Impact of renal function on outcomes of patients with cardiac troponin elevation and non-obstructive coronary arteries

Cardiac troponins: Mechanisms of release and role in healthy and diseased subjects

The cardiac troponins (cTns), cardiac troponin C (cTnC), cTnT, and cTnI are key elements of myocardial apparatus, fixed as protein complex on the thin filament of sarcomere and are involved in the regulation of excitation-contraction coupling of cardiomyocytes in the presence of Ca²⁺ . Circulating cTnT and cTnI (cTns) increase following cardiac tissue necrosis, and they are consolidated biomarkers of acute myocardial infarction (AMI). However, the use of high sensitivity (hs)-immunoassay tests for cTnT and cTnI has made it possible to identify a multitude of other clinical conditions associated with increased circulating levels of cTns. cTns can be measured also in the peripheral circulation of healthy subjects or athletes, suggesting that different mechanisms are involved in the release of cTns in the blood independently of cardiac cell necrosis. In this review, the molecular/cellular mechanisms involved in cTns release in blood and the exploitation of cTnI and cTnT as biomarkers of cardiac adverse events, in addition to cardiac necrosis, are discussed.

Hyperuricemia Predicts Adverse Outcomes After Myocardial Infarction With Non-obstructive Coronary Arteries

Background: Serum uric acid (SUA) is a well-known predictor of adverse outcomes in patients with various clinical conditions. However, the impact of SUA on patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) remains unclear. Here, we aimed at investigating the potential association between hyperuricemia and the adverse outcomes in MINOCA patients. Methods: Overall, 249 MINOCA patients were enrolled in the present study. Clinical characteristics and laboratory data, were measured in all patients. Based on SUA levels, patients were classified into two groups; the hyperuricemia group [SUA level > 6 mg/dL (360 μmol/L) in women and > 7 mg/dL (420 μmol/L) in men], and the normuricemia group. The primary endpoint of our study was major adverse cardiac events (MACE), defined as cardiovascular death, stroke, heart failure, non-fatal MI, and angina rehospitalization. Results: Seventy-two patients were in hyperuricemia group and 177 in normuricemia group. Fifty-two MACE events were recorded after 30 months of follow-up period. The incidence of MACE was higher in hyperuricemia group compared with normuricemia group (31.9 vs. 16.3%, P = 0.006). Kaplan-Meier survival curves illustrated a significantly increased risk of MACE in hyperuricemia group (log-rank P = 0.006). The multivariable logistic analysis demonstrated that hyperuricemia was independently associated with a high risk of MACE after 30 months of follow-up (OR, 2.234; 95% CI, 1.054-4.737, P = 0.036). Conclusion: Hyperuricemia is associated with adverse outcomes and appears to be an independent predictor of MACE in MINOCA patients. This finding suggests that the SUA levels may serve as a surrogate biomarker related to risk prediction and adverse outcomes of MINOCA patients.