Fractional excretion of NGAL instead of 99mTcMAG3 renography to monitor resolution of delayed graft function

J.R. Bank, M.E.J. Reinders, L. Noordermeer, M.J.K. Mallat, S.W. van der Kooij, C. van Kooten, H.J.W. de Fijter

Chair(s): dr. Dennis A. Hesselink, internist-nefroloog, Erasmus MC & dr. Marieke Roemeling, internist i.o., UMC Groningen

Wednesday 9 march 2016

15:40 - 15:50h at Zaal 1 & 2

Categories: Parallelsessie (klinisch)

Parallel session: Parallelsessie V - Klinisch

Introduction:
 Kidneys transplanted from extended criteria donors have a higher prevalence of delayed graft function (DGF). Early identification of factors that prolong duration of DGF may improve clinical outcome and prevent invasive procedures. The standard in our center to monitor resolution of DGF is a renography with 99mTc labelled mercaptoacetyltriglycine (MAG3). Since ischemia/reperfusion injury results in impaired extraction of 99mTcMAG3 via the organic anion transporter, but also in impaired reabsorption of NGAL by PTECs (luminal side), we hypothesize that the excretion of fractional NGAL (FE-NGAL) can replace MAG3 scans to follow resolution of functionally defined DGF(1)(fDGF).

Methods:
92 consecutive DCD transplant recipients were included, all received IL2-RB induction and maintenance therapy with steroids, MMF and delayed-CsA introduction at day 4. Before introduction of CsA on day-4 and at day-10, MAG3 scans were performed and tubular function slope (TFS) score (2) was calculated. Daily FE-NGAL was calculated using urinary and serum NGAL. Statistical analysis included positive and negative predictive values (PPV and NPV).

Results:
 In DCD recipients a day-4 TFS score >1.5 could distinguish patients with mild fDGF (≤7 days) from patients with moderate/severe fDGF (>7 days), with PPV of 93.4% and NPV of 63.3%. Day-4 FE-NGAL <2.5% could even better distinguish patients with mild fDGF from those with moderate/severe fDGF (PPV=92.6%, NPV=100%). Also in patients with residual native kidney diuresis (>1L) FE-NGAL was highly distinctive (PPV=85.7%, NPV=100%). However, for the prediction of moderate (7-20 days) versus severe fDGF (≥21 days), both TFS and FE-NGAL had limited value (PPV=45.6% and 40.5%, NPV=100% and 87.5%, respectively). Furthermore, preliminary results suggest that sequential FE-NGAL may help to identify patients with additional CNI-toxicity and/or rejection.

Conclusion:
 In this cohort of DCD recipients FE-NGAL better distinguished patients with mild fDGF from those with moderate/severe fDGF compared to standard follow-up using 99mTcMAG3 renography, also in patients with preserved residual diuresis. Sequential FE-NGAL may prove to be a useful non-invasive biomarker to guide optimal timing of a renal allograft biopsy in recipients with DGF and additional CNI toxicity and/or acute rejection.

  1. Boom H, et al. Kidney int. 2000/08/01 ed2000. p. 859-66.
  2. El-Maghraby TA, et al. Transplantation. 2002;74(2):203-8.
 

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