Coronary Microvascular Function Assessment using the Coronary Angiography-Derived Index of Microcirculatory Resistance in Patients with ST-segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Ming Li¹, Xi Peng¹, Naixin Zheng¹, Hu Ai¹, Ying Zhao¹, Hui Li¹, Guojian Yang¹, Guodong Tang¹, Fucheng Sun¹, Huiping Zhang^1,*

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¹ Department of Cardiology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, 100730 Beijing, China

^*Correspondence: huipingzhang73@163.com (Huiping Zhang)

Rev. Cardiovasc. Med. 2024, 25(2), 69; https://doi.org/10.31083/j.rcm2502069

Submitted: 30 August 2023 | Revised: 14 October 2023 | Accepted: 23 October 2023 | Published: 20 February 2024

(This article belongs to the Special Issue Cardiac Catheterization: Clinical Updates and Novel Technologies)

This is an open access article under the CC BY 4.0 license.

Abstract

Background: Studies reporting the status of coronary microvascular function in the infarct-related artery (IRA) after primary percutaneous coronary intervention (PCI) remain limited. This study utilized the coronary angiography-derived index of microcirculatory resistance (caIMR) to assess coronary microvascular function in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI. Methods: We used the FlashAngio system to measure the caIMR after primary PCI in 157 patients with STEMI. The primary endpoint was the occurrence of a major adverse cardiovascular event (MACE), defined as a composite endpoint encompassing cardiac mortality, target vessel revascularization, and rehospitalization due to congestive heart failure (CHF), myocardial infarction (MI), or angina. Results: Approximately 30% of patients diagnosed with STEMI and who experienced successful primary PCI during the study period had a caIMR in the IRA of $>$ 40. The caIMR in the IRA was significantly higher than in the reference vessel (32.9 $\pm{}$ 15.8 vs. 27.4 $\pm{}$ 11.1, p $<$ 0.001). The caIMR in the reference vessel of the caIMR $>$ 40 group was greater than in the caIMR $\leq$ 40 group (30.9 $\pm{}$ 11.3 vs. 25.9 $\pm{}$ 10.7, p = 0.009). Moreover, the caIMR $>$ 40 group had higher incidence rates of MACEs at 3 months (25.5% vs. 8.3%, p = 0.009) and 1 year (29.8% vs. 13.9%, p = 0.04), than in the caIMR $\leq$ 40 group, which were mainly driven by a higher rate of rehospitalization due to CHF, MI, or angina. A caIMR in the IRA of $>$ 40 was an independent predictor of a MACE at 3 months (hazard ratio (HR): 3.459, 95% confidence interval (CI): 1.363–8.779, p = 0.009) and 1 year (HR: 2.384, 95% CI: 1.100–5.166, p = 0.03) in patients with STEMI after primary PCI. Conclusions: Patients with STEMI after primary PCI often have coronary microvascular dysfunction, which is indicated by an increased caIMR in the IRA. An elevated caIMR of $>$ 40 in the IRA was associated with an increased risk of adverse outcomes in STEMI patients undergoing primary PCI.