Early clinical experience with the On-X (R) prosthetic heart valve

Background and aim of the study: The study was designed to investigate the clinical performance of the On-X prosthetic heart valve in a multicenter ex perience. Methods: Between September 1996 and September 1999, 301 patients (56% males ) underwent isolated On-X valve replacement (184 isolated aortic (AVR), 117 isolated mitral (R-IVR) at II European centers under a standardized protoc ol. Average age at implant was 60.2 years. Office or hospital follow up was required by the protocol; average follow up on all patients was II months. Results: Thirty-day mortality in the study was 2.2% for AVR and 6.0% for MV R, with valve-related mortality of 0.5% for AVR, There were eight late deat hs (0.7%/pt-yr AVR and 2.3%/pt-yr MVR). Two of these deaths were sudden, an d thus possibly valve-related (one AVR, one MVR). Early total valve-related morbidity was 3.5% for AVR and 2.6% for MVR. In total, 13 thromboembolic e vents occurred; one early event in AVR resulted in death (0.5%), and one tr ansient early event occurred in MVR (0.9%). There were 11 late events (seve n AVR (1.7%/pt-yr) and four MVR (1.8%/pt-yr)), for a two-year freedom from thromboembolism of 96.6% after AVR and 97.1% after MVR. Three late bleeding events occurred, all after AVR (0.7%/pt-yr and 98.9% free at two years). M ajor paravalvular leaks requiring reoperation occurred on two occasions ear ly tone AVR (0.5%), one MVR (0.8%)) and once late in MVR (0.5%/pt-yr). late minor, untreated paravalvular leaks occurred in three AVR patients (0.7%/p t-yr) and in one MVR patient (0.5%/pt-yr). Prosthetic endocarditis occurred four times (two AVR (0.5%/pt-yr), two A?VR (0.9%/pt-yr)), all within the f irst 12 months of surgery. Actuarial freedom from all valve-related events at two years was 88.7% for AVR and 88.1% for MVR. NYHA class was improved i n 75.8% of AVR patients and 70.6% of MVR patients at two years after surger y. Conclusion: These early results indicate that the Only valve provides satis factory clinical outcome in the immediate postoperative period, and that th e valve is both safe and effective.