15.7 Aortic valve replacement in small aortic annulus: Which type of prosthesis should be denied? An “in vitro-in vivo” evaluation

Abstract

This review article analyzes the literature to answer the question of whether stentless aortic bioprostheses possess proven advantages compared with stented bioprosthesis, and which patients might benefit from stentless valve implantation. For this purpose, the United States National Library of Medicine's PubMed and MEDLINE databases were searched for articles dealing with results of stentless aortic bioprostheses or studies comparing stented and stentless prostheses. Key word searches used were as follows: stentless aortic prostheses, stented aortic prosthesis, hemodynamic, hemodynamic performance, degeneration, durability, technique, and long-term follow-up. The analysis focused on stentless prostheses with a clinical experience for more than 5 years. Only a few randomized studies were found. Stentless prostheses were found to be advantageous in patients with severe impaired left ventricular function or a small aortic annulus (ie, evidence of grade II), but no specific advantages could be determined for the majority of patients. The durability results were mixed: the Toronto SPV (St. Jude Medical, Minneapolis, MN) showed an increase in degeneration after 10 years of follow-up, whereas the Freestyle porcine stentless prostheses (Medtronic, Minneapolis, MN) still showed excellent results after this period.