Fully implantable blood pressure system: Implantation experiences

Hypertension is an important risk factor for vascular diseases (arteriosclerosis), renal and heart insufficiency. In Germany, approximately 10 million people suffer from hypertension. 10% of the people affected are difficult to medicate. Furthermore, 10% of this group are candidates for long term monitoring. Therefore a fully implantable and telemetrically controlled blood pressure system is presented to realize a comfortable long term monitoring for these patients. The developed implant consists of a newly designed sensor chip integrated at the tip of a polyurethane tube (Ø 1.05 mm) and a telemetric unit (Ø 17 mm). The dimensions of the system per mit a minimal invasive procedure. The telemetry and the sensor are connected via micro-cable. The implantation procedure follows the steps of Seldinger-technique with a specially de signed collagen based peel-away sheath introducer set (PASIS) for secure insertion of the pressure sensor in the femoral artery (FA). The telemetry was fixed on the muscle fascia be neath the skin. A reference sensor (MIPM, Mammendorfer Institut für Physik und Medizin GmbH, Germany) was placed contra laterally. In vivo experiments for evaluation of implantation procedure and functionality of the implant were per formed in 6 sheep (weight 60 to 80 kg, 4: acute testing, 2: chronic testing).