Mild Induced Hypothermia in Patients with Infarct-Related Cardiogenic Shock and Cardiac Arrest: Insights from the CULPRIT-SHOCK Trial

Background Mild induced hypothermia (MIH) is often applied in patients with cardiac arrest (CA), but its impact on patients with infarct-related cardiogenic shock (CS) and CA remains unclear. Objectives To evaluate the characteristics and outcomes of patients with infarct-related CS and CA who received MIH versus those who did not in the randomized CULPRIT-SHOCK trial and the accompanying registry. Methods We included patients with CS and CA from the CULPRIT-SHOCK trial and registry. The primary endpoint was 1-year mortality. Secondary endpoints included death or renal replacement therapy within 30 days. A multivariate regression analysis was performed for 1-year mortality, adjusted for relevant baseline parameters. Results Among 550 patients with CA, 288 (52.4%) received MIH. Patients treated with MIH were younger (64 vs. 67 years, P=0.03), had higher rates of mechanical ventilation (94.5% vs. 78.8%, p<0.01), and higher mean arterial pressure (82 vs. 76 mmHg, P=0.002). The unadjusted hazard ratio (HR) for 1-year mortality favored MIH (HR: 0.77, 95% confidence interval [CI]: 0.61-0.97, P=0.024); however, after multivariate adjustment, this effect was not statistically significant (HR: 0.83, 95% CI: 0.64-1.09, P=0.18). MIH was associated with a higher need for renal replacement therapy (15.2% vs. 7.5%, P=0.005) and less use of mechanical circulatory support (21.2% vs. 34.2%, P<0.001). Conclusions In this retrospective analysis MIH was not significantly associated with lower 1-year mortality in patients with infarct-related CS and CA. Because of the numerically lower mortality rate, further research is necessary to clarify the role of MIH in this patient population. Trial registration ClinicalTrials.gov Identifier: NCT01927549