THE ROLE OF ARTERIAL HYPERTENSION IN THE FORMATION OF CEREBRAL HEMODYNAMIC DISORDERS IN PATIENTS WITH THYROTOXICOSIS

Background. This article examines the characteristics of cerebral haemodynamics in patients with thyrotoxicosis (TT), both with and without concomitant arterial hypertension (AH), and aims to determine the role of these factors in the development of haemodynamic disturbances. Materials and Methods. A total of 100 patients with TT, AH, and TT combined with AH, as well as 27 essentially healthy individuals, were examined. Using the transcranial duplex scanning method, we measured and analysed the linear blood flow velocity (LBFV) in intracranial vessels and the extracranial segments of the brachiocephalic vessels, the pulsatility index (PI), the resistance index (RI) and the total cerebral blood flow as the sum of the volumetric blood flow through both internal carotid arteries and the volumetric blood flow through both vertebral arteries. Results. In patients with TT, a statistically significant increase in LBFV, IR and IP were observed in the extra- and intracranial segments of the major arteries of the head and neck, which was more pronounced in patients with concomitant AH; this may indicate greater strain on haemodynamic compensatory mechanisms, marked dysregulation of vascular tone, and may complicate the course of the underlying disease in these patients. In the group of patients with TT and AH, a significant increase in total cerebral blood flow was also observed, suggesting that AH acts as an additional factor placing strain on the mechanisms compensating for cerebral blood flow, which may lead to their premature exhaustion. Conclusions. The results obtained suggest that AH should be regarded as an additional factor that significantly impairs cerebral haemodynamics, increases the risk of cerebrovascular complications and may lead to the rapid development of metabolic cerebral disorders in patients with TT.