Therapeutic hypothermia after out-of-hospital cardiac arrest in comatose patients with acute myocardial infarction

Abstract Background Comatous survivors of out-of-hospital cardiac arrest (OHCA) have a high risk of death or poor neurological outcome. Therapeutic hypothermia is recommended for these patients after OHCA. However, there is a lack of data regarding outcomes of therapeutic hypothermia after OHCA in comatose patients with acute myocardial infarction (AMI). Purpose This study aimed to investigate the impact of therapeutic hypothermia on clinical outcomes in comatose patients who underwent primary percutaneous coronary intervention (PCI) for AMI after OHCA. Methods Using a prospective nationwide registry from 2016 to 2021, we examined 2,925 consecutive comatose patients experiencing OHCA in patients with AMI. These patients were categorized into groups receiving hypothermia treatment (n=624) and those without hypothermia treatment (n=2,301). The primary endpoint was the mortality rate upon discharge. The secondary endpoints were mortality rates at 6 or 24 hours, and neurological outcomes at hospital discharge. Results Overall, 624 (21.3%) patients were classified into the hypothermia group. This group showed a notably reduced mortality rate (hazard ratio [HR]: 0.68, 95% confidence interval [CI]: 0.58-0.78, p<0.001) after IPTW analysis (Figure 1). While the worse neurological outcome (as indicated by cerebral performance category [CPC] category 3-5) at hospital discharge was not significantly different between groups after IPTW analysis (odds ratio [OR]: 1.04, 95% CI: 0.93-1.15, p=0.499), early hypothermia within 180 minutes after hospital arrival showed significantly lower mortality rates (HR: 0.64, 95% CI: 0.44-0.95, p=0.027) and reduced occurrence of worse neurological outcome (OR: 0.75, 95% CI: 0.59-0.96, p=0.021) after IPTW analysis (Figure 2). Detailed hypothermia protocol including a targeted temperature of 33°C vs. 36°C or hypothermia duration of 48 hours vs. 24 hours did not significantly reduce the rate of death or poor neurological outcome at discharge. Conclusions Therapeutic hypothermia in OHCA patients complicating AMI was associated with lower mortality rates and comparable neurologic outcomes. However, early hypothermia within 180 minutes after hospital arrival showed significantly improved the mortality and neurological outcomes.all-cause deathAll-cause death and neurological outcome