Aortic valve replacement with the freestyle stentless bioprosthesis - Five-year experience

Background-Stentless aortic Valves were designed to provide a more physiolo gical flow pattern and lower transvalvular gradient, which may have an impo rtant bearing on postoperative left Ventricular function and remodeling. In this study, we prospectively analyzed the 5-year clinical results with the Freestyle valve (Medtronic, Inc) and its hemodynamic performance by serial echocardiography. Methods and Results-Between January 1993 and August 1997, 95 patients with a mean age of 75 years underwent aortic valve replacement with the Freestyl e prosthesis. Sixty-four percent of patients received valves less than or e qual to 23 mm, and 37% had concomitant coronary artery bypass grafting. Ave rage follow-up was 44+/-18 months (mean+/-SD), and echocardiography was per formed preoperatively, at discharge, at 3 to 6 months, and annually thereaf ter. The 30-day operative mortality rate was 3%, with an overall actuarial survival rate of 80+/-6% (mean +/- SEM) at 5 years. Of the 10 late deaths, only 2 were cardiac related, thereby yielding a freedom from cardiac mortal ity of 94+/-3% after 5 years. No patient required reoperation on the aortic valve for any reason, including structural degeneration, nonstructural dys function, or prosthetic valve endocarditis. There were 9 thromboembolic and 3 anticoagulant-related bleeding events, none of which was fatal. The actu arial freedom from valve-related morbidity and mortality was 79+/-4% at 5 y ears. Hemodynamically, the mean transvalvular gradient significantly decrea sed after Valve replacement and was reduced further by 41% by 6 months with a corresponding increase in effective orifice area. Left Ventricular mass index fell to 75% of the preoperative value by 2 years. Conclusions-The Freestyle stentless valve can be implanted safely in the el derly with excellent midterm clinical results. It has superb hemodynamics i n terms of residual transvalvular gradient, effective orifice area, and reg ression of left Ventricular hypertrophy.