Search

Aim: To study a relationship of arterial hypertension (AH) severity with the cerebral blood flow and structural changes in the brain matter, processes of lipid peroxidation and antioxidant defense, parameters of homeostasis, indicators of endothelial dysfunction and apoptosis., Material and Methods: A complex study of 84 patients with AH, aged from 43 to 64 years, was carried out., Results and Conclusion: The severity of atherosclerotic damage increased with the increasing of the AH degree. There were the sings of cerebral atrophy, changes in the white matter of brain hemispheres accompanied by the increase of oxidative stress and insufficient antioxidant activity, appearance of procoagulation shifts in the homeostasis system, along with the moderate activity of fibrinolysis, increase in the level of proinflammatory cytokines and markers of apoptosis, endothelin-1, decrease in nitrogen oxide concentration.

We studied the effect of deproteinized hemoderivative of calf blood, thioctic acid and vinpocetine with piracetam on the endothelial function in patients with chronic cerebral ischemia stage III. After pharmacological treatment, there was the improvement in the endothelium properties of both large and small blood vessels. The index of occlusion that characterized the function of small vessels reached normal values while the phase shift did not approach to the reference values. This notion indicates that in cerebral atherosclerosis small arteries initially are subject to alterations to a lesser extent compared to the arteries of large and medium caliber. The most effective medicines of those used for the correction of endothelial dysfunction are deproteinized hemoderivative of calf blood and thioctic acid.

To determine the peculiarities of clinical presentations of vertebrobasilar transient ischemic attacks in elderly and aged patients (42 patients aged 61-90 years) have been studied using clinical, laboratory, neuroimaging and ultrasound methods. Hemodynamically significant stenosis of vertebral or basilar arteries caused by atherosclerosis was found in 16 patients. It was associated with hypoplasia or kinking of vertebral arteries in 4 patients. Six patients had atrial fibrillation, 15 isolated arterial hypertension and 4 an unspecified type of the disease. Transient ischemic attacks in patients with hemodynamically significant stenosis of vertebral or basilar arteries were characterized by the highest rate and shortest duration of repeated attacks. The most severe clinical course was characteristic of transient ischemic attacks in patients with atrial fibrillation. It was featured by the longest duration of symptoms, highest rate of vision loss, limb numbness and weakness during the attack, high rate of focal neurological signs and high rate of old cerebral infarcts and vascular white matter abnormalities on neuroimages as well as the elevated plasma level of C-reactive protein. Transient ischemic attacks in patients with isolated arterial hypertension were characterized by relatively mild clinical course of the disease.

A study of the functional state of cerebral hemodynamics using transcranial dopplerography and blood excitotoxic amino acids, playing an important role in the pathogenesis of ischemic brain damage, has been carried out in 43 patients with atherosclerotic lesions of the carotid arteries. Neurological deficit that developed as a result of ischemic stroke was related to the changes of cerebral hemodynamics (a decrease of hemodynamic reserve and blood flow velocity in the middle cerebral artery) and an increase of the level of blood amino acids involved in excitotoxic mechanisms of the nerve tissue lesions in brain ischemia. These biochemical disturbances in the non-acute period of ischemic stroke may be explained by the state of chronic excitotoxicity that developed because of blood circulation insufficiency in the brain and a decrease of cerebrovascular reserve. The authors admit that genetically determined features of cerebral metabolism of excitotoxic amino acids, concomitant with their higher release to the extracellular space, along with hemodynamical disturbances, may be risk factors of ischemic brain lesion when cerebral blood flow decreased as a result of stenosis or occlusion of the carotid arteries. This should be taken into account for elaboration of complex methods of neuroprotection in atherosclerosis of the great brain arteries.

Using a complex of ultrasonic methods, vertebral basilar system hemodynamics has been evaluated in normal state and in case of vertebral basilar insufficiency (VBI). The differential diagnostic criteria of atherosclerotic and vertebrogenic types of VBI development have been obtained that enables to individualize the therapeutic approaches.

Based on the data of examination of 224 patients with different stages of cerebral ischemic disturbances (CID) and 84 age-matched controls, an artificial neuronal network was constructed and tried in differential diagnosis of CID stages according to the data of transcranial ultrasonic dopplerography. Diagnostic efficacy of the network was 80% for sensitivity, 100% for specificity and 82.7% for reliability. A modeling of the influence of the main risk factors for cerebral ischemia and of the reserve state of cerebral hemodynamics for establishing the stage of CID was performed.

The influence of smoking on cerebral hemodynamics and biochemical blood indices has been studied in 50 male patients with chronic insufficiency of brain circulation (CIBC), aged 40-50 years, divided into 2 groups: smoking (n=26) and nonsmoking (n=24). Smoking was shown to play a substantial role in the development of discirculatory encephalopathy with atrophic brain changes, causing metabolic disturbances (a shift of acid-basic balance towards acidosis) and microcirculation disorders due to altered cerebrovascular reactivity. These alterations develop previously to hemodynamically significant atherosclerotic arteries lesion and emerge irrespective of the presence of atherosclerotic vascular changes, atherogenic shifts of lipid metabolism, disturbances of free-radical processes and platelet aggregation.

