Adjacent solid boundaries alter the size of regurgitant jets on Doppler color flow maps

Impact of measurement location on direct mitral regurgitation quantification using four-dimensional flow cardiovascular magnetic resonance

BACKGROUND

Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) shows promise for quantifying mitral regurgitation (MR) by allowing for direct regurgitant volume (RVol) measurement using a plane precisely placed at the MR jet. However, the ideal location of a measurement plane remains unclear. This study aims to systematically examine how varying measurement locations affect RVol quantification and determine the optimal location using the momentum conservation principle of a free jet.

METHODS

Patients diagnosed with MR by transthoracic echocardiography (TTE) and scheduled for CMR were prospectively recruited. Regurgitant jet flow volume (RVoljet) and regurgitant jet flow momentum (RMomjet) were quantified using 4D flow CMR at seven locations along the jet axis, x. The reference plane (mid-plane, x = 0 mm) was positioned at the peak velocity of the jet at each cardiac phase, and three additional planes were positioned on either side of the jet, each 2.5 mm apart. RVoljet was compared to RVolTTE, measured by the proximal isovelocity surface area method, and RVolindirect, measured by subtracting aortic forward flow volume from the left ventricle stroke volume derived from two-dimensional phase contrast at the aortic valve and a stack of short-axis cine CMR techniques.

RESULTS

RVoljet and RMomjet were quantified in 45 patients (age 63±13, male 26). In patients with RVoljet at x = 0 mm ≥ 10 mL (n = 25), RVoljet consistently increased as the plane moved downstream. RVoljet measured furthest upstream (x = -7.5 mm) was significantly lower (39±11%, p<0.001) and RVoljet measured furthest downstream (x = 7.5 mm) was significantly higher (16±19%, p<0.001) than RVoljet at x = 0 mm. RMomjet similarly increased from x = -7.5 to 0 mm (57±12%, p<0.001) but stabilized from x = 0-7.5 mm (-2±17%). From x = -7.5 to 7.5 mm, RVoljet was in consistent moderate agreement with RVolindirect (n = 41, bias = -2±24 to 8±32 mL, intraclass correlation coefficient = 0.55-0.63, p<0.001).

CONCLUSION

The location of a measurement plane significantly influences RVol quantification using the direct 4D flow CMR approach. Based on the converging profile of RMomjet, we propose the peak velocity of the jet as the optimal position.

Utilization of Engineering Advances for Detailed Biomechanical Characterization of the Mitral-Ventricular Relationship to Optimize Repair Strategies: A Comprehensive Review

The geometrical details and biomechanical relationships of the mitral valve-left ventricular apparatus are very complex and have posed as an area of research interest for decades. These characteristics play a major role in identifying and perfecting the optimal approaches to treat diseases of this system when the restoration of biomechanical and mechano-biological conditions becomes the main target. Over the years, engineering approaches have helped to revolutionize the field in this regard. Furthermore, advanced modelling modalities have contributed greatly to the development of novel devices and less invasive strategies. This article provides an overview and narrative of the evolution of mitral valve therapy with special focus on two diseases frequently encountered by cardiac surgeons and interventional cardiologists: ischemic and degenerative mitral regurgitation.

Quantitative assessment of aortic regurgitation following transcatheter aortic valve replacement

Introduction: Transcatheter aortic valve replacement (TAVR) is expanding to lower risk and younger patients with severe symptomatic aortic valve disease. Despite clinical and technological improvements, post-procedural aortic regurgitation (AR) remains a limitation of TAVR, particularly when compared to surgical aortic valve replacement. Although several methods for AR quantification after TAVR are currently available, its exact graduation in everyday clinical practice remains challenging.Areas covered: This review describes the currently available evaluation methods of AR after TAVR, with a special emphasis on the quantitative assessment using videodensitometric angiography, echocardiography and cardiac magnetic resonance imaging.Expert opinion: In the majority of clinical scenarios, satisfactory evaluation of post-TAVR AR can be achieved with a combination of post-procedural angiography, hemodynamic indices and transthoracic echocardiography. Nevertheless, some TAVR patients show 'intermediate' forms of post-procedural AR, in which quantitative evaluation is mandatory for prognostic purposes and further decision-making. Notably, interpretation of quantitative measures early post-TAVR is challenging because of the lack of left ventricular enlargement. Video-densitometric angiography is an emerging method that appears to be clinically attractive for immediate post-TAVR assessment, but requires further validation in everyday clinical practice.

Etiology of Atrial Functional Mitral Regurgitation: Insights from Transthoracic Echocardiography in 159 Consecutive Patients with Atrial Fibrillation and Preserved Left Ventricular Ejection Fraction

BACKGROUND

Left atrial (LA) dilatation in patients with atrial fibrillation (AF) can induce functional mitral regurgitation (MR) despite a preserved left ventricular ejection fraction (LVEF). The purpose of this study was to investigate the etiology of this functional MR.

METHODS

We retrospectively examined clinical and echocardiographic data from 5,202 consecutive cases that underwent transthoracic echocardiography. AF appeared in 544 patients, and we selected 159 with AF and LVEF ≥50% after excluding patients with other underlying heart diseases.

RESULTS

Significant (moderate or greater) degrees of functional MR were seen in 13 (8.2%) patients and were more frequently seen in patients with an AF duration of >10 years than in others (27 vs. 4%, p = 0.0057). Multiple regression analysis revealed that both the LA dimension index and the left ventricular (LV) systolic dimension index were independent determinants of the MR grading. Among the mitral morphologic parameters, the mitral annular (MA) dimension index and the hamstringing phenomenon of the posterior mitral leaflet were independent determinants of MR grading. Significant MR was not seen in patients without LA dilatations, but it occurred in 14% of patients with LA dilatation alone and in 55% with both LA and LV dilatations; the MA dimension index increased in this order.

CONCLUSIONS

The grading of functional MR occurring in patients with AF and preserved LVEF depends on both the LA dimension and the LV systolic dimension. The MR grading also depends on both the MA dilatation and the hamstringing phenomenon of the posterior mitral leaflet.

Rationale and design of the Edwards SAPIEN-3 periprosthetic leakage evaluation versus Medtronic CoreValve in transfemoral aortic valve implantation (ELECT) trial : A randomised comparison of balloon-expandable versus self-expanding transcatheter aortic valve prostheses

Background and objectives

Periprosthetic aortic regurgitation (PPR) after transcatheter aortic valve implantation (TAVI) remains an important issue associated with impaired long-term outcomes. The current randomised study aims to evaluate potential differences between the balloon-expandable Edwards SAPIEN-3 and the self-expanding Medtronic CoreValve system with the main focus on post-TAVI PPR by means of novel imaging endpoints, and an additional focus on other clinical endpoints.

Endpoints

The primary endpoint of this study is quantitative assessment of the severity of post-procedural PPR using cardiac magnetic resonance imaging. Several other novel imaging modalities (X-ray contrast angiography, echocardiography) are used as secondary imaging modalities for the assessment of PPR following TAVI. Secondary objectives of the study include clinical outcomes such as cerebral and kidney injury related to TAVI, and quality of life.

