Background-Biological age is a strong determinant of prognosis in patients with acute myocardial infarction(AMI). We sought to examine the impact of age after primary percutaneous coronary intervention in AMI and to determine whether routine coronary stent implantation and/or platelet glycoprotein IIb/IIIa inhibitors improve clinical outcomes in elderly patients after primary angioplasty. Methods and Results-In the CADILLAC trial, 2082 patients with AMI were randomized to balloon angioplasty,angioplasty plus abciximab,stenting alone, or stenting plus abciximab. No patient was excluded on the basis of advanced age; patients ranging from 21 to 95 years of age were enrolled. One-year mortality increased for each decile of age, exponentially after 65 years of age(1.6%for patients< 55 years, 2.1%for 55 to 65 years, 7.1%for 65 to 75 years, 11.1%for patients >75 years; P< 0.0001). Elderly patients also had increased rates of stroke and major bleeding compared with their younger counterparts. Among elderly patients (≥65 years), 1-year rates of ischemic target revascularization (7.0%versus 17.6%; P< 0.0001) and subacute or late thrombosis (0%versus 2.2%; P=0.005)were reducedwith stenting comparedwith balloon angioplasty. Routine abciximab administration, although safe,was not of definite benefit in elderly patients. Rates of mortality, reinfarction, disabling stroke, and major bleeding in the elderly were independent of reperfusion modality. Conclusions-Despite contemporary mechanical reperfusion strategies,mortality, major bleeding, and stroke rates remain high in elderly patients undergoing primary percutaneous coronary intervention, outcomes that are not affected by stents or glycoprotein Ⅱb/Ⅲa inhibitors. By reducing restenosis, however, stent implantation improves clinical outcomes in elderly patients with AMI. Background-Biological age is a strong determinant of prognosis in patients with acute myocardial infarction (AMI). We sought to examine the impact of age after primary percutaneous coronary intervention in AMI and determine whether or not routine coronary stent implantation and / or platelet glycoprotein IIb / IIIa inhibitors improve clinical outcomes in elderly patients after primary angioplasty. Methods and Results-In the CADILLAC trial, 2082 patients with AMI were randomized to balloon angioplasty, angioplasty plus abciximab, stenting alone, or stenting plus abciximab. No patient was excluded on the basis of advanced age; patients ranging from 21 to 95 years of age were enrolled. One-year mortality increased for each decile of age, exponentially after 65 years of age (1.6% for patients <55 years, 2.1% for 55 to 65 years, 7.1% for 65 to 75 years, 11.1% for patients> 75 years; P <0.0001). Elderly patients also had increased rates of stroke and major bleeding compared with their younger counterparts. Among elderly patients (≥65 years), 1-year rates of ischemic target revascularization (7.0% versus 17.6%; P <0.0001) and subacute or late thrombosis (0% versus 2.2%; P = 0.005) were reducedwith stenting comparedwith balloon angioplasty Routine abciximab administration, although safe, was not of definite benefit in elderly patients. Rates of mortality, reinfarction, disabling stroke, and major bleeding in the elderly were independent of reperfusion modality. Conclusions-Despite contemporary mechanical reperfusion strategies, mortality, major bleeding , and stroke rates remain high in elderly patients undergoing primary percutaneous coronary intervention, outcomes that are not affected by stents or glycoprotein IIb / IIIa inhibitors. By reducing restenosis, however, stent implantation improves clinical outcomes in elderly patients with AMI.