Clinical Question: Can off-the-shelf compression stockings prevent post-thrombotic syndrome in patients with a proximal deep venous thrombosis (DVT)?

Setting: Outpatient (primary care)

Study Design: Randomized controlled trial (nonblinded)

Allocation: Concealed

Synopsis: The authors of this study enrolled 180 consecutive patients who presented with a first episode of symptomatic proximal DVT and received conventional anticoagulant treatment. On discharge, the patients were given nothing or below-the-knee elastic compression stockings to wear at least during the day for a minimum of two years. The stockings provided 30 to 40 mm Hg of pressure at the ankle and were available in five sizes. The investigators, who were unaware of treatment assignment, evaluated the patients every three months for at least two years and up to five years.

Using a self-developed and validated 33-point scale, investigators assigned a diagnosis of “mild” post-thrombotic syndrome to patients with scores of 5 to 14 on two consecutive visits, and “severe” post-thrombotic syndrome if they had a score of 15 or greater on two consecutive examinations. Post-thrombotic syndrome occurred in 49.1 percent of patients without stockings, but only 24.5 percent of patients using the stockings (adjusted hazard ratio = 0.49; 95 percent confidence interval [CI], 0.29 to 0.84; P = .011). Over two years, one additional episode of the syndrome was avoided for every four patients who wore the stockings (number needed to treat = 4; 95 percent CI = 2.3 to 18.9).

Bottom Line: Post-thrombotic symptoms such as discomfort, swelling, and skin discoloration occur in up to one third of patients who have experienced a symptomatic proximal DVT. Use of below-the-knee graded compression stockings decreases the cumulative incidence of post-thrombotic symptoms by 50 percent over two years. Patients with a thrombosis should be advised to purchase these stockings following acute treatment. The stockings should be replaced every six months. (Level of Evidence: 2b)