Prevention of perioperative thromboembolism in patients with atrial fibrillation

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.