Impact of impinging wall jet on color Doppler quantification of mitral regurgitation

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.

A practical approach to the quantification of valvular regurgitation

This article reviews the methods of determining the severity of mitral and aortic regurgitation, primarily the quantitation using Doppler echocardiography. The Doppler methods, including spatial mapping, proximal flow convergence, vena contracta, continuous-wave Doppler density, and upstream or downstream effects are explained. Various practical pitfalls and performance issues that impact the reliability of these techniques are discussed.

Mechanism of diastolic mitral regurgitation in candidates for cardiac resynchronization therapy

It was hypothesized that restricted diastolic leaflet motion is implicated not only in the mechanism of systolic mitral regurgitation (MR) but also in the mechanism of diastolic MR observed in patients with severe heart failure. Cardiac resynchronization therapy (CRT) can oppose increased mitral leaflet tethering by increasing transmitral pressure, thereby providing an opportunity to explore this hypothesis. A total of 26 consecutive candidates for CRT with diastolic MR were compared with 26 candidates without diastolic MR. Maximal diastolic mitral leaflet opening and inflow direction and measures of mitral valve apparatus (i.e., mitral annular diameters, calculated mitral annular area, and tethering distance) were assessed from the apical 4-chamber view before and during CRT. There were no significant differences in New York Heart Association functional class, ejection fraction, QRS duration, PR interval, systolic MR grade, or 2-dimensional geometry of the mitral valve apparatus between the groups. Patients with diastolic MR had more restricted maximal diastolic leaflet openings (54 degrees +/- 17 degrees vs 71 degrees +/- 11 degrees , p = 0.003) and substantially smaller inflow angles (66 degrees +/- 7 degrees vs 79 degrees +/- 9 degrees , p = 0.0003) compared with patients without diastolic MR. After the institution of CRT, diastolic MR was eliminated in all patients, although there were no significant changes in any of the parameters of mitral valve apparatus. In conclusion, abnormal mitral valve tethering is a constitutive element of the mechanism of diastolic MR in patients with left ventricular dysfunction. Its acute resolution after CRT does not seem to be caused by changes in mitral valve geometry but rather by an increase in transmitral closing forces.

Color M-mode regurgitant flow propagation velocity: a new echocardiographic method for grading of mitral regurgitation

PURPOSE

The aim of this study was to evaluate the reliability of mitral regurgitation color M-mode regurgitant flow propagation velocity (RFPV) in grading mitral regurgitation (MR).

METHODS

We prospectively examined 52 consecutive patients with grades of MR mild in 10 patients, moderate in 19 patients, and severe in 23 patients with quantitative pulse Doppler echocardiography. MR was evaluated by vena contracta diameter (VCD), regurgitant jet area (RJA), and RFPV. These qualitative and quantitative methods were compared with the pulsed Doppler quantitative flow measurements and concordance of these three methods was determined.

RESULTS

The mean RFPV for mild, moderate, and severe MR were 26.4 +/- 7 cm/sec, 43.3 +/- 7 cm/sec, and 60.3 +/- 7.3 respectively (P < 0.001). RFPV is highly sensitive and moderately specific in differentiating mild and severe MR from other subgroups. Sensitivity and specificity were 92.1%-64.3% for mild and 100%-68.5% for severe MR, respectively. Significant correlation was observed between pulse Doppler quantitative grades, RFPV, VC, and RJA (P < 0.0001, r = 0.87; P < 0.0001, r = -0.84; P < 0.0001, r = 0.76, respectively).

CONCLUSION

This results show that RFPV is a reliable and simple semiquantitative new method that can be used for determining severity of MR.

Functional Mitral Regurgitation During Exercise in Patients With Heart Failure

BACKGROUND

Functional mitral regurgitation (MR) is common in patients with chronic heart failure (CHF) and left ventricular dysfunction. The severity of CHF is expressed in terms of exercise tolerance, so MR during exercise would affect the severity of heart failure. However, it is not well known how much MR increases during exercise, or if it is related with severity of heart failure.

METHODS AND RESULTS

Seventeen subjects underwent dynamic cycle exercise at steady-state levels of 80% and 150% of anaerobic threshold (AT). During each exercise level, the MR jet and left atrial (LA) area were measured, and the degree of MR was expressed as the ratio (MR/LA). The MR/LA increased slightly at 80% AT (rest: 15.5+/-7.8%, 80% AT: 21.7+/-9.3%, p<0.05). It increased more at 150% AT (29.2+/-11.6%, p<0.01). The MR/LA at both 80% and 150% AT weakly correlated with peak oxygen consumption/heart rate (r=-0.509). They showed a weakly positive correlation with the ventilatoly equivalent/CO(2) production slope (r=0.340).

CONCLUSIONS

MR during exercise increases as stroke volume worsens during exercise, so evaluation of MR during exercise is important in the management of patients with CHF.

Transthoracic and Transesophageal Echocardiographic Assessment of Mitral Regurgitation Severity: Usefulness of Qualitative and Semiquantitative Techniques

In this report, we review the advantages, limitations, and optimal utilization of various transthoracic and transesophageal echocardiographic (TTE and TEE) methods used for assessing mitral regurgitation (MR) as published in full-length, peer-reviewed articles since the color Doppler era began in 1984. In addition, comparison is made to other imaging modalities including catheter-based, magnetic resonance and surgical assessment of MR. Although left ventricular (LV) angiography has been traditionally used for validation of various TTE methods and is time-honored, its considerable limitations preclude it from being a real "gold standard." Based on the reviewed literature, no clear "gold standard" for the assessment of MR can be identified at present, but newly emerging TTE and TEE techniques, such as three-dimensional color Doppler, may have the potential to overcome some of the limitations of the two-dimensional methods.

