LAUSR

Background Acute myocardial infarction (AMI) caused by total occlusion of the left circumflex artery (LCX) can present as non-ST-segment elevation myocardial infarction (NSTEMI). We evaluate whether door-to-balloon time (DBT) is associated with cardiac mortality in patients with total occlusion of the LCX. Patients and methods From the Korea Acute Myocardial Infarction Registry, patients with AMI who had total occlusion with a Thrombolysis In Myocardial Infarction flow grade of 0 were included. We determined the factors for delay in primary percutaneous coronary intervention (DBT>90 min) and evaluated cardiac mortality for a median period of 14 months. Results Mean DBT was 68 min (interquartile range=50–156 min), and the achievement rate of DBT less than or equal to 90 min was 66.9% in the entire study population. More than half of patients with total occlusion of LCX were presented as NSTEMI (57.7%). Among patients with total occlusion of the LCX, the mean DBT was 136 min (interquartile range=60–484 min), and the achievement rate of DBT less than or equal to 90 min was 42.8%. On multivariate analysis, LCX occlusion was an important factor for DBT more than 90 min (odds ratio: 1.766, P<0.001). Among patients with LCX occlusion, cardiac mortality was higher in patients with ST-segment elevation (6.2 vs. 11.0%, P=0.024). Conclusion This study showed that LCX occlusion was a significant factor for the delay in primary percutaneous coronary intervention on account of presenting as NSTEMI. Cardiac mortality was not associated with DBT more than 90 min but with ST-segment elevation in AMI patients with total occlusion of the LCX.