Quantitative Troponin and Death, Cardiogenic Shock, Cardiac Arrest and New Heart Failure in Patients With Non-ST-Segment Elevation Acute Coronary Syndromes (NSTE ACS): Insights From the Global Registry of Acute Coronary Events
What is the implication of the absolute level of troponin elevation in patients with non–ST-segment elevation acute coronary syndromes (NSTE-ACS)?
The authors assessed the impact of the absolute troponin level in 16,318 patients with NSTE-ACS enrolled in the Global Registry of Acute Coronary Events (GRACE). The maximum 24-hour troponin value as a multiple of the local laboratory upper limit of normal (ULN) was used to divide the population into five groups, and association with in-hospital death and other outcomes was compared.
An increase in rate of in-hospital death (0.8, 2.2, 3.0, 5.3, and 14.0%; p < 0.001), cardiogenic shock (0.5, 1.4, 2.0, 4.4, and 12.7%; p < 0.001), new-onset congestive heart failure (2.5, 5.1, 7.4, 11.6, and 15.8%; p < 0.001), and cardiac arrest/sustained ventricular tachycardia/ventricular fibrillation (VT/VF) (1.0, 2.4, 3.4, 5.9, and 13.4%; p < 0.001) was seen with every 10-fold increase in troponin level. After adjusting for baseline covariates, troponin ratio was a significant predictor of cardiac arrest, sustained VT, or VF (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.39-1.74); cardiogenic shock (OR, 1.87; 95% CI, 1.61-2.18); and new-onset heart failure (OR, 1.57; 95% CI, 1.45-1.71). Troponin elevation was associated with both early mortality (hazard ratio [HR], 1.61; 95% CI, 1.44-1.81; p < 0.001 for days 0-14) and longer-term (days 15-180) mortality (HR, 1.18; 95% CI, 1.07-1.30; p = 0.001).
The authors concluded that a greater degree of troponin elevation is associated with worse outcome in patients with NSTE-ACS.
This elegant study demonstrates a strong association between the degree of troponin elevation and adverse events in patients with NSTE-ACS. The rate of adverse events was strikingly high in patients who had troponin elevation >100 x ULN, although an increase in adverse events was also seen in patients with a lesser degree of troponin elevation. Troponin level is routinely ascertained in patients with ACS, is readily available, and provides an easy tool for risk stratification of patients with NSTE-ACS.
Keywords: Registries, Acute Coronary Syndrome, Biological Markers, Cardiology, Heart Conduction System, Heart Arrest, Troponin
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