In vivo effect of coronary laser angioplasty on atherosclerotic plaques: Histopathologic analysis

Information from histopathologic examination of coronary arterial atheroscl erotic plaques treated with in vivo laser energy is sparse. Directional ath erectomy provides biopsies for study of tissue changes (injury) due to coro nary arterial debulking devices, including laser. Sixteen patients who pres ented with acute ischemic coronary syndromes underwent debulking of a total of 17 obstructive intracoronary lesions with pulsed-wave holmium:YAG laser (2.1 mum wavelength). Laser was performed with the "pulse and retreat" tec hnique, which incorporates slow catheter advancement (0.5-1 mm/s) with cont rolled emission of energy. Immediately postlasing, directional atherectomy was utilized to obtain irradiated plaque tissue for pathologic examination. Extent of laser-induced tissue injury to plaques was graded as 0 (no tissu e damage), I (small foci or charring and vacuoles), 2 (large amount of chaf fing, edge disruption and vacuoles) and 3 (extensive tissue damage). Angiog raphically and clinically, all 17 lesions were successfully debulked with t he laser energy (mean 47 +/- 25 pulses), with a reduction of target lesion percent diameter stenosis from 92 +/- 6% to 47 +/- 25%. Adjunct balloon dil ations further reduced the target lesions to a final of 10 +/- 10% stenosis . The histopathologic examination of the lased specimens demonstrated that 13 lesions (76%) had no evidence of laser-induced injury (Grade 0). Four le sions had low-level injury (Grade 1), and none had evidence of Grade 2 or 3 laser-induced trauma. Therefore, a laser debulking technique which incorpo rates slow catheter advancement with controlled emission of pulses, does no t cause significant injurious effects to the irradiated plaque. (C) 2001 El sevier Science Inc. All rights reserved.