Abnormal renal perfusion, GFR and tubular function demonstrated with Tc-99m DTPA and MAG3 in patients with hepatorenal syndrome

Objectives Hepatorenal syndrome is an advanced form of renal dysfunction that is associated with advanced hepatic failure and poor patient prognosis. The purpose of this study was to characterize the findings in this clinical entity with respect to glomerular and tubular function using readily available Tc99m labeled radiopharmaceuticals of DTPA and MAG3.

Methods We analyzed 35 patients (22 males, 13 females, mean age 53 ±12years old) with advanced end-stage liver diseases (MELD scores>10) and renal dysfunction. All patients had a Tc99m DTPA and MAG3 renal scan. GFR values were obtained using the Gate’s method. MAG3 studies consisted of a 3sec/frame perfusion study for 1 minute and a function evaluation of 2min/frame for 20min. Renal perfusion, initial renal extraction, and cortical retention of radionuclide were evaluated based on renal to background ratios including 30min/maximum values using an ROI approach. Studies were rated by at least 2 physicians and assigned to one of three groups; mild, moderate or severely decreased renal perfusion and/or initial extraction. Cortical retention was based on retained activity in the renal cortices at the end of the function component of the study.

Results GFR was reduced in all subjects with a mean value of 24cc/min with S.D. ± 14. Renal perfusion was reduced in all subjects, 7=mild, 15= moderate and 13=severe. Initial extraction was reduced in all subjects, 9=mild, 20=moderate and 6=severe. Cortical retention was present in all subjects, 11=mild, 6=moderate, and 18=severe. 30/maximum was 83 ±16 left kidney, 78±16 right kidney (Nl 20±6).

Conclusions From this study, we determined that patients with severe hepatic failure may present with a pattern of diminished GFR, impaired renal perfusion and function with cortical retention simulating an “ATN” pattern. The mechanism of these findings is unclear but likely represents a combination of reduced renal perfusion and severe tubular dysfunction