Hemodynamic performance of the Medtronic Mosaic and Perimount Magna aortic bioprostheses: five-year results of a prospectively randomized study

OBJECTIVE: Clinical outcomes of patients undergoing aortic valve replacement may be influenced by the presence of residual gradients and patient-prosthesis mismatch. The aim of this study was to compare hemodynamic performance and clinical outcomes at 5 years after prospectively randomized porcine versus bovine aortic valve replacement. We also aimed to determine the effects of valve hemodynamics on left ventricular (LV) mass regression. METHODS: A total of 108 patients undergoing aortic valve replacement were randomized to receive either the Medtronic Mosaic (MM) porcine (n=54) or the Edwards Perimount Magna (EPM) bovine pericardial prosthesis (n=54). Clinical outcomes, mean gradients, effective orifice area and LV mass regression were evaluated at 1 and 5 years after surgery. Follow-up echocardiograms were performed on 106 (98%) and 87 (92%) patients, respectively. RESULTS: Preoperative characteristics were similar between groups. Mean aortic annulus diameter and mean implant size were comparable in both groups. At 1 and 5 years, mean transprosthetic gradients were lower in the EPM group: EPM 10.3±3.4mmHg versus MM 16.3 ± 7.6 mmHg (p<0.0001) and EPM 9.6 ± 3.5 mmHg versus MM 16.8 ± 8.7 mmHg (p<0.0001), respectively. Similarly, indexed effective orifice areas (IEOA) at 1 and 5 years were significantly greater in the EPM group: EPM 1.10 ± 0.22 cm(2)m(-2) versus MM 0.96 ± 0.22 cm(2)m(-2) (p<0.004) and EPM 1.02 ± 0.25 cm(2)m(-2) versus MM 0.76 ± 0.19 cm(2)m(-2) (p<0.0001), respectively. At 5 years, the incidence of patient-prosthesis mismatch (IEOA ≤0.85 cm(2)m(-2)) was significantly lower in the EPM group: EPM 22.9% vs MM 73.9% (p<0.0001). Such differences were similar when analysis was stratified by surgically measured annular size and implant valve size. During the first year after surgery, both groups demonstrated similar regression of LV mass index (MM -26.3 ± 43 gm(2) vs EPM -30.1 ± 36 gm(-2); p=0.8); however, at 5 years, regression of LV mass index was significantly greater in the EPM group: (EPM -47.4 ± 35 gm(-2) vs -4.4 ± 36 gm(-2); p<0.0001). Five-year survival was 79.6 ± 4.1% in the MM group and 94.4 ± 2.2% in the EPM group (p=0.03). CONCLUSIONS: At 5 years, the EPM valve was significantly superior to the MM prosthesis with regard to hemodynamic performance, incidence of patient-prosthesis mismatch and regression of LV mass index. The hemodynamic superiority of the EPM prostheses in comparison to MM-prostheses demonstrated at 1 year, increased significantly over time.