True ablation of atheromatous plaques with laser energy. A phase I safety study.

A laser system coupling pulsed dye laser to a 2-mm fiberoptic catheter with incorporated angioscope has been developed for recanalization of occluded arteries. Nine patients with superficial femoral artery occlusions of 4.5 to 49 cm in length were operated on and the recanalized artery harvested for pathologic examination. There were two arterial perforations. The ease of recanalization was determined by plaque composition. Heavily calcified and yellow fibro-fatty lesions were rapidly removed. Smooth white fibrous lesions resisted laser ablation. Direct angioscopy often disclosed discontinuous areas of occlusion that were more susceptible to recanalization. These were not seen on preoperative arteriograms. Microscopic examination of the specimens showed a central core of ablation. There was no evidence of acute damage to the vessel wall, with intact internal elastic lamina demonstrated in the recanalized segments. It appears that fibrous lesions will require a different laser for ablation; however, the delivery/angioscope systems function satisfactorily.