetic mitral regurgitation. Thus, measurement of acceleration flow signals by Doppler color flow imaging is useful in assessing the severity of prosthetic mitral regurgitation.
A case with impeded disc movement caused by thrombus formation in a Medtronic-Hall aortic valve prosthesis is reported. A correct diagnosis, including both mechanism and severity of the prosthesis failure, was established by Doppler echocardiography. The patient was promptly referred for surgery without invasive or other supplementary investigations.
The magnitude and spatial distribution of normal leakage through mechanical prosthetic valves were studied in an in vitro model of mitral regurgitation. The effective regurgitant orifice was calculated from regurgitant rate at different transvalvular pressure differences and flow velocities. This effective orifice area was 0.6 to 2 mm2 for three tilting disc prostheses (Medtronic-Hall sizes 21, 25 and 29) and 0.2 to 1.1 mm2 for three bileaflet valves (St. Jude Medical sizes 21, 25 and 33). In the single disc valves, Doppler color flow examination disclosed a prominent central regurgitant jet around the central hole for the strut, accompanied by minor leakage along the rim of the disc (central to peripheral jet area ratio 3.3 +/- 1.2). The bileaflet prostheses showed a peculiar complex pattern: in planes parallel to the two disc axes, convergent peripherally arising jets were visualized, whereas in orthogonal planes several diverging jets were seen. Mounting the disc and bileaflet valves on a water-filled tube allowed reproduction and interpretation of this pattern: for the bileaflet valve, the jets originated predominantly from valve ring protrusions that contained the axis hinge points and created a converging V pattern in planes parallel to the leaflets and a diverging V pattern in orthogonal planes. Similar patterns were observed during transesophageal echocardiography in 20 patients with a normally functioning St. Jude prosthesis. In 10 patients with a Medtronic-Hall valve, a dominant central jet was observed with one or more smaller peripheral jets. The median central to peripheral jet area ratio was 5 to 1.(ABSTRACT TRUNCATED AT 250 WORDS)
To test whether the continuity equation can be applied to the noninvasive assessment of prosthetic aortic valve function, Doppler echocardiography was performed in 67 patients (mean age, 58 +/- 14 years) within 10 +/- 6 days after valve replacement with St. Jude Medical valves. All patients were clinically stable and without evidence of valve dysfunction. Valve size ranged from 19 to 31 mm, and ejection fraction ranged from 30% to 75%. With the parasternal long-axis view, the left ventricular outflow diameter measured just proximal to the prosthetic valve correlated well with valve size (r = 0.92). Doppler-derived maximal gradients ranged from 9 to 71 mm Hg. Effective prosthetic aortic valve area by the continuity equation ranged between 0.73 cm2 for a 19-mm valve and 4.23 cm2 for a 31-mm valve. With analysis of variance, effective orifice area differentiated various valve sizes (p less than 10(-14)) better than did gradients alone (p = 0.003) and correlated better with actual valve orifice area (r = 0.83 versus - 0.40). A Doppler velocity index, the ratio of peak velocity in the left ventricular outflow to that of the aortic jet, averaged 0.41 +/- 0.09 and was less dependent on valve size (r = 0.43). Thus, the continuity equation can be applied to the assessment of prosthetic St. Jude valves in the aortic position. By accounting for flow through the valve, it provides an improved assessment over the sole use of gradients in the evaluation of prosthetic valve function.
In 131 patients undergoing aortic valve replacement (53 bioprostheses, 78 mechanical), the pressure decrease across the prosthesis was recorded with Doppler ultrasound at a baseline study early postoperatively (mean 11 +/- 5 days) and compared with a repeat measurement 3 to 5 months later. At baseline the hemodynamic state was markedly different, with increased heart rate (89 +/- 14 vs. 74 +/- 13 beats/min, p less than 0.001) and decreased left ventricular ejection time index (367 +/- 21 vs 390 +/- 22, p less than 0.001). A minor and clinically insignificant decrease in pressure decrease with time was found. The 95% confidence interval for the difference was 0.2 to 3.0 and 0.2 to 1.7 mm Hg for the peak and the mean pressure decrease, respectively. The change in pressure decrease was statistically significant for bioprostheses (mean 16 +/- 5 vs 14 +/- 4 mm Hg, p less than 0.01) and smaller (less than or equal to 23 mm) valves (mean 17 +/- 4 vs 15 +/- 4 mm Hg, p less than 0.01), whereas no significant changes were found for mechanical valves or valves of a larger size. The change in mean pressure decrease from baseline to the second examination was within +/- 5 mm Hg for 82% of patients. It is concluded that despite a different hemodynamic state in the early postoperative period, the pressure decrease across aortic valve prostheses obtained at this time can be used as a reference for later comparison.
In summary, this is a report on 5 various malfunctioning mechanical monocuspid mitral prostheses in which Doppler demonstrated intermittent restriction to the prosthetic disc opening, resulting in intermittent obstruction. In all 5 patients, it was mainly this abnormal Doppler signal that alerted us to the presence of prosthetic valve malfunction. In the 3 asymptomatic patients, the variable and intermittent increased delay in prosthetic valve opening was shown to be an early and sensitive echocardiographic sign of prosthesis malfunction in the absence of any significant increase in pressure gradients.
Assessment of prosthetic valve regurgitation by echocardiography remains difficult. To study the value of the newly introduced multiplane transesophageal technology for this purpose, prosthetic valve regurgitation was examined in 63 consecutive patients with 35 mitral and 33 aortic prostheses (23 bioprostheses and 45 mechanical prostheses). Transvalvular, paravalvular and, in mechanical valves, normal or pathologic transvalvular regurgitation were identified first with 0 degrees (transverse) and 90 degrees (longitudinal) planes combined with flexion of the echoscope tip and then additionally with multiple intermediary planes by transducer rotation. In a subgroup of 20 patients interobserver variability was evaluated. Both methods showed regurgitation in 56 of 68 valves; one additional case of regurgitation was seen by multiplane imaging only. However, 19 cases of regurgitation were not clearly classifiable by biplane transesophageal echocardiography compared with only three with multiplane transesophageal echocardiography. Grading of severity was concordant by both modalities in 66 and discordant in only two cases. Observers disagreed on severity in two of 20 cases based on biplane imaging but in none based on multiplane imaging; classification of regurgitation differed in six of 20 (biplane) and one of 20 (multiplane), respectively. Multiplane transesophageal imaging improves classification of prosthetic regurgitation but has little effect on severity grading.
