
Venous thromboembolism causes substantial disability and death. The incidence of deep venous thrombosis (DVT) is about 1 per 1000 person years. The most serious and potentially preventable complication, pulmonary embolus, kills an estimated 50,000 Americans each year. Venous stasis secondary to chronic valvular incompetence, of- ten a consequence of venous thrombosis, causes varying degrees of pain, edema, and ulceration....