Background To evaluate the sex difference of percutaneous coronary intervention(PCI) on octogenarian patients with acute coronary syndrome (ACS).Methods A total of 80 patients aged 80 years old and over with ACS undergoing PCI were enrolled in this study.The in-hospital and 2 years clinical follow-up outcome including all-cause mortality, major adverse cardiac event (MACE),stroke and other major bleeding were collected and analyzed.