More than 5000 artificial heart valves are implanted each year in the United Kingdom. About three quarters are mechanical 1 and about two thirds are implanted in:the aortic position. Echocardiography is universally used to confirm normal fuction or to detect and quantify dysfunction of the valve. Because of shielding it is more difficult to study artificial valves than native valves and the results are harder to interpret because there is no clearcut distinction between normal and abnormal function: all valves are stenotic compared with normal native valves. In addition artificial valves (table 1) have different orifice characteristics, downstream flow profiles, and patterns of physiological regurgitation: experience gained with one type cannot necessarily be applied to another
We evaluated 147 patients with adequate color Doppler and angiographic studies for mitral regurgitation. Sixty-five patients had no mitral regurgitation by both color Doppler and angiography and 82 patients had mitral regurgitation by both techniques. Thus the sensitivity and specificity of color Doppler for the detection of mitral regurgitation was 100%. Three two-dimensional echocardiographic planes (parasternal long and short axis, apical four-chamber view) were used to analyze variables of the mitral regurgitant jet signals in the left atrium. The best correlation with angiography was obtained when the regurgitant jet area (RJA) (maximum or average from three planes) expressed as a percentage of the left atrial area (LAA) obtained in the same plane as the maximum regurgitant area was considered. The maximum RJA/LAA was under 20% in 34 of 36 patients with angiographic grade I mitral regurgitation, between 20% and 40% in 17 of 18 patients with grade II mitral regurgitation, and over 40% in 26 of 28 patients with severe mitral regurgitation. Maximum RJA/LAA also correlated with angiographic regurgitant fractions (r = .78) obtained in 21 of 40 patients in normal sinus rhythm and with no evidence of associated aortic regurgitation. Other variables of the regurgitant jet such as maximal linear and transverse dimensions, maximal area, or maximal area expressed as a percentage of the LAA in one or two planes correlated less well with angiography. Color Doppler is a useful noninvasive technique that is not only highly sensitive and specific in the identification of mitral regurgitation but also provides accurate estimation of its severity.
Steady improvement in cardiac surgical techniques and prosthetic devices during the past two decades has made the postoperative management of valvular surgery patients enormously easier than it once was. Today, if patients are good surgical candidates, and if the procedure has gone smoothly, survival is the rule, and postoperative management is usually not critical. However, since patients are often not ideal candidates and surgery is not always perfect, skilled postoperative care can save lives that would otherwise be lost. In this chapter we will review the principles and techniques of postoperative management from the standpoint of the medical cardiologist. Since early postoperative management and long-term management typically involve somewhat different sets of problems they will be dealt with in separate sections.
Noninvasive techniques are helpful in evaluating the function of mechanical prostheses and tissue valves. Combined phonocardiography and M-mode echocardiography together with cinefluoroscopy are the most useful noninvasive techniques in differentiating normal from abnormal metallic prosthetic valve function. The intensity of the opening and closing clicks and associated murmurs will depend on the type of prosthetic valve, the heart rate and rhythm and the underlying hemodynamic status. Arrhythmias or conduction disturbances, or both, may produce motion patterns that mimic some of the echocardiographic signs of malfunctioning prosthetic valves. Differentiation of thrombus formation or tissue ingrowth from paravalvular regurgitation or dehiscence is possible by noninvasive techniques. Disc variance, a potentially serious and lethal problem with the older Beall valves, can be readily detected by cinefluoroscopy and echophonocardiography.With regard to bioprosthetic valves, two-dimensional echocardiography is superior to M-mode echocardiography in detecting primary valve failure. In addition, detection of vegetations, valve alignment and ring and individual leaflet motion can be best accomplished by two-dimensional echocardiography. Of greater importance is the patient serving as his or her own control in the follow-up assessment of prosthetic valve function by noninvasive techniques.
The color Doppler echocardiographic studies and aortic angiograms of all patients who had these procedures performed within 2 weeks of each other between October 1984 and August 1985 were reviewed to determine whether any parameters of the regurgitant jet visualized by color Doppler study predicted the severity of aortic insufficiency as assessed by angiographic grading. Patients with an aortic valve prosthesis were excluded. Twenty-nine patients had aortic insufficiency and had adequate color Doppler studies for analysis. The mean time between color Doppler examination and angiography was 2.3 days (range 0 to 12).The maximal length and area of the regurgitant jet were poorly predictive of the angiographic grade of aortic insufficiency. The short-axis area of the regurgitant jet from the parasternal short-axis view at the level of the high left ventricular outflow tract relative to the short-axis area of the left ventricular outflow tract at the same location best predicted angiographic grade, correctly classifying 23 of 24 patients. However, the jet could be seen from this view in only 24 of the 29 patients. The height of the regurgitant jet relative to left ventricular outflow tract height measured from the parasternal long-axis view just beneath the aortic valve correctly classified 23 of the 29 patients. Mitral stenosis or valve prosthesis, which was present in 10 patients, did not interfere with the diagnosis or quantitation of aortic insufficiency by these methods.The thickness of the regurgitant stream at its origin relative to the size of the left ventricular outflow tract is a better predictor of the severity of aortic insufficiency as judged by angiographic grading than is the area of the regurgitant jet or the depth to which the jet extends in the left ventricle.
