Intermittent pneumatic compression for DVT prevention

Intermittent pneumatic compression for DVT prevention

 The risk of DVT (deep vein thrombosis) and pulmonary embolism can be reduced by giving intermittent pneumatic compression of the calf muscles [1]. The authors analyzed data from over sixteen thousand patients in seventy clinical trials to assess the benefit of giving intermittent pneumatic compression of the lower limbs in preventing DVT. They also checked the additional benefit of adding pharmacological thromboprophylaxis. Intermittent pneumatic compression reduced the risk of deep vein thrombosis from 16.7% to 7.3%. Pulmonary embolism was reduced to 1.2% from 2.8%, that is an absolute risk reduction of 1.6% (relative risk, 0.48; P<0.01). It was also more effective than thromboembolic deterrent stockings.

Intermittent pneumatic compression was found to be as effective as pharmacological thromboprophylaxis, with an added advantage of lower bleeding risk (relative risk, 0.41; P<0.01). Combining pharmacological DVT prophylaxis and intermittent pneumatic compression further reduces the risk DVT (relative risk, 0.54; P=0.02). The number needed to prevent one deep vein thrombosis was 11 while that for pulmonary embolism was 63 with intermittent pneumatic compression.

Intermittent pneumatic compression have cuffs applied to the legs and tubings attached to a motorised device. The device provides intermittent inflation and deflation of the cuffs so that intermittent compression is applied. This will facilitate venous return, which should normally occur due to contraction of calf muscles in an ambulant person. Thus the device enhances venous return and helps in prevention of stasis and thrombosis.

A Cochrane systematic review assessed the combination of intermittent pneumatic leg compression and pharmacological prophylaxis for prevention of venous thrombosis [2]. They included 22 trials with 9137 participants of which 15 trials with 7762 participants were randomized trials. They found moderate quality evidence that combining both modalities compared to either modality alone decreases the incidence of DVT when compared to compression and incidence of pulmonary embolism when compared to anticoagulation.

Effectiveness of intermittent pneumatic compression was also documented by the Clots in Legs Or sTockings after Stroke (CLOTS) 3 trial in post stroke patients [3]. This was a randomized controlled trial in 2876 patients at 94 hospitals in the United Kingdom.

Another meta-analysis of critically ill patients included 5 randomized controlled trials with a total of 3133 patients [4]. They found that intermittent pneumatic compression alone, anticoagulation alone and the combination of the two were associated with significant reduction of DVT and pulmonary embolism compared to no treatment. But there was no significant difference between these modalities when compared together.

STOP leg clots, a Swedish multicenter trial of outpatient prevention of leg clots is a randomized controlled trial of intermittent pneumatic compression in lower leg immobilized patients [5]. They plan to enroll 700 patients in each arm and study completion is expected by the end of 2022. Subjects will be those with either an acute ankle fracture or Achilles tendon rupture.

References

1. Kwok M Ho, Jen Aik Tan. Stratified Meta-Analysis of Intermittent Pneumatic Compression of the Lower Limbs to Prevent Venous Thromboembolism in Hospitalized Patients. Circulation. 2013 Aug 27;128(9):1003-20.
2. Kakkos SK, Caprini JA, Geroulakos G, Nicolaides AN, Stansby G, Reddy DJ, Ntouvas I. Combined intermittent pneumatic leg compression and pharmacological prophylaxis for prevention of venous thromboembolism. Cochrane Database Syst Rev. 2016 Sep 7;9(9):CD005258. 
3. Dennis M, Sandercock P, Graham C, Forbes J; CLOTS (Clots in Legs Or sTockings after Stroke) Trials Collaboration, Smith J. The Clots in Legs Or sTockings after Stroke (CLOTS) 3 trial: a randomised controlled trial to determine whether or not intermittent pneumatic compression reduces the risk of post-stroke deep vein thrombosis and to estimate its cost-effectiveness. Health Technol Assess. 2015 Sep;19(76):1-90. 
4. Haykal T, Zayed Y, Dhillon H, Miran MS, Kerbage J, Bala A, Samji V, Deliwala S, Bachuwa G. Meta-Analysis of the Role of Intermittent Pneumatic Compression of the Lower Limbs to Prevent Venous Thromboembolism in Critically Ill Patients. Int J Low Extrem Wounds. 2020 Jun 11:1534734620925391. 
5. Svedman S, Alkner B, Berg HE, Domeij-Arverud E, Jonsson K, Nilsson Helander K, Ackermann PW. STOP leg clots-Swedish multicentre trial of outpatient prevention of leg clots: study protocol for a randomised controlled trial on the efficacy of intermittent pneumatic compression on venous thromboembolism in lower leg immobilised patients. BMJ Open. 2021 May 20;11(5):e044103.