Toggle Main Menu Toggle Search

Open Access padlockePrints

Compression stockings in addition to low-molecular-weight heparin to prevent venous thromboembolism in surgical inpatients requiring pharmacoprophylaxis: the GAPS non-inferiority RCT

Lookup NU author(s): Professor Gerard Stansby


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


BACKGROUND: Patients admitted to hospital for surgery are at an increased risk of venous thromboembolism. Pharmaco-thromboprophylaxis and mechanical prophylaxis (usually graduated compression stockings or intermittent pneumatic compression) have been shown to reduce the incidence of venous thromboembolism. The evidence base supporting the National Institute for Health and Care Excellence's recommendation for the use of graduated compression stockings for venous thromboembolism prevention in the UK has recently been challenged. It is unclear if the risks and costs associated with graduated compression stockings are justified for deep-vein thrombosis prevention in moderate- and high-risk elective surgical inpatients receiving low-dose low-molecular-weight heparin pharmaco-thromboprophylaxis. OBJECTIVES: The primary objective was to compare the venous thromboembolism rate in elective surgical inpatients at moderate or high risk of venous thromboembolism who were receiving either graduated compression stockings and low-dose low-molecular-weight heparin (standard care) or low-dose low-molecular-weight heparin alone (intervention). DESIGN: This was a pragmatic, multicentre, prospective, non-inferiority, randomised controlled trial. SETTING: This took place in secondary care NHS hospitals in the UK. PARTICIPANTS: Patients aged ≥ 18 years who were assessed to be at moderate or high risk of venous thromboembolism according to the NHS England venous thromboembolism risk assessment tool (or the trust equivalent based on this form) and who were not contraindicated to low-molecular-weight heparin or graduated compression stockings were deemed eligible to take part. INTERVENTIONS: Participants were randomised 1 : 1 to either low-molecular-weight heparin or low-molecular-weight heparin and graduated compression stockings. MAIN OUTCOME MEASURES: The primary outcome measure was venous thromboembolism up to 90 days after surgery. A combined end point of duplex ultrasound-proven new lower-limb deep-vein thrombosis (symptomatic or asymptomatic) plus imaging-confirmed symptomatic pulmonary embolism. Secondary outcomes included quality of life, compliance with graduated compression stockings and low-molecular-weight heparin during admission, and all-cause mortality. RESULTS: A total of 1905 participants were randomised and 1858 were included in the intention-to-treat analysis. A primary outcome event occurred in 16 out of 937 (1.7%) patients in the low-molecular-weight heparin-alone arm compared with 13 out of 921 (1.4%) patients in the low-molecular-weight heparin plus graduated compression stockings arm. The risk difference between low-molecular-weight heparin and low-molecular-weight heparin plus graduated compression stockings was 0.30% (95% confidence interval -0.65% to 1.26%). As the 95% confidence interval did not cross the non-inferiority margin of 3.5% (p < 0.001 for non-inferiority), the results indicate that non-inferiority of low-molecular-weight heparin alone was shown. LIMITATIONS: In total, 13% of patients did not receive a duplex ultrasound scan that could have detected further asymptomatic deep-vein thrombosis. However, missing scans were balanced between both trial arms. The subpopulation of those aged ≥ 65 years assessed as being at a moderate risk of venous thromboembolism was under-represented in the study; however, this reflects that this group is under-represented in the general population. CONCLUSIONS: For elective surgical patients at moderate or high risk of venous thromboembolism, administration of pharmaco-thromboprophylaxis alone is non-inferior to a combination of pharmaco-thromboprophylaxis and graduated compression stockings. These findings indicate that graduated compression stockings may be unnecessary for most elective surgical patients. FUTURE WORK: Further studies are required to evaluate whether or not adjuvant graduated compression stockings have a role in patients receiving extended thromboprophylaxis, beyond the period of hospital admission, following elective surgery or in patients undergoing emergency surgical procedures. TRIAL REGISTRATION: Current Controlled Trials ISRCTN13911492. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 69. See the NIHR Journals Library website for further project information.WHY DID WE CONDUCT THIS RESEARCH?: People undergoing operations are at risk of developing blood clots in their legs, which is known as a deep-vein thrombosis. Blood clots occur for several reasons, such as not being able to move around after an operation, changes in the blood or damage to the veins in which blood travels. To decrease the risk of getting deep-vein thrombosis, patients having operations are given tight elastic socks to wear called graduated compression stockings. They are also given blood thinning medicine to prevent clotting. There is little evidence that wearing elastic socks in hospital will reduce the risk of blood clots if blood thinners are also given. Many patients say that the socks can hurt or cause bruising and can be difficult to put on. The graduated compression as an adjunct to thromboprophylaxis in surgery (GAPS) trial investigated whether or not patients having an operation would benefit from wearing elastic socks as well as getting blood thinners, or if blood thinners on their own prevented blood clots. WHAT DID WE DO?: A total of 1905 patients who were having operations at seven hospitals in England agreed to take part. They were randomly assigned to different treatments by a computer program. Half of the patients were given elastic socks plus blood thinners, and the other half were given the blood thinners alone. WHAT DID WE FIND?: There was no significant difference in the number of people who had a blood clot in either study group. This could mean that blood thinners are as good at stopping blood clots as blood thinners and elastic socks for patients having operations. WHAT COULD BE CARRIED OUT NEXT?: The NHS spends around £63M per year across England on elastic stockings. This research indicates that patients might not get extra benefit from wearing them if they have taken blood thinners.

Publication metadata

Author(s): Shalhoub J, Lawton R, Hudson J, Baker C, Bradbury A, Dhillon K, Everington T, Gohel MS, Hamady Z, Hunt BJ, Stansby G, Warwick D, Norrie J, Davies AH

Publication type: Article

Publication status: Published

Journal: Health Technology Assessment

Year: 2020

Volume: 24

Issue: 69

Pages: 1-80

Online publication date: 01/12/2020

Acceptance date: 01/07/2020

ISSN (electronic): 1366-5278

Publisher: National Coordinating Centre for Health Technology Assessment


DOI: 10.3310/hta24690

PubMed id: 33275096


Altmetrics provided by Altmetric