Risk of thromboembolism with short-term interruption of warfarin

Excerpt

Background Significant uncertainty exists for patients who must discontinue warfarin prior to an invasive procedure. In part, the controversy results from the lack of published information about the risk of thromboembolism associated with short-term warfarin interruption. Objective To assess the frequency of thromboembolism and bleeding among a large cohort of patients whose warfarin was temporarily withheld before and after an outpatient invasive procedure. Design: prospective, observational cohort study. Setting: 101 sites (primarily community-based physician office practices) in the United States. Patients 1,024 individuals whose warfarin was interrupted for an outpatient invasive procedure. Measurements Thromboembolism or clinically significant hemorrhage within 30 days of warfarin interruption. Results 1,293 episodes of warfarin interruption were included. The mean age was 71.9 years; 43% were female. The most common procedures were colonoscopy, oral and ophthalmic surgery. Seven patients (0.7%) suffered post-procedure thromboembolism within 30 days. None of the 7 patients who experienced thromboembolism received peri-procedural “bridging” therapy; 3 of these thromboembolic events were associated with warfarin interruption ≥7 days. Twenty-three patients (2.3%) suffered clinically significant hemorrhage—of these, 14 received peri-procedural heparin/LMWH. Perioperative heparin or LMWH was used in only 8.3% of cases overall. The duration of warfarin interruption was variable; however, more than 80% of patients had warfarin withheld for 5 days or fewer. Conclusion For many chronically anticoagulated patients who need to undergo a minor, outpatient intervention, a brief (5 or fewer days) peri-procedural interruption of warfarin is associated with a low risk of thromboembolism. The risk for clinically significant bleeding, even among outpatients undergoing minor procedures, should be considered prior to the administration of “bridging” therapy. …