ESPN 53rd Annual Meeting

ESPN 2021


 
PLASMA IOHEXOL CLEARANCE FOR RENAL FUNCTION ASSESSMENT IN PEDIATRIC PATIENTS AFTER CARDIAC SURGERY
EVELYN DHONT 1 ANNICK DE JAEGER 1 KRISTOF VANDEKERCKHOVE 2 SISKA CROUBELS 3 EVELIEN SNAUWAERT 4 JOHAN VANDE WALLE 4 PETER DE PAEPE 5 PIETER DE COCK 6

1- PEDIATRIC INTENSIVE CARE DEPARTMENT, GHENT UNIVERSITY HOSPITAL
2- PEDIATRIC CARDIOLOGY DEPARTMENT, GHENT UNIVERSITY HOSPITAL
3- FACULTY OF VETERINARY MEDICINE, GHENT UNIVERSITY
4- PEDIATRIC NEPHROLOGY DEPARTMENT , GHENT UNIVERSITY HOSPITAL
5- HEYMANS INSTITUTE OF PHARMACOLOGY, GHENT UNIVERSITY
6- PHARMACY DEPARTMENT, GHENT UNIVERSITY HOSPITAL
 
Introduction:

 

Identification of patients with altered renal function after cardio-pulmonary bypass is often delayed due to lack of accurate methods for evaluation of glomerular filtration rate (GFR). We compared GFR measurement by the gold standard technique plasma iohexol clearance (mGFRiohex) with estimated GFR based on the routinely used Schwartz formula (eGFRschwartz) in pediatric patients after cardiac surgery.

Material and methods:

 

Children who underwent cardiopulmonary bypass surgery were included. After IV iohexol bolus injection, plasma iohexol clearance was calculated from the plasma concentration-time curve over a 360-minutes interval. Volumetric absorptive microsampling was used for iohexol blood sampling. Pearson’s correlation coefficient for mGFRiohex and eGFRschwartz was determined and agreement between the methods was assessed visually using Bland-Altman plots. Accuracy of eGFRschwartz was determined as the percentage of GFR estimates within ± 30 % of mGFRiohex (P30). Acute Kidney Injury (AKI) was defined as a decrease of GFR of 25 % of age-specific GFR reference values. Augmented renal clearance (ARC) was defined as a GFR exceeding normal values for age plus two standard deviations.

Results:

 

We included 19 patients with a median age of 2 months (range 0.13-135 months) after closure of atrial septum defect (n=1), ventricular septum defect(n=3), atrio-ventricular septum defect (n=3), arterial switch procedure (n= 8), ROSS procedure (n=1), Norwood procedure (n=1), coronary surgery (n=1) and truncus arteriosus repair (n=1). Median mGFRiohex was 62 ml/min/1.73m2 (range 29-231). Median eGFRschwartz was 63 ml/min/1.73m2 (range 34-193). 21% and 11% of patients presented with AKI according to mGFRiohex and eGFRschwartz respectively. With mGFRiohex  4 patients (21%) were identified as having ARC versus 3 patients (16%) with eGFRschwartz.   eGFRschwartz correlated well with mGFRiohex (r=0,83), however, accuracy was poor with P30=53%.

Conclusions:

 

Widely used eGFRschwartz fails to identify a significant part of children with AKI after cardiac surgery.  mGFRiohex could offer a feasible and safe alternative to accurately evaluate renal function in these vulnerable patients.