Doppler Echocardiographic Assessment of Valvular Regurgitation Severity by Measurement of the Vena Contracta: An In Vitro Validation Study

Sources of Variability in Vena Contracta Area Measurement for Tricuspid Regurgitation Severity Grading: Comparison of Technical Settings and Vendors

BACKGROUND

Previous studies found different cutoffs of vena contracta area (VCA) to define severe tricuspid regurgitation (TR). The aim of this study was to investigate the factors associated with such variability by comparing technical variables and vendors.

METHODS

Sixty-nine patients with scheduled tricuspid surgery were included in this prospective study. For each patient, TR data sets were obtained on three-dimensional color Doppler transthoracic echocardiography on at least two of three systems: GE Vivid E95 (n = 39), Siemens SC2000 Prime (n = 64), and Philips EPIQ 7C (n = 60). VCA was measured using default settings or with color baseline shifted on all three platforms and with minimal color gain (10%-20%) on the GE platform.

RESULTS

Color gain reduction and baseline shift caused significant change sin VCA measurement (-46% and 10%, respectively). Intervendor comparison exhibited wide limits of agreement (narrowest range, -74% to 167%), with either default or optimized settings. Different technical settings, platforms, and reference methods all produced different VCA cutoffs for severe TR.

CONCLUSIONS

VCA measurement in TR is sensitive to technical factors and demonstrates intervendor variability. Technical variables in VCA measurement should be reported in detail to allow comparison among research studies. The same vendor and settings should be used for longitudinal analysis of TR VCA in the same patient in multivendor echocardiography laboratories.

The Mitral/Aortic Flow Velocity Integral Ratio in Mitral Regurgitation

The development of echocardiography was driven, in part, by a need to diagnose mitral regurgitation in patients undergoing finger fracture commissurotomy in the 1950s. Decades later, color Doppler became the cornerstone for noninvasive evaluation of mitral regurgitation. The authors present 2 cases of calcific mitral stenosis in which reliance on color Doppler in transthoracic echocardiography resulted in erroneous conclusions as to the severity of coexisting mitral regurgitation. The possible application of the Mitral to Aortic Flow Velocity Integral Ratio in such cases as a possible adjunct to grading mitral regurgitation is also discussed.

Systolic characteristics and dynamic changes of the mitral valve in different grades of ischemic mitral regurgitation - insights from 3D transesophageal echocardiography

BACKGROUND

Mitral regurgitation in ischemic heart disease (IMR) is a strong predictor of outcome but until now, pathophysiology is not sufficiently understood and treatment is not satisfying. We aimed to systematically evaluate structural and functional mitral valve leaflet and annular characteristics in patients with IMR to determine the differences in geometric and dynamic changes of the MV between significant and mild IMR.

METHODS

Thirty-seven patients with IMR (18 mild (m)MR, 19 significant (moderate+severe) (s)MR) and 33 controls underwent TEE. 3D volumes were analyzed using 3D feature-tracking software.

RESULTS

All IMR patients showed a loss of mitral annular motility and non-planarity, whereas mitral annulus dilation and leaflet enlargement occurred in sMR only. Active-posterior-leaflet-area decreased in early systole in all three groups accompanied by an increase in active-anterior-leaflet-area in early systole in controls and mMR but only in late systole in sMR.

CONCLUSIONS

In addition to a significant enlargement and loss in motility of the MV annulus, patients with significant IMR showed a spatio-temporal alteration of the mitral valve coaptation line due to a delayed increase in active-anterior-leaflet-area. This abnormality is likely to contribute to IMR severity and is worth the evaluation of becoming a parameter for clinical decision-making. Further, addressing the leaflets aiming to increase the active leaflet-area is a promising therapeutic approach for significant IMR. Additional studies with a larger sample size and post-operative assessment are warranted to further validate our findings and help understand the dynamics of the mitral valve.

Real-Time Three-Dimensional Echocardiographic Assessment of Severity of Mitral Regurgitation Using Proximal Isovelocity Surface Area and Vena Contracta Area Method. Lessons We Learned and Clinical Implications

Mitral regurgitation (MR) is considered the most common valve disease with a prevalence of 2-3 % of significant regurgitation (moderate to severe and severe) in the general population. Accurate assessment of the severity of regurgitation was demonstrated to be of significant importance for patient management and prognosis and consequently has been widely recognized in recent guidelines. However, evaluation of severity of valvular regurgitation can be potentially difficult with the largest challenges presenting in cases of mitral regurgitation. Real-time three-dimensional echocardiography (RT3DE) by the use of color Doppler has the potential to overcome the limitations of conventional flow quantification using 2D color Doppler methods. Recent studies validated the application of color Doppler RT3DE for the assessment of flow based on vena contracta area (VCA) and proximal isovelocity surface area (PISA). Particularly, the assessment of VCA by color Doppler RT3DE led to a change of paradigm by understanding the VCA as being strongly asymmetric in the majority of patients and etiologies. In this review, we provide a discussion of the current state of clinical evaluation, limitations, and future perspectives of the two methods and their presentation in recent literature and guidelines.

