Figure - available via license: Creative Commons Attribution-NonCommercial 3.0 Unported
Content may be subject to copyright.
The Doppler equation, where v = velocity directed towards the transducer from the scatterer, ?f = the Doppler shift, f0 = the transmitted frequency, cos θ = cosine of the crossing angle theta and c = the speed of propagation in the medium.
Source publication
Intraoperative transesophageal echocardiography is now used routinely during aortic valve replacement, allowing immediate evaluation of replaced or repaired valves. It is well recognised that high transvalvular pressure gradients can be detected immediately after implantation of a prosthetic aortic valve which may be due to multifactorial confoundi...
Similar publications
Mechanical prosthetic valve dysfunction caused by pannus formation is rare. Pannus restricts move-ment of prosthetic valve leaflets, resulting in severe aortic regurgitation. We describe the case of a 77-year-old woman who presented to the emergency room with increasing dyspnea, ischemia, and shock secondary to mechanical aortic valve dysfunction....
Background:
Pulmonary artery (PA) catheter provides a variety of cardiac and hemodynamic parameters. In majority of the patients, the catheter tends to float in the right pulmonary artery (RPA) than the left pulmonary artery (LPA). We evaluated the location of PA catheter with the help of transesophageal echocardiography (TEE) to know the incidenc...
Citations
... Due to uncertainties to determine the real degree of prosthetic aortic valve obstruction other alternative echocardiographic parameters such as Doppler velocity index, acceleration time, jet contour, valve resistance, percentage stroke work loss, and energy loss have been proposed and may provide additional information in doubtful cases. 9 Others advocate using cardiac magnetic resonance or invasive catheter measurements in discordant cases. 10 In the current era, where different interventional procedures (surgical aortic valve replacement vs transcatheter aortic valve replacement) are being equally offered to a broader range of patients with lower risk profile, younger age, small aortic annulus, bicuspid valves, and reinterventional procedures, it is desirable that a standardized definition of true moderate and severe PPM be uniformly applied and reported in academic research not only to better understand the clinical consequences of the varying degrees of PPM, but also aid in proper patient selection and prosthesis choice based in solid scientific background to improve clinical outcomes. ...
... 8 Again, many factors leading to elevated gradients, such as hyperdynamic states, subvalvular obstruction, supravalvular obstruction, afterload mismatch, or PPM, typically are seen shortly after valve replacement. 10 The late presentation of PPM here is unique, and the case emphasizes the challenges that can be seen with valve-in-valve TAVR. Initial follow-up would suggest that the patient was indeed a good candidate to avoid an increased risk of PPM, but this was not the case with long-term follow-up, as he ultimately underwent another open operation for mechanical valve replacement. ...
... Continuous wave and color flow Doppler showed moderate valvular insufficiency assessed by rate of deceleration and the depth of regurgitant jet penetration into the RVOT, respectively (Fig 1). These assessments were made by two independent cardiologists using guidelines outlined by the American Society of Echocardiography and Standards Committee and the Task Force on Prosthetic Valves [15,27]. The peak to peak xenograft valve gradient measured by right heart catheterization was 8 mmHg ± 4 mmHg. ...
Current research on valvular heart repair has focused on tissue-engineered heart valves (TEHV) because of its potential to grow similarly to native heart valves. Decellularized xenografts are a promising solution; however, host recellularization remains challenging. In this study, decellularized porcine aortic valves were implanted into the right ventricular outflow tract (RVOT) of sheep to investigate recellularization potential. Porcine aortic valves, decellularized with sodium dodecyl sulfate (SDS), were sterilized by supercritical carbon dioxide (scCO2) and implanted into the RVOT of five juvenile polypay sheep for 5 months (n = 5). During implantation, functionality of the valves was assessed by serial echocardiography, blood tests, and right heart pulmonary artery catheterization measurements. The explanted valves were characterized through gross examination, mechanical characterization, and immunohistochemical analysis including cell viability, phenotype, proliferation, and extracellular matrix generation. Gross examination of the valve cusps demonstrated the absence of thrombosis. Bacterial and fungal stains were negative for pathogenic microbes. Immunohistochemical analysis showed the presence of myofibroblast-like cell infiltration with formation of new collagen fibrils and the existence of an endothelial layer at the surface of the explant. Analysis of cell phenotype and morphology showed no lymphoplasmacytic infiltration. Tensile mechanical testing of valve cusps revealed an increase in stiffness while strength was maintained during implantation. The increased tensile stiffness confirms the recellularization of the cusps by collagen synthesizing cells. The current study demonstrated the feasibility of the trans-species implantation of a non-fixed decellularized porcine aortic valve into the RVOT of sheep. The implantation resulted in recellularization of the valve with sufficient hemodynamic function for the 5-month study. Thus, the study supports a potential role for use of a TEHV for the treatment of valve disease in humans.