This study was performed to assess the accuracy of qualitative angiographic grading in persons with aortic regurgitation (AR) or mitral regurgitation (MR) and to determine the factors that may influence the reliability of such grading. In 230 patients (152 men, 78 women, aged 52 +/- 14 years) with AR or MR, forward cardiac index was measured by the Fick and indicator dilution techniques and left ventricular (LV) angiographic index by the area-length method, from which the regurgitant volume index was calculated. In 124 other patients (89 men, 35 women, aged 52 +/- 11 years) without regurgitation, there was good agreement between forward and angiographic cardiac indexes (r = 0.87, p less than 0.001). In the 83 patients with AR, the regurgitant volume indexes in those with 1+ (0.87 +/- 0.57 liters/min/m2) and 2+ (1.72 +/- 1.19 liters/min/m2) angiographic regurgitation were not significantly different from one another, but were significantly different from those with 3+ (3.0 +/- 1.42 liters/min/m2) and 4+ (4.80 +/- 2.25 liters/min/m2) regurgitation; at the same time, the regurgitant volume indexes of patients with 3+ and 4+ AR were not significantly different from one another. In the 147 patients with MR, the regurgitant volume indexes in patients with 1+ regurgitation (0.61 +/- 0.64 liters/min/m2) were significantly lower than other grades, but the regurgitant volume indexes of 2+ (1.14 +/- 0.85 liters/min/m2) vs 3+ (2.14 +/- 1.37 liters/min/m2) and of 3+ vs 4+ (4.60 +/- 2.31 liters/min/m2) were not significantly different. With AR and MR, regurgitant flow within each angiographic grade varied widely, especially in grades 3+ and 4+, and there was considerable overlap of regurgitant volume indexes between grades.(ABSTRACT TRUNCATED AT 250 WORDS)
Doppler echocardiographic characteristics of normally functioning Hancock and Björk-Shiley prostheses in the mitral and aortic positions were studied in 50 patients whose valvular function was considered normal by clinical evaluation. Doppler studies were also performed in 46 patients with suspected malfunction of Hancock and Björk-Shiley valves and who subsequently underwent cardiac catheterization. Mean gradients were estimated for both mitral and aortic valve prostheses and valve area was calculated for the mitral prostheses.Doppler prosthetic mitral valve gradient and valve area showed good correlation with values obtained with cardiac catheterization (r = 0.93 and 0.97, respectively) for both types of prosthetic valves. The correlation coefficient (r = 0.93) for mean prosthetic aortic valve gradient was also good, although Doppler echocardiography overestimated the mean gradient at lower degrees of obstruction. Regurgitation of Hancock and Björk-Shiley prostheses in the mitral and aortic positions was correctly diagnosed. These results suggest that Doppler echocardiography is a reliable method for the characterization of normal and abnormal prosthetic valve function.
Valve prostheses have played an important part in the past two decades in the management of patients with valvular heart disease. However, many of the devices used in valve replacement have introduced new clinical problems. This paper deals with some of the problems associated with valve replacement, including one not previously emphasized--valve prosthesis-patient mismatch, which may cause obstruction to ventricular outflow and/or inflow.
The mean pressure drop across the mitral valve and atrioventricular pressure half-time were measured noninvasively by Doppler ultrasound in 40 normal subjects, in 17 patients with mitral regurgitation, 32 patients with mitral stenosis and 12 with combined stenosis and regurgitation. In normal subjects pressure half-times were 20--60 msec, in patients with isolated mitral regurgitation 35--80 msec and in patients with mitral stenosis 90--383 msec. There was no significant change in pressure half-time with exercise or on repeat examinations, indicating relative independence of mitral flow. In 25 patients with mitral stenosis and seven with combined stenosis and regurgitation, pressure half-time was related to mitral valve area calculated from catheterization data. Increasing pressure half-times occurred with decreasing mitral valve area, and this relationship was not influenced by additional mitral regurgitation. Noninvasive measurement of pressure half-time together with mean pressure drop was useful for evaluating patients with mitral valve disease.
The flow obstruction in mitral valve implants was studied in the immediate postoperative period in 19 patients with Björk-Shiley, Hancock, or Lillehi-Kaster prosthetic mitral valves. The effective valve area (Ae) was used as a measure of the flow obstruction. The blood velocity in the implants was estimated with a non-invasive ultrasound Doppler system. The cardiac output was determined with an indwelling thermodilution catheter. The collected data allowed the determination of Ae. Multiple determinations of Ae, at various cardiac outputs and pulse rate were generally performed in each patient during the first 2--3 postoperative days. The investigation demonstrated that the method employed was useful for the study of mitral implant performance. The obtained values of Ae demonstrated that the flow obstruction in presthetic mitral valve implants is frequently considerable.
The accuracy in determining the pressure gradient in the Björk-Shiley mitral implant from noninvasive ultrasound Doppler data was explored in nine adult patients. Manometric and ultrasound data were collectd simultaneously, and identical diastolic periods were used to compare the manometric gradient (delta Pm) with the gradient obtained from ultrasound data (delta Pu). In the nine patients the mean diastolic value of delta Pm ranged from 2-12.5 mm Hg and the difference between the mean diastolic values of delta Pm and delta Pu was 0.3 +/- 1.0 mm Hg(SD). The results of the investigation indicated that the method is accurate and reliable in the nonivasive determination of the mean diastolic gradient in the Björk-Shiley mitral implant.
