Long-term clinical and echocardiographic follow-up of the freestyle stentless aortic bioprosthesis: the Tel Aviv Medical Center experience.

Background: Stentless aortic bioprostheses were designed to provide improved hemodynamic performance and potentially better survival.

Objectives: To report the outcomes of patients after aortic valve replacement with the Freestyle stentless bioprosthesis at the Tel Aviv Medical Center followed for < or = 15 years.

Methods And Results: Between 1997 and 2011, 268 patients underwent primary aortic valve replacement with a Freestyle bioprosthesis, 211 (79%) of them in the sub-coronary position. Mean age, Charlson comorbidity index and Euro-score were 71.0 +/- 9.2 years, 4.2 +/- 1.5 and 10.2 +/- 11 respectively, and 156 (58%) were male. Peak and mean trans-aortic gradient decreased significantly (75.0 +/- 29.1 vs. 22.8 +/- 9.6 mmHg, P < 0.0001; and 43.4 +/- 17.2 vs. 12.1 +/- 5.4 mmHg, P < 0.0001 respectively) during 3 months of follow-up. Mean overall follow-up was 4.9 +/- 3.1 years and was complete in all patients. In-hospital mortality was 4.1% (n=11) but differed significantly between the first 100 patients operated before 2006 and the last 168 patients operated after January 2006 (8 vs. 3 patients, 8.0% vs. 1.8%, P = 0.01). Overall, 5 and 10 year survival rates were 85 +/- 2.5% and 57.2 +/- 5.7%, respectively. Five year survival was markedly improved in patients operated after January 2006 compared to those operated in the early years of the experience (92.3 +/- 2.3% vs. 76.0 +/- 4.4%, P = 0.0009). All the 21 octogenarians operated after January 2006 survived surgery, with excellent 5 year survival (85.1 +/- 7.9%). Six patients required reoperation during follow-up: structural valve deterioration in five and endocarditis in one.

Conclusions: Aortic valve replacement with the Freestyle bioprosthesis provides good long-term hemodynamic and clinical outcomes, even in octogenarians. Valve calcification is the major (and rare) mode of valve deterioration leading to reoperation in these patients.