Renal allograft hemodynamic and diameter changes after living donor transplantation

Renal ultrasound is a valuable tool to measure allograft diameters and hemodynamic changes, some of which may help us to predict ongoing rejection. Longitudinal (L) and horizontal (H) diameters, and resistive index (RI) of intrarenal arteries of kidneys were measured before transplantation in the donor site, as well as 1 week after transplantation in the recipient site (7.5 MHz probe). We excluded patients with acute rejection, delayed graft function, perinephric collection, suspected allograft artery stenosis, or serum creatinine >2 mg/dL. Finally, allograft measurements were compared with the donor parameters. The mean values of L and H diameters in 32 normal allografts were: L 119 +/- 10.4 mm; H 54 +/- 8.4 mm; L/H ratio 2.25 +/- 0.27; RI 0.57 +/- 0.55. The mean values of these measurements when the kidney was in the donor body were: L 110 +/- 9.4 mm; H 44.3 +/- 5.4 mm; L/H ratio 2.97 +/- 0.25; RI 0.61 +/- 0.040. Both L and H diameters were increased significantly after transplantation, but the L/H ratio and RI were decreased significantly (P < .05). The presumed physiologic explanations for these findings in allograft are increased blood flow, decreased intrarenal arterial resistance, stress relaxation, and lack of sympathetic innervation.