Serial Optical Coherence Tomography Findings After Lesion-Preparation Incorporating the ShockFast™ Intravascular...

Background: Intravascular lithotripsy (IVL) is an established calcium modification strategy for severely calcified coronary lesions. The Shunmei ShockFast™ IVL system is a novel device that appeared safe and feasible in an initial clinical experience. However, its calcium fracture typology, depth distribution, and quantitative stent optimization characteristics have not been characterized by serial optical coherence tomography (OCT). Objectives: To provide the first dedicated serial OCT sub-study of calcium modification patterns and stent optimization metrics achieved with the ShockFast™ IVL system in a cohort of patients with severely calcified de novo coronary lesions. Methods: This is a prospective, single-center OCT imaging sub-study nested within the Cardio-FR registry (NCT04185285). We included 14 patients with OCT assessment performed at three mandatory time points-baseline (before any device delivery), post-IVL, and post-stenting-who underwent PCI with the ShockFast™ IVL system between June 2025 and April 2026. The primary endpoint was OCT-confirmed calcium fracture rate following IVL treatment. Secondary endpoints included calcium fractures ≥2 and type, post-lesion-preparation lumen gain, minimum stent area (MSA), stent expansion (SE), malapposition, and edge dissection rates. Exploratory correlative analyses between baseline calcium morphology and post-IVL stent optimization outcomes were performed. Results: Median baseline OCT MLA was 2.22 mm² (IQR 1.4-3.61). Calcium fractures were identified in 10 of 14 lesions (71%, 95% CI 45-88%) following a lesion-preparation strategy incorporating ShockFast™ IVL, with ≥2 fractures in 43%. Fractures were classified as partial-thickness (non-transmural) in 30% and full-thickness (transmural) in 70% of cases. Median post-lesion-preparation lumen gain was 0.53 mm² (IQR 0.3-0.84). Median final MSA was 4.77 mm² (IQR 3.59-5.34) and median SE was 89.5% (IQR 85-94), with SE >80% achieved in 100% of lesions. No major malapposition or medial edge dissections were recorded. Conclusions: Applied as the central calcium-modification component of a comprehensive lesion-preparation strategy, the ShockFast™ IVL system was associated with OCT-confirmed calcium fractures in the majority of the lesions, with favorable stent expansion and optimization metrics in the absence of major malapposition or edge dissections. These findings provide the first dedicated serial OCT sub-study of calcium modification mediated by a lesion-preparation strategy incorporating ShockFast™ IVL, consistent with feasibility as a novel IVL platform suitable for further investigation in adequately powered comparative studies.