Antithrombotic medications are the mainstay of preventative therapy for deep-vein thrombosis (DVT); however, these drugs are associated with an increased risk of bleeding and are contraindicated in some patients, including those who have experienced a stroke. Mechanical methods of DVT prophylaxis such as compression stockings are an alternative strategy for these patients. However, the effectiveness and optimum length of compression stockings has not been established.

The CLOTS investigators have now reported that thigh-length stockings reduce the risk of DVT by 31% when compared with below-knee stockings among immobile, hospitalized patients with stroke. “This is worrying since most of the stockings used by health services are short,” says CLOTS investigator Martin Dennis. “This may be wasting huge amounts of money and, even worse, providing patients with less than optimal prophylaxis”.

In the international CLOTS 2 trial, 3,114 enrolled patients with ischemic or hemorrhagic stroke were randomly assigned to wear either the long or short stockings on both legs for the duration of their hospitalization. The incidence of DVT in the popliteal or femoral veins was 6.3% in the group that received thigh-length stockings and 8.8% for below-knee stockings (P = 0.007). Skin problems associated with the intervention were more common among patients who wore the thigh-length stockings, but most of these complaints were minor. “Our advice,” says Professor Dennis, “is that ... long stockings should be used whenever practical.”