Renal transplant vein occlusion: an early diagnostic sign?

We report new Doppler ultrasound findings in two patients with renal vein thrombosis and obstruction following renal transplantation. In both cases there was a marked reduction in the systolic peak with relatively normal diastolic flow in the intrarenal arterial waveforms. Venous flow was still detectable at the renal hilum in both cases, and throughout the graft in one case. We suggest that, in the absence of signs of proximal renal artery stenosis, small amplitude arterial waveforms with a depressed systolic peak and maintained diastolic flow, despite intrarenal venous flow, represent renal vein thrombosis in evolution or renal vein obstruction. These findings merit early surgical exploration.