The effects of nicorandil on microvascular function in patients with ST segment elevation myocardial infarction undergoing primary PCI

Background: Nicorandil, as a selective potassium channel opener, has dual action including coronary and peripheral vasodilatation and cardioprotective effect through ischemic preconditioning. Considering those characteristics, nicorandil was suggested to reduce the degree of microvascular dysfunction. Methods: Thirty-two patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention (pPCI) were included in the study. Index of microvascular resistance (IMR) was measured in all patients immediatelly after pPCI before the after administration of Nicorandil. ST segment resolution was monitored before intervention and 60 min after terminating the procedure. Echocardiographic evaluation of myocardial function and transthoracic Doppler derived Coronary flow reserve (CFR) of infarct related artery (IRA) was performed during hospitalization and 3 months later. Results: IMR was significantly lower after administration of Nicorandil (9.9 +/- 3.7 vs. 14.1 +/- 5.1, p < 0.001). There was significant difference in ST segment elevation before and after primary PCI with administration of Nicorandil (6.9 +/- 3.7 mm vs. 1.6 +/- 1.6 mm, p < 0.001). Transthoracic Doppler CFR measurement improved after 3 months (2.69 +/- 0.38 vs. 2.92 +/- 0.54, p = 0.021), as well as WMSI (1.14 +/- 0.17 vs. 1.07 +/- 0.09, p = 0.004). Conclusion: Intracoronary Nicorandil administration after primary PCI significantly decreases IMR, resulting in improved CFR and ventricular function in patients with STEMI undergoing primary PCI.