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After Stroke, Most DVTs Develop Quickly

Preventive therapies should be initiated early and continue beyond four weeks

After stroke, most cases of deep vein thrombosis (DVT) develop within one week, according to a study published recently in the Journal of Thrombosis and Haemostasis. Prophylactic treatment should start early and continue for at least four weeks.

DVT is a common complication of stroke, and often leads to pulmonary embolism. Very little research was available to inform DVT-related therapeutic decisions post-stroke. The authors of the current study therefore sought to learn more through data from CLOTS 1 and 2, two randomized controlled trials conducted at 135 hospitals in nine countries. They screened the 5,632 immobile stroke patients (median age 76 years) for asymptomatic DVT via compression duplex ultrasound at seven to 10 days and again at 25 to 30 days post-enrollment.

The authors identified 641 patients (11.4 percent) with DVT at week one and 176 (3.1 percent) with DVT at one month. Thus, 79 percent of the DVTs occurred within 10 days. A significant number occurred for the first time in the second, third, or fourth week, and in some patients, DVT recognized in week one worsened in subsequent weeks. Thirty-nine percent of DVT patients developed pulmonary embolism. In patients who experienced leg weakness, about 75 percent of DVTs affected the weak leg only. However, bilateral DVT occurred frequently enough to recommend bilateral compression or nerve stimulation when practical, the authors write. They conclude: “to be maximally effective, any prophylaxis needs to be started early and continued for at least four weeks, although it remains unclear how soon after stroke DVTs start to form.”

Source: Dennis M, Mordi N, Graham C, Sandercock P. 2011. The timing, extent, progression and regression of deep vein thrombosis in immobile stroke patients: observational data from the CLOTS multicentre randomised trials. Published on August 23, 2011 on the Journal of Thrombosis and Haemostasis website.