HEMODYNAMIC EVALUATION OF THE CARPENTIER-EDWARDS PORCINE XENOGRAFT

The hemodynamic function of the thin-wall, glutaraldehyde-treated porcine xenograft was evaluated in 37 asymptomatic patients an average of 8 months (range 6-15 months) after operation. Three patients had a double-valve replacement. Cardiac output and simultaneous transvalvular gradients were recorded at rest during moderate supine exercise. In 25 patients with an aortic bioprosthesis, the average mean gradient was 18 mm Hg and the effective orifice area 1.5 cm2 (range 0.5-2.8 cm2). The average aortic valve area for seven patients with a small valve (21 or 23 mm) was 1.2 cm2. during exercise, the mean gradient increased to 23 mm Hg (range 7-36 mm Hg) and the effective orifice area increased to 1.8 cm2 (range 1.0-3.8 cm2). In 15 patients with a mitral bioprosthesis, the average diastolic gradient was 6 mm Hg and the effective orifice area 2.4 cm2 (range 1.4-3.9 cm2). The average mitral valve area for 10 patients with a 27- or 29-mm valve was 2.1 cm2. During exercise, the mean gradient increased to 14 mm Hg (range 6-32 mm Hg) and the effective orifice area increased to 2.8 cm2). Of the 40 valves evaluated, three had mild and one had moderate regurgitation. We conclude that the Carpentier-Edwards valve has hemodynamic characteristics similar to those of other currently used prostheses. Like other bioprostheses, small valve sizes in the aortic position have a small effective orifice area and should be used selectively according to the patient's body surface area. This precaution is not required in valves 25 mm or larger. In the mitral position, all biological and mechanical valves are mildly obstructive due to leaflet, poppet or disc inertia. The Carpentier-Edwards valve has an acceptable effective orifice area in the stent sizes evaluated in this study. However, moderate gradients during supine exercise are common in the smaller valve sizes.