Therapeutic hypothermia for acute myocardial infarction: a narrative review of evidence from animal and clinical studies

Abstract

Myocardial infarction (MI) is the leading cause of death from coronary heart disease and requires immediate reperfusion therapy with thrombolysis, primary percutaneous coronary intervention, or coronary artery bypass grafting. However, myocardial reperfusion therapy is often accompanied by cardiac ischemia/reperfusion (I/R) injury, which leads to myocardial injury with detrimental consequences. The causes of I/R injury are unclear, but are multifactorial, including free radicals, reactive oxygen species, calcium overload, mitochondria dysfunction, inflammation, and neutrophil-mediated vascular injury. Mild hypothermia has been introduced as one of the potential inhibitors of myocardial I/R injury. Although animal studies have demonstrated that mild hypothermia significantly reduces or delays I/R myocardium damage, human trials have not shown clinical benefits in acute MI (AMI). In addition, the practice of hypothermia treatment is increasing in various fields such as surgical anesthesia and intensive care units. Adequate sedation for anesthetic procedures and protection from body shivering has become essential during therapeutic hypothermia. Therefore, anesthesiologists should be aware of the effects of therapeutic hypothermia on the metabolism of anesthetic drugs. In this paper, we review the existing data on the use of therapeutic hypothermia for AMI in animal models and human clinical trials to better understand the discrepancy between perceived benefits in preclinical animal models and the absence thereof in clinical trials thus far.

Liquiritin: A natural flavonoid with potential cardiovascular protection

“…Acute myocardial infarction (AMI) is the main cause of death because of CHD, and its pathogenesis is closely related to free radicals, ROS, calcium overload, mitochondrial dysfunction, inflammation, and neutrophil-mediated vascular injury (Jung et al, 2022). Flavonoids have a good effect on the prevention of AMI (Hua et al, 2022).…”

Pathways to Reduce Late Mortality of Hemorrhagic Shock

“…Hypothermia decreases blood flow to all organs of the body in different manner, the skeletal muscle and extremities being the most sensitive to the reduction, followed by the other internal organs, the lungs as the last. The metabolism of all drugs, in particular opioids and muscle relaxants, is slowed so lower and more distanced doses are required, the more the lower is the temperature [9].…”

“…The faster the cooling is reached, however, the lesser the shivering and the oxygen consumption [77]. Shivering occurs during hypothermia induction at temperatures between 35 and 37°C and less likely at mild hypothermia between 32 and 34°C; thus, shivering may delay reaching lower target temperatures of 32-34°C and offset the therapeutic effects of hypothermia for I/R injury, Pathways to Reduce Late Mortality of Hemorrhagic Shock DOI: http://dx.doi.org/10.5772/intechopen.1004934 pre-requisites of the therapeutical use of hypothermia [9]. Shivering disappears at temperatures <33°C [78].…”

Mesenchymal Stem Cell-Derived Exosomal Noncoding RNAs as Alternative Treatments for Myocardial Ischemia-Reperfusion Injury: Current Status and Future Perspectives

“…Mild and moderate hypothermia are potentially effective therapeutic measures for MIRI. The cardioprotective effect of hypothermia treatment involves reducing the heart rate and myocardial oxygen consumption and inhibiting metabolism to reduce oxygen demand, as well as modulating the mPTP and inhibiting the inflammatory response [ 97 ]. Notably, changes in temperature affect the efficacy of adipose MSC-EXOs, suggesting the need for in-depth studies on the optimal low temperature for different individuals.…”