Comparison of erythrocyte aggregability changes during ischemic and hemorrhagic stroke.

The aim of this work was to perform a comparative investigation of erythrocyte aggregability changes in the peripheral and cerebral circulation during ischemic and hemorrhagic stroke. Subjects of the present study were patients with ischemic brain infarcts (14 patients) and with hemorrhagic stroke (21 patients) from the Intensive Care Unit of the Institute of Neurology and Neurosurgery. The blood samples were obtained from the following blood vessels: the common carotid artery carrying blood to the primarily damaged brain hemisphere, both jugular veins carrying blood from the primarily damaged and the contralateral hemispheres, as well as from the cubital vein to obtain specimens of the systemically circulating blood. Erythrocyte aggregation was evaluated by using the "Georgian technique". We found that the RBC aggregation indices increased in both the regional as well as the systemic circulation of the hemorrhagic stroke patients as compared to ischemic stroke patients. The results of the present study demonstrate different changes of erythrocyte aggregation in ischemic and hemorrhagic stroke patients. Therefore, the role of blood rheological properties in their pathogenesis seems also to be different.

About spread of local cerebral hemorheological disorders to whole body in critical care patients.

PURPOSE: The aim of the present pathophysiological studies was elucidation of the feasible mechanism of spread of the blood rheological disorders from the cerebral to systemic circulation, and vice versa. METHODS: The investigation was carried out in the critical care patients with the brain tissue damage related to stroke (cerebral ischemic infarcts as well as parenchymatous and subarachnoid hemorrhages). The applied diagnostic techniques provided us with valid and quantitative data revealing the degree of the red blood cell aggregability, the value of local hematocrit, and the blood plasma viscosity in the cerebral and systemic circulation. In addition, rabbits experiments were carried out for analysis of the hemorheological disorders associated with the brain damage. RESULTS: Despite the local character of the patients primary brain damage, the hemorheological disorders were found regularly spread not only over the cerebral hemispheres, but even also the systemic circulation. Under such conditions they might cause the generalized brain tissue damage and play significant role in the subsequent damage-cascade of the whole brain. In addition, the rabbits experiments demonstrated pronounced hemorheological disorders in the cerebral cortex capillaries: increase of their numbers with RBC enhanced aggregation and blood stasis, as well as with lowering of the RBC deformability in the narrow capillary lumina. These changes befell simultaneously with increase of water contents in the cerebral tissue evidencing for edema development in the brain. CONCLUSION: Local cerebral hemorheological disorders might spread over the whole brain via the systemic circulation, thus promoting a generalized brain damage and being responsible for the critical state of the patients.

Blood rheological properties and lipid peroxidation in cerebral and systemic circulation of neurocritical patients.

The present study was aimed at investigating the red blood cell (RBC) aggregation and the parameters of lipid peroxidation - malondialdehyde (MDA) and MDA + 4-hydroxyalkenals (HAE) - in the blood of critically deteriorated stroke patients (brain infarcts, parenchymatous and subarachnoid hemorrhages) and in the control group. Measurements were made in blood samples from the common carotid artery, the both internal jugular and cubital veins. The RBC aggregation index was found to increase by about 80 per cent in both the cerebral and systemic circulation as compared to the control blood samples. MDA content appeared also significantly higher in the blood flowing out of the damaged hemisphere of the neurocritical patients as compared to the control group. In the blood flowing out of the damaged hemisphere of the neurocritical patients MDA as well as MDA + HAE content significantly exceeded the values found in blood samples of the jugular vein of the contralateral hemisphere, carotid artery and the cubital vein. The results of this study suggest a certain interdependence between the blood plasma lipid peroxidation and the RBC aggregation in the brain vessels following its damage.