Long-term prognostic significance of left atrial volume in acute myocardial infarction

OBJECTIVES

The aim of this study was to evaluate the significance of increased left atrial (LA) volume determined within the first 48 h of admission as a long-term predictor of outcome in patients with acute myocardial infarction (MI).

BACKGROUND

The LA volume reflects left ventricular (LV) diastolic properties. Whereas other LV Doppler diastolic characteristics are influenced by acute changes in LV function, LA volume is stable and reflects diastolic properties before MI.

METHODS

Clinical and echocardiographic parameters were prospectively collected in 395 consecutive patients with acute MI. Patients with LA volume index (LAVI) >32 ml/m(2) (normal + 2 standard deviations) were compared with those with LAVI <==32 ml/m(2). Independent clinical and echocardiographic prognostic risk factors for five years' mortality were determined by the Cox proportional hazard model.

RESULTS

Left atrial volume index >32 ml/m(2) was found in 63 patients (19%) who had a higher incidence of congestive heart failure on admission (24% vs. 12%, p < 0.01), a higher incidence of mitral regurgitation, increased LV dimensions, and reduced LV ejection fraction when compared with patients with LAVI <==32 ml/m(2). Their five-year mortality rate was 34.5% versus 14.2% (p < 0.001). Significant independent risk predictors of five years' mortality were age (10 years) (odds ratio [OR] 1.45; 95% confidence interval [CI]1.14 to 1.86), Killip class >/=2 on admission (OR 2.30; 95% CI 1.29 to 4.09), LAVI >32 ml/m(2) (OR 2.22; 95% CI 1.25 to 3.96), diabetes (OR 1.94; 95% CI 1.15 to 3.28), and LV restrictive filling pattern (OR 1.89; 95% CI 1.09 to 3.31).

CONCLUSIONS

In patients with acute MI, increased LA volume, determined within the first 48 h of admission, is an independent predictor of five-year mortality with incremental prognostic information to clinical and echocardiographic data.

Color flow imaging of the vena contracta in mitral regurgitation: technical considerations

Qualitative grading of mitral regurgitation severity has significant pitfalls secondary to hemodynamic variables, sonographic technique, blood pool entrainment, and the Coanda effect. Volumetric and proximal isovelocity surface area methods can be used to quantitate regurgitant orifice area, regurgitant volume, and regurgitant fraction, but have several limitations and can pose technical challenges. The vena contracta width method provides a rapid and accurate quantitative assessment of mitral regurgitation severity, but is clinically underused. This article is intended to generate an understanding of the flow mechanics of the vena contracta and the sonographic technique required to provide consistent and accurate measurements of vena contracta width in patients with mitral regurgitation.

Dynamic three-dimensional color flow Doppler: an improved technique for the assessment of mitral regurgitation

BACKGROUND

Prior studies have reconstructed mitral regurgitant flow in three dimensions displaying gray scale renditions of the jets, which were difficult to differentiate from surrounding cardiac structures. Recently, a color-coded display of three-dimensional (3D) regurgitant flow has been developed. However, this display was unable to integrate cardiac anatomy, thereby losing spatial information, which made it difficult to determine the jet origin and its spatial trajectory. To overcome this limitation, an improved method of 3D color reconstruction of regurgitant jets obtained from color flow Doppler using a transesophageal approach was developed to allow the combined display of both color flow and gray scale information.

OBJECTIVES

To demonstrate the feasibility of 3D reconstruction of regurgitant mitral flow jets using an improved method of color encoding digital data acquired by transesophageal echocardiography (TEE).

METHODS

We studied 46 patients undergoing a clinically indicated TEE study. All subjects had mitral regurgitation detected on a previous transthoracic study. Atrial fibrillation or poor image quality were not used as exclusion criteria. The 3D study was performed using a commercial ultrasound imaging system with a TEE probe (Sonos 5500, Agilent Technologies). A rotational mode of acquisition was used to collect two-dimensional (2D) color flow images at 3-degree intervals over 180 degrees. Images were processed off line using the Echo-View Software (TomTec Imaging Systems). Volume-rendered 3D color flow jets were displayed along with gray scale information of the adjacent cardiac structures.

RESULTS

Mitral regurgitant flow, displayed in left atrial and two longitudinal orientations, was successfully reconstructed in all patients. The time for acquisition, post-processing, and rendering ranged between 10 and 15 minutes. There were 28 centrally directed jets and 15 eccentric lesions. Eight patients in the study had periprosthetic mitral regurgitant flow.

CONCLUSIONS

Three-dimensional imaging of mitral regurgitant jets is feasible in the majority of patients. This improved technique provides additional information to that obtained from the 2D examination. Particularly, in patients with paravalvular leaks 3D color flow Doppler provides information on the origin and the extent of the dehiscence, as well as insight into the jet direction. In addition, in patients with eccentric mitral regurgitation, this new modality overcomes the inherent limitations of 2D echo Doppler by depicting the full extent of the jet trajectory.

