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(A) Example of locally present colour flow aliasing at Nyquist limit of 0.48 m/s in the middle RCA (mRCA), located on the right atrioventricular sulcus in a modified subcostal sagittal view, suggestive of stenosis. (B) QCA shows mRCA stenosis (DS, 63%). L, liver; QCA, quantitative coronary angiography; RA, right atrium; TR, tricuspid ring
Source publication
Our aim was to determine the feasibility and accuracy of diagnosing significant coronary artery stenoses using peak stenotic to prestenotic velocity ratio (pSPVR) measurements when compared with results from quantitative coronary angiography and coronary flow velocity reserve (CFVR) assessed by transthoracic echocardiography (TTE).
One hundred and...
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Background: The underuse of invasive fraction flow reserve (FFR) in clinical practice has motivated research towards its non-invasive prediction. The early attempts relied on solving the incompressible three-dimensional Navier–Stokes equations in segmented coronary arteries. However, transient boundary condition has a high resource intensity in ter...
Citations
... This was confirmed by a validation study of E-Doppler TTE vs. FFR in which the BFV % increase cutoff that best predicted an FFR <0.8 was a value >123%, very close to that found in this study (109%) (26). These cutoff data were also precisely confirmed by a different group that found a stenotic to prestenotic velocity ratio of ≥2.2 (120% increment of velocity), as the cut-off value for critical stenoses in coronaries by transthoracic Doppler (45). ...
... RVOT, right ventricular outflow tract; AO, aorta; PV, pulmonary valve; AsF, accelerated stenotic flow. applicability of the method, and in any case, the CFR was not measured (13,45,47,48). Other more recent studies have shown that CFR in the LAD can give added prognostic value to either stress-induced wall motion abnormalities, as assessed by stress echo, or a perfusion defect, as assessed by SPECT studies (49,50). ...
Background
Accelerated stenotic flow (AsF) in the entire left anterior descending coronary artery (LAD), assessed by transthoracic enhanced color Doppler (E-Doppler TTE), can reveal coronary stenosis (CS) and its severity, enabling a distinction between the microcirculatory and epicardial causes of coronary flow reserve (CFR) impairment.
Methods
Eighty-four consecutive patients with a CFR <2.0 (1.5 ± 0.4), as assessed by E-Doppler TTE, scheduled for coronary angiography (CA) and eventually intracoronary ultrasounds (IVUS), were studied. CFR was calculated by the ratio of peak diastolic flow velocities: during i.v. adenosine (140 mcg/Kg/m) over resting; AsF was calculated as the percentage increase of localized maximal velocity in relation to a reference velocity.
Results
CA showed ≥50% lumen diameter narrowing of the LAD (critical CS) in 68% of patients (57/84) vs. non-critical CS in 32% (27/84). Based on the established CA/IVUS criteria, the non-critical CS subgroup was further subdivided into 2 groups: subcritical/diffuse [16/27 pts (57%)] and no atherosclerosis [11/27 pts (43%)]. CFR was similar in the three groups: 1.4 ± 0.3 in critical CS, 1.5 ± 0.4 in subcritical/diffuse CS, and 1.6 ± 0.4 in no atherosclerosis ( p = ns). Overall, at least one segment of accelerated stenotic flow in the LAD was found in 73 patients (87%), while in 11 (13%) it was not. The AsF was very predictive of coronary segmental narrowing in both angio subgroups of atherosclerosis but as expected with the usage of different cutoffs. On the basis of the ROC curve, the optimal cutoff was 109% and 16% AsF % increment to successfully distinguish critical from non-critical CS (area under the curve [AUC] = 0.99, p < 0.001) and diffuse/subcritical from no CS (AUC = 0.91%, p < 0.001). Sensitivity and specificity were 96% and 100% and 82% and 100%, respectively.
Conclusion
E-Doppler TTE is highly feasible and reliable in detecting the CS of any grade of severity, distinguishing epicardial athero from microvascular causes of a severe CFR reduction.
... Functional assessment is a superior way to evaluate stenosis, with very important clinical implications. This basically consists of Doppler recording the transtenotic velocity and normalizing it to a velocity reference [2]. Velocity measurements can allow quantitation of the stenosis (% cross-sectional area reduction) by applying the continuity equation (C-Eq) [3][4][5][6][7][8][9]. ...
