Background: The aim of this study was to examine the expression of circulating microRNA (miR)-133a in acute myocardial infarction (AMI) patients and assess its potential as a diagnostic and prognostic marker.
Methods: This study enrolled 222 consecutive patients who presented with chest pain symptoms suggestive of AMI in either the Department of Emergency or Department of Cardiology at Wuxi Second People’s Hospital from October 2012 through December 2014. Of these, 102 were diagnosed with AMI and 120 with non-AMI chest pain. An additional 110 healthy individuals who received physical examinations in the same hospital during the same period were used as controls.
Results: MiR-133a expression was significantly elevated in the AMI patients compared to both non-AMI patients and healthy controls (p < 0.01 for both). MiR-133a levels were markedly increased in AMI patients within 2 hours after the onset of chest pain and remained elevated over the next 9 hours. MiR-133a concentration at 24 hours after percutaneous coronary intervention (PCI) was significantly lower compared to time of admission in the emergency PCI group (p < 0.01). The elevation in miR-133a was specific and sensitive for the diagnosis of AMI, with an optimal cutoff value of 0.87 (95% confidence interval (CI), 0.812 - 0.928). Kaplan-Meier analysis demonstrated that major adverse cardiovascular events occurred significantly more often in AMI patients who had miR-133a levels above the median (p < 0.01).
Conclusions: Elevated levels of circulating miR-133a were strongly associated with AMI diagnosis. The concentration of miR-133a may provide prognostic information additive to traditional markers for clinical prognosis in AMI patients.