Renal sonography with Doppler for detecting suspected pediatric renin-mediated hypertension - is it adequate?

BACKGROUND: Renal Doppler US is used to evaluate suspected vascular causes of hypertension in children, despite mostly unknown diagnostic performance characteristics.

OBJECTIVE: To evaluate renal Doppler US for detecting vascular causes of hypertension in children with high clinical suspicion of aortic or renal artery narrowing.

MATERIALS AND METHODS: We identified pediatric renal Doppler US examinations performed for hypertension between January 1995 and June 2010 at our institution. We excluded children without follow-up angiography (CT-, MR-, or catheter-based). Two pediatric radiologists reviewed imaging studies and documented relevant findings. Intrarenal spectral Doppler resistive index measurement <0.5 or tardus parvus waveform constituted a positive examination.

RESULTS: Thirty-five boys and 13 girls underwent renal Doppler US and confirmatory imaging (mean age  =  9.0 years). Nineteen US examinations were truly negative, two were falsely negative, 18 were truly positive (16 involved narrowing of the aorta or main renal artery) and nine were falsely positive. Sonography had a sensitivity and specificity of 90% and 68%, respectively, for detecting a vascular cause of hypertension.

CONCLUSION: Renal Doppler sonography reliably detects renin-mediated hypertension caused by aortic or main renal artery narrowing in children. More studies are needed to determine its ability to detect intrarenal and accessory renal artery stenoses.