[Quantification of mitral regurgitation]

The echographic methods of quantification of mitral regurgitation are various. Semiquantitative methods using the color Doppler extension of the regurgitant jet are now replaced by more quantitative methods, including PISA, jet width, and regurgitant fraction. Although sometimes difficult, accurate quantification of mitral regurgitation is now possible in a majority of patients using transthoracic echocardiography.

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.

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.

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.

Progress in mitral and aortic regurgitation

Over the past 15 years there has been rapid and dramatic change in the therapy for valvular heart disease. When mitral and aortic regurgitation are severe, they inevitably cause left ventricular damage, eventually resulting in death. However, when surgical correction of these lesions is timed appropriately, longevity can approach that of a normal population after surgery. As surgical techniques have improved, surgery is now indicated earlier in the course of these diseases. It is clear that some patients with mitral and aortic regurgitation require surgery even though they are entirely asymptomatic. However, it must be emphasized that mitral and aortic regurgitation are quite different from one another. These different lesions result in different loading conditions, different pathophysiologies, and have different means for surgical correction. All of these issues impact on the proper timing of surgery and are discussed.

Assessment of aortic regurgitation by transesophageal color Doppler imaging of the vena contracta: validation against an intraoperative aortic flow probe

OBJECTIVES

This study was performed to validate the accuracy of color flow vena contracta (VC) measurements of aortic regurgitation (AR) severity by comparing them to simultaneous intraoperative flow probe measurements of regurgitant fraction (RgF) and regurgitant volume (RgV).

BACKGROUND

Color Doppler imaging of the vena contracta has emerged as a simple and reliable measure of the severity of valvular regurgitation. This study evaluated the accuracy of VC imaging of AR by transesophageal echocardiography (TEE).

METHODS

A transit-time flow probe was placed on the ascending aorta during cardiac surgery in 24 patients with AR. The flow probe was used to measure RgF and RgV simultaneously during VC imaging by TEE. Flow probe and VC imaging were interpreted separately and in blinded fashion.

RESULTS

A good correlation was found between VC width and RgF (r = 0.85) and RgV (r = 0.79). All six patients with VC width >6 mm had a RgF >0.50. All 18 patients with VC width <5 mm had a RgF <0.50. Vena contracta area also correlated well with both RgF (r = 0.81) and RgV (r = 0.84). All six patients with VC area >7.5 mm2 had a RgF >0.50, and all 18 patients with a VC area <7.5 mm2 had a RgF <0.50. In a subset of nine patients who underwent afterload manipulation to increase diastolic blood pressure, RgV increased significantly (34 +/- 26 ml to 41 +/- 27 ml, p = 0.042) while VC width remained unchanged (5.4 +/- 2.8 mm to 5.4 +/- 2.8 mm, p = 0.41).

CONCLUSIONS

Vena contracta imaging by TEE color flow mapping is an accurate marker of AR severity. Vena contracta width and VC area correlate well with RgF and RgV obtained by intraoperative flow probe. Vena contracta width appears to be less afterload-dependent than RgV.

A semiautomated objective technique for applying the proximal isovelocity surface area method to quantitate mitral regurgitation: Clinical studies with the digital flow map

BACKGROUND

Clinical application of the color Doppler proximal isovelocity surface area (PISA) method to quantify mitral regurgitation (MR) has been limited by the often inaccurate assumption that isovelocity surfaces are hemispheric. This study applied an objective method for selecting the region where the hemispheric geometry holds best on the basis of mathematic analysis of results at different distances from the orifice. We aimed to demonstrate this approach can be applied accurately in the clinical setting and can be semiautomated to promote routine use by extracting velocities from the digital Doppler output and then performing all the calculations automatically.

METHODS

In 75 patients with isolated MR, centerline velocities (V(r)) at each distance (r) from the orifice in the proximal flow field were extracted digitally. The automated analysis calculated peak MR flow rates as 2pir(2)V(r) and plotted these against their respective velocities. The optimal value for peak flow rate was obtained mathematically at the site where the slope of this curve was minimal (least inaccuracy). This value was combined with continuous wave Doppler data to provide regurgitant stroke volume (RSV) and orifice area (ROA), which were compared with quantitative Doppler in 75 patients and angiography in 42.

RESULTS

RSV and ROA by this optimized, semiautomated PISA method correlated and agreed well with values from quantitative Doppler (y = 0.9x + 1.9, r = 0.90, standard error of the estimate [SEE] = 8.1 mL, mean difference = -0.7 +/- 8.5 mL for RSV; y = 0.9x + 0.02, r = 0.90, SEE = 0.048 cm(2), mean difference = -0.005 +/- 0.1 cm(2) for ROA) and correlated well with angiography (rho = 0.90 for both RSV and ROA).

CONCLUSIONS

This objective PISA method for quantifying MR is accurate in the clinical setting and has been semiautomated by use of analysis of digital velocity data to provide a rapid and practical technique suitable to facilitate more extensive application in routine practice.

