Abstract: Objective To observe the effect of nicorandil on slow-flow phenomenon in percutaneous coronary intervention (PCI) in patients with acute non-ST segment elevated myocardial infarction (NSTEMI). Methods A total of 159 NSTEMI patients were enrolled. Based on the TIMI flow of target lesion blood vessels after PCI, patients were divided into two groups. There were 31 cases in no flow/slow flow group (TIMI≤2), and 128 cases in normal group (TIMI=3). The general clinical data, immediate TIMI flow grade of infarct-related artery (IRA) after PCI treatment, post-operative corrected TIMI frame count (CTFC), TIMI myocardial perfusion grade (TMPG), thrombolysis in myocardial infarction signs of a blood clot, number of diseased vessels and major adverse cardiac events were compared between the two groups. The patients in no flow / slow flow group were given nicorandil, and changes of blood flow before and after treatment were observed. The influence factors of no flow/slow flow were analyzed by multifactor Logistic regression. Results The proportions of patients with history of smoking, the proportion of patients with diabetes history, the proportion of patients with hyperlipidemia, the proportion of patients with low blood pressure in operation, and the number of implanted stents, the proportions of patients took tirofiban in operation, post-operative CTFC, the proportions of patients with thrombosis signs were significantly higher in no flow/slow flow group than those in the normal group (P＜0.05). There were no significant differences in heart rates in operation, IRA distribution and the number of lesion vessels between the two groups. There were also no significant differences in the incidence of MACE and left ventricular ejection fraction between the two groups. After the application of nicorandil, the proportion of patients with TIMI blood flow 3 and proportions of cTFC and TMPG were significantly higher than before treatment (P＜0.05). Results showed that smoking history, history of diabetes, multiple stents (more than 3),hypotension in PCI, and signs of blood clot were factors influencing the slow flow of coronary arteries. Conclusion
Nicorandil can significantly improve the no flow/slow flow in PCI in patients with NSTEMI.

Key words: Nicorandil, myocardial reperfusion injury, non-ST segment elevated myocardial infarction, percutaneous coronary intervention, no flow/slow flow