Morphology-Dependent Dose-Response of Intravascular Lithotripsy on Coronary Calcium Fracture

Intravascular lithotripsy (IVL) uses ultrasonic acoustic pressure waves to modify calcification to enable optimal balloon and stent expansion in calcified lesions. However, the dose-response relationship for creating fractures within calcified lesions of different calcium morphologies is unknown.

The aim of this study was to evaluate the dose-dependent effects of IVL on calcium fracture overall and in the setting of calcification arc <180° vs ≥180°.

Micro-computed tomography images were acquired before and after 10, 20, 40, 60, 80, and 120 pulses of IVL treatment (Shockwave Medical) in an ex vivo study of 5 cadaveric human hearts (15 coronary lesions). A total of 30 cross-sections of micro-computed tomography (2 sections per lesion) were analyzed for this study.

Cumulative fracture occurrence increased progressively with the number of IVL pulses delivered, with fractures observed in 33% of sections after 10 pulses, 50% after 40 pulses, and 60% after 120 pulses. Calcification arc ≥180° exhibited a higher fracture occurrence compared with arc <180° (P = 0.028). After adjustment for pulse number, calcification arc ≥180° was associated with significantly higher fracture counts compared with arc <180° (rate ratio = 6.1, P = 0.003).

Fracture occurrence following IVL increased with cumulative pulse delivery and differed significantly according to calcification concentricity. Calcification arc ≥180° demonstrated a higher and earlier likelihood of fracture occurrence than arc <180°, independent of pulse number. These findings establish a clear dose-dependent relationship between IVL pulse delivery and fracture formation and highlight calcification concentricity as a key determinant of fracture response.