Function of the renal homograft in man: significance of EF Na and U-P creatinine as indices of early rejection

Abstract

Renal functions of nine patients with homotransplanted kidney from living donors were consecutively examined during the period of two months after the operation.As parameters of tubular function, excretion fraction of filtered sodium (EFNa) and urine-plasma ratio of creatinine (U/Pcr) were determined as well as clearances of creatinine (Ccr) and para-aminohippurate (CPAH).The following results were obtained as a common functional change of the transplanted kidneys during the period of early Renal functions of nine patients with homotransplanted kidney from living donors were consecutively examined during the period of two months after the operation.As parameters of tubular function, excretion fraction of filtered sodium (EFNa) and urine-plasma ratio of creatinine (U/Pcr) were determined as well as clearances of creatinine (Ccr) and para-aminohippurate (CPAH).The following results were obtained as a common functional change of the transplanted kidneys during the period of early rejection.The earliest change of kidney function was manifested as a reduction of EFNa (less than 2%) and increase of U/Pcr (more than 20) which appeared simultaneously with the general clinical signs such as fever and leucocytosis. However, these changes had no relationship with the severity of the rejection.As EFNa and U/Pcr were restored to the previous levels, urine flow decreased abruptly and an elevation of BUN, acidosis, and decrease of Ccr and CPAH appeared as well.During the oliguric period continuing for 3 to 8 days, EFNa increased as a rebound and U/Pcr decreased reciprocally. In spite of immuno-suppressive therapy, these changes as well as azotemia and lowered clearances advanced markedly even for several days after the cessation of oliguric phase.When recovery of these functional changes initiated, urine volume was still increasing and reached its peak several days later.Functional recovery was observed relatively rapidly with a slight delay in urine flow, EFNa and acidosis.In accord with the reduction of the EFNa, a tendency of hyponatremia and hypochloremia which disappeared after the oliguric phase was noted. When acidosis was present in the polyuric phase, hyperchloremia was concomitantly recognized.Reduction of EFNa and increase of U/Pcr have been reported in stenosis of the renal artery, thrombosis of the renal vein or stricture of the ureter. However it is not so difficult to differentiate the early rejection from these diseases, since there is a difference in the variation pattern of EFNa and U/Pcr after the initial change.It may be concluded that determination of the EFNa and U/Pcr is highly significant for detection of the earliest sign of early rejection, evaluation of the effect of immuno-suppresive therapy and differential diagnosis of oliguria which occur in the homotransplanted kidney.