BACKGROUND: Coronary atherectomy is used to treat severely calcified coronary artery lesions which are more frequent with increasing age, but its impact in older adults has not been sufficiently examined. METHODS: We compared adults ≥ 18 years old who underwent coronary atherectomy during inpatient PCI in 2016-2023 from the Vizient Clinical Data Base and compared outcomes in younger (< 65 years), youngest-old (65-74 years), middle-old (75-84 years), and oldest-old (≥ 85 years) adults. Primary outcome was in-hospital mortality, and secondary outcomes included postprocedural complications. RESULTS: Among 47,337 patients who underwent coronary atherectomy, 19,862 (42.0%) were younger adults and 27,475 (58.0%) were older adults, including 13,583 youngest-old, 10,206 middle-old, and 3,686 oldest-old adults. Compared with younger adults, youngest-old adults had higher mortality (adjusted odds ratio [aOR] = 1.37, P < 0.001), ischemic stroke (aOR = 1.35, P = 0.005), gastrointestinal hemorrhage (GIH) (aOR = 1.44, P < 0.001), acute kidney injury (AKI) (aOR = 1.43, P < 0.001), tamponade (aOR = 1.86, P < 0.001), and pericardiocentesis (aOR = 2.32, P < 0.001). Middle-old adults had higher mortality (aOR = 1.80, P < 0.001), GIH (aOR = 1.42, P = 0.002), AKI (aOR = 1.63, P < 0.001), tamponade (aOR = 2.52, P < 0.001), and pericardiocentesis (aOR = 3.13, P < 0.001). Oldest-old adults had the highest odds for mortality (aOR = 2.03, P < 0.001), GIH (aOR = 1.48, P = 0.016), AKI (aOR = 2.26, P < 0.001), tamponade (aOR = 3.86, P < 0.001), and pericardiocentesis (aOR = 4.21, P < 0.001). There was a significant interaction (P-interaction=0.035) between atherectomy and age groups with regard to the odds of in-hospital mortality. CONCLUSIONS In this large claims-based study, in-hospital mortality, GIH, AKI, tamponade, and pericardiocentesis were higher in older adults compared with younger adults, in a stepwise manner by age group.