Methods and design

The ELECT study is a single-centre, prospective, two-armed randomised controlled trial. For the purpose of this study, 108 consecutive adult patients suitable for transfemoral TAVI will be randomly allocated to receive the SAPIEN-3 (n = 54) or the CoreValve system (n = 54).

Discussion

The ELECT trial is the first randomised controlled trial to quantitatively compare the extent of post-TAVI PPR between the SAPIEN-3 and CoreValve. Furthermore, it will evaluate potential differences between the two prostheses with regard to mid-term clinical outcome and quality of life.

[A history of the clinical research in cardiology]

On January 21 1968, nearly an half-century ago, a small Parisian group of cardiologists presented a directional Doppler prototype making possible the detection of forward and backward flows in the arteries. This princeps report, rapidly followed by the Directional Doppler recording of intracardiac flows, has upset the traditional approach to cardiovascular pathophysiology and launched a new examination method that will spread upon the whole word. Single CNRS researcher among this group of clinical cardiologists, Dr Colette Veyrat recalls this early period….

Timing of Surgical Intervention for Aortic Regurgitation

OPINION STATEMENT

Aortic regurgitation is a frequently encountered condition, in which traditional measurements of severity have proven to be of limited value in identifying those who would be best served by aortic valve replacement. Novel methods of assessing severity are vital, particularly as an entirely new paradigm of aortic regurgitation has surfaced, with the advent of transcatheter aortic valve replacement (TAVR), and the adverse events that are being observed with varying degrees of aortic regurgitation. With that in mind, a comprehensive assessment of aortic regurgitation should now include indexed left ventricular systolic volumes and a comprehensive assessment of right ventricular function, in addition to the quantitative measures that are currently recommended. Cardiac MRI also provides valuable information and should be strongly considered, particularly in challenging cases. The incremental value of additional echocardiographic parameters such as strain imaging, speckle tracking imaging, and tissue Doppler imaging remains unclear, and evidence for their utility is not, as yet, compelling. However, the field of aortic regurgitation assessment has been reinvigorated by the prevalence of paravalvular regurgitation post-TAVR, and many of the abovementioned parameters may need to be re-visited so that we can more accurately determine prognosis and risk stratify patients in a more reliable and evidence-based manner.

Outcome of Significant Functional Tricuspid Regurgitation Late After Mitral Valve Replacement for Predominant Rheumatic Mitral Stenosis

Significant tricuspid regurgitation (TR) can contribute to increased morbidity and mortality in patients undergoing mitral valve surgery for mitral stenosis. The aim of this study was to evaluate the association between the severity of preoperative functional TR and late adverse outcomes in patients undergoing mitral valve replacement (MVR). The study group comprised 68 patients (54 women, 14 men; mean age 45 ±10 years) with rheumatic mitral stenosis (MS) who had undergone MVR without tricuspid valve surgery between 4 and 13 years (mean 8.1 ±2.6 years) before their last clinical examination. All patients underwent a complete preoperative and late postoperative color-Doppler echocardiographic examination. The severity of TR was assessed echocardiographically by using color-Doppler flow images and flow direction in the inferior vena cava or hepatic veins. Patients were classified into 2 groups; 42 with mild (62%) and 26 with significant (38%) TR. Patients with significant TR showed longer preoperative symptomatic period and more atrial fibrillation than those with mild TR. All patients had medical treatment. Functional capacity and NYHA class of the patients in both groups improved significantly after MVR. Freedom from symptomatic heart failure (functional class III or IV) was higher (86% vs 54%) and the need for hospitalization was significantly lower for the mild TR group. Significant preoperative functional TR diagnosed by echocardiography was associated with an adverse outcome. Therefore, further studies are needed to evaluate the effect of concomitant tricuspid valve repair on the late outcome of patients undergoing mitral valve surgery in order to prevent significant late morbidity.

Interventional imaging: the role of echocardiography

Interventional echocardiography is a rapidly evolving field requiring imaging expertise. An increasing number of structural heart interventions now require real-time imaging guidance for device placement and immediate functional evaluation. Continuous 2- and 3-dimensional transesophageal echocardiography are now required by many heart teams during complex structural interventions, including percutaneous closure of atrial septal defects, left atrial appendage occlusion, transcatheter aortic valve replacement (TAVR), transcatheter repair of paravalvular regurgitation, and percutaneous mitral valve repair. In this review, we describe the role of echocardiography during the initial structural evaluation, throughout the device placement procedure, and for the assessment of acute device function and complications.

Proximal isovelocity surface area by single-beat three-dimensional color Doppler echocardiography applied for tricuspid regurgitation quantification

BACKGROUND

The two-dimensional (2D) proximal isovelocity surface area (PISA) method has known technical limitations, mainly the geometric assumptions of PISA shape required to calculate effective regurgitant orifice area (EROA). Recently developed single-beat real-time three-dimensional (3D) color Doppler imaging allows the direct measurement of PISA without geometric assumptions and has already been validated for mitral regurgitation assessment. The aim of this study was to apply this novel method in patients with chronic tricuspid regurgitation (TR).

METHODS

Ninety patients with chronic TR were enrolled. EROA and regurgitant volume (Rvol) were assessed using transthoracic 2D and 3D PISA methods. Quantitative Doppler and 3D transthoracic planimetry of EROA were used as reference methods.

RESULTS

Both EROA and Rvol assessed using the 3D PISA method had better correlations with the reference methods than using conventional 2D PISA, particularly in the assessment of eccentric jets. On the basis of 3D planimetry-derived EROA, 35 patients had severe TR (EROA ≥ 0.4 cm(2)). Among these 35 patients, 25.7% (n = 9) were underestimated as having nonsevere TR (EROA ≤ 0.4 cm(2)) using the 2D PISA method. In contrast, the 3D PISA method had 94.3% agreement (33 of 35) with 3D planimetry in classifying severe TR. Good intraobserver and interobserver agreement for 3D PISA measurements was observed, with intraclass correlation coefficients of 0.92 and 0.88 respectively.

CONCLUSIONS

TR quantification using PISA by single-beat real-time 3D color Doppler echocardiography is feasible in the clinical setting and more accurate than the conventional 2D PISA method.

Haemodynamic evaluation of aortic regurgitation after transcatheter aortic valve implantation using cardiovascular magnetic resonance

AIMS

Echocardiography may underestimate the degree of paravalvular aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) using the Medtronic CoreValve bioprosthesis due to inherent limitations of ultrasound imaging in the evaluation of implanted cardiac prostheses. We aimed to evaluate the accuracy and feasibility of cardiovascular magnetic resonance (CMR) in quantifying regurgitant volume (RV) and regurgitant fraction (RF) in patients treated with this bioprosthesis for severe calcific aortic stenosis, and to compare the results with echocardiography and aortography.

