C-reactive protein after discharge and infarct size in patients with ST segment elevation myocardial infarction

Abstract

Abstract Background C-reactive protein (CRP) peaks at 2 days in patients with ST-segment elevation myocardial infarction (STEMI) after percutaneous coronary intervention (PCI) and can predict final infarct size. It is, however, unknown whether CRP level after discharge, indicative of prolonged inflammation, plays a prognostic role in myocardial damage. Purpose To investigate the prevalence of high CRP level within 3 months after discharge in patients with STEMI and its association with myocardial damage. Methods In the current study, all patients were identified through the xx database and treated with timely PCI at xx hospital from 2011 to 2014. Blood samples were retrieved within 3 months after discharge. High CRP level was defined as CRP >=3 mg/L. Only patients with a cardiac magnetic resonance (CMR) at baseline or follow-up were recruited. The primary outcome was final infarct size. Multiple regression was performed to adjust for potential confounders using any baseline variable with P<0.10 for the difference between groups. Results Of the 1603 patients from xx, 273 patients had CRP measured following discharge and at least one CMR measured. Of them, 200 (73.3%) had high CRP level after discharge. There was no difference in period from PCI to CRP testing between patients with high CRP and those with low CRP [11 days, interquartile range (IQR) (4, 40) vs. 21 days, IQR (4, 42), P=0.31]. Patients with high CRP level showed larger final infarct size [12.5% left ventricle (LV) vs. 7.0% LV, P <0.001] and larger acute infarct size [15.2% LV vs. 10.6% LV, p=0.004] compared with those with low CRP level. Patients with high CRP level also had lower final myocardial salvage index (MSI) (0.67 vs. 0.75, P=0.003) and lower acute MSI (0.47 vs. 0.61, P=0.006). The results persisted after adjusting for potential confounders in multiple regression. Conclusions A large proportion of patients with STEMI undergoing PCI persisted high CRP within 3 months after discharge. High CRP level after discharge was associated with larger acute and final infarct size as well as lower acute and final MSI level.