A knowledge of time parameters of the high mental functions of the brain under normal and pathological conditions may serve as a key to understanding of their intimate mechanisms. During the first stage of the study a set of different tests including "word association", "paired words learning" was used to compare these indices in patients with atherosclerotic discirculatory encephalopathy and in normal individuals. The dynamics and volume of the short-term memory and processes of attention were evaluated. An increase of the response latencies in the paired words' tests and a decrease of both volume of short-term memory and the processes of attention were identified. Application of the tests with semantically similar or unlike words was informative.

More accurate definition of the leading factors of development of discirculatory encephalopathy (DE) in patients with arterial hypertension was the aim of this investigation. The analysis of correlations between clinical and computer tomographical symptoms of DE on the one hand and the indices of central hemodynamics, head blood circulation and presence of atherosclerosis of head arteria on the other hand was performed. It was found that congestion in head venous system was the main factor in DE development. The conclusion was made that both atherosclerosis of head arteria and arterial hypertension promoted venous congestion in head by means of decreasing the amplitude of arterial pulsation and in turn the development of DE. Meanwhile, the increase of minute blood flow prevents it.

The data about the role of blood flow in atherosclerosis development were examined. The aim of the study was determination of hydrodynamic blood resistance and Toms effect in patients with ischemic disorders of cerebral circulation in different periods of the disease. 45 patients with atherosclerotic damages of major arteries of head were observed. Such damages were combined with arterial hypertension in 32 individuals. The value of hematocrit, asymptotic viscosity, hydrodynamic resistance and Toms' effect were determined in blood as well as levels of cholesterol, beta-lipoproteins and platelets. The presence of Toms' effect was found in blood samples of both patients and controls. There was a significant increase of hydrodynamic blood resistance in all the patients as compared to control group. The patients with ischemic disorders of cerebral circulation were compensated by their own blood factor in less degree in acutest and acute periods than later. Low values of Toms' effect in separate patients were prognostic sings for good restoration of neurologic functions; higher values were observed in patients with arterial hypertension. The conclusion was made that hemodynamic properties of blood flow may be considered as predictors of the severity of the course of cerebral circulation disorders.

The microcirculatory state (by the method of conjunctival biomicroscopy) and ADP-induced platelet aggregation were examined in 42 patients with atherosclerotic and 34 patients with involutional depression both before and after the treatment which included vasoactive preparations and calcium antagonists. It was determined vascular and intravascular alterations predominance and increase of platelet aggregation in patients with atherosclerotic depression independently of leading syndrome, in patients with involutional depression with anxiety prevalence as well as in patients in stuporous state. The tendency was revealed of such disturbances increasing as for as psychosis was extended. Trental and Cavinton antiplatelet and spasmolytic properties were potentiated by inclusion of Corinfar in complex therapy and that promoted earlier microcirculatory alterations removal as well as aggregatograms and patient mental state normalization.

The authors studied intracranial hemodynamics in atherosclerotic dyscirculatory encephalopathy (DCE) using extra- and intracranial ultrasound examinations, discuss stage-specific clinical features of DCE, evaluated extracranial arteries, measured collateral blood flow and linear blood flow rate along the intracranial arteries depending on DCE stage.

The paper shows that intravenous administration of trental, curantil, cavinton and sermion to cerebrovascular deficient patients causes a decline in blood circulation rates in the extracranial part of the carotid arteries. Sermion exhibited a biphase reaction: an increase in the blood flow followed by a decrease 15-30 minutes after introduction in the carotid arteries. Trental and curantial act in the intracranial arteries as moderate vasodilators reducing blood flow speed and blood vessel resistance. Cavinton activates intracranial blood flow, especially in the cortical segments of the middle cerebral arteries. Sermion initially increases blood flow rate in the middle cerebral arteries, than decreases it, especially in segments M2 and M3. Cavinton and sermion intravenous infusions are beneficial in cases of arterial hypertension.

The screening of the random sample from an open population of males aged 40-65 was performed to compare frequency and severity of hemodynamic changes in major head arteries (MHA) due to atherosclerosis in subjects with vascular diseases and clinically normal controls. 866 of the examinees were subjected to MHA ultrasonic dopplerography. Normal circulation appeared only in 13% of the examinees. The rest of them had insufficient circulation or at least one vessel affected with stenosis. The standard index of MHA stenosis amounted to 20.2%. The frequency of MHA stenosis was related to the age, vascular involvement and severity of the latter.

Pentoxifylline versus nicergoline therapy has been studied in 56 patients with atherosclerosis of major cerebral arteries who had ischemic apoplexy. Pentoxifylline enhances circulation primarily in the stenotic vessels, while nicergoline in the intact cerebral arteries. The former is more potent in inducing antiaggregation inhibiting spontaneous platelet and red cell aggregation and reducing blood viscosity. The results of the study suggest better response in case of pentoxifylline treatment of patients with hypo- and eukinetic circulation, while in nicergoline treatment hyperkinetic hemodynamics patients benefit more in view of the drug cardiodepressive activity.