Doppler echocardiography was performed in 136 patients with a normally functioning prosthetic valve in the aortic (n = 59), mitral (n = 74) and tricuspid (n = 3) positions. These included patients with St. Jude (n = 82), Björk-Shiley (n = 18), Beall (n = 13), Starr-Edwards (n = 7) or tissue (n = 16) valves. Peak and mean pressure gradients across the prostheses were measured using the simplified Bernoulli equation. The prosthetic valve orifice (PVO, in square centimeters), only in the mitral position, was calculated by the equation: PVO = 220/pressure half-time. In the aortic position, the St. Jude valve had a lower peak velocity (2.3 +/- 0.6 m/s, range 1.0 to 3.9), peak gradient (22 +/- 12 mm Hg, range 4 to 61) and mean gradient (12 +/- 7 mm Hg, range 2 to 32) than the other valves (p less than 0.05) when compared with Starr-Edwards). In the mitral position, the St. Jude valve had the largest orifice (3.0 +/- 0.6 cm2, range 1.8 to 5.0) (p less than 0.0001 compared with all other valves). Insignificant regurgitation was commonly found by pulsed mode Doppler technique in patients with a St. Jude or Björk-Shiley valve in the aortic or mitral position and in patients with a Starr-Edwards or tissue valve in the aortic position. In 17 other patients with a malfunctioning prosthesis (four St. Jude, two Björk-Shiley, four Beall and seven tissue valves) proven by cardiac catheterization, surgery or autopsy, Doppler echocardiography correctly identified the complication (significant regurgitation or obstruction) in all but 2 patients who had a Beall valve. It is concluded that 1) the St. Jude valve appears to have the most optimal hemodynamics; mild regurgitation can be detected by the Doppler technique in normally functioning St. Jude and Björk-Shiley valves in the aortic or mitral position and in Starr-Edwards and tissue valves in the aortic position, and 2) Doppler echocardiography is a useful method for the detection of prosthetic valve malfunction, especially when the St. Jude, Björk-Shiley and tissue valves are assessed.
We performed color Doppler flow mapping in 15 patients, 1 week to 17 years old (mean 42 months), with coarctation of the aorta that was confirmed subsequently by angiography and/or surgery. Twelve patients had native coarctation and three had mild recoarctation after surgical repair. Color Doppler flow maps were analyzed with a digital analysis package and a Sony computer system. The diameter in the region of coarctation from the color Doppler flow map (mean = 2.0 +/- 0.8 mm [SD]) correlated well with the coarctation diameter measured at angiography (mean = 1.8 +/- 0.8 mm; r = .83, SEE 0.43 mm) in the 10 patients with native coarctation undergoing angiography, but the coarctation diameter measured by two-dimensional echocardiography (3.9 +/- 1.5 mm) was poorly predictive of the angiographic severity (r = .23). Additionally, spatial acceleration was seen in all patients proximal to the coarctation site, with an aliased and accelerating stream narrowing progressively as it proceeded toward the coarctation site, a pattern that is not seen in healthy subjects. Computer analysis of the color Doppler images provided pseudo three-dimensional and digital velocity maps for blue, red, and green (turbulent) flow velocities to allow an enhanced appreciation of the accelerating stream, easily separating this from normal descending aortic aliasing patterns. The narrowing of the acceleration area in the proximal descending aorta (distal/proximal acceleration zone ratio) was also predictive of the angiographic severity of coarctation (r = .83). The distribution of low-level turbulence seen proximally paralleled the distribution of the proximal accelerating stream.(ABSTRACT TRUNCATED AT 250 WORDS)
A total of 145 patients with 160 mechanical prostheses of the Björk-Shiley or Starr-Edwards type (15 with double mitral plus aortic valves) underwent clinical and Doppler echocardiography analysis. In the mitral position (85 valves) 10 patients with valve-related symptoms, calculated prosthetic area less than or equal to 1 cm2, or mean transprosthetic gradient greater than 10 mm Hg by Doppler echocardiography were predefined as abnormal. Seven patients had operations, and prosthetic obstruction was confirmed in all. All patients had higher pulmonary pressures (p less than 0.001) before valve replacement. Clinical presentation was variable; however, all those with proved prosthetic thrombosis had a fulminant course and distinctive velocity curves on Doppler. In the 75 patients predefined as normal, calculated valve area (2.3 +/- 0.6 cm2, mean +/- SD, range 1.3 to 3.7 cm2) and mean gradient (4.9 +/- 1.7 mm Hg, range 1.5 to 9.5 mm Hg) were widely spread and were independent of prosthetic size greater than or equal to 27 mm. Clinically 37 of 75 patients were moderately to severely limited. Mean gradient above 5 mm Hg was associated with a higher incidence of chronic atrial fibrillation (p less than 0.05), significant tricuspid regurgitation, failure of the right side of the heart, and significant functional limitation (p less than 0.02 for all). In the aortic position (75 valves) peak gradients were 28.2 +/- 15 mm Hg (8 to 80 mm Hg). Mean gradients were 18 +/- 9.6 mm Hg (6.5 to 46.5 mm Hg). Averaged gradients derived from the average of peak and late systolic gradients were 22.4 +/- 12.7 mm Hg (6 to 62 mm Hg). In all five abnormal patients (two with endocarditis and three with hemodynamic decompensation) but also in 18 of 70 clinically normal valves, peak gradients were greater than or equal to 36 mm Hg (ranges 36 to 65 mm Hg in both). Gradients were unrelated to symptoms or to the duration of the valve in situ (3 weeks to 20 years). Gradients correlated with prosthetic size (r = 0.57) and were higher (p less than 0.001) across small (19 to 23 mm) versus large (25 to 31 mm) valves. Regurgitation was present in 40% of the mitral prostheses. It was detected in 32% of the mitral prostheses defined as normal and was estimated as mild in most. Aortic regurgitation was present in all five abnormal aortic prostheses, significant in four, and in 26 of the valves (37%) defined as normal, significant in two.(ABSTRACT TRUNCATED AT 400 WORDS)
On the hypothesis that Doppler ultrasound fails to penetrate prosthetic valves, an in vitro flow simulation system was constructed in a large water tank. Conventional pulsed, continuous wave and Doppler color flow systems were used to detect flow in tubing placed diagonally within the water and maintained by a continuous pump. After control periods of flow detection within the tubing, six different prosthetic valves were interposed on a stage between the transducer and the tubing. In comparison with control measurements, detection of flow within the tubing was impossible when the Doppler beam traversed the central occluding ball of the Starr-Edwards Silastic prosthesis by any modality. Marked reduction in the detection of the Doppler signal was noted for the Starr-Edwards stellite prosthesis with only slight improvement in the ability to detect the flow signals through the central occluding discs of the Björk-Shiley, Hall-Kastor and St. Jude valves. In distinction to the other valves, the ability of Doppler ultrasound to detect flow behind the cusps of the Carpentier-Edwards heterograft was similar to that during the control period. An understanding of flow masking should improve the clinical utility of Doppler methods for investigating prosthetic valve dysfunction.
