Combined improvements in implantable pump technology and insulin stability allow safe and effective long term intraperitoneal insulin delivery in type 1 diabetic patients: the EVADIAC experience.

OBJECTIVE: To report a long-term multicentre experience with implantable insulin pumps in type 1 diabetic patients, and to test safety and accuracy of the systems following improvements in infused insulin solutions and peritoneal catheter. RESEARCH DESIGN AND METHODS: Forty MiniMed Implantable Pumps model 2001 were consecutively implanted over a two-month period in type 1 diabetic volunteers. The systems were equipped by a new compliant sideport catheter and were refilled at 45-day intervals with HOE 21 PH ETP insulin batches showing enhanced physical stability in vitro. Safety was assessed from the incidence of acute adverse events and effectiveness from quarterly HbA(1c) assays. Accuracy of delivery was measured at each pump refill by comparing residual insulin in the pump reservoir with expected amount according to programmed infusion. The study lasted until pump battery depletion or premature pump explantation.
RESULTS: Cumulated experience was 106 patient-years. Premature explantations occurred in 3 cases, due to one electronic pump failure and two "pump-pocket" infections. Near-normal insulin delivery was sustained until expected battery depletion in 13 cases. Forty underdelivery events occurred in 24 pumps, but 36 among them were related to pump slowdowns due to insulin aggregation in pumps that were promptly solved by an outpatient NaOH rinse procedure. Only 4 underdeliveries were caused by catheter obstructions that required laparoscopy to remove peritoneal tissue overgrowth around the catheter. Over pump lifetime, HbA(1c) was 7.2 +/- 0.2% in the 13 patients with no underdelivery and 7.7 +/- 0.5% in the other ones. Only one severe hypoglycemia and one ketoacidosis occurred during the whole study.
CONCLUSION: Our current experience with improved implantable pumps and insulin solutions shows both long-term safety and effectiveness of this treatment in type 1 diabetic patients following improvement in infused insulin solutions and catheter. This therapy may be a good alternative for patients that experience frequent severe hypoglycemia with intensive subcutaneous insulin therapy.