Assessment of the Willis circle flow changes and the severity of degenerative aortic stenosis and cognitive impairment.

Background: Degenerative aortic stenosis (DAS) and cognitive function deterioration frequently coexist in elderly patients, which affects the prognosis.
Aims: We aimed to evaluate the Willis circle intracranial blood flow parameters and cognitive status in patients with DAS.
Methods: Ultrasonography of the Willis circle and the assessment of cerebral blood flow (CBF) volume, acceleration time (AT), pulsatile and resistive indexes (PI, RI), as well as cognition tests (Mini‑Mental Status Examination [MMSE] and Montreal Cognitive Assessment [MoCA]) were performed in group 1-41 patients with severe DAS (aortic valve area indexed to the body surface area [AVAi] <0.5 cm2/m2) and group 2-41 patients with moderate DAS (AVAi [range], 0.51-0.99 cm2/m2). The control group comprised 52 patients without DAS.
Results: Compared with controls, mean (SD) CBF volume ingroups 1 and 2 was lower (1.37 [0.32] l/min vs 1.5 [0.44] l/min vs 1.71 [0.21] l/min, respectively; P <0.001), while AT (212 [20] ms vs 161 [33] ms vs 86 [21] ms, respectively; P <0.001), RI (0.64 [0.07] vs 0.65 [0.06] vs 0.59 [0.05], respectively; P <0.001), and PI (1.13 [0.21] vs 1.16 [0.17] vs 0.99 [0.12]; P <0.001) were higher. Both MMSE and MoCA scores did not differ according to CBF, RI, PI, and AT. In multivariable regression analysis, age, renal failure, left ventricular ejection fraction, and diabetes, yet not CBF parameters, were independently associated with cognitive function.
Conclusions: Patients with DAS had significantly reduced CBF volume and increased arterial stiffness. However, cognitive impairment may be attributed to concomitant comorbidities rather than CBF parameters.