Comparative effectiveness of interventional treatment strategies for the very elderly with acute coronary syndrome remains poorly defined due to study exclusions. Interventions include percutaneous coronary intervention (PCI), usually with stents, or coronary artery bypass grafting (CABG). The elderly are frequently directed to PCI because of provider perceptions that PCI is at therapeutic equipoise with CABG and that CABG incurs increased risk. We evaluated long-term outcomes of CABG versus PCI in a cohort of very elderly Medicare beneficiaries presenting with acute coronary syndrome