Prognostic Implication of Angiography-Derived IMR in STEMI Patients

Coronary microcirculatory dysfunction has been known to be prevalent even after successful revascularization of STEMI patients. Previous study presented that index of microcirculatory resistance (IMR) in culprit vessel of STEMI patients showed significant association with the risk of cardiac death or heart failure admission. Recent technical development enabled angiographic derivation of IMR without pressure wire, hyperemic agents, or theromdilution method. In this regard, the current study will evaluate prognostic implication of angiography-derived IMR in STEMI patients who were successfully revascularized.

The study cohorts consist with 2 separate cohort: first, diagnostic accuracy cohort, which will evaluate diagnostic accuracy of angiography-derived IMR for invasive IMR. For this, 31 patients with culprit vessel IMR measurement at the time of primary PCI will be evaluated. The patients cohort is the subgroup of previous registry (NCT02186093). Second, prognosis cohort, in which angiography-derived IMR will be measured in the culprit vessel after successful revascularization. Those patients have follow-up data after 10 years from index procedure. This cohort is STEMI subgroup derived from Institutional registry of Samsung Medical Center, whose results were previously published (JACC Cardiovascular Intervention. 2019 Apr 8;12(7):607-620.) Among 490 STEMI patients from the overall study cohorts, 309 patients with available angiograms and who were suitable for angiographic FFR and IMR measurement will be analyzed. Primary clinical outcome will be cardiac death at 10 years from index procedure. Secondary outcome will be any myocardial infarction, ischemia-driven revascularization, definite or probable stent thrombosis, congestive heart failure admission at 10 years from index procedure.

Inclusion criteria

• STEMI patients who were successfully revascularized for culprit vessel
• analyzable angiograms at the index procedure

Exclusion criteria

• Previous coronary artery bypass grafting
• Coronary bypass graft as culprit vessel
• Patients with unclear culprit vessel
• limited image quality of coronary angiography
• Insufficient angiographic project for TIMI frame count
• Severe tortuosity of culprit vessel
• No optimal projection for reconstruction