Published online Aug 27, 2022. doi: 10.4254/wjh.v14.i8.1621
Peer-review started: March 16, 2022
First decision: April 28, 2022
Revised: May 11, 2022
Accepted: June 24, 2022
Article in press: June 24, 2022
Published online: August 27, 2022
Processing time: 162 Days and 18.1 Hours
Renal failure is an independent prognostic factor for survival in patients with cirrhosis. Equations to calculate serum creatinine significantly overestimate the glomerular filtration rate (GFR). Plasma clearance of direct biomarkers has been used to improve the accuracy of evaluations of GFR in this population, but no study has simultaneously measured plasma and urinary clearance, which is the gold standard.
To study calculated plasma and urinary concentrations of iohexol, based on the kinetics of samples collected over 24 h from cirrhotic patients with three different grades of ascites.
One dose of iohexol (5 mL) was injected intravenously and plasma concentrations were measured 11 times over 24 h in nine cirrhotic patients. The urinary concentration of iohexol was also measured, in urine collected at 4, 8, 12 and 24 h.
The plasma and urinary curves of iohexol were similar; however, incomplete urinary excretion was detected at 24 h. Within the estimated GFR limits of our population (> 30 and < 120 mL/min/1.73 m²), the median measured GFR (mGFR) was 63.7 mL/min/1.73 m² (range: 41.3–111.3 mL/min/1.73 m²), which was an accurate reflection of the actual GFR. Creatinine-based formulas for estimating GFR showed significant bias and imprecision, while the Brochner–Mortensen (BM) equation accurately estimated the mGFR (r = 0.93).
Plasma clearance of iohexol seems useful for determining GFR regardless of the ascites grade. We will secondly devise a pharmacokinetics model requiring fewer samples andvalidate the BM equation.
Core tip: Accurately evaluating glomerular filtration rate (GFR) in cirrhotic patients is critical to optimize their management and identify patients who should be prioritized for liver transplantation, and informs discussion of double liver–kidney transplantation. Until now, no formula or direct method for measuring GFR was available. This prospective pilot study is the first to systematically describe the plasma and urinary concentrations of iohexol, based on the kinetics of samples collected over 24 h from cirrhotic patients with three different ascites grades. The next step will be to construct a Bayesian estimator from a limited number of samples.