Combined intermittent pneumatic leg compression and pharmacological prophylaxis for prevention of venous thromboembolism in high-risk patients

 

Abstract

Background

It has been suggested that combined modalities (methods of treatment) are more effective than single modalities in preventing venous thromboembolism (defined as deep vein thrombosis and pulmonary embolism, or both) in high-risk patients.

Objectives

To assess the efficacy of intermittent pneumatic leg compression combined with pharmacological prophylaxis versus single modalities in preventing venous thromboembolism in high-risk patients.

Search strategy

The Cochrane Peripheral Vascular Diseases (PVD) Group searched their Specialized Register (last searched 17 July 2007) and the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched The Cochrane Library 2008, Issue 3). We searched the reference lists of relevant articles to identify additional trials.

Selection criteria

Randomized controlled trials (RCTs) or controlled clinical trials (CCTs) of combined intermittent pneumatic leg compression and pharmacological interventions used to prevent venous thromboembolism in high-risk patients.

Data collection and analysis

Data extraction was undertaken independently by two review authors using data extraction sheets.

Main results

Eleven studies, six of them randomized controlled trials, were identified. The trials included 7431 patients, in total. Compared with compression alone, the use of combined modalities reduced significantly the incidence of both symptomatic pulmonary embolism (PE) (from about 3% to 1%; odds ratio (OR) 0.39, 95% confidence interval (CI) 0.25 to 0.63) and deep vein thrombosis (DVT) (from about 4% to 1%; OR 0.43, 95% CI 0.24 to 0.76). Compared with pharmacological prophylaxis alone, the use of combined modalities significantly reduced the incidence of DVT (from 4.21% to 0.65%; OR 0.16, 95% CI 0.07 to 0.34) but the included studies were underpowered with regard to PE. The comparison of compression plus pharmacological prophylaxis versus compression plus aspirin showed a non-significant reduction in PE and DVT in favor of the former group. Repeat analysis restricted to the RCTs confirmed the above findings.

Authors' conclusions

Compared with compression alone, combined prophylactic modalities decrease significantly the incidence of venous thromboembolism. Compared with pharmacological prophylaxis alone, combined modalities reduce significantly the incidence of DVT but the effect on PE is unknown. The results of the current review support, especially in high-risk patients, the use of combined modalities. More studies on their role in PE prevention, compared with pharmacological prophylaxis alone, are urgently needed.

 

Plain language summary

Combined intermittent pneumatic leg compression and medication for the prevention of deep vein thrombosis and pulmonary embolism in high-risk patients

Deep vein thrombosis (DVT) and pulmonary embolism, or venous thromboembolism, are possible complications of surgery and trauma. These complications extend hospital stay and are associated with long-term disability and death. Patients undergoing total hip or knee replacement surgery or surgery for colorectal cancer are at high risk of venous thromboembolism. Sluggish venous blood flow, increased blood clotting and blood vessel endothelial injury are contributing factors. Treating more than one of these causes may improve prevention. Mechanical intermittent pneumatic leg compression reduces venous stasis while medications such as aspirin and anticoagulants such as low molecular weight heparin reduce blood clotting. The medications can also increase the risk of bleeding.

The present review showed that combining the two methods was more effective than a single preventative measure. Compared to compression alone, compression plus anticoagulant (combined prophylactic modalities) clearly decreased the incidence of both symptomatic pulmonary embolism (from 2.7% to 1.1%) and DVT (from 4% to 1.6%). Compared with medication with anticoagulants alone, combined compression and medication clearly reduced the incidence of DVT (from 4.21% to 0.65%). The effect on pulmonary embolism could not be determined because of the lack of events in the included
studies.

These conclusions are based on 11 controlled trials involving a total of 7431 surgery patients. The mean age of patients, where reported, was 65.5 years. Most patients had either a high-risk procedure or condition. The surgical procedures were orthopedic surgery in six trials and urological, cardiothoracic, general surgery and gynecology procedures in the other trials. The magnitude of the reduction in venous thromboembolism may be less for patients at moderate risk.