Troponin T Levels in Patients with Acute Coronary Syndromes, with or without Renal Dysfunction

Abstract

BACKGROUND: Among patients with suspected acute coronary syndromes, cardiac troponin T levels have prognostic value. However, there is concern that renal dysfunction may impair the prognostic value, because cardiac troponin T may be cleared by the kidney. METHODS: We analyzed the outcomes in 7033 patients enrolled in the Global Use of Strategies to Open Occluded Coronary Arteries IV trial who had complete base-line data on troponin T levels and creatinine clearance rates. The troponin T level was considered abnormal if it was 0.1 ng per milliliter or higher, and creatinine clearance was assessed in quartiles. The primary end point was a composite of death or myocardial infarction within 30 days. RESULTS: Death or myocardial infarction occurred in 581 patients. Among patients with a creatinine clearance above the 25th percentile value of 58.4 ml per minute, an abnormally elevated troponin T level was predictive of an increased risk of myocardial infarction or death (7 percent vs. 5 percent; adjusted odds ratio, 1.7; 95 percent confidence interval, 1.3 to 2.2; P<0.001). Among patients with a creatinine clearance in the lowest quartile, an elevated troponin T level was similarly predictive of increased risk (20 percent vs. 9 percent; adjusted odds ratio, 2.5; 95 percent confidence interval, 1.8 to 3.3; P<0.001). When the creatinine clearance rate was considered as a continuous variable and age, sex, ST-segment depression, heart failure, previous revascularization, diabetes mellitus, and other confounders had been accounted for, elevation of the troponin T level was independently predictive of risk across the entire spectrum of renal function. CONCLUSIONS: Cardiac troponin T levels predict short-term prognosis in patients with acute coronary syndromes regardless of their level of creatinine clearance.