Calculation of mitral regurgitant orifice area with use of a simplified proximal convergence method: initial clinical application

To validate a previously proposed simplified proximal flow convergence method for calculating mitral regurgitant orifice area (ROA), a prospective study was conducted in ambulatory patients and in patients undergoing open heart surgery. Assuming a pressure difference between the left ventricle and left atrium of approximately 100 mm Hg (jet velocity [v(p)] 500 cm/s) and setting the color aliasing velocity (v(a)) to 40 cm/s, we simplified the conventional proximal convergence method formula (ROA = 2pi(r2)v(a)/v(p)) to r2/2, where r is the radius of the proximal convergence isovelocity hemisphere. For 57 ambulatory patients with a wide range of mitral regurgitant severity (1 to 4+), ROA was calculated by the conventional (x) and simplified (y) methods, demonstrating excellent accuracy (r = 0.92; P <.001; DeltaROA [y - x] = 0.004 +/- 0.08 cm2). For 24 intraoperative patients, ROA calculated by the simplified formula (y) correlated well with the pulsed Doppler-thermodilution method (x) (r = 0.84; P <.01; DeltaROA [y - x] = -0.002 +/- 0.08cm2). This simplified proximal convergence formula yields an accurate assessment of ROA for a wide range of regurgitant severity, while the time required for this measurement is shortened by half (1.5 +/- 0.5 minutes versus 3.2 +/- 0.7 minutes). This may increase the frequency of calculating ROA in the clinical laboratory.

Comparison of quantitative and semiquantitative methods for assessing mitral regurgitation by transesophageal echocardiography

Semiquantitative grading of mitral regurgitation (MR) by transesophageal echocardiography (TEE) is widely used for clinical decision making. However, the relation between semiquantitative grading by biplane or multiplane TEE and quantitative measures remains undetermined. Biplane or multiplane TEE was performed in 113 patients in the operating room. MR severity was graded from 1 to 4+ by Doppler color flow mapping. MR was quantified using the thermodilution-Doppler method as mitral regurgitant stroke volume (RSV) derived from the difference between total mitral inflow measured by pulsed Doppler and forward flow measured by thermodilution. Mitral regurgitant orifice area (ROA) was calculated by RSV divided by mitral regurgitant velocity. RSV and ROA were also calculated using the proximal isovelocity surface area method. RSV and ROA significantly correlated with the semiquantitative grading either by TEE or angiogram in a nonlinear fashion, with the best fit being given by an exponential model with correlation coefficients from 0.73 to 0.87 (p <0.001). Substantially increased RSV and ROA were observed in MR grades of > or =3+. In the same grades of 3+ or 4+ MR, the largest RSV was 4 times larger than the smallest (190 to 220 vs 44 to 45 ml), and the largest ROA (1.82 to 2.0 vs 0.26 to 0.27 cm2) was sixfold larger than the smallest. Patients with 2 to 3+ MR had significantly variable RSV and ROA (range 21 to 91 ml and 0.12 to 0.65 cm2, respectively). Color flow mapping by biplane or multiplane TEE or angiography is able to categorize precisely mild (< or =2+) and severe (> or =3+) MR, but cannot accurately determine actual hemodynamic load of MR in more severe degrees of MR.

Mitral regurgitation in hypertrophic obstructive cardiomyopathy: relationship to obstruction and relief with myectomy

OBJECTIVES

This study examined: 1) the impact of myectomy on postoperative mitral regurgitation (MR) and 2) the association between the severity of MR and the left ventricular outflow tract (LVOT) gradient.

BACKGROUND

For patients with hypertrophic obstructive cardiomyopathy (HOCM) and MR, controversy exists as to whether myectomy alone is sufficient in eliminating MR. Furthermore, the relationship between the degree of MR and the LVOT peak gradient has not been well defined.

METHODS

We performed pre- and postoperative transthoracic as well as intraoperative transesophageal studies in 104 consecutive patients with HOCM undergoing septal myectomy. Left ventricular outflow tract gradient and the nature of MR were assessed.

RESULTS

In the 93 patients without independent mitral valve disease, a relationship was observed between MR severity and the LVOT gradient. Left ventricular outflow tract gradient (mean +/- standard deviation) for trivial, mild, moderate and severe MR were: 23.2+/-19.1, 43.8+/-25.4, 70.1+/-21.0 and 104+/-21.0 mm Hg (p < 0.001). Early postoperative, MR was absent or trivial in 80%, mild in 19% and moderate in 1%. None of these patients required additional mitral valve surgery. For patients with independent mitral valve disease (n = 11), five required mitral valve surgery as well as myectomy. The remainder had significant reductions in the degree of MR with myectomy alone.

CONCLUSIONS

For patients with HOCM and MR not due to independent mitral valve disease, myectomy significantly reduced the degree of MR, without requirement for additional mitral valve surgery. In these patients the severity of MR was directly related to the magnitude of the LVOT gradient.

Prognostic significance of mild mitral regurgitation by color Doppler echocardiography in acute myocardial infarction

Mitral regurgitation (MR) complicating acute myocardial infarction (AMI) is associated with increased mortality. The prognostic significance of only mild MR detected by echocardiography in patients with AMI is unknown. This study assessed the long-term risk associated with mild MR detected by color Doppler echocardiography within the first 48 hours of admission in 417 consecutive patients with AMI. No MR was detected in 271 patients (65%), mild MR was seen in 121 patients (29%), and moderate or severe MR was noted in 25 patients (6%). One-year mortality rates were 4.8%, 12.4%, and 24%, respectively (p<0.001). Multivariate analysis revealed that mild MR was independently associated with increased 1-year mortality (p<0.05) after adjustment for age, gender, previous myocardial infarction, diabetes mellitus, systemic hypertension, Killip grade > or =2 on admission, and left ventricular ejection fraction < or =40%. The hazard ratio for 1-year mortality was 2.31 (95% confidence interval 1.03 to 5.20) for mild MR and 2.85 (95% confidence interval 0.95 to 8.51) for moderate or severe MR. Thus, mild MR detected by color Doppler echocardiography within the first 2 days of admission in patients with AMI is a significant independent risk predictor for 1-year all-cause mortality.

