Residual venous thrombosis as predictive factor for recurrent venous thromboembolim in patients with proximal deep vein thrombosis: a sytematic review.

The potential role of the detection of residual thrombosis after deep vein thrombosis (DVT) in the differentiation of patients at risk for recurrent venous thromboembolism (VTE) has not yet been fully established and includes different definitions. We performed a systematic review in order to determine the role of residual thrombosis in predicting recurrent VTE after acute proximal DVT. Databases were searched until June 2010. Randomized, controlled trials or prospective cohort studies were eligible for inclusion if they included patients with objectively diagnosed proximal DVT, measured thrombus diameter after at least 3 months and reported recurrent VTE during follow-up. Two authors independently reviewed articles and extracted data. Data from 11 studies were used for the current analysis; in total 3203 patients were included. Residual thrombosis was positively correlated with recurrent VTE. Large heterogeneity was present, due to differences in study population, timing and the differences in method of measuring residual thrombosis. The effect was more pronounced in patients with malignancy or was dependent on the criteria used. This systematic review shows a positive relationship between residual thrombosis and recurrent VTE during follow-up. Assessing residual thrombosis could be useful in individual recurrence risk estimation.