Although we did not observe a correlation between the RRI and RMD in our study, it is reasonable to assume that a low RRI (≤0.7) mainly affects glomerular blood supply in most CKD patients, an elevated RRI gradually affects the peritubular capillary and that the RRI may be correlated with the CD34 PPA-peritubular capillary and CD34 PPA-total. Here, CD34 is linked to chronic kidney disease.