A deep vein thrombosis (DVT) is a blood clot that forms in a deep vein, partially or completely blocking the flow of blood. A long-term side effect of DVT may be one or more damaged venous valves that allow backward flow of venous blood. Improperly functioning valves lead to venous congestion in the leg, increasing the risk for chronic venous insufficiency (CVI) and new DVT.

30-40 mmHg knee length compression stockings are prescribed to manage the acute symptoms of DVT and to help prevent the long-term effects.