The Extent of Myocardial Injury During Prolonged Targeted Temperature Management After Out-of-Hospital Cardiac Arrest

Kinetics of 2 different high-sensitive troponins during targeted temperature management in out-of-hospital cardiac arrest patients with acute myocardial infarction: a post hoc sub-study of a randomised clinical trial

Introduction

Short term hypothermia has been suggested to have cardio protective properties in acute myocardial infarction (AMI) by reducing infarct size as assessed by troponins. There are limited data on the kinetics of these biomarkers in comatose out-of-hospital cardiac arrest (OHCA) patients, with and without AMI, undergoing targeted temperature management (TTM) in the ICU.

Purpose

The aim of this post hoc analyses was to evaluate and compare the kinetics of two high-sensitivity cardiac troponins in OHCA survivors, with and without acute myocardial infarction (AMI), during TTM of different durations [24 h (standard) vs. 48 h (prolonged)].

Methods

In a sub-cohort (n = 114) of the international, multicentre, randomized controlled study “TTH48” we measured high-sensitive troponin T (hs-cTnT), high-sensitive troponin I (hs-cTnI) and CK-MB at the following time points: Arrival, 24 h, 48 h and 72 h from reaching the target temperature range of 33 ± 1 °C. All patients diagnosed with an AMI at the immediate coronary angiogram (CAG)—18 in the 24-h group and 25 in the 48-h group—underwent PCI with stent implantation. There were no stent thromboses.

Results

Both the hs-cTnT and hs-cTnI changes over time were highly influenced by the cause of OHCA (AMI vs. non-AMI). In contrast to non-AMI patients, both troponins remained elevated at 72 h in AMI patients. There was no difference between the two time-differentiated TTM groups in the kinetics for the two troponins.

Conclusion

In comatose OHCA survivors with an aetiology of AMI levels of both hs-cTnI and hs-cTnT remained elevated for 72 h, which is in contrast to the well-described kinetic profile of troponins in normotherm AMI patients. There was no difference in kinetic profile between the two high sensitive assays. Different duration of TTM did not influence the kinetics of the troponins.

Trial registration: Clinicaltrials.gov Identifier: NCT01689077, 20/09/2012.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02778-4.

Targeted Temperature Management in Out-of-Hospital Cardiac Arrest With Shockable Rhythm: A Post Hoc Analysis of the Coronary Angiography After Cardiac Arrest Trial

OBJECTIVES

The optimal targeted temperature in patients with shockable rhythm is unclear, and current guidelines recommend targeted temperature management with a correspondingly wide range between 32°C and 36°C. Our aim was to study survival and neurologic outcome associated with targeted temperature management strategy in postarrest patients with initial shockable rhythm.

DESIGN

Observational substudy of the Coronary Angiography after Cardiac Arrest without ST-segment Elevation trial.

SETTING

Nineteen hospitals in The Netherlands.

PATIENTS

The Coronary Angiography after Cardiac Arrest trial randomized successfully resuscitated patients with shockable rhythm and absence of ST-segment elevation to a strategy of immediate or delayed coronary angiography. In this substudy, 459 patients treated with mild therapeutic hypothermia (32.0-34.0°C) or targeted normothermia (36.0-37.0°C) were included. Allocation to targeted temperature management strategy was at the discretion of the physician.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

After 90 days, 171 patients (63.6%) in the mild therapeutic hypothermia group and 129 (67.9%) in the targeted normothermia group were alive (hazard ratio, 0.86 [95% CI, 0.62-1.18]; log-rank p = 0.35; adjusted odds ratio, 0.89; 95% CI, 0.45-1.72). Patients in the mild therapeutic hypothermia group had longer ICU stay (4 d [3-7 d] vs 3 d [2-5 d]; ratio of geometric means, 1.32; 95% CI, 1.15-1.51), lower blood pressures, higher lactate levels, and increased need for inotropic support. Cerebral Performance Category scores at ICU discharge and 90-day follow-up and patient-reported Mental and Physical Health Scores at 1 year were similar in the two groups.

CONCLUSIONS

In the context of out-of-hospital cardiac arrest with shockable rhythm and no ST-elevation, treatment with mild therapeutic hypothermia was not associated with improved 90-day survival compared with targeted normothermia. Neurologic outcomes at 90 days as well as patient-reported Mental and Physical Health Scores at 1 year did not differ between the groups.

A systematic review of safety and adverse effects in the practice of therapeutic hypothermia

OBJECTIVE

To carry out a systematic review to estimate the rate and magnitude of adverse effects following therapeutic hypothermia (TH) procedure in patients resuscitated from out-of-hospital cardiac arrest (OHCA) and highlight the specific complications seen after the procedure.

METHODS

A systematic review of currently published studies was performed following standard guidelines. Online database searches were performed for controlled trials for the last twenty years. Papers were examined for methodological soundness before being included. Data were independently extracted by two blinded reviewers. Studies were also assessed for bias using the Cochrane criteria. The adverse effects attributed to TH in the literature were appraised critically.

RESULTS

The initial data search yielded 78 potentially relevant studies; of these, 59 were excluded for some reason. The main reason for exclusion (n = 43, 55.8%) was that irrelevance to adverse effects of TH. Finally, 19 underwent full-text review. Studies were of high-to-moderate (n = 12, 63%) to low-to-very low (n = 7, 37%) quality. Five studies (27.7%) were found to have high risk of bias, while 8 (42.1%) had low risk of bias.

INTERPRETATION

Although adverse effects related to the practice of TH have been studied extensively, there is substantial heterogeneity between study populations and methodologies. There is a considerable incidence of side effects attributed to the procedure, e.g., from life-threatening ventricular arrhythmias to self-limited consequences. Most studies analyzed in this systematic review indicated that the procedure of TH has not caused severe adverse effects leading to significant alterations in the outcomes following resuscitation from OHCA. PROSPERO, registration number is: CRD42018075026.