title: Factors influencing the mean postoperative gradients across stentless porcine valves.
abstract: BACKGROUND
  To study the preoperative and intraoperative variables influencing the mean post-operative transvalvular gradient across stentless porcine valves.
  
  
  METHODS
  From 1995 to 2002, 84 patients underwent stentless valve insertion. The mean age was 73 years, and 63% were male. The valve pathology was aortic stenosis (AS) in 79%, aortic regurgitation (AR) in 12%, and mixed in 9%. Valve sizes ranged from 21 to 29 with size 27 being most frequent. 54% of patients had concomitant procedures. Patients had at least yearly clinical and echocardiographic follow-up.
  
  
  RESULTS
  There was no operative mortality. 9.5% of the patients had significant postoperative complications. The average echo interval was 18.6 months (range 1-88). The overall mean transvalvular gradient was 9.88+/-5.67 (SD) mmHg. Variables associated with significantly reduced gradients were: larger valve sizes (p=0.002), younger age (p=0.05), pre-op AR (p=0.008), and increasing post-operative interval (p=0.05). The mean gradients decreased by 0.28 mmHg for each post-operative year. The method of implantation did not significantly affect gradients (p=0.26).
  
  
  CONCLUSIONS
  Excellent mean transvalvular gradients were achieved with stentless valves studied, with a low operative risk. The gradients did not appear to be related to intra-operative factors, suggesting that insertion techniques can be tailored to suit patient conditions and surgeon preferences.
authors.affiliation: Department of Cardiac Surgery, Austin Hospital, Studley Road, Melbourne, Vic. 3084, Australia.
authors.forename: Pallav J
authors.initials: PJ
authors.lastname: Shah
authors.forename: Brian F
authors.initials: BF
authors.lastname: Buxton
authors.forename: George
authors.initials: G
authors.lastname: Matalanis
mesh_terms: D000368:Aged; D001022:Aortic Valve Insufficiency / Q000453:epidemiology / Q000601:surgery*; D001024:Aortic Valve Stenosis / Q000453:epidemiology / Q000601:surgery*; D001705:Bioprosthesis; D015897:Comorbidity; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000453:epidemiology; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D012189:Retrospective Studies