Whole-body ischemia during out-of-hospital cardiac arrest triggers immediate activation of inflammatory systems leading to a sepsis-like syndrome. The aim was to investigate the association between level of systemic inflammation and mortality in survivors after out-of-hospital cardiac arrest treated with targeted temperature management.
Post hoc analysis.
Single-center study of a prospective multicenter randomized study.
One hundred sixty-nine patients (99%) with available blood samples out of 171 patients included in the Target Temperature Management trial, randomly assigning patients to targeted temperature management at 33°C or 36°C.
At baseline and 24, 48, and 72 hours after out-of-hospital cardiac arrest, blood samples were obtained and screened for a battery of inflammatory markers. Level of interleukin-1β, interleukin-2, interleukin-4, interleukin-5, interleukin-6, interleukin-9, interleukin-10, interleukin-12, interleukin-13, tumor necrosis factor-α, interferon-γ, C-reactive protein, and procalcitonin were measured. Mortality at 30 days was evaluated by Cox analysis, and the predictive capability of inflammatory markers was evaluated by area under the curve. Level of all inflammatory markers changed significantly within 72 hours after out-of-hospital cardiac arrest (all p values < 0.001), but only procalcitonin levels showed overall differences between nonsurvivors and survivors (p = 0.0002). At baseline, interleukin-6 was independently associated with mortality, whereas both interleukin-6 levels (hazard ratio = 1.23 [1.01–1.49]; p = 0.04) and procalcitonin levels (hazard ratio = 1.20 [1.03–1.39]; p = 0.02) 24 hours after out-of-hospital cardiac arrest were associated with 30-day mortality with no interactions between targeted temperature management group and levels of interleukin-6 (p = 0.25) or procalcitonin (p = 0.85). None of the other inflammatory markers were independently associated with mortality. Area under the curve for procalcitonin and interleukin-6, 24 hours after out-of-hospital cardiac arrest, were 0.74 and 0.63, respectively.
Level of inflammation, assessed by interleukin-6 and procalcitonin, was independently associated with increased mortality with the highest discriminative value obtained 24 hours after out-of-hospital cardiac arrest. Interventions aiming at decreasing level of inflammation as a way to improve outcome may be investigated in future studies.
1Department of Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
2Department of Cardiology, Aarhus University Hospital, Skejby, Denmark.
3Department of Cardiothoracic Anaesthesia, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
4Department of Anesthesia and Intensive Care, Lund University, Helsingborg Hospital, Helsingborg, Sweden.
5Department of Anesthesia and Intensive Care, Skåne University Hospital, Lund University, Lund, Sweden.
6The Medical Research Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
* See also p. 1336.
Clinical Trial Registration: http://clinicaltrials.gov/ct2/show/NCT01020916. Unique identifier: NCT01020916.
Supported, in part, by unrestricted grants for cofunding the analysis of biomarkers from The Danish Foundation TrygFonden, Copenhagen.
Dr. Bro-Jeppesen’s institution received grant support from TrygFonden (grant for biochemical analyses). Dr. Kjaergaard’s institution received grant support from TrygFonden (grant for biochemical analyses) and received an EU grant (Interreg IV A programme) for establishing the Centre for Resuscitation Science in the Oresund Region. The works of Kjaergaard, Friberg, and Hassager are supported by the European Union Interreg IV A programme as part of the grant for establishing the Centre for Resuscitation Science in the Oresund Region. Dr. Nielsen lectured for BARD Medical (speaker honorarium). Dr. Friberg lectured for Bard Medical. Dr. Hassager lectured for AstraZeneca. The remaining authors have disclosed that they do not have any potential conflicts of interest.
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