Interventions for preventing venous thromboembolism following abdominal aortic surgery

Abstract

Background: Deep vein thrombosis (DVT) is one of the most common, preventable complications of surgery. Although the relationship between surgery and DVT is well established in general surgical operations and most other subspecialties, the same cannot be said about arterial surgery. Deep vein thrombosis is believed to be less common in aortic surgery where its management is rather controversial with a reported incidence of DVT from 2% to 18%. Intra-operative heparin is believed to provide protection during the period when DVT ismost likely to develop. However, the practice of using intra-operative heparin could increase the risk of haemorrhagic complications if further heparin is used during the recovery period. This can significantly limit the use of such prophylactic measures especially with the low perceived risk of venous thromboembolism (DVT or pulmonary embolism (PE)) following abdominal aortic surgery. However, vascular patients are usually older, with more comorbidity and are subject to prolonged immobility, all of which increase the likelihood of developing venous thromboembolism. Objectives: To determine the efficacy of anticoagulant prophylaxis (with or without mechanical devices) in patients undergoing surgery for abdominal aortic aneurysm. Search strategy: The Cochrane Peripheral Vascular Diseases Group searched their trials register (last searched 8 August 2007) and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, (last searched Issue 3, 2007). The authors searched for additional trials through reference lists of retrieved studies and conference proceedings. Selection criteria: Randomised controlled trials comparing the use of anticoagulants (with or without mechanical devices) with control or no intervention in preventing DVT or PE after abdominal aortic operations. Data collection and analysis: Three authors independently selected potential trials and assessed trial quality. Main results: Two studies (n=147) were included. Both studies had methodological limitations. There were no data to indicate that post operative anticoagulation, with or without the use of mechanical devices, can safely reduce the incidence of DVT after aortic surgery. Neither study reported a significant effect of anticoagulants on the incidence of PE or related mortality. One study was terminated before recruiting sufficient participants due to a higher incidence of bleeding with the use of anticoagulants. The incidence of minor bleeding events was also slightly higher with anticoagulants. Authors' conclusions: There is not enough evidence tomake a definitive conclusion about the use of anticoagulant drugs (with or without mechanical devices) for DVT prophylaxis in patients undergoing abdominal aortic surgery. Copyright © 2008 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.