PATHOPHYSIOLOGY AND NATURAL HISTORY AORTIC DISEASE Reversal of left ventricular dysfunction after aortic valve replacement for chronic aortic regurgitation: influence of duration of preoperative left ventricular dysfunction

Preoperative left ventricular systolic function is an important predictor of postoperative prognosis in patients with aortic regurgitation. Although left ventricular dysfunction is reversible after aortic valve replacement to a greater extent in patients with good preoperative exercise capacity compared with patients with impaired exercise capacity, not all patients with preserved exercise capacity demonstrate improved left ventricular function after aortic valve replacement. To determine the influence of duration of preoperative left ventricular dysfunction on postoperative reversal of left ventricular dysfunction, we studied 37 patients with aortic regurgitation who preoperatively had left ventricular dysfunction. defined as subnormal echocardiographic fractional shortening (less than 29%), and good preoperative exercise capacity, defined as completion of stage 1 of the NIH treadmill protocol without limiting symptoms. Eight patients were asymptomatic. In 1 I patients left ventricular dysfunction was documented 18 to 57 months preoperatively (prolonged); in 10 patients left ventricular dysfunction developed in an interval of 14 months or less preoperatively (brief); in 16 patients duration of left ventricular dysfunction was unknown. Patients with brief vs those with prolonged left ventricular dysfunction did not differ with respect to severity of preoperative symptoms or exercise tolerance, echocardiographically determined left ventricular dimensions or fractional shortening (25 ± 3% [SDI vs 25 + 3%), or radionuclide angiographic ejection fraction (42 + 5% vs 42 ± 5%). After operation, however, patients with brief left ventricular dysfunction developed a smaller left ventricular diastolic dimension (50 ± 3 vs 59 ± 8 mm; p < .005) and a higher ejection fraction (63 + 7% vs 43 ± 12%; p < .001) than patients with prolonged left ventricular dysfunction; postoperative ejection fraction was intermediate in patients with unknown duration of preoperative left ventricular dysfunction (48 ± 1 1%; p < .001). All deaths occurred in patients with either prolonged or unknown duration of left ventricular dysfunction. Thus the duration of preoperative left ventricular dysfunction in patients with aortic regurgitation is an important determinant of the reversibility of left ventricular dysfunction after aortic valve replacement. Circulation 70, No. 4, 570-579, 1984. IN PATIENTS with chronic aortic regurgitation, preoperative left ventricular contractile function is an important determinant of postoperative prognosis. Patients with impaired left ventricular systolic function are at risk of irreversible myocardial dysfunction and subsequent death from congestive heart failure despite technically successful valve replacement. -' However, several studies indicate that preoperative left ventricular dysfunction may be reversible in many patients after operation.9"'7 A major predictor of postoperative From the Cardiology and Cardiac Surgery Branches, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda. Address for correspondence: Robert 0. Bonow, M.D.. Bldg. 10, Room 7B-15, National Institutes of Health. Bethesda, MD 20205. Received March 27, 1984; revision accepted July 5, 1984. results in such patients is the severity of preoperative symptoms, measured either subjectively by functional class6 7 or objectively by exercise tolerance"3; patients with preserved exercise capacity despite left ventricular dysfunction have improved late postoperative survival and a greater likelihood of improvement in left ventricular function than patients with poor exercise capacity.'3 However, although most patients in our experience with left ventricular dysfunction and preserved exercise capacity manifest an improvement in left ventricular function after operation, we have observed several such patients in whom left ventricular function has not changed or has decreased after operation. This led us to suspect that additional factors CIRCULATION 570 by gest on Sptem er 5, 2017 http://ciajournals.org/ D ow nladed from PATHOPHYSIOLOGY AND NATURAL HISTORY-AORTIC DISEASE besides severity of preoperative symptoms might be determinants of reversibility of left ventricular dysfunction. In this study we investigated the influence of the duration of preoperative left ventricular dysfunction on the functional results of aortic valve replacement.