Intracoronary nicorandil improves TIMI flow and reduces AMR in STEMI patients undergoing primary PCI

BackgroundMicrovascular dysfunction remains a major driver of adverse outcomes after ST-segment elevation myocardial infarction (STEMI) despite successful restoration of epicardial patency by primary percutaneous coronary intervention (PCI). Nicorandil has nitrate-like vasodilatory properties and ATP-dependent potassium channel (KATP)-opening properties, effects that may improve reperfusion physiology. However, its effects on wire-free, angiography-derived measures of microvascular function are not well defined. We evaluated whether intracoronary nicorandil administered during primary PCI improves angiography-derived microvascular function assessed by angiographic microcirculatory resistance (AMR) and quantitative flow ratio (QFR).MethodsIn this prospective, single-center randomized trial, 63 patients with first-episode STEMI undergoing primary PCI were allocated 1:1 to intracoronary nicorandil (2 mg after guidewire crossing; n = 32) or control (standard PCI; n = 31). The prespecified primary endpoint was final post-PCI AMR. QFR-derived indices, reperfusion measures [Thrombolysis in Myocardial Infarction (TIMI) flow grade, no-reflow, ST-segment resolution], hemodynamics, biomarkers, and clinical events were analyzed as secondary/exploratory outcomes, with multiplicity controlled using the Benjamini–Hochberg false discovery rate (FDR) where applicable.ResultsBaseline characteristics were balanced between groups. Compared with control, intracoronary nicorandil was associated with a higher rate of post-PCI TIMI grade 3 flow (96.9% vs. 74.2%; overall P = 0.013). Final AMR was significantly lower in the nicorandil group (1.4 ± 0.5 vs. 2.7 ± 0.5; P