title: Prosthetic valve thrombosis: twenty-year experience at the Montreal Heart Institute.
abstract: BACKGROUND
  Prosthetic valve thrombosis is a life-threatening complication. We reviewed the incidence, risk factors, and treatment strategies of this rare complication.
  
  
  METHODS
  From February 1981 through January 2001, 5430 valve operations were performed in 4924 patients at the Montreal Heart Institute. Of this cohort, 39 patients presented with prosthetic valve thrombosis and had complete follow-up data obtained from our prospective valve clinic database.
  
  
  RESULTS
  In this series 82% of patients were women, and the mean age was 58 +/- 11 years. The underlying pathology involved the mitral valve in 75% of cases. Most prosthetic valve thromboses occurred with mechanical prostheses (95%). The time interval from first valve replacement to prosthetic valve thrombosis was 39 +/- 42 months. The most frequent clinical presentation was severe congestive heart failure (44%). On prosthetic valve thrombosis presentation, the international normalized ratio was less than 2.5 in 54%, with inadequate anticoagulation management in 26% and poor compliance in 26%. Eighty-two percent of patients underwent a surgical procedure, consisting of thrombectomy in 47%, mitral valve replacement in 47%, and aortic valve replacement in 6% of patients. The 30-day operative mortality and total in-hospital mortality after prosthetic valve thrombosis were 25% and 41%, respectively. The 10-year actuarial survival after prosthetic valve thrombosis was 46% +/- 10%.
  
  
  CONCLUSIONS
  Inadequate level of anticoagulation is the most important factor involved in the pathogenesis of prosthetic valve thrombosis. The overall mortality rate despite surgical treatment remains high. This study underscores the importance of meticulous surveillance of anticoagulation therapy in patients with prosthetic valves.
authors.affiliation: Department of Surgery, Montreal Heart Institute, Montreal, Quebec, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Dürrleman
authors.forename: Michel
authors.initials: M
authors.lastname: Pellerin
authors.forename: Denis
authors.initials: D
authors.lastname: Bouchard
authors.forename: Yves
authors.initials: Y
authors.lastname: Hébert
authors.forename: Raymond
authors.initials: R
authors.lastname: Cartier
authors.forename: Louis P
authors.initials: LP
authors.lastname: Perrault
authors.forename: Arsène
authors.initials: A
authors.lastname: Basmadjian
authors.forename: Michel
authors.initials: M
authors.lastname: Carrier
mesh_terms: D000925:Anticoagulants / Q000627:therapeutic use; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D015996:Survival Rate; D017131:Thrombectomy; D015912:Thrombolytic Therapy; D013927:Thrombosis / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality / Q000628:therapy
chemical_list: D000925:Anticoagulants