Histology, OCT, and Micro-CT Evaluation of Coronary Calcification Treated With Intravascular Lithotripsy: Atherosclerotic Cadaver Study.

Background: Although intravascular lithotripsy (IVL) has been an emerging novel option to treat vascular calcification, the specific effects on histology have not been systematically examined.
Objectives: The authors examined the histologic effects of IVL on coronary calcified lesions from human autopsy hearts and evaluated the diagnostic ability of optical coherence tomography (OCT) and micro-computed tomography (CT) to detect calcium fracture as identified by the gold standard histology.
Methods: Eight coronary lesions were treated with IVL, and 7 lesions were treated with 10 atm inflation using an IVL catheter balloon without lithotripsy pulses (plain old balloon angioplasty [POBA]). OCT and micro-CT imaging were performed before and after treatment, and the presence of calcium fracture was assessed. The frequency and size of fractures were measured and compared with the corresponding histology.
Results: All 15 treated lesions were diagnosed as sheet calcium by histology. Histological evidence of calcium fracture was significantly greater in the IVL group compared with the POBA group (62.5% vs 0.0%; P = 0.01). Calcified lesions with fracture had a larger maximum arc degree of calcification (median 145.6 [IQR: 134.4-300.4] degrees vs 107.0 [IQR: 88.9-129.1] degrees; P = 0.01). Micro-CT and histology showed an excellent correlation for fracture depth (R ²  = 0.83; P < 0.0001), whereas OCT showed less correlation (R ²  = 0.37; P = 0.11). The depth of fractures measured by OCT were significantly shorter than with those measured by histology (0.49 [IQR: 0.29-0.77] mm vs 0.88 [IQR: 0.64-1.07] mm; P = 0.008).
Conclusions: IVL demonstrated a histologically superior fracturing effect on coronary calcified lesions compared with POBA. OCT failed to identify the presence of some calcium fractures and underestimated the depth of fracture when compared with micro-CT.
Competing Interests: Funding Support and Author Disclosures This study was funded by Shockwave Medical through a grant to CVPath Institute, Inc. Drs Kawai, Sato, Kawakami, Konishi, and Ghosh are employees of CVPath Institute. Dr Hokama is an employee of Shockwave Medical. Dr Virmani is an employee of CVPath Institute; and is a consultant for Abbott Vascular, Boston Scientific, Celonova, OrbusNeich Medical, Terumo Corporation, W. C. Gore, Edwards Lifesciences, Cook Medical, CSI, Recor Medical, SinoMedical Sciences Technology, Surmodics, and Bard BD. Dr Finn is an employee of CVPath Institute; and has received consultant fees/honoraria from Abbott Vascular, Amgen, Biosensors, Boston Scientific, Celonova, Cook Medical, CSI, Lutonix Bard, Sinomed, and Terumo Corporation.
(Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)