Aortic valve replacement using stentless bioprostheses. Surgical principles and step-by-step operational instructions using the Freestyle prosthesis as an example

Stentless valves were designed to improve postoperative hemodynamics in comparison to stented bioprosthesis. The implantation technique of stentless valves is very different from conventional bioprostheses: a stented bioprosthesis maintains its form, due to the rigid stent, whereas the form of a stentless valve depends on the surgical suture lines. The general goal is to snugly fit a stentless valve into the aortic root and, thereby, to ensure optimal hemodynamic results. Insufficient coaptation of the cusps and bulging of the prosthesis into the outflow tract are the results of suboptimal implantation techniques. Residual gradients after stentless valve implantation impede postoperative quality of life and long-term survival. The present paper aims to describe the principles of implantation of stentless valves and to standardize the procedure using the Freestyle prosthesis as an example. The standardization of surgical technique and the identification of common pitfalls are mandatory to avoid unfavorable learning curves and to improve quality of life and long-term survival.