EFFECTS OF VALVE SURGERY ON LEFT-VENTRICULAR CONTRACTILE FUNCTION IN PATIENTS WITH LONG-TERM MITRAL REGURGITATION

Background Patients with long-term mitral regurgitation were studied b oth before and 1 year after successful valve surgery to test the hypot hesis that impaired left ventricular contractile function improves aft er surgery for long-term mitral regurgitation in humans. Methods and R esults Fifteen patients with long-term mitral regurgitation were studi ed. Micromanometer left ventricular pressures and radionuclide angiogr ams for left ventricular volumes were acquired over a range of loading conditions both before and 1 year after successful valve surgery for long-term mitral regurgitation. To assess both left ventricular contra ctility and pump efficiency, we used left ventriculoarterial coupling to evaluate the interaction of the left ventricle with the arterial sy stem with the use of the left ventricular contractile index, E(es), an d effective arterial elastance, E(a). Left ventricular pump efficiency was expressed as the ratio of forward left ventricular stroke work to the corresponding pressure-volume area. All patients had successful m itral valve surgery as manifest by no or only trivial residual mitral regurgitation on physical examination and Doppler echocardiography. Th e average radionuclide regurgitant index of 1.28+/-0.56 was also less than the preoperative value of 2.70+/-0.80 (P<.0001). The mean left ve ntricular end-diastolic volume index decreased from 137+/-37 to 90+/-3 1 mL/m(2) (P<.001), and the average left ventricular end-systolic volu me index also decreased (59+/-29 to 45+/-27 mL/m(2), P<.01), although individual variation was observed. The average left ventricular ejecti on fraction fell from 0.58+/-0.12 to 0.53+/-0.16, which was not signif icant. In contrast, E(es) increased from a mean value of 0.95+/-0.66 m m Hg/mL during the preoperative study to 2.62+/-2.16 mm Hg/mL at the 1 -year postsurgical study (P<.01). This improvement in left ventricular contractility was observed in patients with long-term mitral regurgit ation, who before surgery had preserved left ventricular ejection frac tion (P<.001), less left ventricular dilation at end diastole (P<.01) and end systole (P<.001), and less impaired left ventricular contracti lity. Because effective arterial elastance was unchanged, left ventric uloarterial coupling also improved from an average of 0.47+/-0.39 to 1 .81+/-1.63 (P<.01). Consequently, left ventricular pump efficiency imp roved from a mean preoperative value of 0.23+/-0.10 to 0.55+/-0.22 at the 1-year postsurgical study (P<.0001). Conclusions The results indic ate that left ventricular contractile impairment is reversible in many patients with longterm mitral regurgitation. In fact, these data indi cate that mitral valve surgery can be recommended to preserve left ven tricular contractility in patients with long-term mitral regurgitation , particularly in those patients who before surgery have normal left v entricular ejection fractions and less left ventricular dilation and c ontractile impairment.