Superiority of high sensitivity cardiac troponin T vs. I for long-term prognostic value in patients with chest pain; data from the Akershus cardiac Examination (ACE) 3 study

BackgroundCardiac troponins (cTn) are essential in the diagnostic assessment of non-ST-segment-elevation acute coronary syndrome (NSTE-ACS). Elevated concentrations of cTnT and cTnI predict cardiovascular events in non-acute settings, but the individual troponin isotype association with long-term mortality in patients with suspected unstable angina pectoris (UAP) is less clear.MethodsPatients hospitalized with chest pain between June 2009 and December 2010 were included in the Akershus Cardiac Examination 3 Study and followed for median 6.6 (IQR 6.2-7.1) years. The index diagnosis was adjudicated by an independent committee as NSTE-myocardial infarction (NSTEMI), UAP or non-ACS. Blood samples were collected within 24 h of admission and analyzed with high sensitivity assays for cTnT (hs-cTnT, Roche) and cTnI (hs-cTnI, Singulex).ResultsOf 402 patients included, 74 (18%) were classified as NSTEMI, 88 (22%) UAP and 240 (60%) non-ACS. hs-cTnI concentrations were detectable in all patients (median 3 [IQR 1–11] ng/L), while hs-cTnT concentrations were above the level of blank in 205 (51%) (median 3 [IQR 3–16] ng/L). In patients with UAP, both log₂-transformed hs-cTnT and hs-cTnI were associated with all-cause mortality in analyses that adjusted for other risk factors: HR 2.40 [95% CI 1.75–3.30], p < 0.001 and HR 1.44 [1.14–1.81], p = 0.002. There were no significant sex-dependent differences in the association between hs-cTnT or hs-cTnI and outcome. Time dependent receiver-operating characteristics area under the curve was 0.85 (95% CI 0.79–0.92) for hs-cTnT and 0.74 (0.64–0.84) for hs-cTnI, p = 0.008 for difference between values.ConclusionsHigher concentrations of hs-cTnT and hs-cTnI were both associated with all-cause mortality in patients with UAP, but the association with outcome was stronger for hs-cTnT than for hs-cTnI.