Validity of current recommendation for peri-operative interruption of warfarin in Asians

Temporary interruption of anticoagulation therapy is usually recommended for anticoagulated patients undergoing invasive procedures to minimize their bleeding risks. We validated the current consensus recommendation on warfarin interruption which were based on Western population studies to determine if they could safely be applied to Asians. The international normalized ratios (INR) in twenty warfarinised patients with a stable INR of 2-3 were prospectively measured at days 0, 3 and 5 after stopping warfarin for procedures or at completion of treatment. The median INR at days 0, 3 and 5 were 2.30 (95% CI 2.16-2.43), 1.32 (95% CI 1.22-1.57) and 1.06 (95% CI 1.05-1.13) respectively (P < 0.001 for trend). All patients were below therapeutic INRs by day 3 with 14 patients (70%, 95% CI 49.92-90.08) achieving INR readings below 1.5. By day 5, all INRs were below 1.5 and only 2 patients (10%, 95% CI -3.15 to 23.15) had INRs above 1.2. There were no significant peri-procedure bleeding or thrombotic events in the 1 month following interruption of warfarin. Our results suggest that the current international recommendation of stopping warfarin for 5 days prior to procedure can safely be applied to Asians without compromising risk of bleeding or thrombosis.