Left ventricular mass regression after porcine versus bovine aortic valve replacement: a randomized comparison

It is unclear whether small differences in transprosthetic gradient between porcine and bovine biologic aortic valves translate into improved regression of left ventricular (LV) hypertrophy after aortic valve replacement. We investigated transprosthetic gradient, aortic valve orifice area, and LV mass in patients randomized to aortic valve replacement with either the Medtronic Mosaic (MM) porcine or an Edwards Perimount (EP) bovine pericardial bioprosthesis.

One hundred fifty-two patients with aortic valve disease were randomly assigned to receive either the MM (n = 76) or an EP prosthesis. There were 89 men (59%), and the mean age was 76 years. Echocardiograms from preoperative, postoperative, predismissal, and 1-year time points were analyzed.

Baseline characteristics and preoperative echocardiograms were similar between the two groups. The median implant size was 23 mm for both. There were no early deaths, and 10 patients (7%) died after dismissal. One hundred seven of 137 patients (78%) had a 1-year echocardiogram, and none required aortic valve reoperation. The mean aortic valve gradient at dismissal was 19.4 mm Hg (MM) versus13.5 mm Hg (EP; p < 0.0001), and at 1 year was 20.4 mm Hg versus 13.4 mm Hg (p < 0.0001). These differences were similar when the analysis was stratified by surgically measured annular size. The mean change in aortic valve gradient between predismissal and 1-year echocardiogram was +2.2 mm Hg (p = 0.02) for MM and -0.8 mm Hg (p = 0.33) for EP patients (p = 0.01 MM versus EP). The mean indexed aortic valve orifice area for MM and EP groups at dismissal and at 1 year was 0.9 cm(2)/m(2) versus 1.1 cm(2)/m(2), respectively (p < 0.01; p < 0.0001). During the first year after implantation, both groups demonstrated similar regression of LV mass index (MM, -32.4 g/m(2) versus EP, -27.0 g/m(2); p = 0.40). Greater preoperative LV mass index was the sole independent predictor of greater LV mass regression after surgery (p < 0.01).

Small differences in transprosthetic gradient and indexed aortic valve orifice area exist between porcine and bovine aortic valves. Despite this, both prostheses allow similar regression of LV mass during the first year after aortic valve replacement.