Relation between renin release and blood pressure response to nonsteroidal anti-inflammatory drugs in hypertension.

This issue of Hypertension features an article by Imanishi and colleagues entitled "Aspirin Lowers Blood Pressure in Patients With Renovascular Hypertension." In their study, Imanishi and coworkers compared the effects of intravenously administered aspirin on arterial blood pressure, plasma renin activity in the renal veins and aorta, and plasma levels of prostaglandin E2 in the renal veins and aorta of six patients with unilateral renovascular hypertension and six patients with essential hypertension. Renovascular hypertension was defined by digital subtraction angiography and a renal vein plasma renin activity ratio (stenotic side/normal side) greater than 1.5. In patients with renovascular hypertension, the level of prostaglandin E2 in the renal vein draining the stenotic kidney was elevated compared with the prostaglandin E2 level in the renal vein draining the nonischemic kidney. In contrast, prostaglandin E2 levels were similar in the left and right renal veins in patients with essential hypertension. Intravenous administration of aspirin lowered prostaglandin E2 levels at all sites in both groups of patients, lowered aortic levels of plasma renin activity in both groups of patients, and reduced the renal vein plasma renin activity ratio in renovascular hypertensive patients to less than 1.5. Interestingly, in patients with renovascular hypertension, aspirin reduced arterial blood pressure by 10 mm Hg. In contrast, aspirin significantly increased blood pressure by 4 mm Hg in patients with essential hypertension.