Comparison of On-X and SJM HP bileaflet aortic valves

Background and aim of the study: The study aim was to evaluate the hemodyna mic function after aortic valve replacement (AVR) using the On-X valve, in comparison with St. Jude Medical (SJM) HP bileaflet valves. Methods: Patients received either the On-X (n = 20) or SJM HP prosthesis (n = 20) for AVR. The control (SJM HP) group was computer-matched with the On -X group for age, gender, aortic stenosis as underlying disease, body surfa ce area, NYHA functional class, left ventricular size, mass and function, t ransvalvular pressure gradients and cardiac index. Mean implanted valve siz e was 23.5 mm (three 21 mm, ten 23 mm, six 25 mm, one 27 mm) in both groups . All patients underwent postoperative, and six- and 12-month follow up ech ocardiography. Results: The intra- and postoperative course was uneventful in all patients . There were no significant differences in cross-clamp and cardiopulmonary bypass times, intensive care unit stay, in-hospital stay and postoperative NYHA functional class; Two patients (both On-X) had paravalvular leakage po stoperatively and at follow up. Five patients in the control group had addi tional myocardial revascularization. Transvalvular flow velocities were 2.3 8 +/- 0.3 versus 2.38 +/- 0.4 m/s (p = NS) postoperatively, and 2.08 +/- 0. 2 versus 2.22 +/- 0.3 m/s (p = NS) at one year follow up for On-X and SJM H P valves, respectively. Maximum pressure gradients were 16.9 +/- 6.0 versus 18.5 +/- 8.0 mmHg (p = NS) postoperatively and 14.0 +/- 3.7 versus 16.5 +/ - 5.7 mmHg (p = NS) at one year for the two valve types, respectively. A re latively pronounced transvalvular reflux was diagnosed for On-X valves. Conclusion: At one year after implantation, the On-X bileaflet prosthesis i s equally suited for AVR in comparison with the 'standard' therapy (SJM HP) . Exact sizing requires some experience. There were no significant differen ces between the two prostheses with regard to hemodynamic parameters either postoperatively or at one-year follow up. Long-term prospective randomized studies yet have to be carried out.