Background:
To verify whether the severity of coronary stenosis could be non-invasively assessed by enhanced transthoracic coronary echo Doppler in convergent color Doppler mode (E-Doppler TTE) over a wide range of values (from mild to severe).
Methods:
Color-guided pulsed wave Doppler sampling in the left anterior descending coronary artery (LAD) was performed in 103 diseased LAD segments (corresponding to 94 patients examined) as assessed by quantitative coronary angiography (QCA) or intracoronary ultrasound (IVUS). The E-Doppler TTE examinations consisted of measuring the velocity (vel) at the stenosis site and a reference adjacent segment. Then the continuity equation (C-Eq) was applied to calculate the percent cross-sectional area reduction (%CSA) at the stenosis site. The applied formula was: %CSA = 100 × (1 - [TVIref × 0.5]/TVIs). TVI = the time velocity integral at the stenosis [s] and the reference site [ref], respectively); 0.5 = the correcting factor for a parabolic profile was used only when the % accelerated stenotic flow was >122% (AsF = diastolic peak vel at first site - diastolic peak vel at second site/diastolic peak vel at second site × 100).
Results:
E-Doppler TTE feasibility was 100%. Doppler and QCA/IVUS-derived %CSA stenosis showed very good agreement over a large range of values (from mild to severe), with no significant bias; the maximum difference between QCA/IVUS and transthoracic Doppler %CSA was mostly around 20% with a few patients exceeding this limit (limits of agreement = -27.53 to 23.5%). The scattering was slightly larger for the non-significant stenoses. The correlation was strong (r = 0.89, p < 0.001).
Conclusion:
E-Doppler TTE is a feasible and reliable method for assessing the severity of LAD stenosis by applying the C-Eq.
... In this study, thanks to HR lowering in patients with no flow or minimal suboptimal flow detected at baseline, we were able to record flow to the extent that different grades of AsF (from mild to severe) were also recorded and quantified. These perfectly predicated, in terms of the severity and location, the epicardial atherosclerosis involvement as assessed by angiography (Table 3) [2][3][4]27]. Therefore, the coronary flow Doppler recording is improved to the extent that abnormality of flow can be recorded well enough to properly predict the angiographic coronary abnormality. ...
Background: Coronary blood flow Doppler recording by Transthoracic Doppler in con-vergent mode (E-Doppler TTE) might be further improved by lowering heart rate (HRL) down to <60 bpm, since low HR < 60 b/m causes a disproportional lengthening of the diastole, so the coronaries are still for a longer time, very much improving the Doppler signal/noise ratio. Methods: A group of 26 patients underwent E-Doppler TTE before and after HR lowering in four branches of the coronary tree, namely, the left main (LMCA); left anterior descending (LAD), subdivided into three segments: proximal, mid and distal; proximal left circumflex (LCx); and obtuse marginal (OM). Color and PW coronary Doppler signal was judged by two expert observers as undetectable (SCORE 1), weak or with clutter artifacts (SCORE 2), or well delineated (SCORE 3). In addition, local accelerated stenotic flow (AsF) was measured in the LAD before and after HRL. Results: Beta -blockers significantly decreased the mean HR from 76 ± 5 to 57 ± 6 bpm (p < 0.001). Before HRL, the Doppler quality was very poor in the proximal and mid-LAD segments (median score value = 1 in both), while in the distal LAD, it was significantly better but still suboptimal (median score value = 1.5, p = 0.009 vs. proximal and mid-LAD score). After HRL, blood flow Doppler recording in the three LAD segments was strikingly improved (median score value = 3, 3 and 3, p = ns), so the effect of HRL was more efficacious in the two more proximal LAD segments. In 10 patients undergoing coronary angiography (CA), no AsF as expression of transtenotic velocity was detected at baseline. After HRL, thanks to the better quality and length of color flow, ASF was detected in five patients while in five others, it was not in perfect agreement with CA (Spearman correlation coefficient = 1, p < 0.01). The color flow in the proximal LCx and OM was extremely poor at baseline (color flow length 0 and 0, median (interquartile range) mm, respectively) and improved considerably after HRL (color flow length 23 [13.5] and 25 [12.0] mm, respectively, p < 0.001). Conclusions: HRL greatly improved the success rate of blood flow Doppler recording in coronaries, not only in the LAD, but also in the LCx. Therefore, AsF for stenosis detection and coronary flow reserve assessment can have wider clinical applications. However, further studies with larger samples are needed to confirm these results. Keywords: coronary blood flow Doppler recording; coronary flow reserve; left circumflex blood flow Doppler recording; enhanced transthoracic Doppler; left anterior descending coronary artery; lowering heart rate
... These technical advances are crucially important since coronary flow, and in particular, transtenotic coronary flow velocity are difficult signals to record, being weak intensity and low velocity signals coming from moving coronaries that can be only intermittently insonified, so easily cluttered by the high intensity tissue noise (both cardiac and lung) [7]. The technical advances used in this case and recently validated [5], take over both the previously proposed ones based on contrast enhancement along with second harmonic Doppler technology [14], and the more popular technique based on having a good Doppler technology (i.e., the Doppler module present in the machines Sequoia, Siemens, or in Vivid 7, GE) set basically with a low pulse repetition frequency that, however, works only in very selected "good chest" with relatively low heart rate [22][23][24]. ...
