Bioprosthetic valve durability after stentless aortic valve replacement: the effect of implantation technique

Background: The Freestyle stentless bioprosthesis (FSB) (Medtronic Inc, Minneapolis, MN) is implanted using 2 techniques-subcoronary or aortic root replacement. Our objective was to determine whether the implantation technique had an impact on late reoperation for structural valve deterioration (SVD).

Methods: Between 1993 and 2013, 531 patients underwent aortic valve replacement (AVR) or aortic root reconstruction with an FSB. The implantation technique was subcoronary in 430 patients (group S) and root replacement in 101 patients (group R). Median follow-up was 10.8 years for group S patients and 10.1 years for group R patients. The follow-up was complete in all patients.

Results: Mean age was 68.2 years in group S and 65.2 in group R (p = 0.001). In-hospital mortality was 3.5% and 5.0% in group S and group R, respectively (p = 0.56). Late reoperation was required in 60 (14.5%) hospital survivors in group S and 8 (8.3%) hospital survivors in group R. There were 36 reoperations in group S and 3 in group R for SVD. Freedom from reoperation for SVD was 94.6% and 76.7% at 10 and 15 years, respectively, in group S, and 98.9% and 88.1% at 10 and 15 years, respectively, for group R (p = 0.04). The subcoronary technique was an independent risk factor for late reoperation for SVD (p = 0.002). Implantation technique was not independently associated with in-hospital and long-term mortality.

Conclusions: The Freestyle bioprosthesis implanted as a root replacement was associated with less reoperation for SVD over the long term compared with the subcoronary technique. However, the method of implantation has no influence on early and long-term survival.