The Extent of Myocardial Injury during Prolonged Targeted Temperature Management after Out-of-Hospital Cardiac Arrest

AIM: To evaluate the extent of myocardial injury by cardiac biomarkers during prolonged targeted temperature management of 24h vs. 48h after out-of-hospital cardiac arrest.

METHODS: A randomized Scandinavian multicenter study, that compares the extent of myocardial injury quantified by area under the curve (AUC) of cardiac biomarkers during prolonged targeted temperature management at 33 ±1 °C of 24h and 48h, respectively. Through a period of 2.5-year 161 comatose out-of-hospital cardiac arrest patients were randomized to targeted temperature management for 24h (n = 77) or for 48h (n = 84). The AUC was calculated using both high sensitivity cardiac troponin T (hs-cTnTAUC) and creatine kinase-MB (CK-MBAUC) that were based upon measurements of these biomarkers every 6h upon admission until 96h after reaching target temperature.

RESULTS: The median hs-cTnTAUC of 33827 ng/L/h (IQR 11366-117690) of targeted temperature management at 24h did not differ significantly from that of 28973 ng/L/h (IQR 10656-163655) of 48h. In contrast, the median CK-MBAUC of 1829 μg/L/h (IQR 800-6799) during targeted temperature management at 24h was significantly lower than that of 2428 μg/L/h (IQR 1163-10906) within targeted temperature management at 48h, P < 0.05.

CONCLUSION: This study of comatose out-of-hospital cardiac arrest survivors showed no difference between the extents of myocardial injury estimated by hs-cTnTAUC of prolonged targeted temperature management of 48h vs. 24h although the CK-MBAUC was significantly higher during 48h vs. 24h. Hence, it seems unlikely that the duration of targeted temperature management has a beneficial effect on the extent of myocardial injury after out-of-hospital cardiac arrest, and may even have a worsening effect.