We report the case of a 71-year-old patient with many risk factors for coronary atherosclerosis, who underwent computed coronary angiography (CTA), in accordance with the guidelines, for recent onset atypical chest pain. CTA revealed critical (>50% lumen diameter narrowing) stenosis of the proximal anterior descending coronary, and the patient was scheduled for invasive coronary angiography (ICA). Before ICA he underwent enhanced transthoracic echo-Doppler (E-Doppler TTE) for coronary flow detection by color-guided pulsed-wave Doppler recording of the left main (LMCA) and whole left anterior descending coronary artery (LAD,) along with coronary flow reserve (CFR) in the distal LAD calculated as the ratio, of peak flow velocity during i.v. adenosine (140 mcg/Kg/m) to resting flow velocity. E-Doppler TTE mapping revealed only mild stenosis (28% area narrowing) of the mid LAD and a CFR of 3.20, in perfect agreement with the color mapping showing no flow limiting stenosis in the LMCA and LAD. ICA revealed only a very mild stenosis in the mid LAD and mild atherosclerosis in the other coronaries (intimal irregularities). Thus, coronary stenosis was better predicted by E-Doppler TTE than by CTA. Coronary flow and reserve as assessed by E-Doppler TTE trumps coronary anatomy as assessed by CTA, without exposing the patient to harmful radiation and iodinated contrast medium.
... TTDE can be performed quickly and efficiently making it a possible routine echocardiography [8][9][10]. Recently, several studies have demonstrated the feasibility and usefulness for the detection of significant proximal LCA stenosis by measuring only the CFV at rest using TTDE in hemodynamically stable patients with coronary artery disease [6,8,9,11,12]. ...
... Thus far, an increased CFV in the proximal LCA has been associated with a lesion in the proximal LCA [6,[8][9][10][11], but an association with the prognosis has been uncertain. The following mechanisms can be considered from the present results to explain the association. ...
... First, the proximal LCA lesion has been reported to be fatal because it limits coronary flow for a large part of the myocardium, resulting in broad myocardial ischemia [2][3][4]20]. Similar with previous studies, [8][9][10][11][12] an increased CFV in the proximal LCA was significantly associated with stenosis in the proximal LCA of the CAG in this study. ...
Background:
Lesions in the proximal left coronary artery (LCA) are associated with a poor prognosis compared with other lesional sites. Transthoracic Doppler echocardiography (TTDE) can help to detect proximal LCA flow, and an accelerated coronary flow velocity (CFV) indicates the presence of proximal LCA lesions. This study aimed to investigate the prognostic value of CFV in the proximal LCA measured by TTDE.
Methods:
We enrolled 1472 consecutive hemodynamically stable patients with known or suspected heart disease whose CFV was successfully detected using TTDE accompanied by routine echocardiography between 2008 and 2011. The primary outcome was cardiac death (acute myocardial infarction, heart failure, or sudden cardiac death) and patients were followed up over a median of 6.3 years.
Results:
Overall, 42 cardiac deaths (3%) were observed. An increased CFV was significantly associated with the outcome in several models based on potential confounders (age, rate pressure product, Framingham Risk Score, diabetes, coronary artery disease, hemoglobin, brain natriuretic peptide, estimated glomerular filtration rate, left ventricular mass, left ventricular ejection fraction, and E/e'). Using a receiver operating characteristic curve analysis, the optimal cut-off value for the CFV to the association of the outcome was 37 cm/s (area under the curve, 0.70; sensitivity, 82%; specificity, 62%). In sequential Cox proportional hazards models, the CFV added incremental prognostic information to the clinical and basic echocardiographic parameters (chi-squared: 110.7 to 146.6, P < 0.01).
