Novel Micro Crown Orbital Atherectomy for Severe Lesion Calcification: Coronary Orbital Atherectomy System Study (COAST).

Background: Percutaneous coronary intervention of severely calcified lesions carries a high risk of adverse events despite the use of contemporary devices. The Classic Crown Orbital Atherectomy System (OAS) was safe and effective for severely calcified lesion preparation in the ORBIT II study (Evaluate the Safety and Efficacy of OAS in Treating Severely Calcified Coronary Lesions) but was not optimized for tight lesions. COAST (Coronary Orbital Atherectomy System Study) evaluated the safety and efficacy of calcified lesion preparation before stent implantation with the Diamondback 360 Micro Crown Coronary OAS, designed for use in tighter lesions. Methods: COAST was a prospective, multicenter, single-arm study that enrolled 100 patients with severely calcified de novo coronary lesions at 17 sites in the United States and Japan. The primary effectiveness end point was procedural success, defined as stent delivery with residual stenosis <50% without in-hospital major adverse cardiac events (MACE), and the primary safety end point was freedom from MACE (composite of cardiac death, myocardial infarction, or target vessel revascularization) at 30 days. Results: The OAS Micro Crown was inserted in all patients. A stent was delivered with a residual stenosis <50% in all except one patient (99.0%). Procedural success was achieved in 85 (85.0%) subjects versus 391 (88.9%) in ORBIT II (P=0.30), and freedom from MACE at 30 days was achieved in 85.0% versus 89.6% in ORBIT II (P=0.21). Freedom from MACE was 77.8% at 1 year. Conclusions: Prestent preparation of severely calcified lesions using the novel Micro Crown OAS resulted in similar rates of procedural success and freedom from MACE compared with the Classic Crown OAS.