Echocardiographic and Doppler studies were performed on 183 clinically normal and 58 severely dysfunctioning bioprosthetic mitral, aortic and tricuspid valves. The valve dysfunction resulted from spontaneous cusp degeneration in 49 instances and from paravalvular regurgitation in 9. The pulsed Doppler study demonstrated regurgitant flow in 36 (92%) of 39 regurgitant valves and 8 (90%) of 9 paravalvular regurgitant valves. Diagnostic echocardiographic features were present in only 51 and 10% of the patients, respectively. Although the Doppler regurgitant jet was peripheral in seven of the nine patients with paravalvular regurgitation, it was not possible to differentiate these patients from those who had valve degeneration and cusp tear at the periphery of the valve ring. Eight patients presented with a musical holosystolic murmur of mitral insufficiency. In all eight there was a characteristic honking intonation on the audio signal and a striated shuddering appearance on the video Doppler signal. Ten stenotic mitral bioprosthetic valves (less than or equal to 1.1 cm2 valve orifice) were identified by Doppler study. Diagnostic echocardiographic features were present in only two of these patients. The Doppler-derived valve orifice dimension correlated well (r = 0.83) with cardiac catheterization values. Fourteen asymptomatic or minimally symptomatic patients had echocardiographically thickened mitral cusps (greater than or equal to 3 mm). These patients had a significantly (p less than 0.0001) smaller valve area as compared with normal control valves, and during 4 to 24 months of follow-up, five of these patients developed severe valve regurgitation or stenosis. Doppler ultrasound is more sensitive than echocardiography in diagnosing bioprosthetic valve stenosis and regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)
A total of 135 patients with normally functioning prosthetic aortic valves who were catheterized 6 months after placement of Hancock, modified Hancock or Bjork-Shiley prostheses were studied to determine the magnitude of error in Gorlin formula estimates of prosthetic aortic valve area. All patients were male, selected from 13 participating hospitals and routinely followed after valve replacement for 5 years. Hemodynamically determined Gorlin valve areas were compared with independently verified actual valve areas. Actual Hancock areas were measured from videotapes of valves exercised in a pulse duplicator flow model. Actual Bjork-Shiley areas were calculated directly from the valves' inner ring radius. Gorlin valve areas correlated poorly with actual valve areas (r = 0.39). The mean Gorlin formula error was 0.36 cm2 (standard deviation = 0.32). Gorlin areas overestimated actual areas by greater than 0.25 cm2 in 43 patients (32%) and underestimated actual areas by greater than 0.25 cm2 in 29 (21%). It was concluded that the Gorlin formula inaccurately predicts prosthetic valve area in the aortic position. Overreliance on this formula in assessing aortic stenosis could lead to errant clinical decisions.
The severity of valvular aortic stenosis was assessed by Doppler color flow mapping in 100 consecutive patients who underwent successful cardiac catheterization within 2 weeks of the Doppler study. The maximal width of the aortic stenosis jet seen in 61 of these patients (Group A) was measured at the aortic valve. Color-guided continuous wave Doppler examination was used to measure the mean transaortic pressure gradient, and the aortic valve area was estimated using the simplified continuity equation. The aortic stenosis jet was not seen in 39 patients (Group B), and the mean pressure gradient and aortic valve area in these patients were assessed by conventional Doppler echocardiography alone. The mean pressure gradient obtained by continuous wave Doppler study and cardiac catheterization in the 61 Group A patients correlated well (r = 0.90); the correlation was lower in the 39 Group B patients (r = 0.70). The overall correlation for the combined Groups A and B was good (r = 0.82). The aortic valve area estimated by continuous wave Doppler study and cardiac catheterization in 54 Group A patients correlated well (r = 0.92); the correlation in 22 Group B patients was lower (r = 0.71). The correlation for all 76 patients (Groups A and B) was good (r = 0.80). The maximal aortic stenosis jet width also correlated well with the aortic valve area estimated at catheterization in 54 patients (r = 0.90). Group C represented an additional 14 patients in whom the left ventricle could not be entered during cardiac catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)
Pulsed Doppler echocardiographic diagnosis of periprosthetic valvular insufficiency may be difficult. This report details the pulsed Doppler echocardiographic findings in two patients who developed severe periprosthetic mitral regurgitation after porcine mitral valve replacement. In both patients, mitral regurgitation was difficult to diagnose and left atrial turbulence, when detected, appeared localized, suggesting only mild mitral regurgitation. However, the combination of abnormally high peak transmitral diastolic flow velocity, with a normal pressure half-time, and increased flow velocity in the tricuspid regurgitant jet compatible with severe pulmonary hypertension, in the absence of other apparent left heart disease, suggested the correct diagnosis of severe mitral regurgitation in both cases. Techniques for optimal pulsed Doppler assessment of the mitral anulus region are emphasized, as are the theoretic advantages of continuous wave and color-coded pulsed Doppler echocardiography for detection of periprosthetic regurgitation.
