High-sensitivity troponin-T as a prognostic marker after out-of-hospital cardiac arrest - A targeted temperature management (TTM) trial substudy.

AIM OF THE STUDY: Predicting outcome of unconscious patients after successful resuscitation is challenging and better prognostic markers are highly needed. Ischemic heart disease is a common cause of out-of-hospital cardiac arrest (OHCA). Whether or not high-sensitivity troponin T (hs-TnT) is a prognostic marker among survivors of OHCA with both ischemic and non-ischemic aetiologies remains to be determined. We sought to evaluate the ability of hs-TnT to prognosticate all-cause mortality, death due to cardiovascular causes or multi-organ failure and death due to cerebral causes after OHCA. The influence of the level of target temperature management on hs-TnT as a marker of infarct size was also assessed.

METHODS: A total of 699 patients from the targeted temperature management (TTM) trial were included and hs-TnT was analyzed in blood samples from 24, 48 and 72h after return of spontaneous circulation (ROSC). The endpoints were 180 day all-cause mortality, death due to cardiovascular causes or multi-organ failure and death due to cerebral causes. Subgroups based on the initial ECG after ROSC (STEMI vs all other ECG presentations) were analyzed.

RESULTS: Hs-TnT was independently associated with all-cause mortality which was driven by death due to cardiovascular causes or multi-organ failure and not cerebral causes (at 48h: OR 1.10, CI 1.01-1.20, p<0.05). Hs-TnT was also an independent predictor of death due to cardiovascular causes or multi-organ failure (at 48h: OR 1.13, CI 1.01-1.26, p<0.05). In patients with STEMI, hs-TnT was independently associated with death due to cardiovascular causes or multi-organ failure (at 48h: OR 1.47, CI 1.10-1.95, p<0.01). Targeted temperature management at 33°C was not associated with hs-TnT compared to 36°C.

CONCLUSIONS: After OHCA due to both ischemic and non-ischemic causes, hs-TnT is an independent marker of both all-cause mortality and death due to cardiovascular causes or multi-organ failure. Targeted temperature management at 33°C did not reduce hs-TnT compared to 36°C. Hs-TnT may be a marker of poor prognosis after OHCA and this should be taken into consideration in patients that present with high troponin levels.

TRIAL REGISTRATION: The TTM-trial is registered and accessible at Clinicaltrials.gov (identifier: NCT01020916).