Three-dimensional color Doppler flow reconstruction and its clinical applications

The visualization and quantification of intracardiac blood flow have always been a challenging task for the cardiologist. The advent of color Doppler flow imaging substantially enhanced the clinical diagnosis of heart valve disease. Three-dimensional (3-D) color Doppler, a new diagnostic procedure, refines the diagnostic value of color Doppler by providing unique spatial and temporal information about the actual extension, direction, origin, and size of intracardiac flows. Here, we describe the procedure for 3-D color Doppler reconstruction of intracardiac blood flow velocities and reveal the varied findings in different heart pathologies that cause blood flow disturbances. An automated procedure for the segmentation of turbulent and laminar flows, which allows for the measurement of mitral regurgitant jet volumes, is one of the first 3-D quantitative approaches to the clinical assessment of mitral valve regurgitation. The major technical advances of this procedure include the direct use of digital color Doppler velocity data and an automatic voxel count of the turbulent jet flows. Three-dimensional color Doppler not only can disclose the spatial complex geometry of intracardiac blood flow disturbances but also can quantitatively assess the severity of mitral valve regurgitation.

Evaluation of 3-D colour Doppler ultrasound for the measurement of proximal isovelocity surface area

Three-dimensional (3-D) colour Doppler ultrasound (US) enables flow rate estimation across a diseased valve without the need for a priori geometric assumptions. This study quantitatively evaluates the accuracy of 3-D colour Doppler US for measuring the flow rate (8. 3-75 mL/s) through a valve using the proximal flow convergence field. Flow rate measurements by this 3-D technique underestimate flow through finite circular orifices due to two major sources of error: 1. surface area slicing technique (18.3% +/- 3.8%) and 2. Doppler angle effect (41.0% +/- 1.5%). Combined total underestimation is 51% +/- 3.3%. To utilize 3-D US, the development of an improved proximal isovelocity surface area (PISA) measurement technique and a correction factor for the Doppler angle effect is required.

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.

Transpulmonary passage of Albunex as a marker of intracardiac hemodynamics and outcome in chronic congestive heart failure

BACKGROUND

Aggressive management to reduce pulmonary artery systolic pressure (PASP) and pulmonary capillary wedge pressure (PCWP) reduces hospitalization rates and is crucial for patients awaiting transplantation but may require periodic invasive monitoring with right heart catheterization.

METHODS

The purpose of this study was to define the relation of transpulmonary passage of Albunex (Mallinckrodt Medical, St Louis, Mo) to intracardiac hemodynamics and clinical outcome in patients with chronic congestive heart failure (CHF). Patients (n = 38) with chronic CHF underwent graded dobutamine infusion (baseline, 5, 10, 20 microg/kg per minute; 5-minute stages) with 5.0 mL Albunex injected intravenously at each stage. The dobutamine dose at which Albunex appeared in the left ventricle was determined. All patients had right heart catheterization to determine PASP and PCWP.

RESULTS

Transpulmonary passage of Albunex at baseline or at 5 microg/kg per minute dobutamine infusion predicted PCWP <20 mm Hg with a positive predictive value of 100% and a negative predictive value of 79%. Initial appearance of Albunex in the left ventricle at a dobutamine dose of 20 microg/kg per minute or failure to appear at any dose predicted a PCWP >20 mm Hg with a positive predictive value of 100% and a negative predictive value of 94%. No patient with Albunex passage at baseline sustained a major adverse event. Major adverse events occurred in 11 of 21 patients in whom Albunex either failed to cross or crossed the pulmonary bed at a dose of 20 microg/kg per minute of dobutamine.

CONCLUSION

In patients with chronic CHF, transpulmonary passage of Albunex during dobutamine infusion can be used to predict both elevated and normal intracardiac pressures and to identify a subset of patients at high risk for an adverse outcome.

Mitral regurgitation: comprehensive assessment by echocardiography

Two-dimensional and Doppler echocardiography have become the major modalities for the assessment of mitral regurgitation. The combined use of these techniques provides information regarding the morphology of the valvular apparatus as well as the severity of regurgitation. Transesophageal and three-dimensional echocardiography provide a more-detailed evaluation of valve morphology, which can be valuable in determining suitability for valve repair. In patients with severe mitral regurgitation, echocardiographic assessment of ventricular size and function plays a critical role in determining the optimal timing of surgery.

Effect of general anesthesia on the severity of mitral regurgitation by transesophageal echocardiography

The effect of general anesthesia on the severity of mitral regurgitation (MR) was examined in 43 patients with moderate or severe MR who underwent preoperative and intraoperative transesophageal echocardiography. Systolic blood pressure, mean arterial pressure, and left ventricular end-diastolic and end-systolic dimensions were significantly lower during the intraoperative study, reflecting altered loading conditions. The mean color Doppler jet area and mean vena contracta decreased and the mean pulmonary venous flow pattern changed from reversed to blunted, reflecting a significant reduction in the severity of MR. Overall, 22 of the 43 patients (51%) improved at least 1 MR severity grade when assessed under general anesthesia. Thus, intraoperative transesophageal echocardiography may significantly underestimate the severity of MR. A thorough preoperative assessment is preferable when deciding whether to perform mitral valve surgery.

