Effect of orbital atherectomy in calcified coronary artery lesions as assessed by optical coherence tomography.

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 mm2 or 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.

The effectiveness of excimer laser angioplasty to treat coronary in-stent restenosis with peri-stent calcium as assessed by optical coherence tomography.

AIMS: We aimed to evaluate the effectiveness of excimer laser coronary angioplasty (ELCA) to treat in-stent restenosis (ISR) due to peri-stent calcium-related stent underexpansion as assessed by optical coherence tomography (OCT). METHODS AND RESULTS: We studied 81 patients (81 lesions with ISR, stent underexpansion, and peri-stent calcium >90°) who underwent OCT imaging both pre and post percutaneous coronary intervention and compared lesions treated with ELCA (n=23) vs. without ELCA (n=58). ELCA use was associated with more calcium fracture (ELCA: 61%, non-ELCA: 12%, p<0.01), larger final minimum lumen area (ELCA: 4.76 mm2 [3.25, 5.57], non-ELCA: 3.46 mm2 [2.80, 4.13], p<0.01), and a larger previously implanted stent area (ELCA: 6.15 mm2 [4.83, 7.09], non-ELCA: 4.65 mm2 [3.84, 5.40], p<0.01). In the multivariable model, ELCA use was associated with peri-stent calcium fracture (odds ratio 46.5, 95% confidence interval: 6.8, 315.9, p<0.001) that, in turn, was associated with final larger lumen and stent dimensions. Finally, contrast injection during ELCA was associated with multiple calcium fractures and fractures even in thicker calcium. CONCLUSIONS: ELCA is effective for treating ISR with underexpansion by disrupting peri-stent calcium, facilitating better expansion of the previously implanted stent.

A new optical coherence tomography-based calcium scoring system to predict stent underexpansion.

AIMS: This was a retrospective study to develop and validate an optical coherence tomography (OCT)-based calcium scoring system to predict stent underexpansion. METHODS AND RESULTS: A calcium score was developed using 128 patients with pre- and post-stent OCT (test cohort) and then validated in an external cohort of 133 patients. In the test cohort, a multivariable model showed that the independent predictors of stent expansion were maximum calcium angle per 180° (regression coefficient: -7.43; p<0.01), maximum calcium thickness per 0.5 mm (-3.40; p=0.02), and calcium length per 5 mm (-2.32; p=0.01). A calcium score was then defined as 2 points for maximum angle >180°, 1 point for maximum thickness >0.5 mm, and 1 point for length >5 mm. In the validation cohort, the lesions with calcium score of 0 to 3 had excellent stent expansion, whereas the lesions with a score of 4 had poor stent expansion (96% versus 78%, p<0.01). On multivariate analysis the calcium score was an independent predictor of stent underexpansion. CONCLUSIONS: An OCT-based calcium scoring system can help to identify lesions that would benefit from plaque modification prior to stent implantation. Lesions with calcium deposit with maximum angle >180°, maximum thickness >0.5 mm, and length >5 mm may be at risk of stent underexpansion.