Variations in perioperative warfarin management: outcomes and practice patterns at nine hospitals.

BACKGROUND: Before surgery, most patients receiving oral anticoagulation require temporary cessation of treatment. Physicians sometimes substitute heparin or low-molecular-weight heparin for oral anticoagulation in the perioperative setting ("bridging therapy"). We sought to characterize rates of bridging therapy use at 9 clinical centers to determine the extent to which the use of bridging is explained by clinical characteristics of patients (vs physician style) and to determine the 30-day incidence of thrombotic and bleeding complications.

METHODS: This was a prospective, multicenter, observational study. Periprocedural bridging anticoagulation was classified as none, prophylactic-dose heparin/low-molecular-weight heparin, or full-dose heparin/low-molecular-weight heparin. We collected data on patient and surgery characteristics, anticoagulation management, and thromboembolic and bleeding events.

RESULTS: A total of 492 of 497 consecutive patients completed the study; 54%, 14%, and 33% of patients had no, prophylactic, and full (therapeutic) doses, respectively, of heparin/low-molecular-weight heparin postprocedure. Two hospitals treated more than 80% of their patients with full-dose heparin, whereas the remaining 7 hospitals used full-dose heparin in an average of 22% of cases (P<.001); this variation persisted after adjustment for patient characteristics. There were 4 thromboembolic events (0.8%) and 16 major bleeding events (3.2%). Full-dose heparin/low-molecular-weight heparin postprocedure was associated with a higher likelihood of major bleeding: adjusted odds ratio 4.4 (95% confidence interval, 1.5-14.7).

CONCLUSION: Management of anticoagulation after an invasive procedure varies widely and is not explained by clinical characteristics of patients alone. The risk of major bleeding is strongly associated with the use of postoperative therapeutic doses of heparin/low-molecular-weight heparin.