Abstract P039: The Endogenous Ouabain And Changes In Blood Pressure And Sodium Excretion Following An Acute Saline Load In Essential Hypertension
Among ~25% of patients with essential hypertension (EH), circulating endogenous ouabain (EO) and aldosterone (Aldo) are typically coelevated and their BP is especially salt-sensitive (SS). We probed for exaggerated natriuresis in a large cohort (712) of hypertensive patients that underwent an acute 2hr (T 120 ) load with saline (0.9%/2 L). Results: Using a quartiles analysis of sodium excretion, the 4th quartile subgroups showed higher SBP and DBP at T 120 , and at 2 hrs recovery (T 240 ). Fractional sodium excretion (FE Na) was significantly higher during loading and recovery in the 4 th quartile subgroup. Plasma Aldo was suppressed after saline in all subgroups as expected. SS patients showed an increased EO. In the 4 th quartiles EO was elevated at baseline and after saline (see figure), p Manova > 0.001 and the urinary Na/K ratio output was higher. Further, increases in plasma Na + were greater in the 4 th quartile group (1.91 ± 0.15 vs 0.83 ± 0.13 mM, p<0.001). These data suggest circulating EO is a potential mediator of the exaggerated natriuresis in SS EH, and that this phenomenon is reminiscent of an “aldosterone escape”.