New aspects of cerebrovascular diseases in dialysis patients.

Growing evidence suggests that chronic kidney disease is a significant risk factor for stroke, subclinical cerebrovascular abnormalities, and cognitive impairment, independent of known cardiovascular risk factors. Cerebrovascular disease is also a major cause of death in dialysis patients, who have a much higher incidence of stroke compared to the normal population. Strokes in dialysis patients are also characterized by a higher incidence of hypertensive intracerebral hemorrhage compared with those in the general population. Recent studies on dialysis cohorts have shown that asymptomatic cerebrovascular diseases, including silent cerebral infarction (SCI), white matter hyperintensities (WMHs), and cerebral microbleeds (CMBs), are related to future onset of stroke, cognitive impairment, and dementia. Magnetic resonance imaging studies have revealed a higher prevalence of SCI in hemodialysis patients compared with that in controls, and a subsequent longitudinal study found that SCI is a risk factor for stroke and cardiovascular events as a whole. Other studies have shown that the prevalence of WMHs is significantly higher in dialysis patients than in healthy subjects and that WMHs are a risk factor for cardiovascular events. There is also a high prevalence of CMBs in hemodialysis patients, but the clinical significance of CMBs in these patients has not been examined in a longitudinal study. The incidence of cognitive impairment and dementia in dialysis patients is also twice as high as that in age-matched healthy subjects, and dialysis patients tend to have vascular-type dementia rather than Alzheimer-type dementia. More studies in dialysis patients are required to examine the prevention of stroke, cognitive impairment, and dementia in these patients.