Impact of Physiological States on the Progression and Rupture Risks of Abdominal Aortic Aneurysms: A Hemodynamic Study Combining Computational Fluid Dynamics With in Vitro Experiments.

The 70%-90% mortality rate of ruptured abdominal aortic aneurysms (AAAs) demonstrates the necessity of investigating progression and rupture. The progression and rupture risks of AAAs are influenced by the physiological states of patients, such as exercise and intense emotions. Understanding this association aids in the management of AAAs, but related research remains limited. This study aims to explore the impact of physiological states on progression and rupture risks of AAAs. Different physiological states of a selected AAA patient (characterized by heart rate (HR), stroke volume (SV), blood pressure (BP), pulse pressure (PP), and the rest and exercise conditions) were simulated by altering the inflow and outflow conditions in computational fluid dynamics and in vitro experiments, and hemodynamics were obtained and analyzed. When HR ≥ 105 bpm, systolic pressure of AAA exceeded 140 mmHg (hypertension). SV ≤ 17 mL induced low time-averaged wall shear stress (TAWSS) (< 0.4 Pa) and high oscillatory shear index (OSI) (> 0.25); SV ≥ 26 mL induced systolic pressure ≥ 155 mmHg. Increasing BP from 100/60 to 140/100 mmHg and PP from 20 to 60 mmHg, raised the pressure on AAA vascular wall by 53.42% and 15.09%, respectively. Exercise induced higher TAWSS than rest (2.103 vs. 0.644 Pa). These findings rely on a patient-specific model to preliminarily explore the mechanisms and trends of physiological states affecting AAA progression and rupture risks. Large sample studies are needed in the future to validate the conclusions of this study and establish clinical reference risk thresholds.