Day to day variability of Doppler color flow jets in mitral regurgitation

Even mild mitral regurgitation is associated with incident atrial fibrillation in the general population

AIMS

Mitral regurgitation (MR) can be difficult to quantify. We sought to investigate whether the MR jet area to left atrial (LA) area ratio (MR/LA ratio) method for quantifying MRs can be used to predict incident atrial fibrillation (AF) in the general population.

METHODS AND RESULTS

The study included 4466 participants from the 5th Copenhagen City Heart Study, a prospective general population study, who underwent transthoracic echocardiography. MR jet area was measured and indexed to LA area. The endpoint was incident AF. MR was quantified in 4042 participants (mean age: 57 years, 43% men). Of these, 198 (4.9%) developed AF during a median follow-up period of 5.3 years (interquartile range: 4.4-6.1 years). MR was present in 1938 participants (48%) including 1593 (39%) trace/mild MRs (MR/LA ratio ≤ 20% and ≤4 cm2). In unadjusted analysis, MR/LA ratio was associated with incident AF [HR: 1.06 (1.00-1.13), P = 0.042 per 5% increase] but not after adjusting for CHARGE-AF score. However, the association was modified by age (P for interaction = 0.034), such that MR/LA ratio was associated with AF only in participants ≤ 73 years. In these participants, MR/LA ratio 'was' independently associated with AF after adjusting for CHARGE-AF score [HR: 1.14 (1.06-1.24), P = 0.001, per 5% increase]. This finding persisted when restricting the analysis to participants without moderate or severe MR and normal LA size [HR: 1.35 (1.09-1.68), P = 0.005, per 5% increase].

CONCLUSION

MR, including even trace regurgitations quantified by MR/LA ratio, is independently associated with incident AF in individuals ≤ 73 years of age.

Comparison of early results of percutaneous metallic mitral commissurotome with Inoue balloon technique in patients with high mitral echocardiographic scores

We compared the safety, efficacy, and cost of the newly introduced percutaneous metallic commissurotome (PMC) with the results of Inoue balloon mitral valvuloplasty (BMV) in 80 patients with mitral stenosis (MS). The mean increase in mitral valve area (MVA) was 0.95 +/- 0.19 to 1.7 +/- 0.35 cm(2) for PMC and 0.97 +/- 0.15 to 1.81 +/- 0.36 cm(2) for BMV (P = NS). The Wilkins echocardiographic scores before dilatation did not correlate with any difference in MVA after dilatation. Bilateral commissural splitting was significantly more common with PMC than with BMV (30/39 patients, 76.9%, vs. 21/40 patients, 52.5%; P = 0.02). Postprocedural severe mitral regurgitation occurred in 1/39 (2.6%) in the PMC group and in 4/41 (9.8%) in the BMV group. Because the PMC device is resterilizable, we estimated the cost to be one-fourth the cost of BMV with the Inoue balloon. The estimated device cost ratio of PMC to BMV for each patient was 1 to 4.25. The early results of PMC on the MVA are comparable to BMV. However, PMC had better results not only in patients with high echocardiographic scores, but the PMC device splits commissural calcification better than BMV.

Testing the test: the reliability of echocardiography in the sequential assessment of valvular regurgitation

BACKGROUND AND OBJECTIVE

Substantial variability in serial echocardiographic qualitative assessment of valvular regurgitation may exist. Reader variability is generally well understood, but acquisition variability (portions of variability caused by equipment, sonographers, physiologic changes) has been less frequently assessed, particularly in combination with reader variability. We attempted to determine the relative contributions of acquisition and reader variability as components of total test-retest variability for aortic (AR) and mitral (MR) regurgitation.

METHODS

Outpatient echocardiographic study was done at 2 clinical sites. Twenty-three predominantly obese middle-aged females had 3 echocardiograms, 2 performed 14 +/- 3 days apart and the third performed within 1 to 2 hours of the second. Triplets of echocardiograms were evaluated for change in grade of AR and MR. Medical history, anthropometrics, and blood pressures were obtained.

