262
The most important thing is to acknowledge that BP in CKD is very closely
related with salt and salt intake in CKD patients. This relationship between salt and
BP is also valid in patients with RHT in which salt is thought to play a major role in
the development of RHT, a condition known as “salt sensitivity.”
But how does salt induce RHT? To answer this question one must first know the
normal physiology. Under normal physiologic conditions with healthy kidneys,
there is autoregulation of BP after salt intake within certain limits. This means that
under normal physiologic conditions, a high sodium intake drives sodium excretion
by increasing blood volume, BP, cardiac output, and filtered sodium load [ 26 ]. This
classical concept known as pressure-natriuresis describes the association between
BP and sodium balance. As CKD develops and advances, this physiologic adapta-
tion is lost gradually and kidney damage alters pressure-natriuresis curve and results
in positive sodium balance with increased salt intake. This is due to fact that, as
Fig. 16.1 Factors related with the development of resistant hypertension (CNS central nervous
system, RAS renin angiotensin system)
B. Afsar and A. Kirkpantur