Differential Renal Function Studies During Mannitol Diuresis in Hypertension

Abstract

Differential renal function studies during mannitol diuresis were performed in patients with essential hypertension and hypertension secondary to main renal artery stenosis. Brisk urine flow rates with reproducible flow ratios between the two kidneys were obtained in most studies. Functional differences of more than 15% between the kidneys were demonstrated in 56% of the patients with essential hypertension. Nevertheless, the mean differences for urine flow, osmolality, osmolal clearance, total solute excretion, creatinine and sodium concentrations in urine, sodium and potassium excretion rates, and tubular rejection fraction of sodium were significantly less than those seen in renal artery hypertension. All the latter patients showed excessive water and sodium reabsorption by the ischemic kidney and were sharply differentiated from patients with essential hypertension.