Angiographic characteristics and in-hospital mortality among patients with ST-segment elevation myocardial infarction presenting without typical chest pain: an analysis of China Acute Myocardial Infarction registry

Background: Patients with ST-segment elevation myocardial infarction (STEMI) who present without typical chest pain are associated with a poor outcome. However, whether angiographic characteristics are related to a higher risk of mortality in this population is unclear. This study aimed to investigate whether the higher mortality risk in patients with STEMI without chest pain could be explained by their "high-risk" angiographic characteristics. Methods: We used data of 12,145 patients with STEMI who was registered in China Acute Myocardial Infarction registry from January 2013 to September 2014. We compared the infarct-related artery (IRA), thrombolysis in myocardial infarction (TIMI) flow grade in the IRA, and other angiographic characteristics between patients without and those with chest pain. Multivariable logistic regression model was used to identify independent risk factor of in-hospital mortality. Results: The 2922 (24.1%) patients with STEMI presented without typical chest pain. These patients had a higher TIMI flow grade (mean TIMI flow grade: 1.00 vs. 0.94, P = 0.02) and a lower rate of IRA disease of the left anterior descending artery (44.6% vs. 51.2%, chi(2) = 35.63, P < 0.01) than did those with typical chest pain. Patients without chest pain were older, more likely to have diabetes, longer time to hospital and higher Killip classification, and less likely to receive optimal medication treatment and primary percutaneous coronary intervention and higher In-hospital mortality (3.3% vs. 2.2%, chi(2) = 10.57, P < 0.01). After adjusting for multi-variables, presentation without chest pain was still an independent predictor of in-hospital death among patients with STEMI (adjusted odds ratio: 1.36, 95% confidence interval: 1.02-1.83). Conclusions: Presentation without chest pain is common and associated with a higher in-hospital mortality risk in patients with acute myocardial infarction. Our results indicate that their poor prognosis is associated with baseline patient characteristics and delayed treatment, but not angiographic lesion characteristics.