Influence of aortic valve replacement, prosthesis type, and size on functional outcome and ventricular mass in patients with aortic stenosis

Abstract

Objectives: Two years after surgery for severe aortic stenosis, we prospectively evaluated the influence of aortic valve replacement, as well as valve type (mechanical or stented biologic) and size, on functional status, left ventricular function, and regression of mass. Methods: Patients who received either a mechanical (n = 95) or a biologic valve (n = 42) were studied by echocardiography before the operation and after 2 years. Results: The percentage of patients with severe dyspnea decreased from 53% to 13% ( P = .001). The cardiac index increased from mean 2.6 L/min per square meter (95% CI: 2.48-2.72 L/min per square meter) to 3.1 L/min per square meter (95% CI: 2.94-3.26 L/min per square meter; P = .001). The percentage of the patients with mild-to-moderate diastolic dysfunction decreased from 43% to 18% ( P = .001). The left ventricular mass index was reduced by 42.4 g (95% CI: 35-50 g; P = .001). In comparison with biologic valves of the same size, mechanical valves produced a more pronounced reduction in mass index (overall difference 21.7 g; 95% CI: 37.1-6.4 g; P = .007) and a lower mean Doppler gradient (overall difference 4 mm Hg; 95% CI: 2-6 mm Hg; P = .0002). Conclusions: Patients undergoing aortic valve replacement had an improvement in functional status, as well as systolic and diastolic left ventricular function, and a reduction in left ventricular mass index, irrespective of prosthesis size and type. Mechanical valves are somewhat less obstructive than stented bioprosthetic valves of the same size. They are also associated with a concomitantly more pronounced reduction of left ventricular mass. (J Thorac Cardiovasc Surg 1999;118:57-65)