Evaluation of kidney graft function by arterial flow using colour Doppler flowmetry

Objective: Two-hundred thirty-two stable renal transplant outpatients were studied to identify the most useful colour flow Doppler ultrasound indices defining graft function in the long-term follow-up. Method: Renal artery mean velocity (Vm), renal blood flow (RBF), and resistance index (RI) on the renal and interlobar arteries were measured by the same operator. Results: Vm and RBF averaged respectively 42.1 ± 18.4 cm/s and 321 ± 95 ml/min in 85 patients with normal creatinine levels ( < 105 μmol/l). RBF significantly decreased in patients with plasma creatinine > 105 μmol/l (P < 0.0001). An inverse correlation with the degree of renal impairment, measured by plasma creatinine levels, was shown by RBF (r = 0.73) and Vm (r = 0.69). RI increased along with the reduction of renal function (interlobar artery: r = 0.63 and renal artery: r = 0.57). Conclusions: Vm, RBF and interlobar RI appear to be sensitive parameters to describe the hemodynamical status of the graft. The hemodynamical status appears to be influenced by the graft function. RBF appears the most useful index to evaluate the blood supply in the transplanted kidney.