K and HTN

Q: The relationship of potassium (K) level and hypertension (HTN) is ____________ proportional? - select one

A) directly

B) inversely 

Answer: B

Although sodium intake remains an essential target in hypertension management, considerable evidence suggests that a higher-normal K level significantly lowers blood pressure in patients with HTN (but has an insignificant effect on normotensive patients). Several mechanisms have been proposed to explain this relationship. 

Firstly, low K-intake reduces sodium excretion by activating the chloride-sensitive WNK (With-No-Lysine kinase) pathway, thereby activating the thiazide-sensitive NaCl cotransporter. Conversely, a high intake of potassium increases sodium excretion. Potassium "sensing" via basolateral potassium (K+) channels in the distal convoluted tubule plays a key role in these pathways.

Secondly, potassium modulates the renin angiotensin system, which is upregulated in the setting of hypokalemia.

Thirdly, hypokalemia causes vascular calcification and promotes arterial stiffness by inducing autophagy and promoting vascular smooth muscle calcification.

All forms of K, i.e., bicarbonate, citrate, and chloride, produce the same effect. None is superior to others.

#electrolytes

#CVS

#hemodynamics

References:

1. Aburto NJ, Hanson S, Gutierrez H, et al. Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ 2013; 346:f1378.

2. Binia A, Jaeger J, Hu Y, et al. Daily potassium intake and sodium-to-potassium ratio in the reduction of blood pressure: a meta-analysis of randomized controlled trials. J Hypertens 2015; 33:1509.

3. Poulsen SB, Fenton RA. K+ and the renin-angiotensin-aldosterone system: new insights into their role in blood pressure control and hypertension treatment. J Physiol 2019; 597:4451.

4. Furusho T, Uchida S, Sohara E. The WNK signaling pathway and salt-sensitive hypertension. Hypertens Res 2020; 43:733.