METHODS AND RESULTS

This study included 16 patients with a mean age of 78.7 years (eight women, eight men) who underwent successful TAVI using Medtronic CoreValve bioprosthesis. AR was evaluated by CMR, echocardiography, and aortography. Angiography was performed immediately after valve implantation. CMR and echocardiography were performed four weeks after valve implantation. There was a highly significant correlation between the CMR-derived and the angiographically-estimated degree of AR (r=0.86, p<0.001). On the other hand, there was only a limited correlation between CMR and echocardiography (r=0.374, p=0.15) as well as angiography and echocardiography (r=0.319, p=0.23) regarding the degree of AR. The weighted kappa for agreement between echocardiography and angiography was 0.14, for agreement between echocardiography and CMR 0.20, and for agreement between angiography and CMR 0.72. Echocardiography underestimated AR by one degree compared to CMR in five patients and 2 degrees in two patients; in six of these, the degree of AR obtained by CMR was similar to angiography.

CONCLUSIONS

In patients undergoing TAVI, comparisons between purely quantitative measurements of AR by CMR and qualitative assessment by angiography showed better correlations than those with echocardiography. This suggests that echocardiography may underestimate the degree of AR and CMR in these circumstances has a great potential in reliably measuring the severity of AR in a quantitative manner.

Quantitative echocardiographic determinants of clinical outcome in asymptomatic patients with aortic regurgitation: a prospective study

OBJECTIVES

The purpose of this study was to define the link between aortic regurgitation (AR) quantitation and clinical outcome in asymptomatic patients with AR.

BACKGROUND

Quantitative American Society of Echocardiography (QASE) thresholds are recommended for AR assessment, but impact on clinical outcome is unknown.

METHODS

We prospectively enrolled (1991 to 2003) 251 asymptomatic patients (age 60 +/- 17 years) with isolated AR and ejection fraction > or =50% with quantified AR and left ventricular (LV) volumes using Doppler-echocardiography.

RESULTS

Survival under medical management was independently determined by baseline regurgitant volume (RVol) (adjusted hazard ratio [HR] 1.22 [95% confidence interval (CI) 1.08 to 1.35] per 10 ml/beat, p = 0.002) and effective regurgitant orifice (ERO) (adjusted HR 1.52 [95% CI 1.19 to 1.91] per 10 mm(2), p = 0.002), which superseded traditional AR grading. Patients with QASE-severe AR (RVol > or =60 ml/beat or ERO > or =30 mm(2)) versus QASE-mild AR (RVol <30 ml and ERO <10 mm(2)) had lower survival (10 years: 69 +/- 9% vs. 92 +/- 4%, p = 0.05) independently of all clinical characteristics (adjusted HR 4.1 [95% CI 1.4 to 14.1], p = 0.01) and lower survival free of surgery for AR (10 years: 20 +/- 5% vs. 92 +/- 4%, p < 0.001, adjusted HR 12.9 [95% CI 5.4 to 38.5]). Cardiac events were considerably more frequent with QASE-severe versus -moderate or -mild AR (10 years: 63 +/- 8% vs. 34 +/- 6% and 21 +/- 8%, p < 0.0001). Independent determinants of cardiac events were quantitative AR grading (QASE-severe adjusted HR 5.2 [95% CI 2.2 to 14.8], p < 0.001; QASE-moderate adjusted HR 2.4 [95% CI 1.06 to 6.6], p = 0.035), which superseded traditional AR assessment (p < 0.001) and LV end-systolic volume index (ESVI) (adjusted HR 1.09 [95% CI 1.03 to 1.14 per 10 ml/m(2)], p = 0.002), which superseded LV M-mode diameters. In QASE-severe AR, patients with ESVI > or =45 versus <45 ml/m(2) had higher cardiac event rates (10 years: 87 +/- 8% vs. 40 +/- 10%, p < 0.001). Cardiac surgery for AR reduced cardiac events in patients with QASE-severe AR (adjusted HR 0.23 [95% CI 0.09 to 0.57], p = 0.002).

CONCLUSIONS

Echocardiographic quantitation of AR severity and ESVI provides independent and superior predictors of clinical outcome in asymptomatic patients with AR and ejection fraction > or =50% and should be widely clinically applied. Patients with QASE-severe AR and ESVI > or =45 ml/m(2) should be carefully considered for cardiac surgery, which reduces cardiac events risk.

Proximal Flow Convergence Region as Assessed by Real-time 3-Dimensional Echocardiography: Challenging the Hemispheric Assumption

OBJECTIVE

Traditionally, a hemispheric assumption for the proximal flow convergence region (PFCR) is used when calculating mitral regurgitant (MR) effective orifice area (EROA). However, 2-dimensional (2D) echocardiography limits evaluation of the complete PFCR contour. Real-time 3-dimensional (3D) echocardiography (RT3D) allows direct assessment of the true PFCR contour. We hypothesized that the PFCR contour is not necessarily hemispheric, but rather hemielliptic, and aimed to apply a hemielliptic calculation, based on the 3D contour of the PFCR for more accurate MR quantification.

METHODS

In all, 50 patients with MR underwent RT3D to characterize PFCR contour as hemispheric or hemielliptic. MR EROA by RT3D-derived PFCR was calculated using a hemielliptic formula using 3D data. The 2D EROA was computed using standard hemispheric assumption. EROAs calculated from 2D and RT3D data were compared with quantitative Doppler EROA (mitral inflow--aortic outflow/MR time-velocity integral), used as an independent comparison.

RESULTS

Only 1 of 50 patients (2%) had a hemispheric PFCR contour by RT3D. The remaining had hemielliptic PFCR contours. Compared with Doppler method, 2D echocardiography significantly underestimated EROA (0.34 +/- 0.14 vs 0.48 +/- 0.25 cm(2), P < .001). RT3D EROA was not significantly different from Doppler EROA (0.52 +/- 0.17 vs 0.48 +/- 0.25, P = not significant). Of 33 patients with Doppler EROA greater than 0.3 cm(2) (> or =moderate-severe MR), 45% (15 of 33) were underestimated as having mild to moderate MR by 2D EROA.

CONCLUSIONS

The true PFCR contour as shown by RT3D is generally not hemispheric but hemielliptic, tracking the orifice contour. Based on this 3D shape, a hemielliptic approach can be used for practical clinical application with improved MR quantification.

New quantitative three-dimensional echocardiographic indices of mitral valve stenosis

BACKGROUND

We studied the value of quantitative three-dimensional echocardiography (3DE) in the evaluation of mitral valve stenosis using the measurement of the mitral valve area (MVA) with two new indices: the doming volume and mitral valve volume.

