INCREASED VENOUS VELOCITIES AFTER LIVING DONOR RENAL TRANSPLANTATION

Purpose: Stenoses of the renal transplant vein may result in venous thrombosis and lead to loss of the organ. However, no generally accepted definition of a relevant renal vein stenosis exists in the current literature. We conducted a prospective controlled study after living renal transplantation using duplex sonography to access renal perfusion.

Methods and Materials: Duplex sonography was performed of the donor kidney before transplantation (resistive index), directly postoperative, and one as well as three month after transplantation. Using a standardized protocol the following parameters were collected after transplantation: intrarenal resistive index, peak flow velocities in the iliac artery, at the venous and arterial anastomosis, middle of the renal vein and artery, and the renal hilus.

Results: Between May 2004 and January 2005 a total of 21 patients were included. None of the transplantation failed due to vascular complication. Mean±SD (range) maximal venous peak velocity was 106±55cm/s (22–211) immediately after transplantation and decreased significantly (p<0.005) to 65±42cm/s (18–184) after three month. High peak velocities were observed directly postoperative in the iliac artery 179±47cm/s (94–283), in the renal artery anastomosis 263±82cm/s (141–458) and the middle of the renal artery 194±74cm/s (57–371) without a significant stenosis. These velocities decreased also after three month to 114cm/s (p<0.005), 193cm/s (p<0.005), and 157cm/s (n.s.), respectively. We also observed a slight decrease of the resistive index from the donor from 0.64±0.06 (0.53–0.73) to 0.62±0.08 (0.51–0.80; n.s.) directly postoperative, but a significant increase after one month (0.66±0.08; 0.57–0.86; p<0.005) and three month (0.66±0.06; 0.57–0.83; p<0.005).

Conclusions: High peak velocities in the renal transplant vein and artery were observed direct after transplantion without vascular complications. This may be caused by a maximal postischemic intrarenal vasodilation due to the perioperative stress situation. A definition of a clinically relevant stenosis was not possible despite some very high velocities.