RESULTS

Average intrareader variability (percentage of reads for which there is within-reader disagreement) was 5.6% for AR and 16.7% for MR. The average total test-retest variability (percentage of reads for which there is disagreement between visits) was 29.0% for AR and 24.6% for MR. The acquisition variability for AR was 23.4% +/- 7.7%; for MR, it was 7.9% +/- 10.2%. A significant predictor of change for AR/MR was the initial grade. Change in diastolic blood pressure was positively associated with change in AR and MR.

CONCLUSIONS

Intrareader agreement was substantial for AR and MR. Components of total test-retest variability found were reader, biological (change in diastolic blood pressure), and regression to the mean. Recommendations for clinical practice include monitoring blood pressure changes and understanding the confidence limits of the clinical test. Test-retest variability and its components should be considered in echocardiography and other diagnostic testing.

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.

Comparison of vena contracta width by multiplane transesophageal echocardiography with quantitative Doppler assessment of mitral regurgitation

Mitral regurgitation (MR) severity is routinely assessed by Doppler color flow mapping, which is subject to technical and hemodynamic variables. Vena contracta width may be less influenced by hemodynamic variables and has previously been shown to correlate with angiographic estimates of MR severity. This study was performed to compare mitral vena contracta width by multiplane transesophageal echocardiography (TEE) with simultaneous quantitative Doppler echocardiography in 35 patients with MR. The vena contracta width was measured at the narrowest portion of the MR jet as it emerged through the coaptation of the leaflets; it was identified in 97% of the patients. Vena contracta width correlated well with regurgitant volume (R2 = 0.81) and regurgitant orifice area (R2 = 0.81) by quantitative Doppler technique. A vena contracta width > or = 0.5 cm always predicted a regurgitant volume >60 ml and an effective regurgitant orifice area > or = 0.4 cm2 in all patients. A vena contracta width < or = 0.3 cm always predicted a regurgitant volume <45 ml and a regurgitant orifice area < or = 0.35 cm2. Thus, vena contracta width by multiplane TEE correlates well with mitral regurgitant volume and regurgitant orifice area by quantitative Doppler echocardiography and provides a simple method for the identification of patients with severe MR.

Quantitative Assessment of Simulated Regurgitant Flow Using Direct Digital Acquisition of Doppler Color Flow Images

Analysis of jet momentum and proximal isovelocity surface area (PISA) have been shown to be accurate in quantitating regurgitant flow for axisymmetric free jets. However, eccentric jets directed against chamber walls are often encountered in clinical practice and could confound the assessment of regurgitant flow. Thus, we used direct digital color flow mapping to calculate flow by the momentum method and PISA in a flow model. Steady flow jets were driven through a 2-mm round orifice at flow rates of 3, 6, 9, 12, 15, and 20 mL/sec. Jets were directed centrally and against the lateral wall of a 150 mL chamber. The raw data from a 3.25/2.5 MHz transducer (Vingmed CFM 750) was digitally transferred to a Macintosh IIci computer for analysis of the velocities comprising the jets. By linear regression, PISA was accurate in assessing flow for both free jets and wall jets (r(2) = 0.98) with regression lines approximating unity. The momentum method was highly accurate for free jets (r(2) = 0.98) but systematically underestimated flow for wall jets (r(2) = 0.70, y = 0.21x + 0.88). Thus, analysis of simulated regurgitant flow using digital display of velocities encoded in the color flow jet is accurate for free jets by both the PISA and momentum techniques. In wall jets, the momentum technique underestimates flow because the requirement for jet axisymmetry is not met.

Accuracy of intraoperative transesophageal echocardiography for estimating the severity of functional mitral regurgitation