... The multiple etiologies of elevated pressure gradients across aortic valve prostheses are summarized in Table 1 [9]. High-flow states such as high-output heart failure from valverelated hemolysis would result in increased transvalvular pressure gradients leading to a false impression of severe aortic stenosis. ...
The evaluation of prosthetic valves can provide a unique challenge, and a thoughtful approach is required. High output states like anemia should be kept in the differential when evaluating elevated gradients across prosthetic valves. We present the case of a 69-year-old man with a Starr-Edwards prosthetic aortic valve who presented with symptoms of congestive heart failure and high transvalvular pressure gradients. These symptoms indicate a potential prosthetic valve stenosis. His laboratory evaluation results were consistent with valve-related hemolysis. Resolving his anemia led to a resolution of the symptoms and lowered the pressure gradient on follow-up.
... During the first week and months of valve replacement significant reduction of left ventricular size and myocardial function improvement appears (Gaasch et al. 1983;Fioretti et al. 1985). The general principles for evaluating the prosthetic valve function are similar to those of native valve stenosis (Parnell and Swanevelder 2009;Quiñones et al. 2002). The best parameter for assessment of AV hemodynamic is transvalvular gradient (Bach 2010). ...
... Severe aortic stenosis in a native valve is defined as flow velocity more than 4.5 m/ sec, PGmean more than 50 mmHg and PGmax more than 80mmHg. However, in newly implanted prosthetic valve Vmax, PGmean and PGmax more than 3.5 m/sec, 30mmHg and 50 mmHg respectively would be considered significant (Parnell and Swanevelder 2009). ...
... We classified the valves into groups of normally functioning and suspected dysfunction for the data analysis. We defined normally functioning valves as those that did not show a LOM, and that had a normal range of mean transprosthetic PG (≤ 30 mm Hg) on TTE (15). Valves with suspected dysfunction met one of the following conditions: 1) LOM on CT or 2) elevated PG (> 30 mm Hg) on TTE (16). ...
Objective:
The aims of this study were to compare opening and closing angles of normally functioning mechanical aortic valves measured on dual-source computed tomography (CT) with the manufacturers' values and to compare CT-measured opening angles according to valve function.
Materials and methods:
A total of 140 patients with 10 different types of mechanical aortic valves, who underwent dual-source cardiac CT, were included. Opening and closing angles were measured on CT images. Agreement between angles in normally functioning valves and the manufacturer values was assessed using the interclass coefficient and the Bland-Altman method. CT-measured opening angles were compared between normal functioning valves and suspected dysfunctioning valves.
Results:
The CT-measured opening angles of normally functioning valves and manufacturers' values showed excellent agreement for seven valve types (intraclass coefficient [ICC], 0.977; 95% confidence interval [CI], 0.962-0.987). The mean differences in opening angles between the CT measurements and the manufacturers' values were 1.2° in seven types of valves, 11.0° in On-X valves, and 15.5° in ATS valves. The manufacturers' closing angles and those measured by CT showed excellent agreement for all valve types (ICC, 0.953; 95% CI, 0.920-0.972). Among valves with suspected dysfunction, those with limitation of motion (LOM) and an increased pressure gradient (PG) had smaller opening angles than those with LOM only (p < 0.05).
Conclusion:
Dual-source cardiac CT accurately measures opening and closing angles in most types of mechanical aortic valves, compared with the manufacturers' values. Opening angles on CT differ according to the type of valve dysfunction and a decreased opening angle may suggest an elevated PG.
Aortic valve repair (AVr) aims to preserve the native aortic leaflets and restore normal valve function. In doing so, AVr is a more technically challenging approach than traditional aortic valve replacement. Some of the complexity of repair techniques can be attributed to the unique structure of the functional aortic annulus (FAA), which, unlike the well-defined mitral annulus, is comprised of virtual and functional components. Though stabilizing the ventriculo-aortic junction (VAJ), a component of the FAA, is considered beneficial for patients with chronic aortic insufficiency (AI), the ideal AVr technique remains a subject of much debate. The existing AVr techniques do not completely stabilize the VAJ which may increase susceptibility to recurrent AI due to VAJ dilation. An emerging new technique showing promise for the treatment of both isolated and complex AI is AVr using HAART 300TM geometric annuloplasty ring (GAR). The GAR is implanted below the valve leaflets in the left ventricular outflow tract (LVOT), providing stability and creating a neo-annulus. As with other AVr subtypes, this procedure has a learning curve. There are unique surgical and echocardiographic aspects of AVr with GAR, including the appearance of the LVOT, the aortic valve leaflets, and their motion which cardiac anesthesiologists and echocardiographers must be familiar with. In this work, using an eight-patient echocardiographic case series, we provide an overview of this novel AVr technique, including some unique aspects of device sizing, patient selection, expected post-repair echocardiographic features, and a review of outcomes data.
