Serial Hemodynamics after Renal Allotransplantation in Man

Abstract

Serial measurements of glomerular filtration rate (GFR), independent and simultaneous clearances and extractions of para-aminohippurate (PAH), radiohippuran, and iodopyracet (Diodrast) were made in 11 adults and one child who received renal transplants from living donors. Measurements were made within 3 hours and repeated two to four times during the following 14 days. Immediately after transplantation, PAH clearance averaged 385 ml/min (range, 218 to 510), GFR averaged 54 ml/min (range, 22 to 87), renal plasma flow (RPF) averaged 672 ml/min (range, 309 to 1424), and marked vasodilatation was present with an average renal blood flow (RBF) of 979 ml/min (range, 435 to 2,114). As observed in other studies, immediate diuresis and natriuresis but no glycosuria occurred. Extraction ratios for PAH ( E PAH) were below normal, ranging from 0.59 to 0.94, and those for 125 (or 131) I-hippuran, and 131 I-Diodrast were even lower. Extraction ratio for PAH to radiohippuran averaged 1.43 in 17 simultaneous studies. However, RPF measured simultaneously with these agents was the same, indicating a true difference in transport of these substances. The low extraction ratio for PAH, 131 (or 125) I-hippuran and 131 I-Diodrast was not related to depression of the maximal tubular transport of PAH and may have been a consequence of vasodilatation and increased RBF. Another observation made on these kidneys was a low filtration fraction which averaged 0.089. These hemodynamic changes did not appear to relate to circulating factors in the anephric recipient since they persisted throughout the 13-day study period in eight patients. In four patients showing transient rejection, GFR and the clearance of PAH and 131 I-hippuran decreased proportionately more than RBF. It is concluded that marked vasodilatation and a low filtration fraction are characteristic of uncomplicated renal allotransplantation in man, and that early rejection is expressed by measurable decreases in the clearances of PAH and inulin despite maintenance of RBF. These changes were present prior to clinical evidence of rejection.