title: Hancock II porcine bioprosthesis: excellent durability at intermediate-term follow-up.
abstract: OBJECTIVE
  This study aimed to assess the clinical performance and durability of a new generation of porcine valve, the Hancock II bioprosthesis, at intermediate-term follow-up.
  
  
  BACKGROUND
  Standard porcine bioprostheses undergo progressive structural deterioration, mainly due to cusp and commissural calcification, affecting durability and requiring reoperation. The Hancock II bioprosthesis, which is currently undergoing clinical investigation, is made from a porcine aortic valve treated with a calcium-retarding agent (sodium dodecyl sulfate [T6]), which should delay onset of calcification and increase durability.
  
  
  METHODS
  From May 1983 to December 1992, we used the Hancock II bioprothesis in aortic (59 patients), mitral (101 patients) and mitral-aortic (25 patients), valve replacement procedures. Postoperative follow-up ranged from 0.1 to 8.7 years (mean [+/- SD] 4.5 +/- 2.6 years) and was 100% complete. Freedom from major postoperative events was calculated at 7 years for patients with aortic valve replacement and at 8 years for those with mitral and mitral-aortic valve replacement.
  
  
  RESULTS
  The actuarial survival rate was 48 +/- 10%, 76 +/- 3% and 63 +/- 6%; freedom from valve-related mortality was 91 +/- 4%, 94 +/- 2% and 89 +/- 6%; freedom from thromboembolism was 80 +/- 11%, 90 +/- 2% and 79 +/- 7%; and freedom from reoperation was 100%, 97 +/- 1% and 89 +/- 6% after aortic, mitral and mitral-aortic valve replacement, respectively. No structural valve deterioration occurred.
  
  
  CONCLUSIONS
  At intermediate-term follow-up the Hancock II bioprosthesis showed excellent durability in all positions. However, the effectiveness of anticalcification treatment must be assessed with longer follow-up studies.
authors.affiliation: Department of Cardiovascular Surgery, University of Padova Medical School, Italy.
authors.forename: U
authors.initials: U
authors.lastname: Bortolotti
authors.forename: A
authors.initials: A
authors.lastname: Milano
authors.forename: E
authors.initials: E
authors.lastname: Mazzaro
authors.forename: G
authors.initials: G
authors.lastname: Thiene
authors.forename: E
authors.initials: E
authors.lastname: Talenti
authors.forename: D
authors.initials: D
authors.lastname: Casarotto
mesh_terms: D000206:Actuarial Analysis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000601:surgery; D001705:Bioprosthesis; D004697:Endocarditis, Bacterial / Q000209:etiology; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis / Q000009:adverse effects / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000209:etiology; D015996:Survival Rate; D013923:Thromboembolism / Q000209:etiology