REN and congestive heart failure: In patients with type 2 CRS, hemodynamic changes induced by CHF cause the activation of renin-angiotensin-aldosterone system and release neurotransmitters including nitric oxide (NO), BNP and AngII, which can subsequently lead to renal vasoconstriction, hypoxia, cytokine release, inflammation, and renal fibrosis (Jois and Mebazaa, 2012).