IMPORTANCE OF STRUCTURE OF ATHEROSCLEROTIC PLAQUES AND DEGREE OF STENOSIS OF THE INTERNAL CAROTID ARTERY IN THE CLINICAL PICTURE OF ISCHEMIC DISORDERS OF CEREBRAL CIRCULATION

D.N. Djhibladze, A.V. Pokrovsky, Yu.M. Nikitin, O.V. Lagoda
Research Institute of Neurology, Russian Academy of Medical Sciences,
A.V. Vishnevsky Research Institute of Surgery,
Russian Academy of Medical Sciences,
Moscow, Russia

Ischemic disorders of cerebral circulation are caused most frequently by diverse lesions of the carotid arteries. The mechanism by which stenosis of the carotid arteries manifests itself in focal neurologic symptomatology has not been specified to its conclusion. If the appearance of the symptoms is to be considered the result ofhypoperfusion, the leading part in these cases should be played by the degree of internal carotid artery stenosis; provided that the symptoms are determined by arterioarterial emboli, the structure of an atherosclerotic plaque may be a nore significant factor. The purpose of the study was to analyse the relationship between the clinical picture, the degree of stenosis and the structure of an atherosclerotic plaque and the influence they produce on the pathogenesis of ischemic disorders of cerebral circulation. An analysis was made of the data on 90 patients with internal carotid artery stenosis of varying severity. Of these, 64 patients had transient or stable disorders of cerebral circulation to the carotid vascular bed and 26 presented with symptom free stenoses of the carotid arteries. All the patients underwent ultrasound Doppler, duplex scanning of the carotid and vertebral arteries, computed tomography of the brain, and angiography of the great arteries of the head. Each group was analysed for the relationship between the clinical manifestations and the degree of stenosis, the relationship between the structure of atherosclerotic plaques and the clinical manifestations as well as for the relationship between the degree of stenosis and the structure of atherosclerotic plaques in the internal carotid artery. Isolated stenosis of the carotid artery of varying severity was diagnosed only in 14% of cases in both groups of "symptomatic" and "asymptomatic" patients. In patients with stenoses of minor degree, no heterogeneous atherosclerotic plaques were identified. Meanwhile an ever increasing number of the plaques assumed a heterogeneous structure with the growth of the stenosis degree. The mechanism by which arterioarterial emboli are formed can be realised in carotid stenosis of any degree and may be associated only with the structure of an atherosclerotic plaque. Transient circulatory disorders are associated most clearly with the structure of an atherosclerotic plaque that narrows the lumen of the carotid artery. The patients' group presenting with such disorders is at the highest risk of stroke.

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