MECHANISM OF PRESSOR NATRIURESIS IN PATIENTS WITH ESSENTIAL HYPERTENSION STAGE II. WITH DIFFERENT VARIANTS OF THE CIRCADIAN STRUCTURE OF THE BLOOD PRESSURE

Objective – to improve the diagnosis of impaired pressure- induced renal mechanisms in patients with stage II essential hypertension (EH) under different circadian blood pressure (BP) rhythm variants. Materials and methods. A comprehensive examination was conducted on 86 patients with stage II essential hypertension, classified as grade II-III arterial hypertension. The study included 54 males and 32 females. All patients underwent 24-hour ambulatory blood pressure monitoring (ABPM) using the «Solvaig» device. On the day of ABPM, urine samples were collected from each patient to determine sodium ion concentration using ion-selective electrodes on the SINO-005 device (China). Based on these data, the daily sodium excretion was determined. The effectiveness of the mechanism of pressure natriuresis was assessed by calculating the ratio of daily sodium excretion in urine to the mean daily systemic blood pressure. Results. Among the 86 patients, circadian blood pressure rhythms were observed as follows: Dipper in 34 patients, Non-dipper in 41 patients, and Night picker in 11 patients. The Non-dipper group was the most prevalent, comprising 60.5% of the study population. In patients, the daily excretion of sodium ions differed among the comparison groups: Dipper, Non-dipper, and Night picker, respectively: 178.5 ± 7.89; 165.9 ± 5.10; 154.4 ± 1.98 (mmol), with a significant difference in the Night picker group compared to the Dipper group (p<0.05). The average 24-hour mean arterial pressure in patients from the Non-dipper and Night picker groups was significantly higher than in the Dipper group: 103.9 ± 1.39 and 104.4±1.84 vs. 98.9±1.12 mm Hg (p<0.05). The pressor natriuresis ratio calculated by groups was significantly lower in patients with a low and negative daily index (compared to the Dipper group – 1.82 ± 0.07; Non-dipper – 1.64 ± 0.10; Night picker 1.53 ± 0.03 (p<0.05)). We propose a table for calculating the pressor natriuresis coefficient to assess objectively the degree of disturbance in the pressor natriuresis mechanism, diagnose volumedependent forms of hypertension, and monitor the effectiveness of treatment. Conclusions. According to 24-hour blood pressure monitoring, most patients with Stage II essential hypertension (60.5%) demonstrated a circadian rhythm of blood pressure as «Non-dippers.» In these patients, reduced diuresis and natriuresis were observed compared to the Dipper group and normotensive individuals. The calculation of the pressor natriuresis coefficient in clinical practice enables the diagnosis of volumedependent hypertension and the administration of individualized diuretic therapy and combination treatments.