Clinical and hemodynamic features of advanced rheumatic 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.

Reversibility of mitral regurgitation following rheumatic fever: clinical profile and echocardiographic evaluation

The clinical disappearance of the murmur of rheumatic mitral regurgitation after period of time has been documented by many researchers. However no studies have related the disappearance of the murmur with the functional or anatomical state of the mitral valve. This study was done to elucidate the mitral valve status using doppler and color coded echocardiography among those children who have lost their apical pansystolic murmur on auscultation following a documented attack of rheumatic fever. The study sample consisted of 51 patients including 31 patients in whom the murmur has disappeared (group I), and 20 patients with persistent isolated mitral regurgitation (group II). Patients of group I had significantly lower grades of murmur intensity, lower incidence of cardiomegaly, and had no heart failure in the initial attack. They were more compliant with prophylaxis and had less recurrences than patients of group II. The murmur disappeared in patients of group I from 1/2 to 14 years after the initial attack. Echocardiography revealed that such patients had a normal mitral valve apparatus, and a normal heart size and function. Only 5 patients of this group had a significant regurgitant jet demonstrated by colour doppler. We concluded that recovery of the mitral valve and return of cardiac functions to normal is possible in patients who had mitral regurgitation following rheumatic fever. Some of them may still have an inaudible mild regurgitation. Patients who have lost their murmur may be allowed to exercise freely, yet penicillin prophylaxis should not be discontinued.

Determination of the pulmonary capillary wedge position in patients with giant left atrial V waves

Thirteen patients with giant left atrial V waves during preoperative cardiac catheterization were admitted into the study group. While awake and breathing spontaneously, simultaneous recordings of electrocardiographic leads II and V5, radial arterial traces, and pulmonary arterial or pulmonary capillary wedge traces were obtained. Measurements were made on four consecutive cardiac cycles in the unwedged and wedged positions for the following intervals: Q wave to the radial arterial upstroke (220 +/- 20 milliseconds) and peak (360 +/- 10 milliseconds), Q wave to the pulmonary arterial upstroke (170 +/- 20 milliseconds) and peak (350 +/- 20 milliseconds), Q wave to the V wave upstroke (280 +/- 20 milliseconds) and peak (570 +/- 20 milliseconds), and QT interval (420 +/- 20 milliseconds). These findings indicate that the radial arterial and pulmonary arterial upstrokes and peaks occur nearly simultaneously. Upon wedging, the V wave upstroke occurs significantly later in the cardiac cycle (P less than .05) compared with the pulmonary arterial upstroke, and the V wave peak occurs significantly later compared with both the pulmonary arterial and the radial arterial peak (P less than .05). A rapid, simple beat-to-beat method for differentiating pulmonary arterial from pulmonary capillary wedge positions in the presence of giant left atrial V waves is the superimposition of the pulmonary arterial trace on the radial arterial trace. When a wedge position is attained, there is an immediate rightward shift in the upstroke and peak of the pulmonary arterial pressure trace, which can be easily identified by observing the relationship between the pulmonary arterial and systemic arterial traces.

The Syndrome of Severe Mitral Regurgitation with Normal Left Atrial Pressure

It has been generally thought that significant elevations of the left atrial and pulmonary vascular pressures occur in patients with mitral regurgitation of sufficient severity to produce serious disability and gross enlargement of the left atrium. Ten patients with severe mitral regurgitation have been encountered in whom gross left atrial enlargement was accompanied by normal left atrial and pulmonary artery pressures. These patients ranged in age from 8 to 49 years, all were in functional classes III or IV, and the average duration of symptoms was 7.3 years. Nine patients had rheumatic mitral regurgitation while one had a congenital lesion. Atrial fibrillation and the physical findings of pure mitral regurgitation were present in all patients, as was striking left atrial enlargement on their roentgenograms. Left atrial pressure, determined by left heart catheterization, averaged 9.1 mm. Hg and did not exceed 12 mm. Hg in any patient, and the V wave was not particularly prominent. The cardiac index was markedly depressed and averaged 2.0 L./min./M. 2 B.S.A.

The observed discrepancy between left atrial size and pressure must reflect a disturbance in the compliance of the left atrial wall. It is suggested that long-standing mitral regurgitation may modify the mechanical characteristics of the atrial wall and that the presence of a normal left atrial pressure must not be assumed to exclude the presence of severe mitral regurgitation. The manner in which variations in left atrial compliance affect the clinical picture of mitral regurgitation and the selection of patients for operative intervention are discussed.

Evaluation of Mitral Annuloplasty for Mitral Regurgitation

Eleven patients seriously disabled by mitral regurgitation were re-evaluated 4 to 41 months following mitral annuloplasty (average 19.4 months). Preoperative and postoperative comparative data are presented. One patient was unimproved or worse. The rest were subjectively better.

Mean changes were transverse cardiac diameter -17.8 mm. (median 15 mm.) ( p < .005); resting stroke index +9 ml./beat/M. 2 (median 9 ml./beat/M. 2 , p < .05); resting cardiac index +0.5 L./min./M. 2 ( p = .20); mean pulmonary artery pressure -7.2 mm. Hg, or 29 per cent (median 8 mm. Hg, p < .03); and arteriovenous oxygen difference -12 ml./L. (median 13 ml./L., p < .005). Abnormally prolonged mixing, as shown by indicator-dilution curves, was decreased in all patients ( p < .05). Exercise testing showed varying degrees of improvement in six of the nine so studied.

In six patients mitral regurgitation by angiocardiographic measurements postoperatively represented 0, 0, 21, 24, 35, and 46 per cent of the total left ventricular stroke volume. Two patients had increased end-systolic left ventricular volume as evidence for postoperative left ventricular failure. The other four were probably normal.

Ten of the 11 patients showed postoperative improvement that was felt to be significant in two or more of the above objective measures. Striking x-ray improvement in heart size occurred in two patients, eight others showed decreases in transverse diameter of up to 17 mm. One developed an increase in heart size.

Although probably improved over their preoperative status, two patients had significant mitral stenosis at the time of re-evaluation. Another showed evidences of progressive mitral regurgitation after an initial period of improvement.

Mitral annuloplasty is a palliative procedure with considerable potential for effecting a reduction in regurgitant volume and improving the clinical status of carefully selected patients.