Conclusions:
An increased CFV in the proximal LCA was associated with cardiac death, incremental to the clinical and basic echocardiographic parameters.
... Transthoracic measurements of coronary flow velocity have proved to be highly reproducible and to correlate with invasive measurements (Hildick-Smith et al. 2002;Ueno et al. 2002). A number of previous studies have reported a significant correlation between high local velocities of coronary flow measured by rest Doppler echocardiography and significant stenoses measured by coronary angiography (Accadia et al. 2006;Anjaneyulu et al. 2008;Higashi et al. 2013;Holte et al. 2015;Krzanowski et al. 2000;Moreo et al. 2015;Rigo and Caprioglio 2015;Saraste et al. 2005). However, the value of this useful method as a routine procedure that would permit diagnosis of coronary artery stenoses during routine echocardiography is still underestimated. ...
... Contemporary non-invasive imaging of coronary arteries by transthoracic echocardiography is an emerging diagnostic tool used to study flow in left-sided arteries with high feasibility and reproducibility (Boshchenko et al. 2011;Hildick-Smith et al. 2002;Holte et al. 2015;Krzanowski et al. 2003;Michelsen et al. 2016;Saraste et al. 2005;Vegsundvåg et al. 2009). Direct visualization of segments of the coronary arteries with measurement of their velocity parameters may help in diagnosing significant coronary artery stenoses (Accadia et al. 2006;Anjaneyulu et al. 2008;Boshchenko et al. 2011;Higashi et al. 2013;Holte et al. 2015;Krzanowski et al. 2000;Rigo and Caprioglio 2015;Saraste et al. 2005). ...
... Contemporary non-invasive imaging of coronary arteries by transthoracic echocardiography is an emerging diagnostic tool used to study flow in left-sided arteries with high feasibility and reproducibility (Boshchenko et al. 2011;Hildick-Smith et al. 2002;Holte et al. 2015;Krzanowski et al. 2003;Michelsen et al. 2016;Saraste et al. 2005;Vegsundvåg et al. 2009). Direct visualization of segments of the coronary arteries with measurement of their velocity parameters may help in diagnosing significant coronary artery stenoses (Accadia et al. 2006;Anjaneyulu et al. 2008;Boshchenko et al. 2011;Higashi et al. 2013;Holte et al. 2015;Krzanowski et al. 2000;Rigo and Caprioglio 2015;Saraste et al. 2005). This study revealed the prognostic value of high local velocity in the arteries. ...
There is a lack of information on the prognostic value of local high velocity in coronary arteries during echocardiography. The aim of the study described here was to define the prognostic value of local velocity >70 cm/s in the left main, anterior or circumflex artery during echocardiography. There were 412 patients in the prospective study. Death, non-fatal myocardial infarction, acute pulmonary edema, acute coronary syndrome and revascularization were defined as major adverse cardiac events (MACEs). Over 10.5 mo, there were 207 patients with MACEs. Seventeen patients died, 10 had non-fatal acute cardiac events and 184 underwent revascularization. Deaths occurred in patients with high local velocity (6.4% vs. 0%, p <0.009). Acute cardiac events occurred in 10% versus 0% (p <0.003). MACEs were observed in 62% versus 0% (p <0.0000001). Only maximal velocity was an independent prognostic predictor of death (odds ratio = 1.02, 95% confidence interval: 1.01-1.03, p <0.02) and MACEs (odds ratio = 1.04, 95% confidence interval: 1.02-1.05, p <0.0001). The success rate of coronary artery visualization for at least one segment was 91%.
... This technology is mainly used for defining tissue-of-interests (e.g. endocardial border [20], left ventricular thrombi [21]) and for echocardiographic measurement (e.g. left ventricular volume [22]), but it can be additionally utilized for coronary evaluation. ...
... Doppler US was initially found of value for a functional assessment of, particularly, coronary flow reserve [20]. This early study was followed by more detailed investigations until, very recently Versundsvag et al., after localization of the three main coronaries by US, determined peak systolic flow velocities by Doppler [21]. The determination of the stenotic to prestenotic velocity ratios and color aliasing, allowed to obtain high sensitivity in the diagnosis of stenoses of the LM and LAD, not in the Cx and RCA. ...
