Aortic valve replacement with a small prosthesis.

Abstract

A small aortic prosthesis can be inserted in selected patients with excellent symptomatic improvement. A prospective evaluation was performed on 321 consecutive patients undergoing isolated aortic valve replacement between January 1982 and December 1984. Smaller prostheses (19 or 21 mm, predominantly pericardial valves, 132 patients) were inserted in older patients (p = .0001), women (p = .0001), smaller patients (body surface area: p = .0001), and patients with aortic stenosis (p = .0001). Twelve patients died in-hospital (3.7%) and 33 died during the follow-up period, producing an actuarial survival of 80% +/- 4% at 48 months. Survival was independently predicted by advancing age (p = .009), the preoperative NYHA functional class (p = .04) but not valve size (p = .28). Eighty-nine percent of patients were NYHA class I or II postoperatively compared with 22% preoperatively. Symptomatic recovery was similar for those with smaller size valves. Postoperative Doppler echocardiography in 57 patients revealed significant differences in aortic valve areas and gradients between the valve sizes. The 19 mm pericardial valves had the smallest areas (1.0 +/- 0.3 cm2) and the highest gradients (34 +/- 20 mm Hg). The aortic valve gradient was significantly related to cardiac output and valve size (p = .0001 by analysis of covariance). Linear regression analyses were used to estimate the aortic valve gradient during exercise (a 50% increase in cardiac output). The estimated exercise gradient was disturbingly high for the 19 mm valves (55 +/- 16 mm Hg), but the estimated exercise gradients for the 21, 23, and 25 mm valves were similar, all below 30 mm Hg. Aortic valve replacement with a small prosthesis resulted in excellent symptomatic improvement and acceptable resting valve gradients. However, a 19 mm prosthesis may produce prohibitive gradients during exercise, which may limit symptomatic recovery and should be avoided in active patients.