A Computational Model-Based Study on Trans-Stenotic Pressure Ratio of Carotid Artery Stenosis and Its Predictive Value for Cerebral Ischemia

Trans-stenotic pressure ratio (herein denoted by dpPR) has been proposed as a complementary index to stenosis rate (SR) for assessing the functional severity of carotid artery stenosis (CAS); however, it remains unclear how well dpPR can indicate cerebral ischemia. In this study, a physiology-based computational model of the cerebral circulation was developed to yield a tool for generating large-scale in silico data to characterize the changes of the dpPR of the left internal CAS in response to variations in SR and various anatomical/pathophysiological factors that represent inter-patient differences. In addition, a cerebral ischemia index (CII) was defined to evaluate the predictive value of dpPR for cerebral ischemia. Results showed that dpPR was affected by many factors unrelated to the severity of stenosis, such as the anatomical structure and geometrical size of cerebral arteries, mean systemic arterial blood pressure (MAP), flow autoregulation function of cerebral microcirculation (quantified by CFAI), and coexisting contralateral CAS. In comparison with SR, dpPR exhibited a stronger correlation with CII. In particular, the relationship between dpPR and CII was found to be describable by a mathematical function if MAP and CFAI were fixed. The findings not only deepen our understanding of the physiological implications of dpPR but also provide valuable theoretical insights to guide the application of dpPR in clinical practice.