Abstract 660: Anticoagulation of Patients on Chronic Warfarin Undergoing Arrhythmia Device Surgery: Wide Variability of Perioperative Bridging in Canada
It is common practice to discontinue warfarin in the perioperative period to reduce the risk of bleeding complications, and bridge with heparin while the INR is subtherapeutic. We sought to tk;4determine the perioperative anticoagulation strategies used in Canada. A survey posed 4 clinical scenarios of patients on warfarin undergoing device implantation. The questions collectively presented a gradient of perceived risk of thromboembolism based on the presence of a mechanical heart valve, previous stroke and the remainder of the CHADS2 risk factors. Respondents were offered 6 options that included discontinuing warfarin without heparin, 3 forms of heparin bridging: LMWH before not after the procedure, LMWH before and after, unfractionated IV heparin before and after, reduced dose warfarin and ongoing therapeutic dose warfarin. Heparin formulation, timing of reintroduction and in or out of hospital was also sought. A response was received from 38 of 62 EPs across Canada(61%). In a low risk 78-year-old patient with atrial fibrillation (AF, Table⇓, Case 1, CHADS2 score 1), 83% of respondents held warfarin without bridging. In a 78-year-old patient with AF and a CHADS2 score of 4 without previous stroke, 34% of respondents did not bridge, 37% bridged and 29% continued warfarin. In a 78-year-old patient with a mechanical aortic valve (CHADS2 score 1), 66% chose heparin bridging, with warfarin continued in the remainder. In a 78-year-old patient with previous stroke and a CHADS2 score of 4, 5% did not bridge, 71% used heparin and 24% continued warfarin. When bridging was chosen, each of the 3 heparin regimens was chosen by at least 20% of respondents. When postoperative heparin was chosen, intravenous administration was chosen by 61%, and was started at 24 hours after surgery in 68% of choices. There is a wide range of clinical practice in Canada, supporting the need for comparative studies for optimal patient care strategies.