OBJECTIVES:The aim of this study was to determine the clinical outcomes of patients with long, diffusely calcified coronary artery lesions who underwent orbital atherectomy. BACKGROUND:The presence of severe coronary artery calcification increases the complexity of percutaneous coronary intervention. Orbital atherectomy of long, diffusely calcified lesions may increase the risk of periprocedural angiographic complications. Furthermore, the rate of ischemic complications, including target-vessel revascularization (TVR), in these long, calcified lesions is historically high. METHODS:In this retrospective multicenter registry, which included 458 real-world patients who underwent orbital atherectomy, a total of 154 patients (33.6%) required a total stent length of ≥50 mm (long-stent group). The primary endpoint was the 1-year major adverse cardiac and cerebrovascular event (MACCE) rate, defined as the composite of death, myocardial infarction, TVR, and stroke. RESULTS:The long stent group had a higher rate of perforation (1.9% vs 0.0%; P=.01) and dissection (2.6% vs 0.0%; P<.01). The primary endpoint was similar in the long and short groups (14.2% vs 11.5%, respectively; P=.40), as were the 1-year rates of death (2.6% vs 4.6%, respectively; P=.30), myocardial infarction (1.9% vs 1.6%, respectively; P=.80), TVR (9.7% vs 6.3%, respectively; P=.18), and stroke (1.3% vs 1.3%, respectively; P>.90). The stent thrombosis rate was similar in both groups (1.3% vs 1.3%; P>.90). CONCLUSIONS:Despite the higher angiographic complication rates, orbital atherectomy of long, diffusely calcified lesions was associated with acceptable rates of ischemic complications in this challenging lesion subset at 1-year follow-up.