Previous investigations have suggested that Doppler echocardiography is useful in detecting dysfunction in aortic (AVR) and mitral prostheses (MVR). However, to diagnose abnormalities, the spectrum of normal velocities through these valves must be established. Therefore, we used Doppler echocardiography to study 100 patients with 105 prosthetic valves that had no clinical evidence of valve dysfunction 9 +/- 8 days postoperatively. There were 66 Carpentier-Edwards (C-E), 23 St. Jude (S-J), and 16 Ionescu-Shiley (I-S) valves. In 70 AVR, the peak instantaneous gradient was 26.4 +/- 8.2 Hg, mean systolic gradient was 15.6 +/- 5 mm Hg, and gradients varied inversely with valve size, although differences were significant only when comparing the smallest vs the largest valve sizes (p less than or equal to 0.03). Peak instantaneous gradients greater than 36 mm Hg occurred only in AVR size 23 or smaller. There were no significant differences in gradients among C-E, S-J, and I-S AVR. In 35 MVR, mean gradient was 6.9 +/- 2.3 mm Hg and valve area was 2.7 +/- 0.8 cm2; neither varied significantly with valve size. However, S-J MVR group had smaller mean gradients and larger effective valve area than C-E bioprosthetic MVR (p = 0.01 and p = 0.05, respectively). Regurgitation was more common in AVR (26%) than in MVR (9%), p = 0.04, although all instances were mild and clinically silent. We conclude that normal AVR and MVR of a given size and type have a predictable range of Doppler echocardiographic parameters. Doppler evidence of mild regurgitation is a frequent finding in normal AVR and MVR.(ABSTRACT TRUNCATED AT 250 WORDS)
For patients with stenotic native valves, the modified Bernoulli equation (delta P = 4V2) may be applied to Doppler-measured transvalvular velocities to yield an accurate estimate of transvalvular gradients. Although it would be useful if the same approach could be used for those with stenotic prosthetic valves, no previous study has validated the Doppler technique in this setting. We therefore recorded simultaneous continuous-wave Doppler flow profiles and transvalvular manometric gradients in 12 catheterized patients in whom all atrial and ventricular pressures were directly measured (transseptal left atrial catheterization and transthoracic ventricular puncture were performed where necessary). A total of 13 prostheses were studied: 11 mitral (seven porcine, three Starr-Edwards, and one Björk-Shiley) and two tricuspid (one porcine and one Björk-Shiley). The Doppler-determined mean gradient was calculated as the mean of the instantaneous gradients (delta P = 4V2) at 10 msec intervals throughout diastole. The correlation of simultaneous Doppler (DMG) and manometric mean gradients (MG) for the whole group (n = 13) demonstrated a highly significant relationship (MG = 1.07 DMG + 0.28; r = .96, p = .0001). The correlation was equally good for porcine valves alone (n = 8) (MG = 1.06 DMG + 0.55; r = .96, p = .001) and for mechanical valves alone (n = 5) (MG = 1.06 DMG - 0.04; r = .93, p = .02). In a subset of patients without regurgitation (n = 8), prosthetic valve areas were estimated by two Doppler methods originally described by Holen and Hatle, as well as by the invasive Gorlin method. As expected from theoretical considerations, a close correlation was not demonstrated between results of the Gorlin method and those of either Hatle's Doppler method (r = .65, fp = NS) or Holen's method (r = .14, p = NS). Comparison of the results of the two Doppler methods yielded a somewhat closer correlation (r = .73, p less than or equal to .05). These results suggest that in patients with disk-occluder, ball-occluder, and porcine prosthetic valves, Doppler estimates of transvalvular gradients are virtually identical to those obtained invasively.
In 30 patients with aortic stenosis, 14 of whom also had significant aortic regurgitation, the velocities in the stenotic jet (V') and below the valve (V) were recorded by Doppler ultrasound. With two-dimensional echocardiography, two subvalvular areas (A) were calculated from leading-to-leading edge ("large") and trailing-to-leading edge ("inner") diameter measurements. The aortic valve area was calculated by the equation of continuity (A' = A X peak V/peak V') and by calculating stroke volume below the valve [A X integral of V (t) and dividing by the integral of V' (t) (= A"). Based on cardiac output estimations from single-plane angiographic images, Gorlin's formula was used to calculate invasive valve areas. In patients with no or mild aortic regurgitation a second invasive estimate was based on cardiac output measured by the Fick method. The best correlation was found when A' (with "large" diameter) was compared with invasive results based on cardiac output measured by the Fick method (r = .89, SEE +/- 0.12, n = 16); the worst was found when A" (with "large" diameter) was compared with invasive results based on cardiac output measurements by single-plane angiography (r = .80, SEE +/- 0.20, n = 30). The results indicate that valve area in patients with aortic stenosis can be reliably estimated noninvasively, even in those with significant aortic regurgitation.
Laminar flow through a conduit is equal to the mean velocity times the cross-sectional area of the orifice. Therefore, volume is equal to the time-velocity integral multiplied by the cross-sectional area. In aortic stenosis, flow in the stenotic jet is laminar and the aortic valve area should be equal to the volume of blood ejected through the valve divided by the time-velocity integral of the aortic jet velocity recorded by continuous-wave Doppler echocardiography. To test whether this concept can be used to accurately determine aortic valve area noninvasively by the Doppler method, 39 patients (age 35 to 82 years, mean 63) underwent pulsed Doppler combined with two-dimensional echocardiography for measurement of stroke volume at the aortic, pulmonic, and mitral anulus as well as continuous-wave Doppler recording of the aortic jet. Aortic valve area determined at cardiac catheterization by the Gorlin equation ranged between 0.4 and 2.07 cm2 (mean 0.89 +/- 0.45). Doppler-derived valve area, determined with the stroke volume value from either the aortic, pulmonic, or mitral anulus, correlated well with the area determined at cardiac catheterization (r = .95, .97, and .96, respectively). A simplified method for measuring aortic valve area derived as the cross-sectional area of the aortic anulus times peak velocity just proximal to the aortic valve divided by peak aortic jet velocity correlated well with measurements obtained at cardiac catheterization (r = .94). An excellent separation between critical and noncritical aortic stenosis was seen using either one of the Doppler methods.(ABSTRACT TRUNCATED AT 250 WORDS)
Doppler echocardiography is a useful means of evaluating cardiac valve function noninvasively.1,2 The detection of mitral regurgitation (MR) by Doppler techniques has shown high sensitivity and specificity when correlated to the degree of MR determined by contrast ventriculography.1 However, assessment of prosthetic MR with Doppler echocardiography is more difficult than detection of native valve MR, especially when the tilting disc prosthetic valve has been evaluated, because of difficulty in obtaining Doppler signals from behind the prosthesis.3 We describe a patient with paravalvular MR around a dehiscent Björk-Shiley mitral prosthesis in which the regurgitant jet was easily detected by Doppler, and the calculated mitral valve orifice increased.
