Optical coherence tomography-guided orbital atherectomy for calcified coronary lesions: rationale and design of the CROWN study

Abstract Background The Orbital Atherectomy System (OAS) has demonstrated high procedural success, with excellent stent deliverability and low complication rates. The effects of orbital atherectomy (OA) and its impact on calcified coronary plaques are not yet fully understood, highlighting the need for a larger and more comprehensive study. Objective Calcium Reduction by Orbital Atherectomy in Western Europe (CROWN) is an ongoing study that aims to evaluate the effects of OA in treating de novo, severely calcified coronary lesions before stent placement using optical coherence tomography (OCT), and to assess stent expansion by measuring the OCT-derived minimum stent area (MSA). Methods The CROWN study is a prospective, multicenter, international, single-arm observational study. We will enroll 100 patients with severely calcified coronary lesions undergoing OCT-guided orbital atherectomy and stent placement. All patients will undergo peri-procedural OCT imaging, with assessments conducted before and after OA, as well as following stent placement. Patients will be enrolled at a maximum of 6 sites in the Netherlands, Germany, and Italy. The primary endpoint is to assess the proportion of patients achieving stent expansion, defined as an OCT-derived MSA ≥ 5.5 mm 2 . Conclusion The CROWN study will evaluate the impact of OA on calcified plaques, potentially refine operator practices, and provide additional insights on device selection for treating severely calcified lesions (clinicaltrials.gov NCT06035783).