Can the kidney volume help to differentiate the types of rejection before biopsy?

The aim of this study was to use the volume of the graft as an adjunct tool for better decision making.

Kidney transplanted patients with acute azotemia and documented volume and finally a biopsy were enrolled in this study‌. Graft volumes between rejected patients (antibody-mediated rejection {AMR} and cell - mediated rejection {CMR}) and ‌non rejected but azotemic patients were compared.

A total of 76 patients were enrolled in this study ‌(45 case and 31 control‌). 53.3% of the case group were‌ (AMR)‌ and 46.7% belonged to ‌(CMR). There was no difference between kidney volume according to age or sex. But the case group had a significantly bigger volume than controls (253.09 cm³ and 186.45 cm³; p< 0.001). In addition, there was a significant difference between the volumes of AMR kidneys with CMR and controls ‌(286.24+66.70‌, 224.08+76.79 and 186.95+39.92; P=0.003 and p<0.001, respectively), but not between CMR and controls ‌(P=0.067). A cutoff point of 200 cm³ was determined as rejection with sensitivity and specificity of 70% and a cutoff point of 250 cm³ could be used as AMR cut off with sensitivity of 76% and specificity of 70%.

There was a significant difference in volume between rejection and control group and between AMR and CMR. So, kidney volume determination is an easy and valuable tool to help the clinician to have a more rapid and better decision making.