Duplex Doppler ultrasound for detection of significant renal artery stenosis in transplant kidney with end to side arterial anastomosis

Objective

To evaluate the accuracy of velocity parameters and to define optimum threshold values of these parameters in detection of >60% renal artery stenosis in patients with end to side arterial anastomosis.

Methods

The study group composed of 17 patients of transplant renal artery stenosis confirmed by CT angiography; and 25 control patients with normal Doppler study. Doppler parameters like PSV in main transplanted renal artery, PSV in interlobar artery, PSV in iliac artery, acceleration time, and resistive index were evaluated. Pre-PSV ratio and Post-PSV ratio were calculated. Patients were divided into group A (>60% stenosis) and B (<60% stenosis) according to CT angiography reports. Control group assigned as group C. Difference between Doppler parameters were evaluated by individual t test. Receiver operating curve was performed to determine optimal parameter for diagnosis of >60% stenosis.

Results

Considering better sensitivity and specificity for diagnosis of >60% stenosis the best threshold for Intrarenal RI, acceleration time, PSV, Pre-PSV ratio and Post-PSV ratio were determined to be 0.058, 0.071 s, 3.1 m/s, 2 and 10 respectively. P value of acceleration time between group B and C; and P value of PSV in main renal artery, Pre-PSV ratio and Intrarenal RI between group A and B is >0.05.

Conclusion

Post-PSV ratio is the best parameter for diagnosis of significant stenosis and its optimum threshold value is 10.