The Impact of Patient-Specific Vascular Structure on Localized Cooling in the Human Heart

Acute Myocardial Infarction (AMI) is the leading cause of worldwide death and disability, and approximately 720,000 Americans will experience an AMI in 2018. Studies have shown that rapid hypothermia therapy (< 35°C) before reperfusion in patients with AMI can reduce infarct size by 37%. Localized therapeutic hypothermia has proven the potential to cool heart tissue rapidly following AMI, 3°C in 5 minutes. Using digital imaging software and the finite volume method we analyzed temperature distributions in six patient-specific LCX artery models. A mock circulatory loop was used to determine the exiting temperatures of a standard 7 Fr catheter with flow rates ranging from 9.1 ml/min to 88.9 ml/min for input into our model. The said flow rates were fed into our model using 0.45 W and 128.4 W of cooling, respectively. Our work showed typical exit temperatures were between 35.8°C and 36.9°C using a 29.2 ml/min catheter infusion flow rate in all six heart models. Additionally, results of this study indicate that biovariability in patient-specific vascular structures significantly impacts Therapeutic Hypothermia (TH) treatment methods. These results indicate that further research is needed to examine more accurate physiological effects, such as pulsatile flow. Future models will be used to provide insight to guide more efficient TH device designs and operational parameters to optimize patient outcomes following AMI.