Calcific aortic valve disease (CAVD) is a leading cause of death. Due to insufficient understanding of the molecular mechanisms that govern the disease, the current therapeutic options lack medical therapies and are limited to aortic valve (AV) replacement. AV calcification occurs preferentially in the fibrosa side of the valve, which is exposed to unstable hemodynamic conditions. In contrast, the ventricularis side is exposed to more stable hemodynamic conditions and is relatively protected from the disease, suggesting the role of biomechanical forces in CAVD. Recent studies have shown the role and mechanisms of biomechanical forces on regulation of AV biology and CAVD pathophysiology. Here, we review the molecular mechanisms by which biomechanical forces regulate mechanosensitive genes, especially microRNAs, and their roles in CAVD. Expression of these microRNAs can be easily manipulated, leading to effective inhibition of CAVD. These mechanosensitive microRNAs could be used for detection and treatment of CAVD.
OBJECTIVES Intraoperative transesophageal echocardiography (iTEE) has an important role in diagnosing the results of mitral valve (MV) replacement and repair. However, intraoperative Doppler features may be dissimilar from those measured at the postoperative follow-up period due to hemodynamic variations. There are no studies regarding MV surgery and comparisons between iTTE and postoperative transthoracic echocardiography (post-TTE). We aimed to evaluate the Doppler flow profiles observed in iTEE after MV replacement and repair and compare them with those observed in post-TTE.
METHODS We conducted an observational study of 76 patients who underwent MV surgery (replacement or repair) over a 10-month period. iTEE was performed with Doppler evaluation (mean pressure gradient [MPG] and functional area). Patients were re-evaluated with TTE 72 hours after surgery (post-TTE). iTEE and post-TTE Doppler values were then compared and correlated.
RESULTS The patients’ mean age was 59 ± 18 years and 55% were women. The prevalence of severe mitral regurgitation and severe mitral stenosis was 77.6% and 22.4%, respectively. MV repair was performed in 71% of cases. iTEE Doppler parameters correlated with post-TTE parameters, with minimal differences, specially in the MV repair group. The postoperative MPG was +0.4 ± 1 mmHg higher in the MV repair group and +1.0 ± 1.8 mmHg in the MV replacement group. There was global improvement in terms of systolic pulmonary artery pressure, although left ventricular ejection fractions were slightly reduced during the postoperative evaluation.
CONCLUSIONS Our study demonstrates the usefulness of iTEE and its importance in establishing possible reference values for postoperative follow-ups.
The clinical significance of pannus detected on computed tomography (CT) has not yet been investigated. The purposes of this study were to investigate the clinical significance of pannus detected on cardiac CT in patients who underwent aortic valve replacement (AVR) with mechanical valves, and to determine predictors for pannus severity. A total of 92 patients who underwent cardiac CT and TTE and who had undergone mechanical AVR were included. The geometric orifice area (GOA), the presence of limitation of motion (LOM) and pannus were evaluated on CT. The GOA, presence of LOM, and presence and severity of pannus were compared with echocardiographic parameters. Logistic regression analysis was performed to determine the predictors for pannus severity. The GOA on CT positively correlated with effective orifice area on TTE (r = 0.733, P < 0.0001). Pannus was found in 77.2 % and LOM in 14.0 %. With increasing pannus severity, mean transvalvular pressure gradient (PG) was significantly higher (P < 0.0001). Patients with elevated PG showed a smaller GOA, a higher incidence of pannus, more severe pannus and LOM than patients with normal PG (P < 0.05). Small valve size (≤19 mm), Carbomedics valve, rheumatic etiology, and young age at AVR (<48.8 years) were independent predictors of moderate to severe pannus (P < 0.05). Cardiac CT is helpful in the evaluation of pannus formation in patients with mechanical aortic valves. Moderate to severe pannus formation frequently occurred in patients with small mechanical valve size, Carbomedics valves, rheumatic heart disease and young age at AVR.
