One of the well-recognised complications of surgery is deep venous thromboembolism (DVT) and much work has been done to reduce the incidence of hospital acquired thrombosis, including the use of mechanical devices (stockings) and drugs (e.g Heparin). Current UK venous thromboembolism (VTE) prevention recommendations state that surgical patients at medium or high risk for VTE, in whom there are no contraindications, should receive both pharmacological and mechanical thromboprophylaxis in the form of graduated compression stockings. A similar recommendation is made to US physicians by the American College of Chest Physicians (ACCP). However, the evidence base upon which clinical guidelines have been developed is weak and has been widely contested. As a clinical trial manager within a vascular unit, I have gained in depth knowledge of the pros and cons of stockings for DVT prophylaxis and our most recent study published in The BMJ, was designed to address some of this controversy.
Anecdotal feedback I received from patient and public involvement groups was that stockings are generally difficult to wear with many stating that “they are hot”, “itchy” and “they don’t stay up”. Physicians and nurses are also aware that poorly fitting stockings can cause discomfort, contact dermatitis, skin discoloration and blistering. At worse they can lead to pressure sores or worsen ischaemia in patients with poor arterial circulation.
The cost of purchasing and applying stockings to surgical inpatients at risk for VTE in England is estimated at £63.1 million per annum which begs the question as to whether the risks and costs associated with graduated compression stockings both medically or health-economically are justified for DVT prevention.  The authors of the GAPS trial believe that they do not. Our large multicentre randomised controlled trial demonstrated that thromboprophylaxis alone is no worse than the current UK standard combination of graduated compression stockings and low molecular weight heparin.
Elective surgical patients were recruited to take part in the trial from seven hospitals in England. Recruitment faced the usual problems that most trials encounter but notably, patients often had difficulty with the idea of randomisation when faced with the possibility of not receiving the usual standard care. “I don’t want to be treated as a guinea pig” and “I don’t want to miss out on the stockings” were common reasons cited by those who declined to participate. That being said, outside of the trial setting, adherence with stockings can be extremely variable with one hospital audit showing that up to 60% of inpatients were not wearing any form of graduated compression stockings when inspected. 
Although adherence with stockings in the trial was good (even with some crossover in both arms) we were somewhat surprised to find the rate of VTE in our elective surgical population lower than anticipated at 1.7%. Thorough analysis halfway through the trial and careful review of data gathered up to that point, led us to conclude that hospital acquired thrombosis reduction strategies, including the mandatory risk assessment of patients have significantly improved outcomes for patients over the last decade.
The results of the GAPS trial add to a growing body of evidence that does not support the use of graduated compression stockings in this patient population. This is also supported by data from Salisbury NHS Foundation Trust where the policy has been not to use graduated compression stockings in elective surgical patients receiving thromboprophylactic dose low molecular weight heparin over the last five years and whose VTE outcomes are comparable to national figures.
As our health service faces a challenge unlike anything we’ve ever seen, and we enter a period of huge economic uncertainty, it’s clear the NHS will be expected to find many innovative ways to reduce costs in the future. One way may be through review of health technologies long established in clinical practice, where there is a paucity of evidence supporting their current use. We strongly recommend the urgent re-consideration of the need for stockings for this patient population and publish this trial to support future guidance and policy in VTE prevention worldwide.
Rebecca Lawton, Clinical Trial Manager GAPS trial, Imperial College London.
Competing interests: Please see linked research
- Mandavia R, Shalhoub J, Head K, Davies AH. The additional benefit of graduated compression stockings to pharmacologic thromboprophylaxis in the prevention of venous thromboembolism in surgical inpatients. Journal of vascular surgery Venous and lymphatic disorders. 2015;3(4):447-55.e1.
- Walker L, Lamont S. The use of antiembolic stockings. Part 2: a clinical audit. British Journal of Nursing. 2008;17(1):32-6.