Changes of the cerebral blood flow and the cognitive functions in chronic hemodialysis patients

ABSTRACT

Patients on hemodialysis [HD] therapy are increasingly at risk for cerebrovascular ishcemic stroke. Alteration in cerebral blood flow [CBF] may in part contribute to cognitive impairment in HD patients. The study aimed at screening HD patients for assessment of CBF together with identifying the patient and dialysis related factors that could influence the changes in the CBF induced by the HD session. The study included 32 patients on regular HD. Before and after HD therapy; body weight, blood pressure, heart rate, serum urea nitrogen, hemoglobin, hematocrit and acid-base parameters were measured. Before and after HD therapy, transcranial Doppler examination [TCD] was performed to determine the mean flow velocity [MFV] in the middle cerebral artery [MCA] as an indicator of CBF. Wechsler Adult Intelligence Scale [WAIS] was carried out to evaluate some of cognitive functions before and after HD session. Serum lipids for each patient were obtained once before HD. The CBF and cognitive functions were reduced significantly after HD. A statistically significant inverse correlation was found between changes in CBF and increasing age [r=0.35, p=0.05], increasing intra-dialytic weight loss [r=0.63, p<0.001], increasing levels of hemoglobin and hematocrit [r=0.36, p=0.04], and decreasing both systolic and diastolic blood pressure [r=0.34, p<0.05]. There was a statistically significant correlation between MFV in the MCA and digit symbol subtest of WAIS [r=0.43, p<0.01]. HD patients with hypotension, increased intra-dialytic fluid removal and relative increased blood viscosity had decreased CBF after HD. It could be of value using TCD to monitor the decreased CBF in HD patients at risk to manage accordingly and to improve quality of the delivered dialysis session