Long-term, continuous intravenous heparin administration by an implantable infusion pump in ambulatory patients with recurrent venous thrombosis

We studied the effect of long-term intravenous heparin infusion, delivered by a self-recycling, totally implantable infusion pump developed in our laboratory, in 21 patients with recurrent thromboembolic disease. Continuous infusions were maintained in these patients from 1 to 36 months, during which pumps were refilled by percutaneous needle injection at 4- to 8-week intervals. We maintained plasma heparin levels between 0.1 and 0.3 U/ml plasma. This regimen prevented thromboembolic phenomena in all except one patient, who apparently is refractory to heparin as well as oral anticoagulant drug therapy. Marked reduction of pain and improvement of mobility were reported by several patients with vena caval ligature syndrome. No spontaneous hemorrhagic complications occurred; however, several episodes of pump site hemorrhage were associated with pump refills. Bone mineral densities measured in eight subjects after 1 year of heparin infusion [1.00 ± 0.06 (SE) gm/cm] were not significantly (P = 0.5) different from baseline values (0.98 ± 0.08 gm/cm); however, osteoporosis did occur in one subject. Serum calcium, phosphorus, alkaline phosphatase, cholesterol, and triglycerides also remained unchanged in these subjects. These data suggest that continuous long-term heparin infusion is a viable therapeutic alternative in subjects with refractory thromboembolic disease.