Mitroflow synergy prostheses for aortic valve replacement:: 19 years experience with 1,516 patients

Background. Pericardial prostheses have been used as valvular substitutes since 1975. They combine excellent hemodynamic characteristics with a low risk of valve failure during long-term observation. The aim of this article is to describe the clinical long-term performance of the Mitroflow Synergy pericardial valve (Sorin Group Inc, Mitroflow Division, Vancouver, Canada) in the aortic position for as long as 19 years. Methods. Data were obtained between February 1985 and April 2004 from patients with aortic heart valve replacements (n = 1,464) or from patients with replacements of existing prosthetic aortic valves (n = 52). The age group distributions are less than 70 years (n = 175); 70 to 74 years (n = 462); 75 to 79 years (n = 532); 80 to 84 years (n = 273); and greater than or equal to 85 years (n = 74). The cause of the aortic valve lesions was combined (insufficiency and stenosis) in the majority of patients (62.4%). Concomitant procedures were performed in 897 patients (59.2%) and coronary artery bypass grafting was the most common (53.5%). Mean follow-up was 5.5 +/- 0.09 years. Total follow-up was 8,408 patient-years. Results. The early mortality (30 days) was 6.6% (n = 99) and late deaths were 60.8% (n = 921). Actuarial event-free rates at 5, 10, and 15 years of follow-up are given as mean standard error for endocarditis: 96.9 +/- 0.5, 92.8 +/- 1.2, and 92.0 +/- 1.4, respectively; embolism: 96.7 +/- 0.6,88.8 +/- 1.7, and 82.9 +/- 3.5, respectively; bleeding: 98.5 +/- 0.4, 97.2 +/- 0.6, and 94.4 +/- 1.7, respectively; structural valve deterioration: 99.0 +/- 0.3, 82.8 +/- 2.2, and 62.8 +/- 5.8, respectively, and reoperation: 98.2 +/- 0.4, 79.2 +/- 2.4, and 63.4 +/- 5.3, respectively. The rate of endocarditis, structural valve degeneration, and reoperation was lower in patients 75 years of age and older compared with younger patients, whereas embolism occurred more frequently in elderly than in younger patients. Conclusions. Adverse events after implantation of Mitroflow aortic bioprosthesis rarely occurred during the first 5 years after valve replacement. The results of the prosthesis indicates reliable long-term morbidity rates and good durability in patients 75 years of age and older.