The Freestyle Stentless Bioprosthesis in more than 1000 Patients: A Single-Center Experience over 10 Years

Background and Aim: Early and mid-term clinical outcomes after aortic valve replacement (AVR) with stentless bioprostheses in a large cohort of patients are presented. Methods: Between April 1996 and November 2005, 1014 patients underwent AVR with the stentless Medtronic Freestyle bioprosthesis, with 168 using the full-root technique. The mean age was 73 +/- 3 (range: 20 to 90) years. Follow-up included 2953 patient-years and was 95% complete for adverse events. Results: Operative mortality was 3.4% (N = 34). Overall survival was 46 +/- 9% at nine years and similar to age- and gender-matched German general population. Freedom from prosthetic valve endocarditis, major bleeding, neurological events, and reoperation after nine years was 97 +/- 6%, 92 +/- 7%, 70 +/- 16%, and 92 +/- 9%, respectively. Freedom from structural valve deterioration was 97 +/- 5% at 9 years. During the learning phase, mean transprosthetic gradients of 23.5 +/- 3.0 mmHg and 24.8 +/- 3.1 mmHg were observed for valve sizes 21 and 23 mm, respectively, 10 days after subcoronary implantation in 1997, which could be lowered to 16 +/- 2.1 mmHg and 14.9 +/- 0.9 mmHg in 2005, respectively, with increasing experience of the surgeons. During the follow-up period, mean gradients dropped on average by 15 mmHg in patients presenting higher gradients at discharge. Conclusions: The Freestyle stentless bioprosthesis showed encouraging midterm durability with low rates of valve-related morbidity, and can be safely implanted without increased operative risk even during the learning phase. Special training of the surgeons is recommended to achieve optimal hemodynamic performance. (J Card Surg 2009;24:41-48).