Although intraoperative transesophageal echocardiography (TEE) is used to guide mitral valve reconstructive procedures, the effects of hemodynamic alterations accompanying general anesthesia on mitral regurgitation (MR) are unknown. This study was performed to evaluate the effect of general anesthesia on MR jet size using TEE with color Doppler imaging in patients undergoing mitral valve surgery. Matched preoperative TEEs performed with the patient under intravenous conscious sedation, and intraoperative studies performed with the patient under general anesthesia were retrospectively reviewed in 46 patients undergoing mitral valve surgery. Patients were divided into groups based on etiology of MR, including 21 patients with myxomatous degeneration and leaflet flail, 19 patients with structurally normal leaflets and functional regurgitation due to abnormal leaflet coaptation, and 6 patients with rheumatic mitral disease. On both preoperative and intraoperative studies, regurgitation was quantified using maximal jet area and jet diameter at the vena contracta on color flow Doppler. Patients with leaflet flail and patients with functional MR had similar measures of regurgitation severity on preoperative imaging. On intraoperative imaging, regurgitant jet size was unchanged compared with preoperative studies among patients with leaflet flail (jet diameter 1.04 +/- 0.26 vs 1.10 +/- 0.28 cm, area 9.8 +/- 4.5 vs 10.1 +/- 5.2 cm2 on preoperative studies), although jet size decreased significantly in patients with functional MR (jet diameter 0.79 +/- 0.33 vs 1.10 +/- 0.29 cm [p < 0.001], area 5.7 +/- 3.5 vs 10.0 +/- 3.8 cm2 [p < 0.001] on preoperative studies). These findings were not accounted for by variation in heart rate, blood pressures, echocardiographic instrumentation, or Doppler Nyquist limit.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiplane transesophageal echocardiographic assessment of mitral regurgitation by Doppler color flow mapping of the vena contracta

Assessment of the severity of mitral regurgitation (MR) by Doppler color flow mapping is limited by dependence of jet area on hemodynamic and technical variables. The width of the MR jet at its origin may be less dependent on hemodynamic variables, and thus should more accurately reflect the severity of MR. Doppler color flow mapping was performed in 80 subjects by transesophageal echocardiography (TEE) within 48 hours of catheterization. Width of the MR jet at its vena contracta was measured by both single plane and multiplane TEE and compared with the angiographic grade of MR and regurgitant volume. The width of the MR jet correlated closely with angiographic grade by both methods. A jet width > or = 6 mm identified angiographically severe MR with a sensitivity and specificity of 100% and 83% by single-plane TEE, and 95% and 98% by multiplane TEE. The sensitivity and specificity for detecting a regurgitant volume > or = 80 ml was 93% and 76% for single-plane TEE, and 86% and 95% for multiplane TEE. Thus, the width of the MR jet at its vena contracta by Doppler color flow mapping is an accurate marker of the severity of MR. By virtue of its ability to obtain orthogonal views specifically oriented to mitral leaflet coaptation, multiplane TEE is superior to single-plane TEE in assessing MR jet width.

Effect of captopril on functional mitral regurgitation in dilated heart failure: a randomised double blind placebo controlled trial

OBJECTIVE

To determine the efficacy and dose requirements of captopril to reduce functional mitral regurgitation in patients with dilated heart failure.

DESIGN

A randomised double blind placebo controlled parallel arm trial. Incremental daily doses of 25 mg, 50 mg and 100 mg captopril used for a four week period each for a total of 12 weeks preceded by a two week placebo washout. Twenty eight ambulatory patients (mean age 72) New York Heart Association (NYHA) class II or III with apparently controlled ischaemic dilated heart failure (ejection fraction 29% (0.04%)) on digoxin, diuretics, and nitrates were randomised. All had at least grade 2/4 functional mitral regurgitation (> 5 cm2 regurgitant area on colour flow Doppler).

RESULTS

Twenty three patients completed the study (13 on placebo and 10 on captopril). Significant improvements were confined to the captopril group. Compared with placebo the following improvements were noted in the captopril treated group: mitral regurgitant area decreased from a threshold at 50 mg/day (p < 0.05, mean (95% confidence interval (95% CI)) 3.1 (0.2 to 6.0) cm2), with a further decrease at 100 mg/day (p < 0.01, mean (95% CI) 5.3 (3.1 to 7.5) cm2). Significant improvements in all the other measurements were noted only after 100 mg/day. Stroke volume increased (p < 0.01, mean (95% CI) 11, (1.4 to 21) ml), systemic vascular resistance decreased (p < 0.05, mean (95% CI) 414 (35 to 793) dyn s cm5), left atrial area decreased (p < 0.05, mean (95% CI) 4.3 (0.03 to 8.6) cm2), and deceleration time increased (p < 0.01, mean (95% CI) 52 ms (7 to 98) ms). Left ventricular diameter decreased marginally (p = 0.06, mean (95% CI) 4 (-0.05 to 9 mm). Duke activity index score increased (p < 0.001, median (95% CI) 6.8 (4.5 to 12) points). Heart rate, mean arterial blood pressure, serum creatinine, and serum potassium did not change with either placebo or captopril. No patient was withdrawn directly due to the side effects of captopril. In an open phase nine placebo patients given captopril in rapid increments reaching 100 mg/day in the fourth week showed similar improvements.