Standard Versus Simplified Proxizmal Isovelocity Surface Area: An Echocardiographic Approach

A noninvasive approach to quantitatively assessing mitral valve regurgitation is called the proximal isovelocity surface area (PISA) method. The basis for the PISA technique is to use color and spectral Doppler to measure flow velocity and effective area and then calculate effective regurgitant orifice area and regurgitant flow volumes as defined by the conservation of mass theory. Moreover, the complexity of these calculations leads to the search for a simplified approach to this laborious quantification method. It is with this in mind that a close clinical correlation of the standard PISA and the newly derived simplified PISA is established through the use of noninvasive techniques. In a prospective study, 21 patients (10 men and 11 women; mean age, 68.9 years) with at least mild mitral regurgitation were evaluated by color and spectral Doppler echocardiography. Two-dimensional imaging measurements also were recorded. This study used the simplified proximal convergence flow rate (r2 X Va), the standard PISA calculation, and the left atrial volume measurement. The simplified proximal convergence method correlated well with the standard PISA method but lacked a solid linear relation with the left atrial volume assessment. Simplified PISA shows accuracy in stratifying mild mitral regurgitation and moderately severe to severe mitral regurgitation. However, there remains a range (10-20 mL/s) in which further assessment may be necessary, either invasively or noninvasively, to accurately quantify the degree of mitral regurgitation.

Progression of mitral regurgitation: a prospective Doppler echocardiographic study

OBJECTIVES

This study was performed to define the rates and determinants of progression of organic mitral regurgitation (MR).

BACKGROUND

Severe MR has major clinical consequences, but the rates and determinants of progression of the degree of regurgitation are unknown. Quantitative Doppler echocardiographic methods allow the quantitation of regurgitant volume (RVol), regurgitant fraction (RF) and effective regurgitant orifice (ERO) to define progression of MR.

METHODS

In a prospective study of MR progression, 74 patients had two quantitative Doppler echocardiographic examinations of MR (with at least two methods) 561 +/- 423 days apart without an intervening event.

RESULTS

Progression of MR was observed, with increase in RVol (77 +/- 46 ml vs. 65 +/- 40 ml, p < 0.0001), RF (47 +/- 16% vs. 43% +/- 15%, p < 0.0001), and ERO (50 +/- 35 mm2 vs. 41 +/- 28 mm2, p < 0.0001). Annual rates (95% confidence interval) were, respectively, 7.4 ml/year (5.1, 9.7), 2.9%/year (1.9, 3.9) and 5.9 mm2/year (3.9, 7.8). However, wide individual variation was observed, and regression and progression of RVol >8 ml was found in 11% and 51%, respectively. In multivariate analysis, independent predictors of progression of RVol were progression of the lesions, particularly a new flail leaflet (p = 0.0003), and progression of mitral annulus diameter (p = 0.0001). Regression of MR was associated with marked changes in afterload, particularly decreased blood pressure (p = 0.008). No significant effect of treatment was detected.

CONCLUSIONS

Organic MR tends to progress over time with increase in volume overload (RVol) due to increase in ERO. Progression of MR is variable and determined by progression of lesions or mitral annulus size. These data should help plan follow up of patients with organic MR and future intervention trials.

[Echocardiographic evaluation in unoperated congenital heart disease in adults]

Echo and Doppler echocardiographic procedures have gained special importance in the diagnostics of congenital diseases in adults. These procedures permit detailed visualization of the pathomorphology of the heart as well as reliable evaluation of the hemodynamic changes. There are differentiated indications for the various procedures, such as transthoracic and transesophageal echocardiography, Doppler and color-Doppler echocardiography, contrast echocardiography and 3-dimensional echocardiography. This article discusses the opposition of the various echo and Doppler echocardiographic procedures with respect to the diagnostics of the most frequent non-operated congenital diseases in adults. The pathomorphology of the various congenital diseases will be summarized and then the important echocardiographic criteria presented which are decisive for the diagnostic procedure. In simple congenital malformation of cardiac valves, such as bicuspid aortic valve (Figure 1: aortic ring abscess), pulmonary valve stenosis (Figure 2), Ebstein's anomaly (Figure 3) or malformations of the mitral valve (Figure 4: cleft in the anterior mitral cusp), the diagnosis can often be made using transthoracic echo and Doppler echocardiography, and the severity of the defect determined. However, the sonographic conditions, especially in adults, are frequently too limited to permit recognition of detailed smaller changes, so that transesophageal examination is required to finally confirm the diagnosis in these patients. In the diagnostics of diseases of the left ventricular outflow tract and the thoracic aorta, such as subvalvular aortic valve stenosis (Figure 5), the sinus of Valsalva aneurysm or the coarctation of the aorta (Figure 6), the left ventricular outflow tract can be evaluated morphologically from a transthoracic procedure and the accelerations of flow can be recorded by continuous wave Doppler. If there is no sclerosis of the fibrous membrane, these can often not be depicted by transthoracic procedures, so that a supplementary transesophageal examination is meaningful. This is required in any case for diseases of the descending thoracic aorta. In the case of congenital lesions, such as atrial septal defects (Figure 7: anomalous pulmonary venous return, Figure 8: 3-dimensional visualization of an atrial septal defect, Figure 9: sinus venosus defect), ventricular septal defect or a patent ductus arteriosus Botalli (Figure 10), color-Doppler and contrast echocardiography have become especially important. Transesophageal examination is also indicated for these congenital diseases for direct depiction of the defect as well as for precise evaluation of the shunt. Moreover, in atrial septal defects, it has been shown that a 3-dimensional echocardiography provides additional advantage with respect to spatial relationship of the defect to the other cardiac structures, as well as presenting dynamic changes during a heart cycle. Extensive knowledge of complex congenital heart disease, such as tetralogy of Fallot (Figure 11), complete transposition of the great arteries, congenitally corrected transposition of the great arteries (Figure 12), the double-outlet right ventricle, truncus arteriosus communis, the cor triatriatum, tricuspid atresia (Figure 13) or the univentricular heart (Figure 14) usually requires performance of a transthoracic echo- and Doppler echocardiographic examination to assess the pathomorphological changes and to examine hemodynamics. In the majority of patients, supplementary transesophageal echocardiography and an echo contrast examination are important. Initial examinations using 3-dimensional echocardiography are very promising in this connection and with respect to the exact spatial presentation of pathoanatomical structures.

