short- and long-term outcomes of patients with acute myocardial infarction in the territory of left circumflex artery in relation to st-segment elevation on admission electrocardiogram

Background: Thrombotic occlusion of left circumflex artery (LCX), may often present without ST-segment elevations; the clinical outcomes of such patients remain unclear.

Objective: We aimed to examine short- and long-term clinical outcomes of patients with Acute Myocardial Infarction in the territory of left circumflex artery in relation to ST-segment elevation on admission ECG.

Methods: Observational, retrospective cohort, dual center study, performed between 2009 and 2019. Data about adult patients with LCX related myocardial infarction (MI) was collected after 30 days and 12 months and included recurrent PCI, Admission due to acute coronary syndrome (ACS) and mortality. Risk factors for short- and long-term mortality were assessed using multivariate backward stepwise logistic regression analysis.

Results: During study period, 897 patients with LCX related MI were included. Most of them (56.6%) presented with NSTEMI. Patients with NSTEMI were younger with less co-morbidities. More patients with non-ST elevation MI (non-STEMI) at presentation had on coronary angiography TIMI flow of 0/1 in infarct related artery (IRA) (62.5% vs 29.7%, p<0.001). Majority of this patients had Left dominant coronary arteries circulation (29.6% vs 15.7%, p<0.001). ST elevation MI (STEMI) was associated with higher 30 days mortality (3.9% vs. 1.7%, p=0.05). NSTEMI was associated with higher rates if one-year ACS re-admissions (15.8% vs 11.1%, p=0.05) and PCI (20.9% vs 14.4%, p=0.05). Left dominance (OR 2.62, 95% CI [1.4-4.7]) and diabetes mellitus (OR 2.13, 95% CI [1.2-3.6]) were independent predictors for long- term mortality. STEMI (OR 3.53, 95% CI [1.4-8.6]) , proximal lesion (OR 2.47, 95% CI [1.02-5.96]), Left dominance ( OR 2.51, 95% CI [1.01-6.22]) and diabetes mellitus ( OR 2.55, 95% CI [1.04-6.25]) were the additional predictors of short-term mortality.

Conclusions: Patients with STEMI have higher short-term mortality; Diabetes mellitus and Left dominance circulation independently predicts long- and short-term mortality in LCX related acute MI.