Relationship between postoperative blood pressure change and renal pathophysiology in primary aldosteronism

32 patients with primary aldosteronism due to adrenal adenoma were studied to elucidate the relationship between blood pressure (BP) and renal functions before and after the removal of aldosteronoma. The relationship between either BP or renal functions and the structural changes of the renal biopsy specimens obtained at the operation was also examined. Renal function studies included serum urea nitrogen (BUN), creatinine, creatinine clearance (Ccr), phenolsulfonphthalein (PSP) test, and urine concentration test (max SG). Renal plasma flow (RPF), renal blood flow, and filtration fraction (FF) were measured. Serum sodium was significantly decreased and potassium was increased after the removal of the aldosteronomas. The levels of BUN, Ccr, PSP, and max SG were not significantly correlated to either pre- or postoperative BP levels, and to the improvement of hypertension after the operation. On the other hand, BP was significantly correlated with RPF and FF before surgery. Furthermore, the postoperative improvement of hypertension was correlated with the decrease of FF and the increase of hematocrit after surgery. The influence of duration of preoperative hypertension on BP response after adrenalectomy was not significant in the present study. The higher the BP level, the more marked histological changes were found. But, there was no relationship between renal functions and histological changes of renal biopsy specimens. The results indicate that RPF may participate in the hypertension of primary aldosteronism and that the BP level after surgery may be predicted by examination of the pathological changes present in the kidney.