OBJECTIVE: The aim of the study was to establish the concentration of blood pressure regulating hormones in premenopausal women with isolated systolic hypertension (ISH) related to hyperthyroidism (HT).
MATERIAL AND METHODS: 61 females with HT were enrolled in the study, including 28 with ISH (Group A), 33 with normal arterial blood pressure (Group B) and 34 healthy individuals (Group C). It was determined - plasma renin activity (PRA), plasma concentration of arginine vasopressin (AVP), atrial natriuretic hormone (ANH) and aldosterone (Aldo). PRA and Aldo tests were performed twice, firstly under basal conditions and then after a 3-day low-sodium diet. In hyperthyroid patients tests were repeated during thyreostatic treatment. Patients with sodium-sensitivity of blood pressure were selected. Cardiac index (CI) and total peripheral resistance index (TPRI) were calculated.
RESULTS: In ISH patients the basal PRA was lower than in patients of Groups B and C. The highest poststimulatory PRA was observed in patients of Group B. ANH concentration was higher in both HT groups compared to the Group C. AVP concentration in ISH patients was higher than in Group C. In HT patients blood pressure correlated with basal PRA, CI and TPRI. Sodium sensitivity of blood pressure was observed more frequently in patients from Group A.
CONCLUSIONS: In women, ISH in HT is the consequence of the increased cardiac output and the decreased peripheral vascular resistance. ISH related to HT results in the reduction in basal PRA probably as the result of intensified cardiac ejection function. ISH in hyperthyroid patients shows a higher sodium-sensitivity.