Continuous-wave Doppler spectra of aortic flow velocity were recorded in duplicate in 20 consecutive patients with aortic porcine valves by 1 technician and 3 occasions: initially and 1 week and 1 month later. The highest maximal aortic velocity recorded from at least 2 transducer locations was taken from 5 consecutive beats that did not vary. The 120 tracings were coded and read by 1 observer. In blinded fashion, 20 records were read twice and 26 were read by 2 interpreters. Variability was calculated from the square root of pooled variances and expressed in meters per second and also related to the mean velocity and expressed as percent coefficient of variation for the following categories: interpretive [intraobserver +/- 0.019 (0.8%), interobserver +/- 0.071 (2.7%)], technical [duplication +/- 0.048 (1.9%)], temporal/biologic [+/- 0.125 (5.0%)]. Doppler measurements of aortic velocity can achieve excellent reproducibility by maintaining constant technique. With a methodologic variability of +/- 2%, the variability associated with the passage of time was significantly different at +/- 5% and was a result of fluctuations in the physiology of a few subjects. Thus, the technique can distinguish small method errors from minor drifts of the biology and, by implication, detect the onset of bioprosthetic degeneration.
To determine the source of errors in the Gorlin formula for estimating stenotic valvular orifice area, we used a pulsatile flow model that emulated left ventricular and aortic pressures and flow and allowed control of ventricular outflow orifice area. After comparing orifice areas calculated by the Gorlin formula with actual orifice areas, the Gorlin formula constant (k) was found to be highly correlated with the square root of the mean transvalvular gradient (r = .95). A new formula was derived empirically and predicted areas more accurately and with smaller standard errors than the Gorlin formula in the model (r = .98, SEE = 0.11 and r = .87, SEE = 0.28, respectively) in a series of 19 patients with Hancock porcine xenograft valves (r = .89, SEE = 0.07 and r = .60, SEE = 0.12, respectively) and in the original series of patients reported by Gorlin and Gorlin in proposing the Gorlin formula (r = .93, SEE = 0.11 and r = .91, SEE = 0.12, respectively).
In patients with symptoms of heart failure after mitral valve replacement, identification of a stenosed prosthesis may be difficult. Twelve such patients were evaluated, presenting at a mean of 8.4 years after mitral valve replacement (four mechanical, eight porcine). Transvalvular pressure gradients were obtained using both indirect (pulmonary capillary wedge) and direct (transseptal catheterization) measurements of left atrial pressure. In all 12 patients, the diastolic gradient across the prosthetic valve was overestimated when pulmonary wedge rather than transseptal measurements were used. Calculated mitral valve prosthetic area was underestimated by the pulmonary wedge determinations. These findings may be caused by either the phase delay of the pulmonary wedge V wave relative to the transseptal V wave, resulting in a higher diastolic mean left atrial pressure, or the faulty wedge determinations in the setting of pulmonary hypertension, or both. In patients being considered for repeat mitral valve replacement because of prosthetic valve stenosis, transseptal catheterization allows for more accurate determination of prosthetic valve area and more accurately defines the need for repeat mitral valve surgery.
One hundred thirty-four patients with prosthetic or bioprosthetic heart valves were investigated with Doppler echocardiography to determine normal values for commonly used prosthetic valves and to test the specificity of abnormal Doppler findings. In 70 patients the aortic valves had been replaced and in 64 the mitral valves had been replaced. Gradients across prostheses in the aortic position were calculated from maximal velocity. Peak calculated aortic transvalvular gradients in normal subjects were 22 +/- 10 mm Hg in 33 Björk-Shiley valves, 23 +/- 10 mm Hg in 27 porcine valves and 29 +/- 13 mm Hg in 6 Starr-Edwards valves. Mild aortic regurgitation was seen in 42% of Björk-Shiley valves, 26% of porcine valves and 2 of 6 Starr-Edwards valves. Mitral valve orifice was calculated by the pressure half-time method. In clinically normal patients with mitral valve prostheses, the effective mitral valve orifice was 2.5 +/- 0.8 cm2 in 35 Björk-Shiley valves, 2.1 +/- 0.7 cm2 in 17 porcine valves, and 2.0 +/- 0.3 cm2 in 10 Starr-Edwards valves. Mitral regurgitation was found in 11% of Björk-Shiley valves, 19% of porcine valves and 30% of Starr-Edwards valves. Repeat studies at 2 weeks to 14 months revealed no difference in 8 aortic and 14 mitral prostheses. Seven aortic and 4 mitral valves functioned abnormally as determined by Doppler, and the abnormal function was confirmed in each at surgery or at cardiac catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)
1.The results of left ventricular angiography in 243 patients have been reviewed in order to assess its accuracy in the diagnosis of mitral incompetence. In 228 patients, the left ventricle was entered via the aortic valve: in 15 patients the approach to the left ventricle was via trans-atrial septal catheterisation.2.Thirty eight patients with mitral valve disease were subsequently examined at operation or autopsy. The findings agreed better with the angiographic diagnosis than with the mitral valve assessment on clinical examination.3.False mitral incompetence was observed at angiography in 19 out of 121 patients with normal mitral valves, but in only one case was the incompetence more than slight (one or two small regurgitant puffs).4.The accuracy of left ventriculography did not appear to be affected significantly by the presence of extrasystoles. Multiple extrasystoles were not associated with a greater incidence of mitral incompetence than in patients without extrasystoles.5.It is concluded that left ventricular angiography is a reliable method of demonstrating significant mitral incompetence provided that one excludes those cases in whom only one or two small regurgitant puffs of contrast medium are seen.
