• anticoagulation;
  • bleeding;
  • low-molecular-weight heparin;
  • surgery;
  • warfarin

Summary.  Background: Appropriate periprocedural management for chronically anticoagulated patients requires assessment of patient-specific thrombosis and bleeding risks. However, predictors of post-procedure bleeding are unknown. Objectives: To determine the 3-month cumulative incidence and independent predictors of peri-procedural bleeding in chronically anticoagulated patients requiring temporary warfarin interruption for an invasive procedure. Methods: In a protocol driven, cohort study design, all patients referred to the Mayo Clinic Thrombophilia Center for peri-procedural anticoagulation management (1997–2007; n = 2182), were followed forward in time to determine the 3-month cumulative incidence of peri-procedural bleeding (Kaplan–Meier product limit) and potential predictors of bleeding (Cox proportional hazards). Decisions to ‘bridge’ with low-molecular-weight heparin were based on estimated thromboembolism and bleeding risk. Results: Indications for chronic anticoagulation included venous thromboembolism (38%), atrial fibrillation (30%) and mechanical heart valves (27%). Of these, 1496 (69%) patients received bridging therapy. The 3-month cumulative incidence rates of major and overall bleeding were 2.1% and 5.1%, respectively. Major bleeding occurred more frequently in patients receiving bridging therapy (3% vs. 1%; P = 0.017). Independent predictors (hazard ratio; 95% confidence interval) of major bleeding included mitral mechanical heart valve (2.2; 1.1–4.3), active cancer (1.8; 1.0–3.1), prior bleeding history (2.6; 1.5–4.5) and re-initiation of heparin therapy within 24 h after the procedure (1.9; 1.1–3.4). Conclusion: Factors predisposing to peri-procedural bleeding are primarily patient-specific. Premature heparin re-initiation is an avoidable provider-specific variable to consider.