Hemodynamics in the circle of Willis and prognostic factors in subarachnoid hemorrhage

Since stroke is a major cause of death worldwide, understanding its underlying pathology and determining prognostic factors is essential. The circle of Willis (CoW) is a critical arterial relay system located at the base of the brain. Therefore, hemodynamics within the CoW plays an important role in the pathology of stroke. In this thesis, CoW anatomy and internal carotid artery (ICA) stenosis are pointed out to influence cerebrovascular territory perfusion. This is clinically relevant if the ICA-stenosis grade is more than 70%.
With a numerical model, hemodynamics in the CoW can be simulated. This thesis introduces a simplified numerical model for personalized CoW hemodynamics. The CoW-model is explained and validated, against the background of a systematic review of the literature. Since there is an extensive heterogeneity between proposed numerical models, in current studies hemodynamic parameters based on CoW-configuration still cannot be associated with the development of anatomical causes for stroke, such as intracranial aneurysm. Additional simulation accuracy is warranted before the numerical model can be applied in clinical practice. Finally, in this thesis, myosteatosis was found to be associated with the clinical severity of a subtype of stroke, the subarachnoid haemorrhage. However, muscle atrophy and myosteatosis were not associated with neurological outcome nor long term survival.
In conclusion, this thesis is a next step in the association between hemodynamics in the CoW and several stroke types, and thus in personalizing and optimizing stroke management.