Uric acid and mild renal impairment in patients with ST-elevation myocardial infarction

Aims. Mild renal impairment (estimated GFR 60-89 ml/min/1.73 m²) is a strong independent risk factor for mortality in ST-elevation myocardial infarction (STEMI), and is submitted to mechanical revascularization. Patients with renal impairment have decreased excretion of uric acid (UA) and they are thus particularly prone to have elevated serum UA concentrations. This study was aimed at assessing the association between increased UA and mortality in STEMI patients with mild renal impairment. Methods. We prospectively assessed, in 578 STEMI patients with mild renal impairment, whether elevated UA levels are associated with increased mortality both in the short term and in the long term. Results. Patients in the highest UA tertile showed a higher incidence of Killip class III-IV (p = 0.003) and lower values of ejection fraction (EF) (p <0.001). Lower values for estimated glomerular filtration rate (eGFR) at admission, nadir, and discharge were detected in the highest UA tertile, together with the highest values of peak troponin I (Tn I) (p = 0.002), and NT-proBrain Natriuretic Peptide [NT-proBNP] (p <0.001). No difference was found in mortality rates (both during their stay in the intensive cardiac care unit [ICCU], and at the 1-year post-discharge follow-up) among the UA tertiles. Conclusions. The UA levels seem to serve as markers of the severity of coronary artery disease, since they identify a subset of patients characterized by an advanced age, more hemodynamic derangement, and reduced renal function. However, neither short nor long-term mortality was affected.