Bileaflet mechanical prostheses performance in mitral position

Objective: The experience with the Carbomedics (CM) and the St. Jude Medical (SJM) bileaflet mechanical prostheses was evaluated to determine thromboembolic and hemorrhagic complications and predictive risk factors. Methods: From 1989 to 1994, a total of 625 patients had mitral valve replacement (CM, 240; SJM, 385); 32.5% (203), concomitant procedures and 32.8% (205), previous cardiac surgery, primarily valve replacement procedures. Results: The pre-operative variables did not distinguish the populations, except for previous surgery CM 37.9% and SJM 29.6% (P < 0.05). The pre-operative variables (type of prostheses, cardiac rhythm, coronary artery bypass, NYHA III/IV, advancing age, gender, urgency status and previous surgery) were not predictive of overall thromboembolism (TE), major TE, minor TE, prosthesis thrombosis and hemorrhage (P not significant; P = NS). The linearized rate of total TE events for overall MVR was 5.0%/patient-year (CM 4.3; SJM 5.4). The less than or equal to 30 day major crude rate was 0.44%, while the > 30 day late major event rate was 2.0%/patient-year. Of the total TE events 91% of less than or equal to 30 days and 75%, > 30 days had an INR < 2.5 at or immediately prior to the event. The thrombosis rate (included in TE events) was 0.63%/patient-year (ten events, four managed successfully with thrombolysis, five successfully with reoperation, and one fatality identified at autopsy). The freedom, at 5 years, from major/fatal TE, thrombosis and hemorrhage from anticoagulation was 88.2%, and 89.5% exclusive of early events. Conclusions: This non-randomized prospective observational evaluation of the CarboMedics and St. Jude Medical prostheses has not revealed any differentiation in performance of the prostheses. The study serves as a single institution experience with the potential for future comparative evaluation. (C) 1999 Elsevier Science B.V. All rights reserved.