The Mitral Regurgitation Index: an echocardiographic guide to severity

OBJECTIVES

The purpose of this study was to develop a semiquantitative index of mitral regurgitation severity suitable for use in daily clinical practice and research.

BACKGROUND

There is no simple method for quantification of mitral regurgitation (MR). The MR Index is a semiquantitative guide to MR severity. The MR Index is a composite of six echocardiographic variables: color Doppler regurgitant jet penetration and proximal isovelocity surface area, continuous wave Doppler characteristics of the regurgitant jet and tricuspid regurgitant jet-derived pulmonary artery pressure, pulse wave Doppler pulmonary venous flow pattern and two-dimensional echocardiographic estimation of left atrial size.

METHODS

Consecutive patients (n = 103) with varying grades of MR, seen in the Adult Echocardiography Laboratory at UCSF, were analyzed retrospectively. All patients were evaluated for the six variables, each variable being scored on a four point scale from 0 to 3. The reference standards for MR were qualitative echocardiographic evaluation by an expert and quantitation of regurgitant fraction using two-dimensional and Doppler echocardiography. A subgroup of patients with low ejection fraction (EF < 50%) were also analyzed.

RESULTS

The MR Index increased in proportion to MR severity with a significant difference among the three grades in both normal and low EF groups (F = 130 and F = 42, respectively, p < 0.0001). The MR Index correlated with regurgitant fraction (r = 0.76, p < 0.0001). An MR Index > or =2.2 identified 26/29 patients with severe MR (sensitivity = 90%, specificity = 88%, PPV = 79%). No patient with severe MR had an MR Index <1.8 and no patient with mild MR had an MR Index >1.7.

CONCLUSIONS

The MR Index is a simple semiquantitative estimate of MR severity, which seems to be useful in evaluating MR in patients with a low EF.

Three-dimensional color Doppler: a clinical study in patients with mitral regurgitation

OBJECTIVES

The purpose of this study was to assess the clinical feasibility of three-dimensional (3D) reconstruction of color Doppler signals in patients with mitral regurgitation.

BACKGROUND

Two-dimensional (2D) color Doppler has limited value in visualizing and quantifying asymmetric mitral regurgitation. Clinical studies on 3D reconstruction of Doppler signals in original color coding have not yet been performed in patients. We have developed a new procedure for 3D reconstruction of color Doppler.

METHODS

We studied 58 patients by transesophageal 3D echocardiography. The jet area was assessed by planimetry and the jet volumes by 3D Doppler. The regurgitant fractions, the volumes, and the angiographic degree of mitral regurgitation were assessed in 28 patients with central jets and compared with those of 30 patients with eccentric jets.

RESULTS

In all patients, jet areas and jet volumes significantly correlated with the angiographic grading (r = 0.73 and r = 0.90), the regurgitant fraction (r = 0.68 and r = 0.80) and the regurgitant volume (r = 0.66 and r = 0.90). In patients with central jets, significant correlations were found between jet area and angiography (r = 0.86), regurgitant fraction (r = 0.64) and regurgitant volume (r = 0.78). No significant correlations were found between jet area and angiography (r = 0.53), regurgitant fraction (r = 0.52) and regurgitant volume (r = 0.53) in the group of patients with eccentric jets. In contrast, jet volumes significantly correlated with angiography (r = 0.90), regurgitant fraction (r = 0.75) and regurgitant volume (r = 0.88) in the group of patients with eccentric jets.

CONCLUSIONS

Three-dimensional Doppler revealed new images of the complex jet geometry. In addition, jet volumes, assessed by an automated voxel count, independent of manual planimetry or subjective estimation, showed that 3D Doppler is also capable of quantifying asymmetric jets.

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.

Three-dimensional echocardiographic analysis of valve anatomy as a determinant of mitral regurgitation after surgery for atrioventricular septal defects

