Prognostic Value of Coronary Microvascular Dysfunction Assessed by Coronary Angiography–Derived Index of Microcirculatory Resistance in Patients With ST‐Segment Elevation Myocardial Infarction

ABSTRACT Background CaIMR is proposed as a novel angiographic index designed to assess microcirculation without the need for pressure wires or hyperemic agents. We aimed to investigate the impact of caIMR on predicting clinical outcomes in STEMI patients. Methods One hundred and forty patients with STEMI who received PCI in Putuo Hospital of Shanghai from October 2021 to September 2022 were categorized into CMD and non–CMD groups according to the caIMR value. The baseline information, patient‐related examinations, and the occurrence of MACE at the 12‐month follow‐up were collected to investigate risk factors in patients with STEMI. Results We divided 140 patients with STEMI enrolled into two groups according to caIMR results, including 61 patients diagnosed with CMD and 79 patients diagnosed with non–CMD. A total of 21 MACE occurred during the 1 year of follow‐up. Compared with non–CMD group, patients with CMD showed a significantly higher risk of MACE. A multivariate Cox regression model was conducted for the patients, and it was found thatcaIMR was a significant predictor of prognosis in STEMI patients (HR: 8.921). Patients with CMD were divided into culprit vascular CMD and non‐culprit vascular CMD, and the result found that culprit vascular CMD was associated with the incidence of MACE (OR: 4.75) and heart failure (OR: 7.50). Conclusion CaIMR is a strong predictor of clinical outcomes and can provide an objective risk stratification for patients with STEMI. There is a strong correlation among leukocyte index, the use of furosemide, Killips classification, and clinical outcomes.