Stentless aortic valves. Current aspects.

The design of stentless valve prostheses is intended to achieve a more physiological flow pattern and superior hemodynamics in comparison to stented valves. First - generation stentless bioprosthesis were the Prima valve, the Freestyle valve and the Toronto stentless porcine valve. The second generation of stentless valves, as the Super stentless aortic porcine valve, need only one suture line. The Sorin Pericarbon Freedom and the Equine 3F heart Valve belong to the third generation of stentless valve pericardial bioprostheses. A stentless valve to replace a full root can be implanted by several surgical techniques: complete or modified subcoronary, root inclusion and full root. The full root technique is accompanied by the lowest incidence of patient-prothesis mismatch. Our own clinical experience reflects more than 3000 stentless valve implantations since April 1996. Randomized study trials showed a hemodynamic advantage for stentless valves, but several could not reach a significant level. Also reported was a significant advantage of stentless bioprostheses concerning transvalvular gradients, effective valve area and quicker regression of the left ventricular mass 6 months after the operation, but at 12 months. Advantages are obvious in patients with a decreased left ventricle ejection fraction of less than 50% and in smaller implanted valve size, concomitant aortic root pathology (e.g. dissection) and aortic valve endocarditis. A survival advantage for stentless bioprostheses in comparison to stented ones has been reported by all studies in the literature. Stentless valves enrich the surgical armamentarium. Time will define the place of stentless valves in the future.