METHODS AND RESULTS

A total of 45 consecutive patients with mitral valve stenosis were studied. MVA was measured using Doppler with the pressure half-time (PHT) method. Following a diagnostic multiplane transesophageal (TEE) examination, data for 3DE were acquired with a rotational mode of acquisition. MVA was assessed by anyplane echocardiography (APE) and from surface rendered images. Moreover, the doming volume, i.e., the volume subtended by the anterior and posterior mitral valve and annular cut plane was measured by APE. Comparing PHT-derived with 3DE-derived MVA's, using both APE and surface rendered images, only moderate correlations were observed: PHT-derived MVA versus APE-derived MVA: r = 0.74, P < 0.0001; PHT-derived area versus 3DE-surface rendered MVA: r = 0.70, P < 0.0001. Multiple linear regression analysis showed a relation of atrial fibrillation to the doming volume (P = 0.04), but not to PHT-derived MVA (P = 0.28), APE-derived area (P = 0.33) and mitral valve volume (P = 0.08). Comparison of patients with MVA < 1 cm(2) and MVA > 1 cm(2) revealed significant difference in mitral valve volume: mean mitral valve volume in critical stenosis was 3.7 ml versus 1.4 ml in non-critical stenosis (P = 0.04).

CONCLUSIONS

Only moderate correlations between 3DE and Doppler-derived MVA's were observed. Measurement of the doming volume allows quantification of the 3DE geometry of the mitral apparatus. Patients with conical or funnel-like geometry are more likely to have sinus rhythm, whereas, patients with flat geometry are likely to have atrial fibrillation. Mitral valve volume can be used for the evaluation of mitral stenosis severity. These new 3DE indices might be used for selection of patients for balloon valvuloplasty.

Real-time three-dimensional color Doppler flow imaging: an improved technique for quantitative analysis of aortic regurgitation

The recently introduced real-time three-dimensional color Doppler flow imaging (RT-3D CDFI) technique provides a quick and accurate calculation of regurgitant jet volume (RJV) and fraction. In order to evaluate RT-3D CDFI in the noninvasive assessment of aortic RJV and regurgitant jet fraction (RJF) in patients with isolated aortic regurgitation, real-time three-dimensional echocardiographic studies were performed on 23 patients with isolated aortic regurgitation to obtain LV end-diastolic volumes (LVEDV), end-systolic volumes (LVESV) and RJV, and then RJF could be calculated. The regurgitant volume (RV) and regurgitant fraction (RF) calculated by two-dimensional pulsed Doppler (2D-PD) method served as reference values. The results showed that aortic RJV measured by the RT-3D CDFI method showed a good correlation with the 2D-PD measurements (r = 0.93, Y = 0.89X + 3.9, SEE = 8.6 mL, P < 0.001); the mean (SD) difference between the two methods was--1.5 (9.8) mL. % RJF estimated by the RT-3D CDFI method was also correlated well with the values obtained by the 2D-PD method (r = 0.88, Y = 0.71X + 14.8, SEE = 6.4%, P < 0.001); the mean (SD) difference between the two methods was--1.2 (7.9) %. It was suggested that the newly developed RT-3D CDFI technique was feasible in the majority of patients. In patients with eccentric aortic regurgitation, this new modality provides additional information to that obtained from the two-dimensional examination, which overcomes the inherent limitations of two-dimensional echocardiography by depicting the full extent of the jet trajectory. In addition, the RT-3D CDFI method is quick and accurate in calculating RJV and RJF.

Broad-beam spectral Doppler sonification of the vena contracta using matrix-array technology: A new solution for semi-automated quantification of mitral regurgitant flow volume and orifice area

OBJECTIVES

The objective of this study was to evaluate broad-beam spectral Doppler sonification of the vena contracta using a matrix-array transducer for quantification of mitral regurgitation (MR).

BACKGROUND

Noninvasive assessment of the severity of valvular regurgitation remains challenging. A recent technique measures regurgitant flow directly at the vena contracta based on the product of velocity times backscattered Doppler power (proportional to orifice area). That approach, however, has been limited by relatively narrow conventional beamwidths. Matrix-array transducers, recently developed for three-dimensional imaging, can potentially provide broader beams. Therefore, we addressed the hypothesis that deliberate broadening of the Doppler beam can encompass larger regurgitant cross-sectional areas to capture a broader range of regurgitant flows.

METHODS

A matrix-array transducer system was modified to provide a three-dimensionally expanded spectral Doppler sample volume. Calculations of orifice area, flow rate, and regurgitant stroke volume (RSV) from Doppler power were automated on board a routinely used echocardiographic scanner and tested in vitro. In 24 patients with isolated MR, RSV was compared with magnetic resonance imaging (MRI) mitral inflow minus aortic outflow from phase-velocity maps.

RESULTS

The calculated flow rate and RSV correlated and agreed well with reference values in vitro (r = 0.98 to 0.99) and in patients (r = 0.93, mean difference 0.4 +/- 3.2 ml, p = NS vs. 0), with sufficient sonification to measure flow orifices up to 0.85 cm in diameter. Agreement with MRI was comparable in 17 patients with central and seven with eccentric jets (p = NS vs. 0).

CONCLUSIONS

The broad-beam spectral Doppler technique provides accurate, largely automated quantification of regurgitant flow rate and integrated RSV directly at the lesion. The accuracy related to broader sonification is made possible by the new matrix-array transducer design.

New index for grading the severity of aortic regurgitation based on the cross-sectional area of vena contracta measured by color Doppler flow mapping

This study was designed to examine whether the cross-sectional area of vena contracta measured by color Doppler flow mapping (CFM) could be used for assessing aortic regurgitation (AR) and developing an index for grading AR. The 75 study patients with AR were classified into quadrant grades according to New York Heart Association functional class, regurgitant fraction, left ventricular (LV) end-diastolic dimension and LV end-systolic dimension. Using CFM, the cross-sectional area of the vena contracta was measured and it could distinguish all grades without significant overlap. An area of less than 0.10 cm(2) corresponded to Grade 1, 0.10-0.19 cm(2) corresponded to Grade 2, 0.20-0.29 cm(2) corresponded to Grade 3 and an area of more than 0.30 cm(2) corresponded to Grade 4. An area of vena contracta of more than 0.30 cm(2) identified high-scoring AR (Grade 4) in 11 of 11 (sensitivity 100%) and correctly predicted the absence of high-scoring AR in 60 of 64 (specificity 94%). Conversely, there was considerable overlap between the jet distances with the clinical grades. The cross-sectional area of the vena contracta measured by CFM can provide a simple quantitative assessment of AR that correlates well with the clinical grade of AR.

Outcome of significant functional tricuspid regurgitation after percutaneous mitral valvuloplasty

BACKGROUND

The outcome of significant functional tricuspid regurgitation (TR) associated with mitral stenosis (MS) after percutaneous mitral valvuloplasty (PMV) remains to be clarified.

METHODS

From 265 patients who underwent PMV at our institution from 1995 to 2000 and who were regularly observed, we selected 71 patients (55 women, mean age 43 +/- 11 years) who showed significant moderate to severe functional TR before PMV. We analyzed data from the echocardiograms performed before, 24 hours after, and long after the intervention (29 +/- 12 months) and analyzed clinical outcomes. Resolution of TR was defined as trace or mild TR on the follow-up color Doppler study.

