title: Pulsed holmium laser ablation of cardiac valves.
abstract: Ablation efficiency and residual thermal damage produced by pulsed holmium laser radiation were investigated in vitro for bovine mitral valves and human calcified and noncalcified cardiac valves. Low-OH quartz fibers (200 and 600 microns core diameter) were used in direct contact perpendicular to the specimen under saline or blood. Etch rate was measured with a linear motion transducer. Radiant exposure was varied from 0 to 3 kJ/cm2. For 200-microns fibers, the energy of ablation was approximately 5 kJ/cm3 in noncalcified and 15 kJ/cm3 in calcified valves. Etch rates were dependent on mechanical tissue properties. Maximum etch rate at 1,000 J/cm2 was 1-2 mm/pulse at 3 Hz repetition rate. Microscopic examination revealed a zone of thermal damage extending 300 microns lateral into adjacent tissue. Thermal damage was independent of radiant exposure beyond twice threshold.
authors: Wellman Laboratories of Photomedicine, Massachusetts General Hospital, Boston 02114.
authors: L
authors: L
authors: Lilge
authors: W
authors: W
authors: Radtke
authors: N S
authors: NS
authors: Nishioka
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000601:surgery*; D002114:Calcinosis / Q000601:surgery*; D002417:Cattle; D006349:Heart Valve Diseases / Q000601:surgery*; D006695:Holmium; D006801:Humans; D066298:In Vitro Techniques; D007259:Infrared Rays; D008028:Light Coagulation / Q000379:methods*; D008943:Mitral Valve / Q000601:surgery*; D011829:Radiation Dosage
chemical_list: D006695:Holmium