Improved imaging of intravascular lesions may improve safety and results of laser angioplasty. We evaluated a catheter capable of both real-time intravascular 2D ultrasound (US) guidance and radially directing holmium laser energy (HLE) in human xenograft implants in dogs. Following general anesthesia, atherosclerotic stenotic coronary arteries dissected from human cadaver hearts were anastomosed into femoral arteries. Catheters (2.7f) were introduced via carotid artery cutdowns and baseline angiography performed. HLE (2.1µm) was emitted perpendicular to the catheter axis via a laser window. A 2D-US imaging sensor adjacent to the laser window allowed simultaneous radial and longitudinal imaging of the stenosis and an extracorporal magnetic field sensed at the distal tip of the catheter by a magnetic sensor in the catheter body allowed positioning of the laser window. Once US imaging was accomplished in a .2 cm segment and the laser window positioned perpendicular to the stenosis, HLE (100-500 mJ/pulse) was fired with a real-time US imaging of ablation progress and vascular wall dimensions. Stenotic lesions were removed and images were confirmed angiographically. We conclude that a 2D US guided HLE atherectomy catheter provides longitudinal and radial imaging with magnetic field-guided catheter positioning which is potentially adequate for real-time management of laser atherectomy.
Gregory, KW, Martinelli MA, Aretz TH,. Butterly JR: Intravascular ultrasound-guided holmium laser atherectomy. Circulation (Suppl. III) 82: III-677, 1990.