Effect of preoperative ejection fraction on survival and hemodynamic improvement following aortic valve replacement.

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Abstract
Patients (93) with aortic valve disease were evaluated to determine the effect of the preoperative left ventricular ejection fraction (EF) on the results of aortic valve replacement (AVR). Patients (46) had aortic stenosis (AS), 16 had aortic insufficiency (AI) and 31 had mixed aortic stenosis and insufficiency (MX). Immediate and long-term survival curves in AS and MX, and in AS patients with adequate preoperative EF (.gtoreq. 0.50) and those with depressed preoperative EF (< 0.50), were compared. There was a trend toward a greater early mortality rate (0-1 mo. after AVR), but this difference did not reach the level of statistical significance (P > 0.05). In patients surviving the 1-mo. preoperative period there was no significant difference in the long-term survival between the EF groups. Surviving patients (32), those with EF .gtoreq. 0.50 (18) and 14 with EF < 0.50, were further evaluated clinically and hemodynamically at an average interval of 29 mo. (range 9-66 mo.) after surgery. All AS and MX patients stayed at or improved to New York Heart Association (NYHA) class I or II. Of the AS or MX patients with depressed EF, 6 had distinctly abnormal arteriovenous O2 (A-VO2) difference (> 6 vol%) preoperatively. Surgery resulted in normalization of the A-VO2 difference in 4. The preoperative mean pulmonary arterial (PA) pressure was elevated to > 20 mm Hg in 5 of the AS or MX patients with depressed EF. Postoperatively, 4 of the 5 showed significant decreases (> 10 mm Hg) in the mean PA pressure, but most (4/5) of the patients remained abnormal (mean PA > 20 mm Hg). Hemodynamics obtained during 300 kg-m/min exercise showed gross abnormalities of pressure and flow in 7 of 8 patients with depressed EF. Stress-induced hemodynamic abnormalities were also present in 6 of 12 with EF .gtoreq. 0.50, but the abnormality was limited to moderate rises in the mean PA pressure in 5 of the 6. Similar clinical and hemodynamic changes were seen in the 8 restudied patients with AI, except that 2 patients with depressed EF were not improved clinically (remained NYHA class III postoperatively) and continued to have marked hemodynamic abnormalities postoperatively. A depressed preoperative EF may cause a moderate increase in the perioperative mortality rate, with little effect on subsequent long-term survival in patients with AS or MX undergoing AVR. Resting hemodynamic abnormalities seen in the depressed EF group often show significant improvement after surgery.