François Gaillard

Estimated or Measured GFR in Living Kidney Donors Work-up?

The value of estimated glomerular filtration rate (eGFR) in living kidney donors screening is unclear. A recently published web‐based application derived from large cohorts, but not living donors, calculates the probability of a measured GFR (mGFR) lower than a determined threshold. Our objectives were to validate the clinical utility of this tool in a cohort of living donors and to test two other strategies based on chronic kidney disease epidemiology collaboration (CKD‐EPI) and on MDRD‐eGFR. GFR was measured using 51Cr‐ ethylene‐diamine tetraacetic acid urinary clearance in 311 potential living kidney donors (178 women, mean age 50 ± 11.6 years). The web‐based tool was used to predict those with mGFR < 80 mL/min/1.73 m2. Inputs to the application were sex, age, ethnicity, and plasma creatinine. In our cohort, a web‐based probability of mGFR <90 mL/min/1.73 m2 higher than 2% had 100% sensitivity for detection of actual mGFR <80 mL/min/1.73 m2. The positive predictive value was 0.19. A CKD‐EPI‐eGFR threshold of 104 mL/min/1.73 m2 and an MDRD‐eGFR threshold of 100 mL/min/1.73 m2 had 100% sensitivity to detect donors with actual mGFR <80 mL/min/1.73 m2. We obtained similar results in an external cohort of 354 living donors. We confirm the usefulness of the web‐based application to identify potential donors who should benefit from GFR measurement.

What is the significance of end-stage renal disease risk estimation in living kidney donors?

Two end‐stage renal disease (ESRD) risk calculators were recently developed by Grams et al., and Ibrahim et al. to calculate ESRD risk before donation among living kidney donors. However, those calculators have never been studied among potential donors for whom donation was refused due to medical contraindications and compared to a group of donors. We compared 15‐year and lifetime ESRD risk of donors and nondonors due to medical cause as estimated by those two calculators. Nondonors due to medical cause (n = 27) had a significantly higher 15‐year ESRD risk compared to donors (n = 288) with both calculators (0.25 vs. 0.14, P < 0.001 for that developed by Grams et al. and 2.21 vs. 1.43, P = 0.002 for that developed by Ibrahim et al.). On the contrary, lifetime ESRD risk was not significantly different between the two groups. At both times (15 years and lifetime), we observed a significant overlap of ESRD risk between the two groups. ESRD risk calculators could be complementary to standard screening strategy but cannot be used alone to accept or decline donation.

From Isonatric to Isotonic Hemodialysis

Background: Isonatric hemodialysis aims at maintaining stable cellular hydration through a close control of natremia, considered a surrogate of tonicity. However, 2 methods are available to perform isonatric hemodialysis: one based on natremia derived from plasma conductivity (Na_Cond) and the other based on natremia measured at laboratory (Na_Lab). We compared the control of tonicity obtained by isonatric hemodialysis based on Na_Lab or Na_Cond. Methods: Changes in tonicity Na_Lab and Na_Cond were recorded during 55 hemodialysis sessions. Sessions were divided according to the variation of tonicity: hypotonic sessions (tonicity decrease ≥2 mOsm/kg); isotonic sessions (tonicity variation <2 mOsm/kg); hypertonic sessions (tonicity increase ≥2 mOsm/kg). Results: During isotonic hemodialysis, Na_Cond decreases significantly by 1 mmol/L, whereas Na_Lab remained stable. Conclusions: Isonatric hemodialysis based on Na_Lab and isonatric hemodialysis based on Na_Cond is to be distinguished. Isotonic hemodialysis could be performed by decreasing Na_Cond by 1 mmol/L or maintaining Na_Lab stability.