Renal Artery Stenosis – Plasma Renin	

The measurement of renal vein renin is important in the diagnosis of a haemodynamically significant renal artery stenosis (Fig. 10.12). The renin level in the renal vein that drains from the kidney on the opposite side to the stenosis should mimic the level in a peripheral blood sample taken simultaneously, thus indicating that the kidney is suppressed. There should be a gradient across the kidney on the affected side and, the ratio between the renal vein plasma renin activity on the affected side and the renal vein plasma renin activity on the normal side should be greater than 1.5:1. In patients with this pattern of renin secretion, renal artery surgery or transluminal balloon dilatation will probably reduce the blood pressure.