Clinical outcomes of acute myocardial infarction with occluded left circumflex artery.

Left circumflex artery (LCX) related acute myocardial infarction (AMI) has been known to be under diagnosed with 12-lead electrocardiogram (ECG). However, there were only a few studies that have focused on the clinical characteristics of LCX-related AMI. We studied the clinical characteristics and hospital mortality in patients with angiographically confirmed LCX-related AMI. A total of 2281 AMI patients with single acutely occluded culprit vessel in coronary angiography (pre-Thrombolysis In Myocardial Infarction flow: 0) were enrolled in the Korea Acute Myocardial Infarction Registry (KAMIR) from November 2005 to January 2008. These patients were divided into three groups according to culprit vessel [left anterior descending artery (LAD), right coronary artery (RCA), and LCX]. This study showed the patients with LCX-related AMI were less likely to present with ST elevation in ECG (46.3%, 87.0%, and 82.3%; p<0.001) and primary percutaneous coronary intervention (PCI) (43.4%, 78.9%, and 74.5%; p<0.001) and door to balloon time <90 min (31.3%, 52.8%, and 51.0%; p<0.001), compared with LAD and RCA. However, no statistical difference was found in hospital mortality among the three groups. Multivariate analysis showed primary PCI decreased the hospital mortality in patients with occluded coronary artery. In conclusion, AMI patients with an occluded LCX presented with less ST elevation and primary PCI. These results suggest that clinical physicians should be careful with patients presenting with chest pain but apparently normal ECG and must rule out LCX occlusion.