Insulin Resistance and Its Association With no Reflow Phenomenon After Primary PCI in Type II Diabetic STEMI Patients.

Successful restoration of epicardial coronary artery patency in acute myocardial infarction (AMI) does not always guarantee adequate myocardial tissue perfusion or effective salvage of ischemic myocardium. In a substantial proportion of patients, microvascular dysfunction persists despite successful recanalization after percutaneous coronary intervention (PCI), limiting the expected clinical benefit of reperfusion therapy. This condition, known as the no-reflow phenomenon, is characterized by inadequate myocardial perfusion in the absence of angiographic evidence of mechanical vessel obstruction. No-reflow occurs in 2-60% of patients with ST-segment elevation myocardial infarction (STEMI) and is strongly associated with adverse ventricular remodeling, malignant arrhythmias, heart failure, and increased short- and long-term mortality.

Distal embolization of thrombus and plaque debris during PCI is a major mechanism underlying microvascular obstruction and no-reflow, emphasizing the importance of identifying high-risk coronary lesions before intervention. The SYNTAX score, an angiographic tool reflecting coronary lesion complexity, has been shown to predict clinical outcomes and the occurrence of no-reflow in patients undergoing PCI. Patients with type 2 diabetes mellitus (T2DM) represent a particularly vulnerable group, as they frequently exhibit more complex coronary lesions and a higher incidence of no-reflow.

Insulin resistance (IR) plays a central role in endothelial dysfunction, vascular inflammation, and atherothrombosis. The triglyceride-glucose (TyG) index, a simple and reliable surrogate of IR, has been associated with adverse cardiovascular outcomes and has recently been shown to predict the occurrence of no-reflow in STEMI patients with T2DM undergoing PCI.