Doppler ultrasound in the diagnosis of renal allograft rejection and in monitoring the effect of treatment.

Thirty-six consecutively transplanted renal allograft patients were prospectively monitored with ultrasound-Doppler examinations three times weekly during the first 3 weeks after transplantation. Although triple-immunosuppressive therapy consisting of cyclosporin A, azathioprine and prednisolone was used, acute rejection occurred in 11 patients. Nine patients had immediate onset of graft function and no rejection. Ten patients had acute tubular necrosis (ATN) without any signs of rejection and were treated with dialysis for 1-3 weeks after transplantation. Thrombosis of the renal artery was diagnosed in four patients. During rejection episodes pulsatility index (PI) was above normal range in all patients. In patients with mild to moderate ATN and PI was normal throughout the clinical course whereas two patients with severe ATN but no signs of rejection in the kidney biopsy also had high PI. It is concluded that serial Doppler velocity examination after kidney transplantation is a non-invasive, cheap and reliable method for monitoring of the graft. The method can be used in the early diagnosis of rejection, and it is of special value in monitoring grafts without function.