title: Stentless aortic valve replacement with the biocor prosthesis: indications and outcome.
abstract: OBJECTIVE
  Due to improved hemodynamic properties stentless bioprostheses represent a new therapeutic option in the surgical treatment of aortic valve disease.
  
  
  METHODS
  Between February 1993 and June 1995 22 patients with a small aortic root regarded as suboptimal for a stented bioprosthesis (diameter < or = 23 mm, mean 21.6 +/- 1.9 mm) underwent aortic valve replacement with a Biocor stentless prosthesis. Mean age was 63.9 +/- 15.4 years (17-85 years). Valve size ranged from 21 to 27 mm (mean 25 mm) and exceeded the root diameter by 4 mm. As compared to a control group of patients with root enlargement (n = 10) total bypass time and cross-clamp time in the stentless group were significantly shorter (83.3 +/- 12.7 and 60.9 +/- 9.2 min versus 95.8 +/- 27.1 and 69.5 +/- 16.5 min, p = 0.054 and p < 0.05), respectively.
  
  
  RESULTS
  Three patients died postoperatively unrelated to the choice of valve. There were no late deaths. No thromboembolic or bleeding events were observed. Follow up data are available over a period of 1-25 months (mean 12.5 months, median 16 months). Echocardiographic evaluation revealed no aortic regurgitation; mean valve gradients were 9.9 +/- 4.1 mmHg (peak 19.2 +/- 6.0 mmHg). For specific root diameters these gradients were compared to established data for Hancock bioprostheses demonstrating significant differences in transvalvular gradients between the two valve designs for given root diameters. Unloading the left ventricle resulted in regression of left ventricular hypertrophy (decrease in wall thickness from 13.6 +/- 1.7 mm to 11.2 +/- 2.0 mm). Exercise capacity improved from NYHA III-IV preoperative to I-II postoperative.
  
  
  CONCLUSIONS
  In patients with a small aortic root stentless valves represent a new option. Compared to root enlargement with standard bioprosthesis myocardial ischemia is shorter and implantation of larger valve sizes results in superior hemodynamics.
authors.affiliation: Division of Thoracic and Cardiovacular Surgery, Hannover Medical School, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Achtelik
authors.forename: K
authors.initials: K
authors.lastname: Pethig
authors.forename: H J
authors.initials: HJ
authors.lastname: Schäfers
authors.forename: H G
authors.initials: HG
authors.lastname: Borst
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000473:pathology / Q000601:surgery*; D001705:Bioprosthesis / Q000295:instrumentation*; D005260:Female; D006350:Heart Valve Prosthesis / Q000295:instrumentation* / Q000379:methods; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology*; D011379:Prognosis; D011474:Prosthesis Design; D015607:Stents; D015996:Survival Rate