Spectrum of renal findings in pediatric fibromuscular dysplasia and neurofibromatosis type 1

Abstract

Fibromuscular dysplasia (FMD) and neurofibromatosis type 1 (NF1) are the most common causes of pediatric renal artery stenosis (RAS) in western countries, and characterization of their angiographic features could aid in an accurate diagnosis and in treatment. This study characterizes renal angiographic findings in pediatric fibromuscular dysplasia (FMD) and neurofibromatosis type 1(NF1). We reviewed 68 angiograms performed over 11 years on 43 children with renovascular hypertension (20 male, 23 females; ages 1 month to -19 years; median/average 9.8 years). Ten patients were diagnosed with NF1, and 33 had presumed FMD. The frequency, extent and distribution of lesions were determined and analyzed. Stenosis was found in 91% of patients (n=39/43), with 86% showing stenosis of 1st or 2nd order arteries, and 12% distal to 2nd order. Stenoses in multiple 1st/2nd order arteries were found in 32% of patients, and 36/43 patients had 1-2 stenoses. The most common lesion was a ≤ 5 mm stenosis in a 1st/2nd order artery, in 42%. Mean percentage of stenosis in a 1st/2nd order vessel was 62%; ≥ 70% stenosis was found in 53%, and ≥ 90% stenosis in 29%. Bilateral disease was noted in 30% of patients. Intraparenchymal disease, distal to 2nd order branches, was seen in 30%. Aneurysms were seen in 28%, beading in 19% and collaterals in 51% (associated with ≥ 70% stenosis). Mid-aortic narrowing was seen in 16%, more often in patients with NF1. We provide a descriptive characterization of renal angiographic findings in pediatric FMD and NF1.