RESULTS

Patients with moderate to severe TR showed more severe MS and pulmonary hypertension and more atrial fibrillation than patients with less than moderate TR. TR was resolved on the follow-up echocardiography in 23 of the 71 patients with significant TR before PMV (32%). The TR jet area before PMV (P <.05) and the late decrement of peak transmitral pressure gradient (P <.01) were independent determinants of resolution. TR was resolved in only 6.7% of patients (1/15) with an unsuccessful long-term PMV result, but was resolved in 39% of patients (22/56) with a successful long-term result (P <.05). During the clinical follow-up period (mean length 38 +/- 20 months), 4 patients underwent open heart surgery 24 to 39 months after PMV, and there was no overall mortality.

CONCLUSIONS

Significant functional TR was associated with more severe MS, and it could be diminished when the transmitral pressure gradient was sufficiently relieved with PMV.

Automated quantification of aortic regurgitant volume and regurgitant fraction using the digital colour Doppler velocity profile integration method in patients with aortic regurgitation

BACKGROUND

The recently introduced automated cardiac flow measurement (ACM) technique provides a quick and an accurate automated calculation of stroke volume and cardiac output. This is obtained by spatio-temporal integration of digital Doppler velocity profile data.

OBJECTIVE

To evaluate the use of the ACM method in the non-invasive assessment of aortic regurgitant volume and per cent regurgitant fraction (%RF) in patients with aortic regurgitation.

METHODS

Aortic outflow volume and mitral inflow volume were calculated by the ACM method in 22 patients with isolated aortic regurgitation. Aortic regurgitant volume and %RF were calculated using the following equations: aortic regurgitant volume = [aortic outflow volume] - [mitral inflow volume]; %RF = [aortic regurgitant volume]/[aortic outflow volume] x 100. The results were compared with those obtained using pulsed Doppler cross sectional echocardiography (PD-2D).

RESULTS

Aortic regurgitant volumes measured by the ACM method showed a good correlation with the PD-2D measurements (r = 0.95, y = 0.9x + 3.9, SEE = 8.6 ml); the mean (SD) difference between the two methods was -1.5 (8.5) ml. %RF estimated by the ACM method also correlated well with the values obtained by the PD-2D method (r = 0.91, y = 0.9x + 4.9, SEE = 6.0%); the mean difference between the two methods was -1.5 (6.0)%. Total time required for aortic regurgitant volume (for one cardiac cycle) by the ACM method was significantly shorter than by the PD-2D method (130 (16) v 230 (32) s, p < 0.01).

CONCLUSIONS

The newly developed the ACM method is quick and accurate in the automated assessment of aortic regurgitant volume and per cent regurgitant fraction in patients with isolated aortic regurgitation.

Prognostic significance of mitral regurgitation and tricuspid regurgitation in patients with left ventricular systolic dysfunction

BACKGROUND

Mitral regurgitation (MR) and tricuspid regurgitation (TR) frequently develop in patients with left ventricular systolic dysfunction (LVSD). Ventricular volume overload that occurs in patients with MR and TR may lead to progression of myocardial dysfunction. We hypothesized that MR and TR would provide markers of risk in patients with LVSD.

METHODS

We reviewed clinical, electrocardiographic, and echocardiographic data on 1421 consecutive patients with LVSD (left ventricular ejection fraction < or =35%). Predictors of survival (freedom from death or United Network for Organ Sharing [UNOS]-1 transplantation) were identified in a multivariable analysis with a Cox proportional hazards analysis. The impact of MR and TR (none to mild, moderate, or severe) then was assessed separately with Kaplan-Meier survival analysis.

RESULTS

During the follow-up period (mean +/- SD, 365 +/-364 days), death occurred in 435 study subjects (31%) and UNOS-1 transplantation in 28 subjects (2%). Multivariable predictors of poor outcome included increasing MR and TR grade, cancer, coronary artery disease, and absence of an implantable cardiac defibrillator. Relative risk was 1.84 (95% CI 1.43-2.38) for severe MR and 1.55 (95% CI 1.14-2.11) for severe TR. Survival with Kaplan-Meier analysis related inversely to MR grade (none to mild 1004 +/-31 days, moderate 795 +/-34 days, severe 628 +/-47 days, P <.0001) and TR grade (none to mild 977 +/-28 days, moderate 737 +/-40 days, severe 658 +/-55 days, P =.0001).

CONCLUSION

Patients with severe MR or TR represent high-risk subsets of patients with LVSD. Future study is warranted to determine whether pharmaceutical or surgical strategies to relieve MR and TR have a favorable impact on survival.

Quantitative assessment of regurgitant flow with total digital three-dimensional reconstruction of color Doppler flow in the convergent region: in vitro validation

BACKGROUND

This study was designed to develop and test a total digital 3-dimensional (3D) color flow map reconstruction for proximal isovelocity surface area (PISA) measurement in the convergent region.

METHODS

Asymmetric flow convergent velocity field was created in an in vitro pulsatile model of mitral regurgitation. Image files stored in the echocardiographic scanner memory were digitally transferred to a computer workstation, and custom software decoded the file format, extracted velocity information, and generated 3D flow images automatically. PISA and volume flow rate were calculated without geometric assumption. For comparison, regurgitant volume was also calculated, using continuous wave Doppler, 2-dimensional (2D), and M-mode color flow Doppler with the hemispheric approach.

RESULTS

Flows from 3D digital velocity profiles showed a closed, excellent relation with actual flow rates, especially for instantaneous flow rate. Regurgitant volume calculated with the 3D method underestimated the actual flow rate by 2.6%, whereas 2D and the M-mode method show greater underestimation (44.2% and 32.1%, respectively).

CONCLUSION

Our 3D reconstruction of color flow Doppler images gives more exact information of the flow convergent zone, especially in complex geometric flow fields. Its total digital velocity process allows accurate measurement of convergent surface area and improves quantitation of valvular regurgitation.

Jet eccentricity: a misleading source of agreement between Doppler/catheter pressure gradients in aortic stenosis

Characterization of the severity of aortic stenosis relies on accurate measurement of the pressure gradient across the valve and the valve area. Pressure gradients measured by Doppler ultrasound based on the clinical form of the Bernoulli equation often overestimate pressure gradients by catheter as the result of pressure recovery. Doppler techniques measure the velocity of the vena contracta of the stenotic jet. This corresponds to the maximal pressure gradient and the minimal effective valve area. Pressure recovery can be characterized by analysis of the spread of the stenotic jet downstream of the valve as it fills the aorta and should be influenced by the shape of the velocity profile of the decaying jet. In this study, we addressed the hypothesis that the site of complete pressure recovery (the point at which the jet fully expands to the size of the aorta), the effective valve area, and the maximal pressure gradient are affected by jet eccentricity. To accomplish this, we developed a computational model of aortic stenosis that provides detailed velocity and pressure information in the vicinity of the valve. The results show that the width of the eccentric wall jet decreased and maximal velocity increased with greater jet eccentricity. Furthermore, for a constant anatomic area, the effective valve area decreased, the distance to complete pressure recovery increased, and the maximal pressure gradient increased with the degree of eccentricity. Failure to take this into account could fortuitously drive Doppler and catheter measurements toward agreement because the distal pressure sensor will not record the fully recovered pressure. Therefore the pressure gradient across a stenotic valve depends on jet eccentricity. The spread of the wall jet after attachment must be characterized to develop a robust method for the prediction of pressure recovery.

