Development of a method to discriminate salt sensitivity in hypertension by single-nephron blood flow (SNBF) index and new insights into the relationship between SNBF and hypertension.

Abstract

Abstract More than 95% of hypertensive patients have essential hypertension, which can be divided into salt-resistant hypertension (SRH) and salt-sensitive hypertension (SSH). They differ in several aspects. If they can be easily diagnosed, treatment, complications and prognosis can be improved. But there is no easy way to differentiate them. We focused on renal salt excretion process and renal blood flow (RBF). RBF of SRH decreases by increasing renal vascular resistance, and RBF of SSH increases by fluid accumulation for decreasing salt excretion efficiency. Since both can be distinguished by measuring RBF, we created a renal blood flow index using uric acid. Then, we divided RBF into 2 categories: whole renal blood flow (WRBF) and single-nephron blood flow (SNBF). We studied in 26 SRH and 16 SSH patients from 3/1/ to 30/11, 2018. SSH was higher than SRH in WRBF and SNBF, with no significant difference in WRBF (81.3±29.8 vs 73.3±32.4, p=0.43), but significant difference in SNBF (1.94±0.75 vs 1.04±0.39, P<0.01), suggesting that SNBF can distinguish SSH and SRH. Therefore, SNBF allows differentiation between SRH and SSH, and this study showed that essential hypertension is an abnormal condition in which SNBF is increased or decreased from the physiological range of SNBF.