Characteristics of children and adolescents with fibromuscular dysplasia: a systematic review and meta-analysis

Based on data from large international registries, the clinical presentation of fibromuscular dysplasia (FMD) in adult patients is now well established. By contrast, characteristics of FMD in children and adolescents remain poorly described. We present the first systematic review and meta-analysis focused on pediatric FMD. Seven databases were searched for studies published since 2000. Data were pooled using random-effects models. Subsequently, the characteristics of pediatric FMD patients were compared with those of adult patients included in the US and FEIRI registries. Nine retrospective studies totalizing 218 children/adolescents with FMD were identified. All had renal FMD and 93.7% were revascularized. The mean age at diagnosis was 11.7 years. Fifty-two % were females (U.S. Registry 94.7%; FEIRI 81.5%). Most patients (66.6%) had focal FMD (U.S. Registry 24.0%; FEIRI 28%). Despite incomplete screening, multivessel FMD was identified in 19.1% (U.S. Registry 55.1%; FEIRI 57.4%), and aneurysms and dissections in 15.3% and 1.7%, respectively (U.S. Registry 22.7%, 28.1%; FEIRI 21.6%, 5.6%). The proportion of mid-aortic syndrome (MAS) was 6.3%. In ethnicity-stratified analyses, the female proportion was 43.5% in Asian vs. 58.2% in Caucasian children, and the prevalence of multifocal FMD was 21.8% vs. 37.9%. In conclusion, compared with adult patients, children/adolescents with FMD are characterized by a lower proportion of females and a higher proportion of focal FMD, both in Asians and Caucasians. While associated MAS appears less frequent than previously thought, multivessel involvement and aneurysms were frequently reported, suggesting the interest of a systematic arterial exploration in children with FMD, as recommended in adults.