title: The Freestyle stentless bioprosthesis in more than 1000 patients: a single-center experience over 10 years.
abstract: OBJECTIVE
  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.
authors.affiliation: Institute of Cardiovascular Medicine, Witten-Herdecke University, Witten, Germany.
authors.forename: Jürgen A C
authors.initials: JA
authors.lastname: Ennker
authors.forename: Ina C
authors.initials: IC
authors.lastname: Ennker
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Albert
authors.forename: Ulrich P
authors.initials: UP
authors.lastname: Rosendahl
authors.forename: Stefan
authors.initials: S
authors.lastname: Bauer
authors.forename: Ines
authors.initials: I
authors.lastname: Florath
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D001705:Bioprosthesis; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult