Microperfusion pump-systems and development

Transluminal coronary angioplasty has become an established form of treatment for coronary artery disease. The dilatiation time is normally restricted by the ischaemic tolerance. Until today passive perfusion catheters have been used to maintain coronary blood flow to the distal segment. However, such continuous perfusion has often been insufficient to retain myocardial function. Active perfusion catheters, instead, have not been introduced so far for technical reasons. Active coronary perfusion via dilatation catheters with an intracorporal rotary micropump was the objective of investigations by Fraunhofer IPA and the University of Essen. The result of the development activities was an internal geared pump with an outer diameter of 2,5 mm. Several design studies were undertaken to integrate the micropump in a PTCA catheter. The most important aspect of the integrated micropump is that the dilatation time can be prolonged. First in vitro tests with whole-blood showed acceptable mechani cal haemolysis of the pump system. Further in vitro tests will lead to an optimized pump design with low mechanical haemolysis and a high flow rate.