Impact of orbital and rotational atherectomy on side branch patency in severely calcified coronary artery lesions.

Severe coronary artery calcification is associated with reduced procedural success and increased long-term adverse events. Orbital atherectomy (OA) and rotational atherectomy (RA) are two commonly used plaque-modification strategies in this setting. However, their comparative impact on side branch (SB) patency remains undefined. To evaluate side branch patency and associated clinical outcomes in patients with severely calcified coronary lesions undergoing OA versus RA. We conducted a single-center, retrospective analysis of 471 patients who underwent coronary atherectomy between January 1, 2021, and December 1, 2024, including 272 treated with OA and 199 with RA. We identified and included lesions with an adjacent SB ≥ 2.0 mm in diameter within 5 mm of the atherectomy treatment area. A total of 151 SB vessels were identified in the OA cohort and 144 in the RA cohort. Post-procedural SB TIMI flow grade was assessed, procedural complications and major adverse cardiovascular events (MACE) were recorded at discharge, 30 days and 1 year. Baseline clinical and angiographic characteristics were similar between the two groups, although adjunctive device use was more frequent in the RA cohort. Balloon angioplasty of the SB was performed more commonly in the RA group (28.5 % v 15.2 % p 0.006), with no significant difference in SB stent implantation (9.9 v 9.7 p 0.951). Post-procedural SB TIMI 3 flow was significantly more frequent in the OA group (adjusted OR 3.99; 95 % CI, 1.46-10.88; p = 0.007). Procedural complications rates and MACE at discharge, 30-days and 1-year were comparable between the two groups. In this single-center, retrospective analysis, orbital atherectomy was associated with higher likelihood of achieving post-procedural SB TIMI 3 flow compared to rotational atherectomy, with similar procedural and long-term outcomes. These findings are hypothesis-generating and highlight the need for further prospective, multicenter studies to define the impact of atherectomy strategy on side branch preservation.