Midterm outcome after aortic root replacement with stentless porcine bioprostheses

Objective: Midterm clinical outcome was evaluated after aortic root replacement with Freestyle ® stentless aortic root bioprostheses. Methods: Between April 1996 and December 2007, 301 patients underwent aortic valve replacement with stentless Medtronic Freestyle ® bioprostheses in full-root technique at a single center. Concomitant coronary artery bypass grafting (CABG) was required in 96 patients (32%). In 94 patients (31%), the ascending aorta was replaced. The mean age was 71.6±9.1 (range: 36-89) years. Follow-up was closed in October 2008, 99% complete and encompassed 916 patient-years. Results: Overall mortality within 30 days was 5%. A total of 62 patients died during the follow-up period. Overall survival at 5 and 9 years was 74±4% and 53±6%, respectively. Re-operations were required in three patients: in one patient due to structural valve deterioration, and in two patients due to prosthetic valve endocarditis. Non-structural dysfunctions were not observed. In eight patients, prosthetic valve endocarditis occurred, in most of them (N=6) during the first year after surgery. Rate of freedom from re-operation, structural valve deterioration, prosthetic valve endocarditis, thrombo-embolic and major bleeding events at 9 years was 94±6%, 94±6%, 94±3%, 87±5%, and 95±2%, respectively. The linearized rates of late adverse events in percent per patient-year were 0.35, 0.12, 0.83, 1.7, and 0.7, respectively, for re-operation, structural valve deterioration, prosthetic valve endocarditis, thrombo-embolic and major bleeding events. A little less than a quarter (22%) of the patients required anticoagulation therapy. Conclusions: Aortic root replacement with the stentless Freestyle ® bioprosthesis provided a respectable short-term mortality, optimal valve durability and acceptable rates of valve-related complications within 9 years