Introduction: The prevalence of total coronary occlusion of an infarct‑related artery (IRA) and its impact on the outcome can differ between patients with non‑ST‑elevation myocardial infarction (NSTEMI) and those with ST‑segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI).
Objectives: We evaluated the impact of IRA occlusion on the outcome of myocardial infarction according to the presence or absence of ST‑segment elevation and the location of the culprit lesion.
Patients and methods: We analyzed 4581 patients with STEMI and 2717 patients with NSTEMI who underwent PCI and were enrolled in the Polish Registry of Acute Coronary Syndromes. Patients were divided into 3 cohorts depending on the IRA: left anterior descending artery (LAD), left circumflex artery (LCx), or right coronary artery (RCA). Patients were further divided according to preprocedural Thrombolysis in Myocardial Infarction (TIMI) flow to either a subgroup with total occlusion (TO; TIMI flow grade, 0) or a subgroup with incomplete occlusion (nTO; TIMI flow grade ≥1).
Results: TO was observed in 2949 patients (64.4%) with STEMI and 723 patients (26.6%) with NSTEMI. The most common IRAs were the RCA (49.4%) and LCx (48.4%) in the STEMI and NSTEMI groups, respectively. STEMI patients with TO of the LAD showed higher mortality during the 36‑month follow‑up; mortality in the NSTEMI group was comparable between patients with TO and nTO. STEMI and NSTEMI groups with TO of the LCx showed higher in‑hospital mortality. No differences were observed between patients with TO and nTO of the RCA.
Conclusions: Totally occluded IRA (TIMI flow grade 0) on baseline angiogram was not associated with higher 36‑month mortality rates after both NSTEMI and STEMI treated with PCI in comparison with patients with patent IRA except for totally occluded LAD in STEMI.