Prevention of perioperative thromboembolism in patients with atrial fibrillation

Abstract

Abstract Background The aim of this retrospective study was to review the safety and efficacy of two regimens for the prophylaxis of perioperative thromboembolism in patients with atrial fibrillation. Methods From a database of 14 801 procedures, atrial fibrillation occurred in 1·9 per cent of patients. Those not on oral anticoagulation (n = 146) received low molecular weight heparin (LMWH) before and after surgery (nadroparine 40 units per kg). Patients on oral anticoagulation before surgery (n = 136) received intravenous unfractionated heparin (UFH) after surgery at a dose adequate to maintain the thrombin time at a therapeutic level. Results The incidence of perioperative arterial or venous thromboembolism was independent of pre-existing risk factors and occurred in 4·6 per cent of patients, without significant difference between the two regimens (P = 0·780). Logistic regression revealed that thromboembolism was significantly associated with increased perioperative mortality (odds ratio 9·5, (95 per cent confidence interval 2·5 to 35·8); P = 0·001). The rate of postoperative bleeding was 4·8 per cent in patients who had LMWH and 17·6 per cent in those who had UFH (P < 0·001). Conclusion Postoperative anticoagulation with therapeutic UFH in patients with atrial fibrillation was associated with an increased rate of bleeding without reducing the risk of thromboembolism.