Direct Comparison of Rotational vs Orbital Atherectomy for Calcified Lesions Guided by Optical Coherence Tomography

Background: There are several retrospective studies comparing rotational atherectomy (RA) and orbital atherectomy (OA), but all percutaneous coronary interventions (PCIs) in those studies were not performed under intracoronary imaging guidance. Objectives: This study sought to compare the efficacy and safety of optical coherence tomography (OCT)-guided PCI with RA vs OA. Methods: The DIRO (To directly compare RA and OA for calcified lesions, a prospective randomized trial) trial was conducted. We enrolled patients with de novo calcified lesions (arc >180°) assessed by OCT or angiographically moderate or severe calcifications if the OCT catheter could not cross the lesion before any intervention. Eligible patients were randomly 1:1 allocated to lesion preparation with RA vs OA. Stent expansion was defined as the minimum stent area divided by the distal reference area multiplied by 100. Tissue modification was assessed using preatherectomy and postatherectomy OCT images. Procedural outcomes including periprocedural myocardial infarctions were evaluated. Furthermore, clinical events and vascular healing evaluated by OCT at 8 months postprocedure were assessed. Results: The stent expansion was significantly greater in the RA group vs the OA group (99.5% vs 90.6%; P = 0.02). The maximum atherectomy area was significantly larger in the RA group than in the OA group (1.34 [IQR: 1.02-1.89] mm² vs 0.83 [IQR: 0.59-1.11] mm²; P = 0.004). The procedural outcomes and clinical events at 8 months did not differ between the groups. The vascular healing was sufficient in both groups. Conclusions: The prospective randomized DIRO trial revealed that RA could produce a more favorable tissue modification, which may lead to a larger stent expansion than OA in heavily calcified lesions.