In patients at moderate or high risk of venous thromboembolism (VTE) who are having elective surgery, compression stockings may not be a necessary add-on to pharmacological thromboprophylaxis, a trial found.
Researchers conducted an open randomized controlled noninferiority trial at seven National Health Service (NHS) tertiary hospitals in the U.K. to assess whether stockings offer any adjuvant benefit to low-molecular-weight heparin (LMWH) for VTE prophylaxis in adult patients undergoing elective surgery. Participants were randomly assigned 1:1 to receive LMWH alone or LMWH plus graduated compression stockings. The primary outcome was imaging-confirmed lower-limb deep venous thrombosis (with or without symptoms) or pulmonary embolism with symptoms within 90 days of surgery. Secondary outcome measures included quality of life, lower-limb complications related to stockings, and adverse reactions to LMWH. Results were published May 13 by The BMJ.
Between May 2016 and January 2019, 1,905 elective surgical inpatients at moderate or high risk for VTE were randomized. Of these, 17 were identified as ineligible after randomization and 30 did not have surgery, leaving 1,858 participants who were included in the intention-to-treat analysis (937 in the LMWH group and 921 in the combination group). A primary outcome event occurred in 16 (1.7%) patients in the LMWH-alone group, compared with 13 (1.4%) in the combination group. The risk difference between the two groups was 0.30% (95% CI, −0.65% to 1.26%). Because the 95% CI did not cross the noninferiority margin of 3.5% (P<0.001 for noninferiority), LMWH alone was confirmed to be noninferior to LMWH and stockings. This finding was sustained in subgroup analyses based on participant age (<65 years or ≥65 years) and baseline VTE risk (moderate or high). In secondary outcome analyses, there were no differences in quality-of-life outcomes between groups at baseline, at one week or hospital discharge, at 14 to 21 days, or at 90 days. Fifty-five of those who received compression stockings reported related complications (mostly discomfort), and eight patients had adverse reactions to LMWH (mostly abnormal liver enzymes).
Among other limitations, 281 (15.1%) participants did not receive a duplex ultrasound scan, which could have detected more patients with deep venous thrombosis without symptoms, the authors noted, although the number of missed scans was comparably distributed between groups. “If we consider the potential adverse events and cost of [graduated compression stockings], urgent revision of national and international VTE prevention guidelines is recommended,” they concluded.
A linked opinion piece by one of the authors, a clinical trial manager within a vascular unit, said that anecdotal feedback from patients has been that stockings are generally difficult to wear because they are hot, itchy, and don't stay up. Given the risks and costs associated with graduated compression stockings, their use is not justified for deep venous thrombosis prevention, the article said.
“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,” the trial manager wrote. “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.”