**1.1 Cerebrovascular disorders in patients undergoing long-term programmed hemodialysis (HD)**

Cerebrovascular disorders in patients with CKD of the pre-dialysis and dialysis periods are usually classified as acute (transient ischemic attacks, ischemic and

#### *Specific Cerebrovascular Risk Factors, Colon Microbiocenosis and Its Correction in Patients… DOI: http://dx.doi.org/10.5772/intechopen.101300*

hemorrhagic strokes, subarachnoid hemorrhages) and chronic cerebrovascular diseases (chronic cerebral ischemia due to various variants of vascular cerebral microangiopathy (CMA), including cerebral amyloid angiopathy (CAA) and/or calcifying uremic arteriolopathy).

The remodeling of the micro- and macrocirculatory cerebral vessels continues in patients with dialysis stage of CKD, new vascular risk factors directly related to the dialysis procedure are aggravated and added, and cerebrovascular disorders progress [6]. It has been established that CKD and dialysis are also the causes of the development of CMA, which underlies the development of vascular cognitive impairments and acute cerebrovascular pathology. CMA is characterized by the damaged cerebral microvasculature (perforating cerebral arterioles, capillaries and venules) and damage of the white matter and brain nuclei [7–9]. In our studies, neuroimaging signs of CMA of varying severity were found in 100% of the examined patients who had been receiving renal replacement therapy with the long-term programmed HD. Expansion of perivascular spaces (100%) and white matter hyperintensity (81.4%) prevailed in the structure of MR signs of CMA. Cortical atrophy (67%), cerebral microbleeds (47%), asymptomatic lacunas (35.7%) and small subcortical infarctions (2.9%) were somewhat less common.

In dialysis patients, the risk of stroke and chronic cerebrovascular accidents increases multiple times, the risk of developing cognitive impairment is aggravated, and the quality of life of dialysis patients decreases [10, 11]. According to a metaanalysis conducted by Etgen in 2012, CKD is a statistically significant independent somatic risk factor for the development of cognitive impairment [12]. Epidemiological studies have also revealed a clear relationship between a decrease in glomerular filtration rate and high cardiovascular mortality in dialysis patients [13, 14], the proportion of which is extremely high among patients on renal replacement therapy [15]. According to our data, in patients undergoing programmed HD for more than 1-year, cognitive impairments were found much more often (75.5–81.1% of cases, *p* = 0.05) compared with people without renal pathology. The presence of ESRD and the presence of a patient on programmed HD, regardless of gender and educational level, can directly affect the development of cognitive impairment. For the screening assessment of the neuropsychological status of dialysis patients, the timely use of various neuropsychological scales is necessary: in particular, the use of the SLUMS and MoCA scales is possible. The risk factors for the development of cognitive impairment in persons receiving programmed HD can be considered an increase in the dialysis experience and the age of patients, as well as a low calculated dialysis adequacy index for urea (Kt/V less than 1.4).

In general, the problem of acute and chronic cerebrovascular disorders in dialysis patients remains the most urgent. Description of the spectrum of risk factors for cerebrovascular pathology in dialysis patients and effective control over them seems to be an effective strategy aimed at increasing the duration and quality of life in patients receiving renal replacement therapy.
