title: Commissural dehiscence: a rare and peculiar cause of porcine valve structural deterioration.
abstract: OBJECTIVE
  Calcification is the main cause of structural valve deterioration; however, other causes of failure have been identified, and among them, dehiscence of a commissure from the stent has been reported in several models of porcine valves. The aim of this study was to analyze the rate and mode of occurrence of this complication in first- and second-generation porcine bioprosthetic explants.
  
  
  METHODS
  Among 586 porcine xenografts explanted and analyzed at the Institute of Pathological Anatomy of the University of Padua, 17 (2.9%) have been replaced for incompetence because of commissural dehiscence. All these explants were in the mitral position, with the exception of a Carpentier-Edwards supra-annular aortic valve prosthesis.
  
  
  RESULTS
  Dehiscence was observed in 9 (1.9%) of 455 Hancock standard explants, in 1 (3.2%) of 31 Hancock II, in 3 (8.6%, 2 standard and 1 supra-annular) of 35 Carpentier-Edwards, in 1 (2.4%) of 42 Bioimplants, and in 3 (50%) of 6 Xenotech after a mean time function of 157 +/- 50, 156, 96 +/- 29, 143, and 130 +/- 8 months, respectively. Dehiscence was the sole cause of incompetence in 6 cases. An impending commissural dehiscence caused by blood creeping was observed in one case. This might be an explanation for the dehiscence other than excessive trimming of the aortic wall.
  
  
  CONCLUSIONS
  Commissural dehiscence is an uncommon and peculiar mode of failure of porcine valves implanted in the mitral position and was observed earlier and more frequently with Carpentier-Edwards porcine explants (P < .05). We speculate that pericardial strip protection of the suture between the Dacron fabric and porcine aortic wall, as used in the Biocor porcine valve, might prevent this complication.
authors.affiliation: Department of Cardiovascular Surgery, University of Padua Medical School, Padua, Italy. bottio@med.unibs.it
authors.forename: Tomaso
authors.initials: T
authors.lastname: Bottio
authors.forename: Marialuisa
authors.initials: M
authors.lastname: Valente
authors.forename: Giulio
authors.initials: G
authors.lastname: Rizzoli
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Tarzia
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Bisleri
authors.forename: Elena
authors.initials: E
authors.lastname: Pettenazzo
authors.forename: Gino
authors.initials: G
authors.lastname: Gerosa
authors.forename: Gaetano
authors.initials: G
authors.lastname: Thiene
mesh_terms: D000368:Aged; D001705:Bioprosthesis; D020878:Device Removal; D019544:Equipment Failure Analysis; D005260:Female; D006349:Heart Valve Diseases / Q000601:surgery*; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure