Study Disputes Benefit of Compression Stockings for Preventing VTE

May 14, 2020
Patrick Campbell

New research has found use of medication alone was noninferior to using medication and graduated compression socks for preventing VTE following non-emergency surgery.

Despite being a staple in follow-up care for years, data from a new clinical trial is challenging the idea of compression stockings to prevent blood clots in most patients undergoing elective surgery.

The randomized, controlled trial, which included nearly 2000 patients, found use of medication for thromboprophylaxis alone was noninferior to using graduated compression stockings and medication for thromboprophylaxis for preventing venous thromboembolism (VTE).

"These findings indicate that graduated compression stockings might be unnecessary in most patients undergoing elective surgery, and current guidelines based on historical data should be revised," investigators wrote.

To evaluate the impact of graduated compression stockings on the occurrence of VTE following non-emergency surgeries, a UK-based team of investigators designed the current study as an open, multicenter, randomized, controlled, noninferiority trial using patients enrolled from 7 medical centers across the UK from May 2016-January 2019. To compare the 2 strategies, investigators randomized patients in 1:1 ratio to pharmaco-thromboprophylaxis with low molecular weight heparin and graduated compression stockings or low molecular weight heparin alone.

In total, 1905 patients were randomized in the trial, but only 1858 underwent surgery and were included in the intent-to-treat analysis. Of the 1858 patients included, 937 were randomized to low molecular weight heparin alone and 921 were randomized to the adjuvant graduated compression stocking group.

Patients randomized to graduated compression stockings received above or below knee stockings providing 18 mmHg compression at the level of the ankle. Those randomized to medication alone were asked not to wear any kind of compression stocking for 90 days following surgery.

The primary outcome of the analysis was new VTE within 90 days of surgery, which investigators defined as lower limb deep vein thrombosis with or without symptoms, proven by duplex ultrasound, or pulmonary embolism with symptoms confirmed by imaging. Secondary outcomes included quality of life, compliance with treatments, graduated compression stocking-related lower limb complications, bleeding complications, adverse reactions to low molecular weight heparin, and all-cause mortality.

Upon analysis, investigators identified a primary outcome event in 1.7% (n=16) of patients receiving low molecular weight heparin alone compared to 1.4% (n=13) of patients receiving low molecular weight heparin and graduated compression stockings. Based on results, the risk difference between the 2 arms of the study was calculated to be 0.30%—because the confidence interval did not cross the noninferiority margin of 3.5%, investigators concluded low molecular weight heparin alone was considered noninferior.

Results also indicated deep vein thrombosis symptoms occurred in .2% of patients in the low molecular weight heparin alone group and in 0.1% of patients receiving low molecular weight heparin and using graduated compression stockings. Investigators pointed out there were no differences in quality of life outcomes at 90 days between the 2 groups.

Investigator pointed out multiple limitations within their study. Limitations include a percentage of participants who did not receive a duplex ultrasound scan, the subgroup of patients 65 years and older assessed as being moderate VTE risk was underrepresented, and more than 66% of patients had a score of 5 or greater according to the Caprini score.

This study, “Graduated compression stockings as adjuvant to pharmaco-thromboprophylaxis in elective surgical patients (GAPS study): randomized controlled trial,” was published in The BMJ.