Mitral regurgitation (MR) is a significant complication after atrioventricular septal defect (AVSD) surgery. The relation of the valve leaflet morphology and the MR mechanism remains a conundrum. Two-dimensional echocardiography depicts leaflet edges, whereas volume-rendered 3-dimensional echocardiography provides direct visualization of the surface areas of the mitral valve leaflets. This study examines the relation of mitral valve anatomy as determined by 3-dimensional echocardiography with MR origins in patients after AVSD repair. Twenty-seven patients with AVSD surgery and Doppler color MR were prospectively enrolled (median age was 5 years and 16 patients had Down syndrome). Doppler color flow imaging of the MR jet and 3-dimensional echocardiography of the mitral valve were performed with a probe in the transthoracic or transesophageal position. Enface 3-dimensional views of the mitral valve from the left atrium were reconstructed. Analysis of the 3-dimensional data was possible in 21 of the 27 patients. Mean area ratios of the 3 mitral leaflets were calculated (superior 40 +/- 7%, inferior 35 +/- 5%, mural 25 +/- 6%). Both intra and interobserver variability on the area measurements were <5%. In 12 patients (group 1) the jet appeared to emanate medially from the region of coaptation of the superior and inferior components of the anterior leaflet. In 9 patients (group 2) the jet emanated more laterally from the region toward the mural leaflet. The area ratios of the inferior leaflet were 32 +/- 4% in group 1 and 38 +/- 6% in group 2 (p = 0.02). The area ratios of the mural leaflet were 28 +/- 5% in group 1 and 21 +/- 5% in group 2 (p = 0.007). The superior leaflet area ratio was not different in groups 1 and 2, 40 +/- 9% and 41 +/- 6%, respectively. Three-dimensional echocardiography provides new insight into the anatomic determinants of MR following AVSD surgery.

Three-dimensional color Doppler: a new approach for quantitative assessment of mitral regurgitant jets

Color Doppler echocardiography does not provide adequate information about the severity of mitral regurgitation in patients with eccentric mitral regurgitation. We have developed a new procedure for 3-dimensional (3D) color Doppler reconstruction and for segmentation of regurgitant jets. The volume of regurgitant jets was compared with jet area in 63 patients with mitral regurgitation. Mitral regurgitation was assessed by angiography, regurgitant fraction and volume by pulsed Doppler, JA by planimetry, and JV by 3-dimensional Doppler. Twenty-eight patients with central jets were compared with 35 patients with eccentric jets. In the patients with eccentric jets, JV showed significant correlations with regurgitant volume (r = 0.90; P <.01) and regurgitant fraction (r = 0.76; P < .01) and was able to separate groups with different degrees of mitral regurgitation (P <.01). Three-dimensional Doppler revealed origin, direction, and spatial spreading of complex jet geometry. JV, a new parameter of mitral regurgitation, was also capable of quantifying asymmetrical 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.

Three-dimensional color Doppler for assessing mitral regurgitation during valvuloplasty

OBJECTIVE

Transesophageal color Doppler (or 2D Doppler) is the most widely used technique for intraoperative assessment of mitral valve repair. However, the most severe mitral regurgitations produce eccentric jet flows which cannot be assessed by 2D imaging. Up to now the indications for surgical intervention and intraoperative decisions after valve repair have been based on 2D Doppler examinations. Aim of this study was to compare conventional 2D Doppler to three-dimensional (3D) Doppler for assessing residual regurgitation in patients after mitral valvuloplasty.

METHODS

Twenty-four patients were referred to surgery for mitral valve repair. They underwent transesophageal echocardiography and 3D data acquisition during mitral valve reconstruction. Conventional assessment of mitral valve regurgitation, measured by color Doppler jet area, was compared to the volume of regurgitant jets obtained by 3D Doppler. Regurgitant volume and fraction were measured by pulsed Doppler and two-dimensional echocardiography. The 3D reconstructions of color Doppler data were accomplished by means of the 'Heidelberg Raytracing Algorithm' developed at our institution.

RESULTS

The jet areas did not show any significant correlation to the regurgitant fraction (r = 45; P = NS) or regurgitant volumes (r = 0.40; P = NS). In contrast the jet volumes correlated significantly to regurgitant fraction (r = 0.71; P < 0.01) and regurgitant volume (r = 0.85; P < 0.01). The reproducibility analysis of repeated jet volume and jet area measurements also showed that the parameter jet volume has a lower variability and higher agreement of repeated measurements than jet area.

CONCLUSIONS

Three-dimensional color Doppler flow imaging revealed the complex geometry of eccentric regurgitant jets and showed that the assessment of mitral regurgitation, based on conventional 2D Doppler, can be misleading. This new technique has a great potential for becoming a reference method for assessing mitral valve repair.

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.

Assessment of mitral regurgitant jets by three-dimensional color Doppler

BACKGROUND

Color Doppler echocardiography is a standard technique for assessing mitral regurgitation before and after mitral valvuloplasty. Mitral valve prolapse produces complex eccentric jet flows that cannot be visualized and measured by two-dimensional color Doppler echocardiography. The aim of this study was to evaluate the clinical impact of three-dimensional color Doppler echocardiography, a new technique developed at our institution, for assessing mitral regurgitation.

METHODS

Forty-five patients with mitral regurgitation underwent intraoperative transesophageal echocardiography and three-dimensional Doppler data acquisition. The grade of mitral regurgitation was assessed by angiography. The jet areas were calculated by planimetry from conventional color Doppler; the jet volumes were obtained by three-dimensional Doppler data.

RESULTS

New patterns of mitral regurgitant flows were recognized according to the origin, direction, and spatial spreading into the left atrium. Conventional jet areas failed to separate the groups of patients with different degrees of regurgitation, whereas the jet volumes were able to divide patients with different regurgitation grades. No significant correlation was found between jet area and angiographic grading (r = 0.63, p = NS). Jet volumes were significantly correlated to angiography (r = 0.89, p < 0.001).

CONCLUSIONS

Three-dimensional color Doppler echocardiography revealed new patterns of regurgitant flow and allowed a more accurate semiquantitative assessment of complex asymmetrical regurgitant jets.

[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.

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.