Optical Coherence Tomography Characterization of Coronary Lithoplasty for Treatment of Calcified Lesions

OBJECTIVES This study sought to determine the mechanistic effects of a novel balloon-based lithoplasty system on heavily calcified coronary lesions and subsequent stent placement using optical coherence tomography (OCT). BACKGROUND The Shockwave Coronary Rx Lithoplasty System (Shockwave Medical, Fremont, California) delivers localized, lithotripsy-enhanced disruption of calcium within the target lesion (i.e., lithoplasty) for vessel preparation before stent implantation. METHODS We analyzed OCT findings in 31 patients in whom lithoplasty was used to treat severely calcified stenotic coronary lesions. RESULTS After lithoplasty, intraplaque calcium fracture was identified in 43% of lesions, with circumferential multiple fractures noted in >25%. The frequency of calcium fractures per lesion increased in the most severely calcified plaques (highest tertile vs. lowest tertile; p = 0.009), with a trend toward greater incidence of calcium fracture (77.8% vs. 22.2%; p = 0.057). Post-lithoplasty, mean acute area gain was 2.1 mm(2), which further increased with stent implantation, achieving a minimal stent area of 5.94 +/- 1.98 mm(2) and mean stent expansion of 112.0 +/- 37.2%. Deep dissections, as part of the angioplasty effect, occurred in 13% of cases and were successfully treated with stent implantation without incidence of acute closure, slow flow/no reflow, or perforation. CONCLUSIONS High-resolution imaging by OCT delineated calcium modification with fracture as a major mechanism of action of lithoplasty in vivo and demonstrated efficacy in the achievement of significant acute area gain and favorable stent expansion. (C) 2017 by the American College of Cardiology Foundation.