Urinary excretion rates of multiple renal indicators after kidney transplantation: clinical significance for early graft outcome

Post-reperfusion inflammation as well as anti-allograft response occur following kidney transplantation. We evaluated tissue damage by multiple renal indicators and searched for rejection predictors forewarning serum creatinine upturns. Twenty recipients (43 ± 9 y; donors' age 35 ± 16 y) of first renal grafts were studied. All through their hospital stay (35 ± 18 d, range 17-75 d) we measured serum levels of urea, creatinine and electrolytes along with urinary excretion rates of total protein, albumin, enzymes (GGT, NAG, AAP) and electrolytes. During the period of observation, peaks were seen on the 1st day for serum creatinine, serum K+ and urine albumin output; on the 2nd day for urine Na+ GGT, AAP and protein excretion rates; on the 4th day for urea and creatinine outputs; on the 5th day for NAG output. On the 14th day, serum urea and creatinine as well as urine GGT, NAG, AAP, albumin and total protein were still elevated compared to 20 healthy control subjects. Delayed/slow graft function was observed in six recipients with higher pre-transplantation plasma lipids and lower donor HDL cholesterol. Hospital stay time was correlated with need for post-transplantation dialysis (p = 0.01) and recipient proteinuria by time 0 (TO) to day 3 (p = 0.02). Cold ischemia time was positively associated with 0-3 d serum creatinine, 0-3 d urinary urea and protein outputs (multiple r 0.9, p < 0.001). Multivariate analysis of longitudinal data showed that recipients' serum creatinine was positively correlated (p < 0.001) with urine AAP and negatively correlated with urine albumin, with diuresis volume and urine creatinine (p < 0.01). Serum creatinine elevations were preceded (previous 1-7 d) by increases in urinary indicators, the probability being higher in the presence of multiple simultaneous abnormalities. Useful parameters predictive of favorable graft outcome prior to transplantation included a brief cold ischemia time and a normal donor/recipient serum lipoprotein profile. Following transplantation, useful parameters were a high diuresis volume at time zero along with low urine NAG and high albumin outputs; early (first opst-graft 3 d) polyuria, low urea and GGT, high K+, NAG and total protein excretions.