Renal vein renin measurements in children with hypertension.

Renal venous renin activity was measured in 50 children with hypertension. Main renal vein and segmental renal vein sampling was feasible in children as young as 15 months. In all cases in which there was a clear difference in renin secretion between the kidneys--that is, a main vein renin ratio above 1.5--surgery, when undertaken, successfully restored normal blood pressure. Most of the children with main renal vein renin ratios below 1.5 had bilateral disease or apparently normal kidneys. Segmental renal vein sampling contributed useful information additional to that provided by main renal vein measurements and permitted identification of local sources of renin production. In children with renal transplants who developed hypertension renal vein renin measurements helped in determining the cause and facilitating the management of the raised blood pressure.