Effects of blood viscosity on proximal flow convergence calculations of regurgitant flow rate and jet dimensions as evaluated by color Doppler flow mapping: an in vitro study

There are limited data on the potential influence of blood viscosity on the quantification of valvular regurgitation by color Doppler in the clinical setting. This study was designed to evaluate the effects of blood viscosity on jet dimensions and the proximal flow convergence (proximal isovelocity surface area, PISA) method of estimating valvular insufficiency severity. We used an in vitro flow model filled with human blood at varying hematocrits (15%, 35%, and 55%) and blood viscosity (blood/water viscosity: 2.6, 4.8, 9.1) in which jets were driven through a known orifice (16 mm(2)) into a 110-mL compliant receiving chamber (compliance: 2.2 mL/mm Hg) by a power injection pump. Blood injections (2 and 4 mL) at flow rates of 4, 6, 8, 10, and 12 mL/s were performed. Proximal flow convergence and spatial distribution of jets were imaged by a 3.5-MHz transducer. Pressure and volume in the flow model were kept constant before each injection. Ultrasound settings were the same for all experiments. Jet area decreased significantly with increasing blood viscosity, but the difference in jet dimensions was much larger for lower than for higher flow rates and for highest blood viscosity. Estimation of flow rate by the PISA method was not significantly influenced by blood viscosity. Blood viscosity has a major influence in jet area, especially for lower flow rates, but did not change significantly the grading of regurgitation by the PISA method. Thus this factor should be considered for determining the method of choice when quantification of valvular regurgitation is performed in patients with anemia or polycythemia.

Simple method for estimating regurgitant volume with use of a single radius for measuring proximal isovelocity surface area: an in vitro study of simulated mitral regurgitation

The proximal isovelocity surface area (PISA) color Doppler method with use of a hemielliptic formula is reported to be accurate for quantitating regurgitant volume (RV). However, this formula ideally requires the measurement of 2 or 3 radii and therefore is not widely used clinically. The purpose of this in vitro study was to derive a simple PISA formula for estimating RV with use of a single radius axial to the valve orifice and to compare it with the clinically used single-radius hemispherical formula (2 x pi R(2) x AV x TVI/Vp), where AV is the apparent color Doppler aliasing velocity, R is the PISA color Doppler aliasing radius, TVI is time-velocity integral of the jet by continuous wave Doppler, and Vp is the peak velocity of the jet by continuous wave Doppler. Pulsatile flow studies were performed across a convex curvilinear surface, which more closely approximates the shape of the mitral valve than does a planar surface. Pulse rates (60 to 80 bpm), peak flow velocities (4.0 to 6.0 m/s), and regurgitant orifice areas (0.2 to 1.0 cm(2)) were varied to simulate mitral regurgitation. The AVs were varied from 11 to 39 cm/s, and a single PISA aliasing radius was measured at each AV. Excellent linear correlations were obtained between the PISA radius and the actual RV measured with use of a beaker (r = 0.94 to 0.97, P <.0001). A series of simplified formulas was derived from the regression line of the PISA radius versus the RV. For example, with an AV of 21 cm/s, RV was estimated by a simplified PISA formula (where RV[mL] = 10 x R [mm] - 30) with an accuracy of 3.3 +/- 6.3 mL versus -20.3 +/- 8.7 mL for the standard single-radius PISA method (P <.0001). By using the standard single-radius hemispherical PISA formula, RV was underestimated if the radius was <20 mm. By using simplified regression equations, the PISA radius accurately estimated RV at a PISA radius <20 mm. Clinical studies are necessary to validate this concept.

The power-velocity integral at the vena contracta: A new method for direct quantification of regurgitant volume flow

BACKGROUND

Noninvasive quantification of regurgitation is limited because Doppler measures velocity, not flow. Because backscattered Doppler power is proportional to sonified blood volume, power times velocity should be proportional to flow rate. Early studies, however, suggested that this held only for laminar flow, not for regurgitant jets, in which turbulence and fluid entrainment augment scatter. We therefore hypothesized that this Doppler power principle can be applied at the proximal vena contracta, where flow is laminar before entrainment, so that the power-times-velocity integral should vary linearly with flow rate and its time integral with stroke volume (SV).

METHODS AND RESULTS

This was tested in vitro with steady and pulsatile flow through 0.07- to 0.8-cm(2) orifices and in 36 hemodynamic stages in vivo, replacing the left atrium with a rigid chamber and column for direct visual recording of mitral regurgitant SV (MRSV). In 12 patients, MRSV was compared with MRI mitral inflow minus aortic outflow and in 11 patients with 3D echo left ventricular ejection volume-Doppler aortic forward SV. Vena contracta power in the narrow high-velocity spectrum from a broad measuring beam was calibrated against that from a narrow reference beam of known area. Calculated and actual flow rates and SV correlated well in vitro (r=0.99, 0.99; error=-1.6+/-2.5 mL/s, -2. 4+/-2.9 mL), in vivo (MRSV: r=0.98, error=0.04+/-0.87 mL), and in patients (MRSV: r=0.98, error=-2.8+/-4.5 mL).

CONCLUSIONS

The power-velocity integral at the vena contracta provides an accurate direct measurement of regurgitant flow, overcoming the limitations of existing Doppler techniques.

Assessment of severity of aortic regurgitation using the width of the vena contracta: A clinical color Doppler imaging study

BACKGROUND

The width of the vena contracta (VC-W), the smallest area of regurgitant flow, reflects the degree of valvular regurgitation and is measurable by color Doppler imaging, but this method has not been validated in aortic regurgitation (AR).

METHODS AND RESULTS

We prospectively examined 79 patients with isolated AR and 80 patients without regurgitation. The VC-W was measured from the long-axis parasternal view and compared with 2 simultaneous reference methods (quantitative Doppler and 2D echocardiography). In patients without regurgitation, the agreement between methods was excellent. In patients with AR, good correlations (all P<0.0001) were obtained between VC-W and effective regurgitant orifice (ERO) area and regurgitant volume recorded by quantitative Doppler (r=0.89 and 0.90, respectively) and 2D echocardiographic (r=0.90 and 0.89, respectively) methods. These correlations were similar with eccentric or central jets (all P>0.60). The other methods used showed good correlations of VC-W with aortographic grading of AR (n=8, r=0.82, P=0.01), with the proximal flow convergence method (n=53, r=0.85, P<0.0001), and with left ventricular end-diastolic volume (r=0.81, P<0.0001). Sensitivity and specificity of VC-W >/=6 mm for diagnosing severe AR (ERO >/=30 mm(2)) were 95% and 90%, respectively.

