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You are here: Contents > 2012 > Volume 21 Number 1 January 2012 > ANTICOAGULATION > Twenty Years’ Single-Center Experience with Mechanical Heart Valves: A Critical Review of Anticoagulation Policy

Twenty Years’ Single-Center Experience with Mechanical Heart Valves: A Critical Review of Anticoagulation Policy

Guido J. Van Nooten, Frank Caes, Katrien François, Yves Van Bellleghem, Thierry Bové, Guy Vandenplas, Yves Taeymans 

Heart Centre, University Hospital Ghent, Ghent, Belgium

Background and aim of the study: 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 ≥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 ≥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.
Conclusion: 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.


The Journal of Heart Valve Disease 2012;21:88-98

Twenty Years’ Single-Center Experience with Mechanical Heart Valves: A Critical Review of Anticoagulation Policy

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