OBJECTIVES - We sought to assess plaque modification and stent expansion following orbital atherectomy (OA) for calcified lesions using optical coherence tomography (OCT).

BACKGROUND - The efficacy of OA for treating calcified lesions is not well studied, especially using intravascular imaging in vivo.

METHODS - OCT was performed preprocedure, post‐OA, and post‐stent (n = 58). Calcium modification after OA was defined as a round, concave, polished calcium surface. Calcium fracture was complete discontinuity of calcium.

RESULTS - Comparing pre‐vs post‐OA OCT (n = 29), calcium area was significantly decreased post‐OA (from 3.4 mm² [2.4–4.7] to 2.9 mm² [1.9–3.9], P < 0.001). Poststent percent calcium fracture (calcium fracture length/calcium length) correlated with post‐OA percent calcium modification (calcium modification length/calcium length) (r = 0.31, P = 0.01). Among 75 calcium fractures in 35 lesions, maximum calcium thickness at the fracture site was greater with vs without calcium modification (0.58 mm [0.50–0.66] vs 0.45 mm [0.38–0.52], P = 0.003). Final optimal stent expansion, defined as minimum stent area ≥6.1 mm²or stent expansion ≥90% (medians of this cohort) at the maximum calcium angle site, was observed in 41 lesions. Larger post‐OA lumen area (odds ratio 2.64; 95% CI 1.21–5.76; P = 0.02) and the presence of calcium fracture (odds ratio 6.77; 95% CI 1.25–36.6; P = 0.03) were independent predictors for optimal stent expansion.

CONCLUSIONS - Calcium modification by OA facilitates poststent calcium fracture even in thick calcium. Greater calcium modification correlated with greater calcium fracture, in turn resulting in better stent expansion.

© 2018 Wiley Periodicals, Inc.