Sensitive cardiac troponin in the diagnosis and risk stratification of acute heart failure

. Arenja N, Reichlin T, Drexler B, Oshima S, Denhaerynck K, Haaf P, Potocki M, Breidthardt T, Noveanu M, Stelzig C, Heinisch C, Twerenbold R, Reiter M, Socrates T, Mueller C (University Hospital, Basel). Sensitive cardiac troponin in the diagnosis and risk stratification of acute heart failure. J Intern Med 2012; 271: 598607. Background. The aim of our study was to investigate the diagnostic and prognostic value of a sensitive cardiac troponin I (s-cTnI) assay in patients with acute heart failure (AHF). Methods. Sensitive cardiac troponin I was measured in 667 consecutive patients at presentation to the emergency department with acute dyspnoea. Three s-cTnI strata were predefined: below the limit of detection (<0.01 mu g L-1, undetectable), detectable but still within the normal range (0.010.027 mu g L-1) and increased (=0.028 mu g L-1, =99th percentile). The final diagnosis was adjudicated by two independent cardiologists blinded to the s-cTnI levels. Median follow-up in patients with AHF was 371 days. Results. Levels of s-cTnI were higher in patients with AHF (n = 377, 57%) compared to patients with noncardiac causes of acute dyspnoea (median 0.02 vs. <0.01 mu g L-1, P < 0.001). In patients with AHF, in-hospital mortality increased with increasing s-cTnI in the three strata (2%, 5% and 14%, P < 0.001). One-year mortality also increased with increasing s-cTnI (21%, 33% and 47%, P < 0.001). s-cTnI remained an independent predictor of 1-year mortality [adjusted odds ratio 1.03 for each increase of 0.1 mu g L-1, 95% confidence interval (CI) 1.021.05, P < 0.001] after adjustment for other risk factors including B-type natriuretic peptide. The net reclassification improvement was 68% (P < 0.001), and absolute integrated discrimination improvement was 0.18 (P < 0.001). The diagnostic accuracy of s-cTnI for the diagnosis of AHF as quantified by the area under the receiver operating characteristic curve was 0.78 (95% CI, 0.750.82). Conclusions. Sensitive cardiac troponin I is a strong predictor of short- and long-term prognosis in AHF that helps to reclassify patients in terms of mortality risk. Detectable levels of s-cTnI, even within the normal range, are independently associated with mortality.