Some studies in renal hypertension

Kidney Function after Renal Revascularization for Hypertension

Kidney function was evaluated in 53 patients with renal arterial hypertension before and after renal revascularization and was correlated with changes in blood pressure. Data were derived from an analysis of personal observations and of findings reported by others.

Revascularization produced a significant decrease in blood urea nitrogen and serum creatinine in 13 azotemic patients. It did not significantly affect glomerular filtration rate when normal in 20 patients, but caused a rise in renal blood flow in three patients. Improvement in renal function was more closely correlated with preoperative functional status than with cure of hypertension.

Glomerular filtration rate and renal blood flow increased significantly in the revascularized kidney, but decreased in the contralateral kidney. Urine flow and sodium concentration in the revascularized kidney rose to levels equal to, or greater than, those in the contralateral kidney. The preoperative disparity in urine osmolality between kidneys was narrowed, whereas the concentration of nonresorbable urine solute became equal to, or lower than, that of its mate postoperatively. In most cases, the Howard test reverted to negative. The tubular rejection fraction ratio of sodium became normal or suggested contralateral renal arterial disease. The only functional differences between patients whose hypertension was cured and those whose blood pressure failed to respond to revascularization related to glomerular filtration rate and the Howard test.

Impairment of function of the contralateral uninvolved kidney was rarely observed after surgery. The revascularized kidney frequently exhibited excessive natriuresis and diuresis, independent of changes in systemic blood pressure or glomerular filtration rate.