CONCLUSION

Captopril is efficacious in reducing functional mitral regurgitation in dilated heart failure. Patients require and must tolerate high doses (50-100 mg/day) for additive effects over supervised conventional treatment to occur.

Comparison of transthoracic and transesophageal echocardiography in evaluation of 47 Starr-Edwards prosthetic valves

OBJECTIVES

Our objectives were to characterize by transesophageal echocardiography the normal appearance of the Starr-Edwards prosthetic heart valve and to compare the utility of transesophageal and transthoracic echocardiography in detection of valve abnormality.

BACKGROUND

The Starr-Edwards prosthetic heart valve, the first mechanical valve to be used, has demonstrated excellent durability.

METHODS

Fifty transthoracic and transesophageal echocardiographic studies on 37 patients with 47 Starr-Edwards prosthetic valves were analyzed retrospectively. Six cases of surgically confirmed infective endocarditis were studied.

RESULTS

Vegetation or abscess formation, or both, was identified by transesophageal echocardiography in all six cases of infective endocarditis but was found in only one of these cases by transthoracic echocardiography. Thrombus was detected by transesophageal echocardiography in 9 of 11 patients with transient ischemic attacks or stroke and in 2 patients by transthoracic echocardiography with 3 confirmed at surgery. In 26 of the 30 patients with a mitral Starr-Edwards valve, the valve demonstrated a trivial or mild "closing volume" early systolic or holosystolic leak on transesophageal echocardiography alone. Transthoracic evaluation identified significant mitral regurgitation in six of the eight patients who had this finding on transesophageal echocardiography. Serial studies were performed to assess response to treatment or need for surgical intervention in eight patients. Seventeen valves have been implanted for 12 years; six of these had significant leakage without apparent cause, a finding not observed more recently implanted valves.

CONCLUSIONS

These observations demonstrated the unique utility of transesophageal echocardiography in patients with Starr-Edwards prosthetic valve dysfunction, endocarditis or thrombus formation, and of the clear superiority of transesophageal echocardiography over transthoracic echocardiography in these situations.

Influence of the Coanda effect on color Doppler jet area and color encoding. In vitro studies using color Doppler flow mapping

We studied surface adherence and its effects on color Doppler jet areas and color encoding in an in vitro model with a noncompliant receiving chamber into which a steady flow jet was directed parallel to either a straight or a curved surface adjacent to and 4 mm away from the inflow orifice (1.50 mm2) with the control condition being a free jet matched for flow rates and driving pressures. Jets were imaged perpendicular to the plane of the surface, the plane in which most clinical images of jet-surface interactions are obtained. Ten different flow rates ranging from 0.13 to 0.30 l/min were used. Surface-adherent jet areas were smaller than control jets for every driving pressure-volume combination (paired t test, p less than 0.01). Computer analysis of color Doppler images showed more green and blue (reverse flow) pixels on the surface side of the adherent jets than the control jets (p less than 0.05), suggesting that viscous energy loss and flow deceleration and reversal play a role in the jet-surface interaction. Analysis of variance demonstrated that linear regression slopes of flow rate versus jet area for surface jets were lower (slopes, 11-21 cm2/l/min; r = 0.95-0.97) than those for the control (slope, 33 cm2/l/min; r = 0.97) (p less than 0.0001). Surface adherence (Coanda effect) influences jet size and color encoding, causing smaller color Doppler jet areas and greater variance and reverse velocity encoding.

