Bidirectional fluid–solid–heat interaction: Impact of extreme temperatures on aortic stenosis complications

Aortic stenosis is prevalent among veterans who underwent military training in extreme temperature regions. These individuals face elevated risks of complications, including atherosclerosis and thrombosis, due to extreme temperature exposure. However, the existing models for assessing the risk of complications in aortic stenosis have overlooked the impact of temperature on the vascular wall stress field and blood flow dynamics, thereby limiting their applicability in extreme temperature environments. Therefore, this study proposed a parametric simulation model based on bidirectional fluid–solid–heat interaction to investigate the multiphysical field responses of aortic hemodynamics under normal temperature (293.15 K), extremely cold conditions (233.15 K), and extremely hot conditions (317.15 K). Corresponding risk coefficients were proposed to evaluate atherosclerosis and thrombosis risks. Results revealed that extreme temperatures induced fluctuations in local wall shear stress within the aortic root, aortic arch, and branch arteries. Under three different temperature conditions, thrombosis high-risk regions consistently localized to the aortic root's great curvature and branch arteries, while atherosclerosis high-risk regions concentrated on the aortic root's lesser curvature and the aortic arch's greater curvature. Within a cardiac cycle, thrombosis risk was 4.72% and 3.92% higher under extreme heat compared to extreme cold and normal temperatures, respectively. Atherosclerosis risk under extreme cold was 83.91% and 93.86% higher than under extreme heat and normal temperatures, respectively. This study can develop personalized health monitoring programs for soldiers training in extreme temperature areas through dynamic risk assessment.