Early clinical experience with the On-X prosthetic heart valve.

The study aimed to assess the performance of the On-X valve (Medical Carbon Research Institute, Austin, TX). Between December 2000 and January 2003 On-X valves were implanted in 400 patients aged 19-85 years (mean: 55.6+/-16), 290 males and 210 females. There were 120 cases of aortic valve replacement (AVR), 258 mitral valve replacement (MVR) and 22 combined aortic and mitral valve replacement (DVR). Additional procedures were performed in 144 patients. Patients were followed up prospectively at 3- to 6-month intervals. Mean follow-up was 38.4+/-11.8 months (maximum 55.6 months). Overall hospital mortality was 3.5%. Freedom from adverse events at 4 years in the study were as follows: thromboembolism, 99.1% for AVR, 98.3% for MVR and 94.7% for DVR patients; thrombosis, 100% for AVR, 99.2% for MVR and 94.7% for DVR; bleeding events, 99.1% for AVR, 99.2% for MVR and 88.8% for DVR; prosthetic endocarditis, 98.2% for AVR, 99.2% for MVR and 94.7% for DVR. Overall survival at 4 years was 92+/-1%. At echocardiographical examination within 1 year of the AVR, the mean aortic valve gradient was 12.8+/-6, 10.3+/-3, 9.0+/-4, 8.3+/-3, and 6.2+/-3 mmHg for 19, 21, 23, 25, 27/29 mm valve sizes, respectively. MVR mean gradient was 4.9+/-2, 4.5+/-1.2 and 4.0+/-0.8 mmHg for 25, 27/29, 31/33 mm valve sizes, respectively. On-X valve is a highly effective mechanical valve substitute with low morbidity and mortality and good functional results.