BACKGROUND: This study investigated the effects of the intracoronary injection of nicorandil and tirofiban on myocardial perfusion and short-term prognosis in elderly patients with acute ST-segment elevation myocardial infarction (STEMI) after emergency percutaneous coronary intervention (PCI).METHODS: Seventy-eight STEMI patients with age >65 years who underwent emergency PCI were consecutively enrolled. These patients received conventional PCI and were randomly divided into a control group and a treatment group (n=39 per group). The control group received an intracoronary injection of tirofi ban followed by a maintenance infusion for 36 hours after surgery. The treatment group received intracoronary injection of tirofiban and nicorandil, and then intravenous infusion of tirofi ban and nicorandil 36 hours after surgery. The following parameters were measured: TIMI grade, corrected TIMI frame count (cTFC), TIMI myocardial perfusion grade (TMPG), ST-segment resolution (STR) rate 2 hours post-operatively, resolution of ST-segment elevation (STR) at 2 hours postoperatively, peak level of serum CK-MB, left ventricular end diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF) at 7–10 days postoperatively, and major adverse cardiac events (MACEs) in-hospital and within 30 days post-operatively. RESULTS: Compared with the control group, more patients in the treatment group had TIMI 3 and TMPG 3, and STR after PCI was significantly higher. The treatment group also had significantly lower cTFC, lower infarction relative artery (IRA), lower peak CK-MB, and no refl ow ratio after PCI. The treatment group had signifi cantly higher LVEDD and LVEF but lower incidence of MACEs than the control group. CONCLUSION: The intracoronary injection of nicorandil combined with tirofi ban can effectively improve myocardial reperfusion in elderly STEMI patients after emergency PCI and improve short-term prognoses.