title: Twenty years' single-center experience with mechanical heart valves: a critical review of anticoagulation policy.
abstract: OBJECTIVE
  Since January 1990, a variety of mechanical valves (St. Jude Medical, CarboMedics, ATS Medical) have been implanted routinely at the authors' institution. The study aim was to analyze, retrospectively, the 20-year clinical results of those mechanical valves, and to challenge the anticoagulation policy employed over the years.
  
  
  METHODS
  Between January 1990 and December 2008, a total of 2,108 mechanical valves was inserted into 1,887 consecutive patients (1,346 aortic, 725 mitral, 27 tricuspid, 10 pulmonary). The mean age of the patients was 63 +/- 13.2 years, and the majority (61%) were males. Preoperatively, 71% the patients were in NYHA class > or = III (average 3.01). The most frequent comorbidities included: atrial fibrillation (n = 594), coronary disease (n = 567) and diabetes (n = 398). The follow up (99% complete) totaled 13,721 patient-years (pt-yr), and ranged from 12 to 241 months (average 84 months).
  
  
  RESULTS
  In-hospital mortality was 5.2% (n = 98, 14 valve-related). Of the 629 late deaths, the majority were cardiac (n = 276). Survival (Kaplan-Meier estimation) was significantly better for aortic valve patients compared to mitral or multiple valve replacement (Mantel-Cox, p < 0.0001). The overall linearized incidences (as %/pt-yr) were: valve thrombosis 0.31, thromboembolism 1.08, and bleeding 0.91. However, as repeated events occurred in several patients, the hazard function was not constant. Multivariate analysis (Cox regression model) showed age > 70 years (p < 0.0001), NYHA class > or = III (p < 0.0001), non-sinus rhythm (p = 0.001), concomitant coronary artery bypass grafting (p = 0.008) and higher International Normalized Ratio (INR) values (p = 0.013) as significant risk factors for death, with a trend for redo operations (p = 0.052). Multivariate analysis found variable INR, non-sinus rhythm and NYHA class > II as significant risk factors for thromboembolism, while long-acting coumadin and NYHA class > II were significant risk factors for bleeding.
  
  
  CONCLUSIONS
  This 20-year experience demonstrated excellent clinical outcomes for patients with mechanical prostheses, with no valve structural failure and an acceptable incidence of adverse events. INR values between 2-2.5 for aortic valve patients, and 3-3.5 for mitral valve patients, yielded the fewest major adverse events.
authors.affiliation: Cardiac Surgery Department, 5K12 University Hospital Ghent, De Pintelaan, 185, 9000 Ghent, Belgium. guido.vannooten@ugent.be
authors.forename: Guido J
authors.initials: GJ
authors.lastname: Van Nooten
authors.forename: Frank
authors.initials: F
authors.lastname: Caes
authors.forename: Katrien
authors.initials: K
authors.lastname: François
authors.forename: Yves
authors.initials: Y
authors.lastname: Van Bellleghem
authors.forename: Thierry
authors.initials: T
authors.lastname: Bové
authors.forename: Guy
authors.initials: G
authors.lastname: Vandenplas
authors.forename: Yves
authors.initials: Y
authors.lastname: Taeymans
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects; D001530:Belgium / Q000453:epidemiology; D001777:Blood Coagulation / Q000187:drug effects; D002423:Cause of Death; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects* / Q000706:statistics & numerical data; D006470:Hemorrhage / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D019934:International Normalized Ratio / Q000592:standards; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011050:Policy Making; D011183:Postoperative Complications / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013923:Thromboembolism / Q000209:etiology / Q000517:prevention & control; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D000925:Anticoagulants; D014859:Warfarin