Association of Kidney Function and Cerebral Arterial Stiffness

Abstract

Background and Purpose: Chronic kidney disease (CKD) is known to have affected the systemic vasculature and its remodeling, which eventually led to the systemic arterial stiffness. However, the relationship between cerebral circulation and impaired renal function is poorly understood. To evaluate the effect of renal dysfunction to increase systemic and intracranial arterial stiffness, we assessed the relation between renal resistive index (RRI) and pulsatility index (PI) of the middle cerebral artery (MCA). Methods: We included patients with acute lacunar infarction. Demographic and clinical data were collected by retrospective chart review. Bilateral transcranial Doppler ultrasound (TCD) examination of the MCAs was performed using the ST3 Ultrasound system (Spencer Technologies) and PI were calculated. RRI was obtained through kidney Doppler sonography. Subjects with occlusion or significant stenosis of MCA, atrial fibrillation, bilaterally absent transtemporal sonographic windows were excluded. Results: Of the 283 included subjects (mean age 67.8 ± 10.2), 74 patients had renal dysfunction (glomerular filtration rate < 60ml/min/1.73m2 at admission) and 49 patients underwent kidney Doppler ultrasound within 1 year since their acute stroke. Renal dysfunction was significantly associated with higher arterial stiffness (median PI 1.12, IQR 0.85 to 1.57 vs. controls PI 0.84, IQR 0.54 to 1.22 [p<0.0001]). There was a proportional relationship between the degree of renal dysfunction and the distal vascular resistance. In multivariate adjusted regression analysis, renal function was related to high PI (p<0.001). Furthermore, there is strong correlation between RRI and PI (r=0.65, p<0.001). Conclusions: In patients with lacunar infarction, renal impairment is an independent determinant of increased arterial stiffness in cerebral circulations. In addition, PI is significantly associated with RRI.