There is no need to worry about blood clots in the legs of the elderly, and it is important to distinguish whether they are arterial clots or venous clots. If there are symptoms in the acute stage, such as sudden occurrence of venous thrombosis will cause acute swelling of the leg, while sudden occurrence of arterial thrombosis will cause sudden coldness, numbness, pain and even necrosis of the leg. In addition to these two cases need emergency medical treatment, other cases can be based on the results of the examination, including ultrasound and D-dimer, if the thrombus is less hypoechoic, appeared solid or hyperechoic this kind of situation, in combination with the D-dimer if not high, usually for the old thrombus, do not need special treatment and do not need to worry about special.