Laser ablation and the need for intra-arterial imaging.

In 48 patients with severe claudication due to a total obstruction of the femoropopliteal artery, percutaneous recanalization was attempted with a 2.2 mm diameter rounded sapphire contact probe in conjunction with a continuous wave Nd:YAG laser. In eight patients the contact probe laser catheter took a subintimal course that could not be redressed. Laser recanalization needs high-resolution diagnostic information on the complex anatomy of the obstruction. Intra-arterial ultrasound imaging may provide the necessary information to evaluate, monitor or guide novel angioplasty techniques. The design of an ultrasound catheter which combines high-resolution diagnostic imaging with steerability, flexibility and controlled ablation is now the major engineering challenge in interventional cardiology.