Evaluation of mitral regurgitation by Doppler echocardiography

The diagnosis and assessment of mitral regurgitation has been one of the main challenges for cardiac ultrasound. Imaging techniques (M-mode and two-dimensional echocardiography) provide direct morphologic and etiologic information of the evaluation of patients with suspected mitral regurgitation. The advent of cardiac Doppler increased tremendously the ability to evaluate mitral regurgitation noninvasively. Continuous-wave and pulsed Doppler have been found to be sensitive and specific in the detection of mitral regurgitation. The introduction of color flow Doppler simplified enormously the assessment of patients with suspected mitral regurgitation. The maximal regurgitant area and maximal regurgitant area corrected for left atrial size have become the most commonly used parameters to evaluate mitral regurgitation by color flow Doppler in the clinical setting. However, the color regurgitant jet area is highly dependent on anatomical, hemodynamic, and equipment factors. A new method, based on the proximal isovelocity surface area, is being evaluated and appears to be relatively independent of equipment factors. Transesophageal echocardiography has been shown to be exquisitely sensitive in the detection of mitral regurgitation. Quantitation of mitral regurgitation by transesophageal echocardiography is currently based on the maximal regurgitant area and this parameter appears to correlate closely with the angiographic degree of mitral regurgitation. Pulmonary venous flow analysis had been used in conjunction with color flow mapping for the evaluation of mitral regurgitation by transesophageal echocardiography. The presence of reversed systolic flow has been shown to be sensitive and specific for the diagnosis of severe mitral regurgitation. Patients with clinically difficult surface studies, flail mitral valve leaflets, and prosthetic mitral valve are best evaluated by the transesophageal approach with interrogation of pulmonary venous flow.

Quantification of mitral regurgitation: comparison between transthoracic and transesophageal color Doppler flow mapping

We reviewed transthoracic (TTE) and transesophageal (TEE) echocardiograms of 100 consecutive patients: 63 male, 37 female, mean age 50 years (range 16-83 years), 32 with neoplastic disease, 18 aortic disease, 28 mitral valve disease, and 22 with other diseases. Absence or presence of mitral regurgitation (defined as mild, moderate, or severe) was assessed. TEE showed mild mitral regurgitation in 26 patients where TTE was negative. The overall estimate of regurgitant lesion severity was concordant at TEE and TTE in 64% of cases. The overall estimate of regurgitant lesion severity was also greater by one grade in 1% of cases at TTE, and in 35% of cases at TEE. Maximal digitized jet areas were 3.60 +/- 6.35 cm 2 at TTE and 3.04 +/- 3.79 cm 2 at TEE (P = NS). Correlation was r = 0.69 (TEE = 0.41 TTE + 1.55; P less than 0.001). TEE yielded a higher prevalence of mitral regurgitation than TTE with a trend toward greater overall estimate of mitral regurgitation at the semi-quantitative analysis. TTE and TEE showed similar mean results at the quantitative assessment of maximal jet areas. However, a highly significant random variability was observed in quantifying mitral regurgitation at TEE.

Intraoperative transesophageal Doppler color flow imaging used to guide patient selection and operative treatment of ischemic mitral regurgitation

BACKGROUND

Intraoperative transesophageal Doppler color flow imaging (TDCF) affords the opportunity to assess mitral valve competency immediately before and after cardiopulmonary bypass (CPB). The purpose of this study was to assess the utility of TDCF to assist in the selection and operative treatment of ischemic mitral regurgitation (MR).

METHODS AND RESULTS

Two hundred forty-six patients undergoing surgery for ischemic heart disease were prospectively studied. All had preoperative cardiac catheterization. Catheterization and pre-CPB TDCF were discordant in their estimation of MR in 112 patients (46%). Compared with patients in whom both techniques agreed in estimation of MR, patients with discordance in MR were more likely to have had unstable clinical syndromes at the time of catheterization (79% versus 40%, p less than 0.05) or to have received thrombolytics (16% versus 8%, p less than 0.05). Pre-CPB TDCF resulted in a change in the operative plan with respect to the mitral valve in 27 patients (11%). Because less MR was found by TDCF than catheterization, 22 patients had only coronary bypass grafting when combined coronary bypass and mitral valve surgery had been planned. Because more MR was found by TDCF than catheterization, five patients had combined coronary bypass and mitral valve surgery when coronary bypass alone had been planned. Unsatisfactory results noted by TDCF following mitral valve surgery in five patients resulted in immediate corrective surgery. Cox regression analysis identified residual MR at the completion of surgery to be an important predictor of survival (chi 2 = 21.4) after surgery--more important than patient age (chi 2 = 8.3) or left ventricular ejection fraction (chi 2 = 5.3).

CONCLUSIONS

These results indicate that TDCF is useful in guiding patient selection and operative treatment of ischemic MR and that in such patients, intraoperative TDCF should be performed routinely.