title: Postoperative warfarin following mitral valve repair or bioprosthetic valve replacement.
abstract: OBJECTIVE
  Short-term postoperative warfarin therapy has been used to decrease neurologic events following mitral valve repair or bioprosthetic replacement (MVR). The study aim was to compare the short- and long-term outcomes of patients undergoing mitral valve surgery with or without short-term postoperative warfarin.
  
  
  METHODS
  A single academic US institution retrospective review was performed on discharged patients who underwent MVR between January 1996 and March 2010. Patients were allocated to two groups: MVR with four to six weeks of postoperative warfarin (n = 315; Warfarin group) or MVR without postoperative warfarin (n = 257; No warfarin group). Patients who required either preoperative or postoperative warfarin for any disease process (e.g., atrial fibrillation, mechanical valve, deep venous thrombosis) were excluded. Logistic and Cox proportional hazards regression models were constructed to evaluate the effects of warfarin on short- and long-term outcomes, respectively. Adjusted odds ratios (AOR) and adjusted hazard ratios (AHR), with 95% confidence intervals (CI) were constructed for each outcome. To reduce selection bias, propensity scoring methods were employed to balance the groups with respect to 54 preoperative variables.
  
  
  RESULTS
  Mean age was not significantly different between groups (No warfarin group = 56.8 +/- 14.5 years versus Warfarin group 55.9 +/- 12.9 years; p = 0.46). The average length of hospital stay was 9.8 +/- 8.4 days and 7.3 +/- 4.5 days in the No warfarin and Warfarin groups, respectively (p < 0.001). At the six-week follow up the incidences of stroke (p = 0.74), pleural effusions (p = 0.88), pericardial effusions (p = 0.75), and bleeding complications (p = 0.30) were similar between the two groups. In an unadjusted Kaplan-Meier analysis, the No warfarin group had a poorer long-term survival than the Warfarin group (p < 0.001). However, after propensity adjustment, the benefit of warfarin was not statistically significant (AHR = 0.66, 95% CI 0.40-1.08, p = 0.098).
  
  
  CONCLUSIONS
  The use of postoperative warfarin following MVR does not reduce the incidence of stroke at early follow up. However, there remains a trend for improved long-term outcomes in those patients receiving postoperative warfarin therapy.
authors.affiliation: Structural Heart and Valve Program, Clinical Research Unit, Division of Cardiothoracic Surgery, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia 30308, USA. vthoura@emory.edu
authors.forename: Vinod H
authors.initials: VH
authors.lastname: Thourani
authors.affiliation: Structural Heart and Valve Program, Clinical Research Unit, Division of Cardiothoracic Surgery, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia 30308, USA.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Gunter
authors.affiliation: Structural Heart and Valve Program, Clinical Research Unit, Division of Cardiothoracic Surgery, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia 30308, USA.
authors.forename: Stuart
authors.initials: S
authors.lastname: Hurst
authors.affiliation: Department of Biostatistics, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia 30308, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Kilgo
authors.affiliation: Structural Heart and Valve Program, Clinical Research Unit, Division of Cardiothoracic Surgery, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia 30308, USA.
authors.forename: Murali
authors.initials: M
authors.lastname: Padala
authors.affiliation: Structural Heart and Valve Program, Clinical Research Unit, Division of Cardiothoracic Surgery, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia 30308, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Puskas
authors.affiliation: Structural Heart and Valve Program, Clinical Research Unit, Division of Cardiothoracic Surgery, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia 30308, USA.
authors.forename: Omar M
authors.initials: OM
authors.lastname: Lattouf
authors.affiliation: Structural Heart and Valve Program, Clinical Research Unit, Division of Cardiothoracic Surgery, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia 30308, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Halkos
authors.affiliation: Structural Heart and Valve Program, Clinical Research Unit, Division of Cardiothoracic Surgery, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia 30308, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Guyton
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage; D001705:Bioprosthesis; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D005845:Georgia / Q000453:epidemiology; D006349:Heart Valve Diseases / Q000601:surgery*; D006350:Heart Valve Prosthesis; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery*; D011182:Postoperative Care / Q000379:methods*; D012189:Retrospective Studies; D020521:Stroke / Q000453:epidemiology / Q000517:prevention & control*; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D014859:Warfarin / Q000008:administration & dosage*
chemical_list: D000925:Anticoagulants; D014859:Warfarin