Over a period of 18 years, 191 consecutive patients had interruption of the inferior vena cava with the Hunter-Sessions balloon for complications of deep venous thrombosis and pulmonary embolism. Causes of deep venous thrombosis and pulmonary embolism included the postoperative state (33%), cancer (32%), and stroke (11%). There were 93 females and 98 males; ages ranged from 17 to 90 years (average, 57 years). Indications for placement of the Hunter-Sessions balloon were as follows: contraindication to anticoagulants (33%), anticoagulant complications (24%), pulmonary embolism despite anticoagulants (45%), and others including inferior vena cava thrombus (12%). Sixty-eight percent had clinical phlebitis and 36% had positive venography results. Pulmonary embolism had occurred in 165 patients (86%). It was diagnosed by ventilation-perfusion scanning (75%), angiography (23%), or on clinical grounds (2%) in patients with confirmed deep venous thrombosis. At the time of the procedure 52% were in significant cardiopulmonary distress, and 10% were intubated and on respirators. Transjugular placement was done in 188 patients, and transfemoral placement was performed in three. All All tolerated inferior vena cava interruption. Thirty patients (15%) died while in the hospital an average of 21 days after balloon placement, which was unrelated to the deaths. Follow-up was 45 months. Ninety-four patients are dead, 95 are alive, and the status of two patients is unknown. Twenty-nine of 64 patients (45%) who died after they left the hospital died of cancer. At last follow-up, 75% of patients had legs free of edema and 25% had need for elastic stockings. No malfunction or migration has occurred with the device. No patient had a pulmonary embolism while in the hospital after insertion of the Hunter-Sessions balloon, and no patient died of pulmonary embolism. Late minor pulmonary embolism occurred in three patients.