CONCLUSIONS

For assessment of the degree of AR, VC-W shows good correlations with simultaneous quantitative measures (regardless of jet direction), shows good correlations with other methods of assessment of AR, and provides a high diagnostic value for severe AR. VC-W is a simple, reliable method that can be used clinically as part of comprehensive Doppler echocardiographic assessment of AR.

Quantification of tricuspid regurgitation by measuring the width of the vena contracta with Doppler color flow imaging: a clinical study

OBJECTIVE

We sought to evaluate the vena contracta width (VCW) measured using color Doppler as an index of severity of tricuspid regurgitation (TR).

BACKGROUND

The VCW is a reliable measure of mitral and aortic regurgitation, but its value in measuring TR is uncertain.

METHODS

In 71 consecutive patients with TR, the VCW was prospectively measured using color Doppler and compared with the results of the flow convergence method and hepatic venous flow, and its diagnostic value for severe TR was assessed.

RESULTS

The VCW was 6.1+/-3.4 mm and was significantly higher in patients with, than those without, severe TR (9.6+/-2.9 vs. 4.2 +/- 1.6 mm, p<0.0001). The VCW correlated well with the effective regurgitant orifice (ERO) by the flow convergence method (r = 0.90, SEE = 0.17 cm2, p<0.0001), even when restricted to patients with eccentric jets (r = 0.93, p < 0.0001). The VCW also showed significant correlations with hepatic venous flow (r = 0.79, p < 0.0001), regurgitant volume (r = 0.77, p<0.0001) and right atrial area (r = 0.46, p< 0.0001). A VCW > or =6.5 mm identified severe TR with 88.5% sensitivity and 93.3% specificity. In comparison with jet area or jet/right atrial area ratio, the VCW showed better correlations with ERO (both p<0.01) and a larger area under the receiver operating characteristic curve (0.98 vs. 0.88 and 0.85, both p<0.02) for the diagnosis of severe TR.

CONCLUSIONS

The VCW measured by color Doppler correlates closely with severity of TR. This quantitative method is simple, provides a high diagnostic value (superior to that of jet size) for severe TR and represents a useful tool for comprehensive, noninvasive quantitation of TR.

Fluid mechanics of regurgitant jets and calculation of the effective regurgitant orifice in free or complex configurations

The velocity fields of turbulent jets can be described using a single formula which includes two empirical constants: k(core) determining the length of the central core and k(turb) the jet widening. Flow models simulating jet adhesion, confinement and noncircular orifices were studied using laser Doppler anemometer and the modifications of the constants were derived from series of velocity profiles. In circular free jets, k(core) was found equal to 4.1 with a variability of 1.4%. In complex configurations, its variability was equal to 15.2%. For k(turb), the value for free circular jets was of 45.2 with a variability of 6.0% and this variability in complex configurations was significantly higher (30. 1%, p=0.025). The correlation between the actual orifice size and the jet extension was poor (r=0.52). However, the almost constant value of k(core) allowed to define a new algorithm calculating the regurgitant orifice diameter with the use of outlines of the jet image (r=0.89). In conclusion, the fluid mechanics of regurgitant jets is modified in complex configurations but, due to the relative independency of the central core, velocity fields could be used to evaluate the dimensions of the effective regurgitant orifice.

Quantitation of Doppler color flow jet areas for mitral regurgitation in children: angiographic correlation

Eighteen patients with chronic isolated rheumatic mitral regurgitation aged between 7 and 19 years (mean age +/-SD, 12.69+/-3.47 years) were analyzed with color Doppler imaging. Sixteen patients were performed cardiac catheterization within 24 h. Jets were classified as eccentric and central. Regurgitant jet area and its ratio to left atrial area and body surface area were measured by Doppler color flow imaging. Regurgitant volume and regurgitant fractions were calculated with angiography. There was a good correlation between regurgitant jet area and angiographic grade of mitral regurgitation (P<0.01). The correlation between regurgitant jet area/left atrial area ratios and angiographic grade of mitral regurgitation was limited (P<0.01). There was excellent correlation between regurgitant jet area/body surface area and angiographic regurgitant fraction (r = 0.85; P<0.001). There was also a good correlation between regurgitant jet area and regurgitant fraction (r = 0.82; P<0.001). However, the relation of regurgitant jet area/left atrial area to regurgitant fraction was weak (r = 0.72; P<0.01). In conclusion, the measurement of regurgitant fraction and its ratios to left atrial area and body surface area by color Doppler flow imaging can predict the angiographic severity in children who have even eccentric regurgitant jets.

Clinical value of parameters derived by the application of the proximal isovelocity surface area method in the assessment of mitral regurgitation

To determine the clinical value of several parameters derived by application of the proximal isovelocity surface area method in the assessment of mitral regurgitation (MR), 28 consecutive patients with angiographic diagnosis of MR underwent color Doppler echocardiography within 48 h of cardiac catheterization. Aliasing velocities (V(N)) were baseline-shifted to 25 cm/s and the maximal radius (R) was measured from the first aliasing boundary to the tips of the mitral valve. By continuity, the regurgitant orifice area (ROA) and regurgitant stroke volume (RSV(PISA)) were obtained. We have related them to the angiographic grade, and with determination of the regurgitant stroke volume (RSV(DE)) and the regurgitant fraction (RF), we calculated the volume of the transmitral flow according to Fisher's method.

RESULTS

RSV(DE) correlated well with RSV(PISA) (r = 0.98). A clear relation existed between the isovelocity radius and the RSV(DE) and RF (r = 0.95 and 0.88, respectively). A radius of 8 mm or more was identified well with an RSV(DE) of 40 cm3 or more (sensitivity: 100%, specificity: 95%) and an RF of 35% or more (sensitivity: 88%, specificity: 94%). The ROA was closely related to the RSV(DE) and RF, with r = 0.92 and 0.88, respectively. An ROA of 20 mm2 or more identified well patients with RSV(DE) values of 40 cm3 or more and RF values of 35% or more. The radius, RSV(PISA) and ROA were closely related to the angiographic grade of MR (r = 0.91, 0.83 and 0.92, respectively). A radius of 7 mm or more identified patients with grade III or IV of regurgitation (sensitivity: 82%, specificity: 94%), while an ROA of 15 mm2 or more discriminated well significant regurgitation (sensitivity: 91%, specificity: 94%).

CONCLUSIONS

Parameters derived by application of the proximal isovelocity surface area method provide quantitative information that can be helpful in predicting the severity of mitral regurgitation noninvasively.

