Safety and Effectiveness of Hypothermia as Adjunctive Therapy in Percutaneous Coronary Intervention for ST-elevation MI: A Comprehensive Meta-analysis

Aim: This meta-analysis aims to assess the effectiveness of hypothermia as an adjunctive therapy in percutaneous coronary intervention (PCI) for patients with ST-elevation MI. Methods: A comprehensive literature search was conducted using electronic databases to identify relevant studies published up to September 2023. Studies investigating the use of adjunctive hypothermia in ST-elevation MI patients undergoing PCI were included. Data on clinical outcomes, including mortality, infarct size, left ventricular function, major adverse cardiac events and microvascular obstruction, were extracted and analysed. Bleeding and infection events as primary safety endpoints in the safety analysis were also assessed. Results: Eight studies involving 488 patients were included in this meta-analysis. The pooled analysis revealed no significant difference in all-cause mortality between the adjunctive hypothermia group and the control group (OR 0.60; 95% CI [0.24–1.53], p=0.29). There was no significant difference in major adverse cardiac event rates between the two groups (OR 1.59; 95% CI [0.63–4.01]). Additionally, no significant differences were observed in infarct size, left ventricular function or microvascular obstruction. In the safety analysis, hypothermia significantly increased the risk of infection (OR 7.22, 95% CI [2.47–21.10]; p=0.0003; I²=0%) but showed no significant impact on bleeding events (OR 2.27; 95% CI [0.76–6.78]; p=0.14; I²=0%). Conclusion: While previously believed to show promise, hypothermia as adjunctive therapy in PCI fails to achieve any significant superiority over standard interventions according to our analysis. Furthermore, hypothermia was associated with a significantly increased risk of infection without a notable impact on bleeding events, raising concerns about its safety profile. Nevertheless, our findings should be interpreted with caution, considering the limitations of our analysis, such as the small number of studies available in the literature. Continued research efforts on larger sample sizes are essential to either refine or refute the current findings.