The growing need for coronary evaluation has raised interest in non-radioactive, non-invasive monitoring systems. In particular, radiation exposure during coronary investigations has been shown to be a possible cause of an enhanced risk of secondary tumors. Literature search has indicated that transthoracic echocardiography (TTE) has been widely applied to coronary arteries up to 2003, following which the lack of adequate equipment and the increased availability of invasive diagnostics, has reduced interest in this low cost, low-risk technology. The more recent availability of newer, more sensitive machines, allows evaluation of a larger number of arterial trees, including the aorta in newborns, the prenatal aortic intima-media thickness, as well as the detection of coronary artery anomalies in the adult. Improved technology for this highly operator sensitive technique may thus predict a possible evolution toward the clinical diagnostics of coronary disease and, eventually, also of the progression/regression of disease. We sought to evaluate the present status of this seldom quoted non-invasive technology.
... 9 This extraordinary new opportunity of evaluating a coronary flow functionally and non-invasively had a great impact on patient outcomes. 9,10 Starting from this pathophysiological concept, Dr Holte et al. 11 has published an interesting non-invasive experience on the assessment of coronary disease, highlighting a new parameter that represents the expression of transstenotic flow velocity and seems to be a good predictor of coronary artery narrowing. These authors combined findings of pSPVR ≥2.0 and mosaic flow at Nyquist limit ≥0.48 m/s; the sensitivity and specificity of demonstrating significant stenoses in the LM, LAD, Cx, and RCA were 75 and 98%, 74 and 95%, 40 and 87%, and 34 and 98%, respectively. ...
About 40 years ago, K. Lance Gould proposed the concept of coronary flow reserve (CFR) to quantify the effect of epicardial narrowings on myocardial blood flow reserve in animal models,1 experiments that still constitute the basis of our understanding of coronary physiology. The development of flow velocity catheters,2,3 progress in positron emission tomography-derived absolute flow measurements,4 and, more recently, transthoracic Doppler flow velocity measurements4 extended Gould's findings into patients with coronary artery disease. Until the development of the concept of fractional flow reserve,4,5 CFR was the only index commonly used in the clinical field, enabling us/doctors/practitioners to quantify flow limitation due to a plaque. Yet the main problem with CFR in clinical practice resides in its lack of specificity for the epicardial vessel: an excessively low CFR …
Aim
To explore the feasibility and value of transthoracic echocardiography (TTE) postprocessing subtraction technique in the detection of a stent in the coronary artery.
Method
Transthoracic echocardiography was used to examine 46 coronary artery stents in 30 patients by two‐dimensional ultrasound postprocessing subtraction technique. The shape of each stent and its flow patency were observed. The patency was assessed according to blood flow and mosaic flow in the stent. Then, the results were compared with those of percutaneous coronary intervention (PCI) records and coronary angiography (CAG).
Results
Transthoracic echocardiography detected 36 stents among 46 stents (two in the LMCA, 23 in the LAD, seven in the RCA, and two in the LCX); the detection rate was 78.3%. The average length of the stents was 21.8 ± 4.1 mm, and the average diameter was 2.4 ± 0.5 mm; both are shorter than those from PCI records (P < .001). Of the 36 stents, blood flow could be observed in 27. Compared with the results of CAG, TTE had 75% feasibility and 92.6% accuracy in detecting flow patency in the stents.
Conclusion
Transthoracic echocardiography postprocessing subtraction technique could be a noninvasive method for detecting a coronary artery stent and, although the measurements of stent length and diameter were shorter than those of PCI records, an accurate detection of flow patency in the stents was achieved.
Echocardiography of coronary arteries is challenging, however current high–end systems offer sufficient quality for several clinically relevant applications of the method. Transesophageal echocardiography allows the imaging of proximal coronary arteries with high quality and power to detect stenotic flow. Transthoracic imaging of coronary ostia is feasible to define anomalous coronary arteries and other congenital abnormalities. This approach is also used for recording of distal coronary flow at rest and during vasodilator administration to calculate coronary flow reserve. Transthoracic detection of coronary stenosis is strongly dependent on acoustic window but is very specific based on the finding localized high velocity diastolic flow.