Quantitative assessment of chronic aortic regurgitation with 3-dimensional echocardiographic reconstruction: comparison with electromagnetic flowmeter measurements

Two-dimensional echocardiography and color Doppler are useful in the qualitative assessment of aortic regurgitation. However, color Doppler planar methods are not accurate in quantifying regurgitant flow, in part because of the complex geometry of aortic regurgitant flow events. Three-dimensional echocardiographic reconstruction is a new technique that provides dynamic 3-dimensional images of intracardiac color flow jets. We sought to determine whether the measurement of aortic regurgitant jet volume by 3-dimensional echocardiography correlated with the true regurgitant volume, measured by electromagnetic flowmeter in vivo, to accurately reflect the severity of aortic regurgitation. We performed volume-rendered 3-dimensional echocardiography in 6 sheep with surgically induced chronic eccentric aortic regurgitation. We obtained a total of 22 aortic regurgitation states by altering loading conditions. Instantaneous regurgitant flow rates were obtained by aortic and pulmonary electromagnetic flowmeters. The maximum aortic regurgitant jet volume by 3-dimensional echocardiography and the maximum jet area by 2-dimensional echocardiography were measured and compared with electromagnetic flowmeter data. By electromagnetic flowmeter, aortic regurgitant flow rate varied from 0.14 to 3.1 L/min (mean 1. 25 +/- 0.78); aortic regurgitant stroke volume varied from 1 to 34 mL/beat (mean 12 +/- 8), and regurgitant fraction varied from 3% to 42% (mean 25% +/- 12%). The maximum jet volume by 3-dimensional echocardiography correlated very well with the aortic regurgitant stroke volume (r = 0.92; P <.0001), with the mean regurgitant flow rate (r = 0.87; P <.0001), and with the regurgitant fraction (r = 0. 87; P <.0001) derived from electromagnetic flowmeter. Both intraobserver and interobserver variability on the measurement of the jet volume by 3-dimensional echocardiography were excellent (r = 0.98; P <.0001 and r = 0.90; P <.001, respectively). The maximum jet area by 2-dimensional echocardiography did not correlate with the aortic regurgitant stroke volume (r = 0.41; P = not significant) and related poorly with the regurgitant fraction (r = 0.52; P <.05) by electromagnetic flowmeter. Dynamic 3-dimensional echocardiography can allow better determination of the geometry of the aortic regurgitant jet and may assist of quantifying the severity of aortic regurgitation.

[The measurement of jet width at its origin in assessing mitral prosthetic regurgitation. The effect of the spatial disposition of the jet]

INTRODUCTION AND OBJECTIVES

The study was performed to test the influence of the jet spatial disposition on the correlation degree between the measurement of the jet width at its origin and the severity of mitral prosthetic regurgitation by transesophageal Doppler color flow imaging.

MATERIAL AND METHODS

In 165 patients with mitral valve prosthesis which were submitted for transesophageal echocardiography examination due to suspected prosthetic dysfunction, we studied 126 with pathological mitral regurgitation. On these patients, studies of jet spatial disposition, maximum width in its origin and severity quantification by means of maximum regurgitation area were performed.

RESULTS

For the free jet group of patients (90), jet width at its origin correlated with maximal regurgitation area (r = 0.75); whereas for the wall jet group (36), the correlation degree was 0.59. We observed a relationship (p < 0.05) between severe mitral regurgitation assessed by maximal regurgitant jet size and jet width > or = 5 mm in both groups: the sensitivity and specificity of 72.7% and 95% respectively for free jets, and 70.7% and 64.4% for wall jets.

CONCLUSIONS

The correlation between the area measurement and the width in its origin is better for free jets than for wall jets. A statistically significant relationship between the presence of severe mitral regurgitation and width in its origin > or = 5 mm could be observed, independently of the jet spatial disposition.

Temporal variability of vena contracta and jet areas with color Doppler in aortic regurgitation: a chronic animal model study

OBJECTIVE

The purpose of our study was to determine the temporal variability of regurgitant color Doppler jet areas and the width of the color Doppler imaged vena contracta for evaluating the severity of aortic regurgitation.

METHODS

Twenty-nine hemodynamically different states were obtained pharmacologically in 8 sheep 20 weeks after surgery to produce aortic regurgitation. Aortic regurgitation was quantified by peak and mean regurgitant flow rates, regurgitant stroke volumes, and regurgitant fractions determined using pulmonary and aortic electromagnetic flow probes and meters balanced against each other. The regurgitant jet areas and the widths of color Doppler imaged vena contracta were measured at 4 different times during diastole to determine the temporal variability of this parameter.

RESULTS

When measured at 4 different temporal points in diastole, a significant change was observed in the size of the color Doppler imaged regurgitant jet (percent of difference: from 31.1% to 904%; 233% +/- 245%). Simple linear regression analysis between each color jet area at 4 different periods in diastole and flow meter-based severity of the aortic regurgitation showed only weak correlation (0.23 < r < 0.49). In contrast, for most conditions only a slight change was observed in the width of the color Doppler imaged vena contracta during the diastolic regurgitant period (percent of difference, vena contracta: from 2.4% to 12.9%, 5.8% +/- 3.2%). In addition, for each period the width of the color Doppler imaged vena contracta at the 4 different time periods in diastole correlated quite strongly with volumetric measures of the severity of aortic regurgitation (0.81 < r < 0.90) and with the instantaneous flow rate for the corresponding period (0.85 < r < 0.87).

CONCLUSIONS

Color Doppler imaged vena contracta may provide a simple, practical, and accurate method for quantifying aortic regurgitation, even when using a single frame color Doppler flow mapping image.

A simplified, practical approach to assessment of severity of mitral regurgitation by Doppler color flow imaging with proximal convergence: validation with concomitant cardiac catheterization

OBJECTIVE

To compare the proximal convergence method for quantification of mitral regurgitation with findings on concomitant left ventriculography.

MATERIAL AND METHODS

In 41 patients (22 men and 19 women, 63 +/- 13 years of age), mitral regurgitation was evaluated concomitantly by Doppler color flow jet area, proximal convergence method, and left ventriculography. A simplified measurement of the proximal convergence, consisting of the aliasing radius and velocity of the proximal isosurface (r2 x V), was used.

RESULTS

Angiographic grade correlated well with the proximal convergence method (r2 x V) but had poor correlation with the Doppler color flow jet area method. All patients with a proximal convergence flow rate of less than 10 cm3/s had grade 1 or 2 mitral regurgitation, whereas patients with a proximal convergence flow rate of more than 20 cm3/s had grade 3 or 4 mitral regurgitation. The severity of mitral regurgitation was indeterminate in patients with proximal convergence flow rates from 10 to 20 cm3/s.

CONCLUSION

Doppler color flow jet area correlates poorly with angiographic grade of mitral regurgitation. A simplified proximal convergence method is useful for separating grade 3 and 4 from grade 1 and 2 mitral regurgitation in most patients. A group of patients with indeterminate severity of mitral regurgitation remains, however, in whom further assessment is necessary.

Evaluation of mitral valve disease using transesophageal echocardiography

In the past 10 years, clinical application of transesophageal echocardiography (TE) has grown explosively. Intraoperative TE offers a powerful diagnostic and monitoring tool for the physicians in the cardiac operating room. The use of TE revolutionizes the assessment of patients with mitral valve disease. Surgical decisions are often altered based on the information obtained from TE. This review describes the basic features of TE as well as its uses in the intraoperative setting for evaluation of the mitral valve.