Stentless aortic valve replacement: current status and future trends.

Stentless aortic xenografts were introduced into clinical practice as aortic valve substitutes over a decade ago. Stentless prosthetic valves were expected to provide enhanced durability and more physiologic hemodynamic behavior when compared with stented bioprostheses. Whilst the former expectation has not been fulfilled, partly due to concomitantly improved durability of second-generation stented bioprostheses, the latter has consistently been satisfied in early and late clinical observation. Evidence is accumulating suggesting improved long-term survival due to more timely and thorough regression of ventricular hypertrophy. In addition, stentless xenografts have shown extreme versatility when adopted in a variety of complex clinical conditions associated with aortic valve disease, including small aortic anulus, ascending aortic aneurysm, endocarditis and left ventricular dysfunction. Future research in the form of prospective, multicenter, randomized trials must address the issues of very long-term durability and survival, while simplification in valve design is required to promote wider use of stentless valves.