Complex equilibrium involving aldosterone underlies the pathophysiology of renovascular hypertension.

The mechanisms underlying the maintenance of hypertension in renovascular hypertension (RVH) are not well understood. To test the current concept of RVH pathophysiology, circulating aldosterone levels in clinical cases were investigated through a literature survey of pediatric cases. Fifty-four patients with documented aldosterone levels were identified. Of these, 42 patients (78%) were assigned to the high renin (HR) group and the rest to the low-normal renin (LR) group. Patients in the HR group were more likely to have unilateral lesions (35/42) than those in the LR group (6/12). In the LR group (corresponding to volume-dependent RVH), 50% (6/12) of patients had elevated aldosterone levels, indicating that the equilibrium between renin and aldosterone shifted towards aldosterone dominance. In the HR group (corresponding to renin-dependent RVH), aldosterone levels were much higher, with 76% (32/42) of patients exceeding the reference range and 14 patients developing hypokalemia. These results are consistent with the notion that pressure natriuresis allows continuous aldosterone action in renin-dependent RVH. In conclusion, the aldosterone status observed in the clinical cases is in agreement with the current understanding of the pathophysiology of RVH, in which a complex equilibrium state involving renin, angiotensin-II, pressure natriuresis, and aldosterone exists.