Doppler ultrasonography after renal transplantation: value of reversed diastolic flow in diagnosing renal vein obstruction.

The observation of reversed diastolic flow during Doppler ultrasonography (US) of renal transplants has been described as sensitive but not specific in the diagnosis of renal vein thrombosis. To determine the diagnostic accuracy of reversed diastolic flow for renal vein obstruction in patients who underwent renal transplantation at a tertiary-care teaching hospital over a 3-year period, the authors identified all patients in whom reversed diastolic flow was observed during Doppler US (17 patients) and those in whom complete renal vein obstruction occurred, necessitating nephrectomy (16 patients). Three types of reversed diastolic flow were found; the wave-forms of two of these had a large reversed component. One of these two types was present in nine of the patients in whom complete venous obstruction occurred. The sensitivity, specificity and positive predictive value of reversed diastolic flow were 82%, 99% and 75% respectively. The authors conclude that a US finding of reversed diastolic flow with a large reversed component is a sensitive and specific sign of renal vein obstruction, usually renal vein thrombosis.