Predictors of Survival and Modes of Failure After Mitroflow Aortic Valve Replacement in 1,003 Adults

Background: Midterm outcomes are unknown for patients undergoing aortic valve replacement (AVR) with a Mitroflow bovine pericardial prosthesis (Sorin Group, Inc) and without anticalcification treatment. Recent reports warn of early senescence in younger adults.

Methods: From January 2004 through December 2011, 1,003 adults underwent Mitroflow AVR. The mean follow-up time was 25.0 (standard deviation [20.6]) months (total, 2,060 patient-years; maximum, 9 years). The patients were stratified for analysis according to age at implantation: group A, <60 years (n = 63, 6.3%); group B, 60-69 years (n = 173, 17.2%); group C, 70-79 years (n = 432, 43.1%); and group D, 80 years or older (n = 335, 33.4%).

Results: The mean age was 74.8 years (SD 9.8), and 609 patients (60.7%) were men. Aortic valve stenosis was present in 912 patients (90.9%), and 113 (11.3%) had severe aortic regurgitation. There were 27 (2.7%) early deaths, 15 of 431 (3.5%) underwent concomitant coronary artery bypass grafting while 12 of 572 (2.1%) did not (p = 0.18), and 151 patients (15.1%) died during follow-up. Nineteen AVRs (1.9%) required re-replacement through August 2013; 12 (63.2%) were associated with structural valve deterioration. The overall rates of freedom from valve-related reoperation at 3 and 5 years were 98.3% and 93.8%, respectively. Group A had the greatest number of reoperations (6/63; p < 0.001). The overall survival rates at 1 and 5 years were 91.2% and 67.3%, respectively. Independent predictors of mortality were poorer New York Heart Association functional class (hazard ratio [HR], 2.1; p < 0.001), atrial fibrillation (HR, 1.8; p = 0.002), and prior cardiac operation (HR, 1.8; p = 0.003).

Conclusions: Midterm follow-up shows acceptable hemodynamic performance of the Mitroflow biologic aortic valve prosthesis in selected patients 60 years old and older. Ongoing follow-up will be necessary to understand long-term performance and outcomes.