EARLY SYSTEMIC AND RENAL RESPONSES TO NEPHRECTOMY IN NORMOTENSIVE KIDNEY DONORS

The present studies were designed to assess the effect of uninephrecto my (UNX) on arterial pressure and renal excretory function in normal s ubjects. Baseline values of arterial pressure, renal function, paramet ers of the renin-angiotensin and renal kallikrein kinin systems and th e response to acute saline loading (VE, 1800 ml in 3 h) were estimated in 18 kidney donors prior to and 1 year following UNX. Within the fol low-up period of 14 +/- 1 months mean arterial pressure (MAP) increase d by 7 +/- 2 mmHg, creatinine clearance decreased by 38 +/- 4%, plasma renin activity (PRA) decreased, urinary kallikrein remained unchanged , and the renal response to VE was blunted. According to individual ch anges in MAP associated with UNX, subjects were classified as responde rs (R, increase in MAP greater-than-or-equal-to 10%, n = 8) and non-re sponders (NR, n = 10). Age, incidence of a family history of hypertens ion, decrease in creatinine clearance, and predonation PRA, urinary ka llikrein, and the natriuretic response to VE were similar in the two g roups. However, following UNX, PRA decreased whereas 24-h urinary sodi um and thus sodium intake increased only in the R group. In conclusion , in normotensive subjects a 50% reduction in renal mass may result in a consistent increase in MAP and sometimes the development of de novo hypertension (4/18 subjects). Baseline characteristics as well as the predonation renal response to VE do not provide a means of detecting kidney donors in whom arterial pressure will increase consistently aft er UNX. The increase in MAP associated with UNX may result from a chan ge in body sodium as indicated by the decline in PRA and the increase in sodium intake found in the R group.