The Mitroflow pericardial valve. First five years of follow-up evaluation

The first 5 years durability study on a substantial number of Mitroflow pericardial valves makes the substance of the present report. One hundred eighty-eight valves were implanted on 166 patients before December 1985: 149 patients were discharged and are recalled annually. Follow up is 99% complete. In October 1988, mean follow up was 3.5 years (3-5.5). Total patients times years is 582. Sixty-two percent of the patients are asymptomatic, 58% in sinus rhythm. Forty-seven percent do not receive any anticoagulant therapy. The linearized rates of thromboembolism (1.2% per patient-year) and endocarditis (0.17 per patient-yr) is minimal. Seven patients only had valve dysfunction requiring explantation (1.2% per patient-yr). At 5 years, freedom of structural deterioration is 95.2% +/- 2.1. Single cusp tear at a stent post is the most frequent lesion (86%) as calcifications are observed in three only (major in two, microscopical in one). Histology does not permit to ascertain whether the tear is due to tissue fatigue or abrasion. Moderate microscopic architectural disruption of the valvular tissue is observed. Composite indices of all valve mortality and morbidity show at 5 years a 89.7% +/- 2.9 freedom of events. These data, associated to the high mechanical and optimal clinical characteristics of the valve, published previously, confirm the satisfactory performances of the valve at 5 years.