Cineaortography, quantitative biplane left ventricular angiocardiography and Fick cardiac output studies were performed in 69 patients with aortic regurgitation to evaluate the usefulness of the aortogram in quantitating regurgitation. Thirteen patients had coexistent aortic stenosis and 12 had coexistent mitral stenosis. Patients with concomitant mitral regurgitation were excluded because their aortic regurgitant flow cannot be separately quantified with biplane ventriculography. Twenty-eight other patients without valvular regurgitation were also studied to assess further the accuracy of the quantitative ventriculography, and the stroke volumes derived from Fick and angiographic methods were found to correlate well (r = 0.97). Aortic regurgitation in the 69 patients, graded on a 1 to 5 scale from the aortogram, correlated significantly with the percent and volume of regurgitation (r = 0.56 and 0.65, P < 0.01), respectively). However, there was a wide range in amount of regurgitant flow within the aortographic grades, especially in grades 4 and 5, and there was considerable overlap between the grades. The degree of aortic regurgitation was more commonly overestimated than underestimated from the aortogram, but the correlation tended to be better in the patients with a large end-diastolic volume and normal ejection fraction and without aortic or mitral stenosis.
Aortic root cineangiography has been carried out in 21 consecutive survivors of replacement of the aortic valve with a Starr-Edwards ball-valve prosthesis. In nine of 21 patients, a significant leak around the rim of the prosthesis was demonstrated. In four reoperated patients, this leak was confirmed to be secondary to disruption of the suture material, usually in patients with heavily calcified annuli. Cineangiographic studies are necessary for complete postoperative evaluation of prosthetic values.
A noninvasive method for real time blood-flow imaging using ultrasound has long been required in the fields of cardiology, and cardiovascular surgery. Recently, we developed a method of two-dimensional Doppler echocardiography (hereafter abbreviated as "2-D Doppler") for clinical use which allows us to obtain noninvasively, intracardiac blood-flow images in real time. The main purpose of this paper is to describe the newly developed blood-flow imaging system "2-D Doppler" and to demonstrate its clinical usefulness in acquired valvular diseases, particularly in the evaluation of valvular regurgitation.
The device, in principle, combines a conventional pulsed-Doppler system and a newly developed auto-correlator, in which blood-flow images within a given cross section of a beating heart are noninvasively displayed in real time, simultaneously with conventional two-dimensional echocardiograms. The system can provide three kinds of information, direction, velocity and turbulence of blood flow.
The 2-D Doppler examinations were carried out on 72 patients with acquired valvular diseases whose diagnoses were confirmed by angiography and/or surgery. Studies were performed comparing the findings of the 2-D Doppler and those of angiography (for aortic and mitral lesions) or with operative findings (for tricuspid lesions) in the quantitative evaluation of valvular regurgitation. Aortic, mitral and tricuspid valvular regurgitation have been quantitatively demonstrated with 2-D Doppler, and, for each value, the severity of the regurgitation showed a high correlation between the findings of 2-D Doppler and of angiography or surgery. In conclusion, we have found that (1) 2-D Doppler is very useful in detecting and estimating the severity of valvular regurgitation, and that (2) 2-D Doppler may replace conventional angiography in some situations.
From June 1974 to December 1978, 714 Hancock valves have been placed in 605 patients. One hundred seventy-five patients with a mitral xenograft have been restudied. The results were questionable due to the wide scatter and disparity between the calculated and the theoretical orifice of each valve size. To elucidate these differences, the hemodynamic data of 40 isolated, normal functioning mitral Hancock valves were reviewed. Early, middle and late diastolic mitral valve gradients were measured by planimetry and their corresponding flows were estimated by angiography. The paired data were fitted to exponential functions and specific lines for each Hancock valve size were obtained. By superimposing Gorlin's pressure and flow curves on these lines, the instantaneous effective orifice for each Hancock valve can be determined. We concluded that 1) the Hancock valve effective orifice is flow related and always lower than its theoretical opening; 2) normal function frequently cannot be firmly established by the mean effective area; and 3) the nomogram described may help in determining the time-related variations of a particular valve.
1.1. Standard hydrokinetic orifice formulas have been applied to stenotic mitral, pulmonic, tricuspid, and aortic valves, patent ductus arteriosus, and atrial and ventricular septal defects. These formulas were considered applicatble because of the high kinetic energy losses through small orifices or in the presence of high volume flow.2.2. In its general form, the formula is as follows: where A = cross-sectional area in cm.2 of the orifice F = flow rate in c.c. per second C = empirical constant g = gravity acceleration h = pressure gradient across the orifice in mm. Hg.3.3. Cross-sectional valve areas have been calculated in twenty-one patients with mitral stenosis. Calculated and measured areas have checked within 0.2 cm.2 in six post-mortem examinations and in five patients at the time of operation. Repeated calculations from different sets of data in the same patient have checked well in all instances. Valve area showed a good correlation with severity of pulmonary symptoms. Changes in valve area following finger fracture valvuloplasty were observed in two patients. The exponential relation of pressure to flow and valve area is briefly discussed.4.4. The stenotic cross-sectional area has been calculated in ten patients with pulmonic stenosis with one post-mortem observation and in two patients with patent ductus arteriosus with operative correlations.5.5. Calculations have likewise been made but without post-mortem confirmation in tricuspid stenosis, atrial septal defect, and ventricular septal defect. Formulas are presented for calculation of the size of the aortic orifice in aortic stenosis. In these groups, the empirical constant, C, has not as yet been determined and must await the collection of post-mortem data.6.6. In each case an attempt has been made to assess the sources of error as well as the degree of accuracy involved in the particular formula.7.7. The chief value of these formulas is that they present an objective evaluation of surgical procedures designed to widen stenotic orifices or to abolish abnormal shunts. Furthermore, a theoretical prediction of the benefit to be derived from surgical widening of stenotic valves may be made.
Color Doppler assessment of prosthetic valve function and its limitations (abstr)
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Prosthetic mitral regurgitation detected by Doppler echocardiography Limitations of pulsed and continuous wave Doppler echocardiography
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Limitations of pulsed and continuous wave Doppler echocardiography
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Color guided continuous wave Doppler assessment of effective prosthetic valve area (abstr)
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Color Doppler assessment of prosthetic valve function and its limitations (abstr)
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