Deep vein thrombosis (DVT) is always one of frequent clinical issues of hospitalized patients. Pulmonary emboli (PE) – an acute complication of DVT – can cause death. Many chronic complications of DVT such as post-thrombosis syndrome and chronic venous ulcers both damage significantly to the health of patients. Until now Vietnam, diagnosis and preventive strategies of DVT for hospitalized individuals in internal medicine or surgery departments have not been done routinely, especially in patients with chronic heart failure who usually had high risks of DVT resulted from either circulatory stasis or restriction of movements.