How to predict and diagnose postthrombotic syndrome.

Postthrombotic syndrome (PTS) is the most frequent complication of deep vein thrombosis (DVT). From 20% to 50% of the patients will develop PTS after DVT, and from 5% to 10%, severe PTS. PTS is diagnosed on clinical grounds, based on the presence of signs and symptoms of venous insufficiency in the leg ipsilateral to DVT. The Villalta scale, a clinical scale that incorporates venous symptoms and signs, is a recommended standard for the diagnosis of PTS. Identifying which patients are at high risk of developing PTS would help improve the management of patients with DVT and allow physicians to provide patients with individualized information on their expected prognosis. Clinical predictors of PTS have been progressively characterized, but the ability to predict which patient with DVT is likely to develop PTS remains limited. A number of risk factors for PTS have been identified; of these, proximal location of DVT and a previous ipsilateral DVT are the most important. This review discusses the knowledge gained over the last decade on the diagnosis and predictors of PTS.