Planimetric measurement of the regurgitant orifice area using multidetector CT for aortic regurgitation: a comparison with the use of echocardiography

Objective

This study compared the area of the regurgitant orifice, as measured by the use of multidetector-row CT (MDCT), with the severity of aortic regurgitation (AR) as determined by the use of echocardiography for AR.

Materials and Methods

In this study, 45 AR patients underwent electrocardiography-gated 40-slice or 64-slice MDCT and transthoracic or transesophageal echocardiography. We reconstructed CT data sets during mid-systolic to enddiastolic phases in 10% steps (20% and 35-95% of the R-R interval), planimetrically measuring the abnormally opened aortic valve area during diastole on CT reformatted images and comparing the area of the aortic regurgitant orifice (ARO) so measured with the severity of AR, as determined by echocardiography.

Results

In the 14 patients found to have mild AR, the ARO area was 0.18±0.13 cm² (range, 0.04-0.54 cm²). In the 15 moderate AR patients, the ARO area was 0.36 ± 0.23 cm² (range, 0.09-0.81 cm²). In the 16 severe AR patients, the ARO area was 1.00 ± 0.51 cm² (range, 0.23-1.84 cm²). Receiver-operator characteristic curve analysis determined a sensitivity of 85% and a specificity of 82%, for a cutoff of 0.47 cm², to distinguish severe AR from less than severe AR with the use of CT (area under the curve = 0.91; 95% confidence interval, 0.84-1.00; p < 0.001).

Conclusion

Planimetric measurement of the ARO area using MDCT is useful for the quantitative evaluation of the severity of aortic regurgitation.

Direct measurement of proximal isovelocity surface area by real-time three-dimensional color Doppler for quantitation of aortic regurgitant volume: an in vitro validation

OBJECTIVE

The proximal isovelocity surface area (PISA) method is useful in the quantitation of aortic regurgitation (AR). We hypothesized that actual measurement of PISA provided with real-time 3-dimensional (3D) color Doppler yields more accurate regurgitant volumes than those estimated by 2-dimensional (2D) color Doppler PISA.

METHODS

We developed a pulsatile flow model for AR with an imaging chamber in which interchangeable regurgitant orifices with defined shapes and areas were incorporated. An ultrasonic flow meter was used to calculate the reference regurgitant volumes. A total of 29 different flow conditions for 5 orifices with different shapes were tested at a rate of 72 beats/min. 2D PISA was calculated as 2pi r(2), and 3D PISA was measured from 8 equidistant radial planes of the 3D PISA. Regurgitant volume was derived as PISA x aliasing velocity x time velocity integral of AR/peak AR velocity.

RESULTS

Regurgitant volumes by flow meter ranged between 12.6 and 30.6 mL/beat (mean 21.4 +/- 5.5 mL/beat). Regurgitant volumes estimated by 2D PISA correlated well with volumes measured by flow meter (r = 0.69); however, a significant underestimation was observed (y = 0.5x + 0.6). Correlation with flow meter volumes was stronger for 3D PISA-derived regurgitant volumes (r = 0.83); significantly less underestimation of regurgitant volumes was seen, with a regression line close to identity (y = 0.9x + 3.9).

CONCLUSION

Direct measurement of PISA is feasible, without geometric assumptions, using real-time 3D color Doppler. Calculation of aortic regurgitant volumes with 3D color Doppler using this methodology is more accurate than conventional 2D method with hemispheric PISA assumption.

Direct assessment of size and shape of noncircular vena contracta area in functional versus organic mitral regurgitation using real-time three-dimensional echocardiography

BACKGROUND

Vena contracta width (VCW) as an estimate of effective regurgitant orifice area (EROA) is an accepted parameter of mitral regurgitation (MR) severity. However, uncertainty exists in cases in which VCW at the same time appears narrow in 4-chamber (4CH) view and broad in 2-chamber (2CH) view as common in functional MR with noncircular or slit-like regurgitant orifices. We therefore hypothesized that new real-time 3-dimensional color Doppler echocardiography (RT3DE) can be used for direct assessment of the size and shape of vena contracta area (VCA) in an en face view and to determine the potential error of conventional VCW measurement on estimation of EROA.

