Optical Coherence Tomography Characterization of Coronary Lithotripsy Following Atherectomy for Treatment of Severely Calcified Lesions

BACKGROUND: A combined strategy of atherectomy followed by intravascular lithotripsy (dual-prep strategy) for severely calcified lesions may optimize stent deployment, but mechanistic evidence from prospective optical coherence tomography (OCT) imaging is limited. This study was designed to comprehensively characterize patterns of calcium modification during a dual-preparation strategy and to explore imaging determinants of calcium fracture and stent expansion using serial and 3-dimensional OCT assessment. METHODS: This was a prespecified, multicenter, single-arm OCT substudy of the DUAL-PREP registry, enrolling patients with severely calcified lesions for whom combined treatment with atherectomy and intravascular lithotripsy was deemed preferable based on imaging findings. OCT was analyzed by an independent core laboratory. Multivariable models examined predictors of fracture and stenting performance, including calcium thickness, length, angle, calcified nodules, and morphology (circumferential, eccentric spiral, and eccentric straight types). RESULTS: OCT images were available for 114 of 118 patients (116 lesions; age, 75.9±9.1 years; 69.3% male). All lesions had an OCT calcium score of 4. Calcium fractures were uncommon after atherectomy (2/106 lesions [1.9%]) but markedly increased following intravascular lithotripsy (89/106 lesions [84.0%]; 2.05±1.59 fractures per lesion), with a further increase after stent implantation (101/109 lesions [92.7%]; 2.89±1.67 fractures per lesion). Final stent expansion index was 0.81±0.15 (eccentricity, 0.72±0.09; asymmetry, 0.39±0.15). Eccentric straight-type calcification was associated with a lower likelihood of fracture at final OCT (odds ratio, 0.07 [95% CI, 0.00–0.77]; P =0.029), whereas eccentric spiral and circumferential types showed higher fracture occurrence. CONCLUSIONS: This OCT analysis demonstrated a stepwise increase in calcium fracture during a dual-preparation strategy, with minimal fracture after atherectomy, a marked increase following intravascular lithotripsy, and a further increase after stent implantation. Calcium morphology may provide additional insight into fracture occurrence, supporting the potential value of 3-dimensional assessment in severely calcified lesions. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: jRCT1032230384.