ETIOLOGICAL FACTORS OF NEUROLOGICAL COMPLICATIONS IN MODERN CARDIAC SURGERY PRACTICE. CONCEPTS AND GROUND CONCEPTS

Abstract

SUMMARY. The initial study is devoted to the issues of structural and functional priming of etiopathogenetic complications of modern cardiac surgery interventions in patients with neurological pathology. The author analyzes the historical and social omissions of the rapid development of cardiac surgery in the second half of the twentieth century, emphasizes the importance of the latter as a derivative of modern intensive care, defines the role and importance of the latter methodological arsenal of artificial blood circulation, BC. Due to this, it was possible to perform radical reconstructive and bypass operations for severe heart and aortic diseases. However, the primary stage of knowledge and skills accumulation was accompanied by analysis and generalization of manifestations of nervous system dysfunction/deep lesions (coma, cerebral edema, pareses/paralysis, structural and functional changes of cerebral substance). The latter inevitably stimulated the search of etiopathogenetic factors of psychoneurological pathology as a side effect of cardiac surgical interventions.

The aim – to substantiate the role and importance of etiological factors of neurological complications in the modern practice of cardiac surgery.

Material and Methods. Data of complex clinical and anamnestic examination of patients in the preoperative period (n₂=118 persons) hospitalized in the corresponding department of the State Institution «Heart Institute of the Ministry of Health of Ukraine». A special thematic patient chart was an integral part of the primary material. The symptomatology and syndromology of asthenic (n_2.1=48 persons), astheno-anxiety (n_2.2=31 persons), astheno-subdepressive (n_1.3=24 persons), and disomic (n_1.4=15 persons) manifestations were studied in detail. To objectivize information for the purpose of in-depth grounding of the work, we applied resources of retrospective analysis from our own databases and previously accumulated annals of materials corresponding to the theme and tasks of the study. Data search was obligatorily performed on known databases (Google, Yandex, etc.).

Results. Gruntation of etiopathogenetic potential of neurological complications by cardiosurgical interventions proved the presence of leading four groups of factors. Myogenic regulation of cerebral blood flow, based on the works of W. Folkow, V.I. Acute and brilliantly confirmed by the research practice of A. Bayliss. The essence of the mentioned concept is focused on the activity of vascular smooth muscles as mechanoreceptors (their tension leads to increase of the frequency of action potentials generation, spreading of the latter to neighboring cells, further growth of vascular tone, reduction of arterial opening). The cerebral blood flow is maintained at a constant level, it does not depend on fluctuations of the systemic BP. The second priming: humoral-metabolic regulation (related, on the one hand, to the regulatory response to vasoactive substances: adenosine, histamine, serotonin; on the other hand, to changes in pH environment (products of tissue metabolism). The third priming is focused on neurogenic/autoregulation of blood circulation (announced in the studies of E. Dahl and E. Nelson, M. Rennels, S. Sato with establishment of polymorphism of efferent innervation of cerebral vessels). The final postulate belongs to peculiarities of cerebral blood flow of the elderly, there is a start of polymorphism of pathological processes (decrease of parameters of general circulation, compensatory mechanisms, development of relative respiratory insufficiency).

Conclusions. Based on the results of clinical and anamnestic studies, it has been found out that the etiological factors of the most frequent neurological complications of modern cardiac surgery practice are myogenic, humoral-metabolic, neurogenic regulation of cerebral blood flow, which distinctly potentiate age-related systems. The basis of the above biological algorithm lies in the metabolic needs of the brain and is focused on the maintenance of stable perfusion pressure under fluctuating systemic arterial parameters.