METHODS

RT3DE was performed in 57 patients with relevant MR of different etiologies. Manual tracing of VCA in a cross-sectional plane through the vena contracta was compared with VCW in 4CH and 2CH views. As a comparative approach to VCA-3D, EROA was calculated using the hemispheric and hemielliptic proximal isovelocity surface (PISA) area method.

RESULTS

Direct measurement of VCA-3D was feasible in all patients within 2.6 +/- 0.7 minutes. RT3DE revealed significant asymmetry of VCA in functional compared with organic MR (P < .001). Among all patients, VCW-4CH and VCW-2CH correlated only moderately to VCA-3D (r =.77; r =.80). Mean VCW correlated and agreed best with VCA-3D (r =.90). VCA-3D correlated and agreed well with EROA by hemielliptic PISA (r = .96, mean error: -0.09 +/- 0.14 cm(2)) compared with significant underestimation of hemispheric PISA in noncircular lesions.

CONCLUSIONS

Direct assessment of VCA using RT3DE revealed significant asymmetry of VCA in functional MR compared with organic MR, resulting in poor estimation of EROA by single VCW measurements.

Diagnostic Value of Color Flow Mapping and Doppler Echocardiography in the Quantification of Mitral Regurgitation in Patients with Mitral Valve Prolapse or Rheumatic Heart Disease

OBJECTIVES

The objective was to analyze the diagnostic value of the echocardiographic methods used for quantification of mitral regurgitation (MR) in patients with mitral valve prolapse (MVP) or rheumatic heart disease (RHD).

METHODS

The study included 50 patients with MR (mean age of 46.1 years; 35 women), 27 (54%) with RHD and 23 (46%) with MVP. Quantification of the mitral valve regurgitation was obtained by regurgitant orifice area (ROA) and regurgitant volume (RV) by the flow convergence region (FCR) and two-dimensional Doppler echocardiographic methods, regurgitant fraction, jet area (JA), jet area/left atrial area ratio (JA/LAA), and vena contracta (VC). Patients were clinically followed to identify cardiovascular events. Data were analyzed by Pearson, kappa, and receiver operator characteristic curve tests; significance was defined as a P value less than .05.

RESULTS

The correlation between the two methods for ROA and RV were r = 0.79 and r = 0.80, respectively, and between these parameters and regurgitant fraction, VC, JA, and JA/LAA varied from r = 0.54 to r = 0.94 (P lt; .05); the agreement varied from kappa = 0.19 to kappa = 0.83. The highest accuracy to identify patients with clinically significant MR (events at follow-up) was 96% for ROA by FCR, 94% for VC, 86% for RV by FCR, and 86% for JA. No method showed a significant difference between MVP and RHD.

CONCLUSIONS

The methods analyzed had significant correlation and good agreement. ROA by FCR and VC had the best performance to identify severe MR; no significant difference between MVP and RHD was observed.

64-Slice Multidetector Computed Tomography (MDCT) for Detection of Aortic Regurgitation and Quantification of Severity

BACKGROUND

Recent advances in 64-slice multidetector computed tomography (MDCT) provide an opportunity to assess coronary artery disease, left ventricular function and, potentially, valvular heart disease.

OBJECTIVE

To determine the ability of 64-MDCT to both detect and to quantify the severity of aortic regurgitation (AR), as compared with transthoracic echocardiography (TTE).

METHODS

We evaluated a total of 64 patients (43 males, mean age 63+/-11 years), 30 with varying severities of AR as assessed by TTE and 34 matched controls. The severity of AR by TTE was determined using the vena contracta, the ratio of jet to left ventricular outflow tract (LVOT) height, and the ratio of the jet to LVOT cross-sectional area. AR by MDCT was defined as a lack of coaptation of the aortic valve leaflets in diastole and, if detected, the maximum anatomic aortic regurgitant orifice was determined.

RESULTS

All 34 control patients without AR were correctly identified by MDCT. There were 14 patients with mild AR, 10 with moderate AR, and 6 with severe AR by TTE. Of these patients, MDCT correctly identified 21 patients with AR (sensitivity 70%, specificity 100%, positive predictive value [PPV] 100%, and negative predictive value [NPV] 79%). Anatomic regurgitant orifice area measured by MDCT correlated well with the TTE-derived vena contracta (r=0.79, P<0.001), ratio of jet to LVOT height (r=0.79, P<0.001), and ratio of jet to LVOT cross-sectional area (r=0.75, P<0.001).

CONCLUSIONS

Direct planimetric measurement of the aortic valve anatomic regurgitant orifice area on 64-MDCT provides an accurate, noninvasive technique for detecting and quantifying AR.