Thermal angioplasty is a newly developed technique that employs a heated metallic tip to thermally ablate atherosclerotic plaques for recanalization of obstructed peripheral arterial blood vessels. However, the current Laser Thermal Probe employs a high power continuous argon laser which is large in size and high in cost. Last year, we developed an electrically heated thermal tip catheter as a possible alternative to the laser probe, and preliminary testing of this device in an in vivo animal model appears promising. Another economical method of heating a metallic tip is to harvest the chemical energy from the combustion of hydrogen gas. This energy can be released and harvested inside a catheter tip in a safe manner by utilizing a palladium sponge catalyst which initiates and maintains the chemical combustion in a controlled fashion. A prototype catalytic thermal tip catheter has been designed and fabricated for in vitro testing. A temperature feed back control device has been added to avoid excessive tissue heating with the aim of minimizing the incidence of vessel wall perforation. A commercialized model of the catalytically heated tip has been supplied and evaluated in several in vivo animal models. A human test application is anticipated.
