[Vascular complications in pediatric renal transplant: echographic diagnosis]

The purpose of this study was to assess the incidence of vascular complications in pediatric renal transplant patients and to evaluate the accuracy and limitations of duplex-Doppler color ultrasound (US) in their diagnosis.

The US studies of 89 transplants performed in 76 patients were reviewed. Ages of the patients ranged from 11 months to 23 years (mean 13 years). The US exams were performed every 24 hours during the first week post-transplantation, once a week during the hospital stay and whenever graft dysfunction occurred. A vascular map of the graft was performed with color Doppler and maximum systolic velocity, systolic acceleration time, resistive index and flow velocity in the renal vein were determined with pulsed Doppler. An angiography was performed in all patients with US diagnosis of vascular thrombosis, stenosis or arteriovenous fistula.

Seventeen grafts (15%) showed vascular complications including renal artery stenosis (8 cases), renal artery thrombosis (4 cases), arteriovenous fistula (4 cases) and one renal vein thrombosis. US studies were able to detect six renal artery stenosis (false negative results in two cases), seven renal artery thrombosis (false positive results in three grafts), all of the arteriovenous fistulas and one renal vein thrombosis.

Doppler-duplex color US has a high sensitivity and specificity in diagnosis of vascular complications and should be the first approach for their diagnosis. The presence of false positive and false negative results makes it necessary to perform angiography when symptomatic thrombosis, arteriovenous fistula or stenosis is suspected.