Calcium Modification After Orbital Atherectomy and Balloon Angioplasty in Severely Calcified Lesions: The ECLIPSE OCT Substudy

BACKGROUND: The treatment of calcified coronary lesions requires optimal lesion preparation to achieve a larger minimal stent area (MSA), the strongest predictor of long-term outcomes. The comparative mechanisms of action of calcium-modifying therapies have not been well defined. METHODS: In a prospective, multicenter ECLIPSE trial (Evaluation of Treatment Strategies for Severe Calcific Coronary Arteries: Orbital Atherectomy Versus Conventional Angioplasty Technique Before Implantation of Drug-Eluting Stents), 2005 patients with severely calcified lesions were randomized to vessel preparation with orbital atherectomy (OA) versus balloon angioplasty (BA) before drug-eluting stent implantation. The primary end point of the optical coherence tomography (OCT) substudy was the MSA at the site of maximal calcification; MSA across the entire stent was also assessed. RESULTS: Postprocedural OCT images were available in 286 lesions in 276 patients treated with OA and 292 lesions in 279 patients treated with BA. By angiographic core laboratory analysis, 567 (98.1%) of lesions were severely calcified. By postprocedural OCT, the maximal calcium arc, maximal calcium thickness, and total calcium length measured 204° (149°–268°), 0.85 mm (°0.69–1.03°), and 22.0 (16.0–31.0) mm. Compared with BA, calcium modification was greater in the OA group (greater number, total length, and maximal depth of calcium fractures), especially in lesions with thicker calcium. Nonetheless, the MSA at the site of maximal calcification was large in both groups and not different (median [interquartile range], 7.44 [6.03–8.94] mm 2 versus 7.05 [5.78–8.66] mm 2 ; P =0.08). Similar results were observed for the MSA across the entire stent (5.86 [4.60–7.38] mm 2 versus 5.57 [4.50–6.97] mm 2 ; P =0.10). Among patients in the OCT substudy, 1-year target-vessel failure rates were low and not different between the groups (7.8% with OA and 6.6% with BA, P =0.61). CONCLUSIONS: In lesions that are severely calcified by angiography, the extent of calcification by OCT was highly variable. Despite greater calcium modification after OA, the acute MSA and 1-year target-vessel failure rates were not different between OA and BA. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03108456.