REN and hypertensive disorder: This approach suggests that patients with low-renin, volume-dependant hypertension (PRA < 0.65 ng/ml−1/h−1) should be treated with an “anti-volume” drug such as a diuretic whereas those with high-renin vasoconstriction hypertension (PRA > 0.65 ng ml−1 h−1) should be managed with an antagonist of the renin-angiotensin system such as an ACE inhibitor [11].