Role of carotid elasticity in arterial baroreflex function

Prof. Dr. Márk Kollai took a degree of M.D. at the Semmelweis University in 1969. He is currently a distinguished professor and head of Department of Physiology at our University. He is also in charge as vice-rector andas director of the Foreign Students’ Program. Professor Kollai acquired a PhD degree on a thesis about reflex mechanisms of the autonomic nervous system and a DSc title on his researches about cardiac autonomic nervous activity. The research interests turned him to the wide field of clinical physiology, studying the function of the central cardiovascular control as well as the regulation of large arteries. The outstanding publication achievements of Professor Kollai include more than 80 original articles in international journals. His is a member of numerous Hungarian and international societies. The accomplishment of his contribution to the advancement of clinical physiology has been recognized with several awards, including the prominent Jendrassik Award.

Abstract

Arterial baroreflex sensitivity is an established risk factor of cardiac mortality. Low baroreflex sensitivity results in increased cardiac sympathetic and reduced vagal activity levels, which can lead to arrhythmia and sudden cardiac death. Factors influencing baroreflex sensitivity (BRS), therefore, are of great clinical importance. Arterial baroreceptors are embedded in the wall of large elastic arteries and are activated by stretching of the vessel wall. In young healthy adults about 60% of BRS variability is accounted for by individual differencesin carotid distensibility, and these parameters usually change parallel. With increasing age and in hypertension impaired baroreflex function is associated with stiffening of the carotid artery. In young patients with end stage renal disease BRS and carotid distensibility are reduced, which abnormalities are largely reversed by kidney transplantation. BRS and carotid distensibility are reduced in the sedentary offspring of hypertensive parents, which abnormalities are prevented by exercise training. On the other hand, BRS is increasing in childhood in spite of gradual stiffening of the carotid artery; and also in young patients with congenital heart disease carotid artery stiffening is associated with normal age related BRS values. These phenomena might be explained by central autonomic neural maturationand adaptation mechanisms.