AORTIC INVOLVEMENT IN FIBROMUSCULAR DYSPLASIA: REPORT FROM ARCADIA-POL

Abstract

Objective: Fibromuscular dysplasia (FMD) affects the walls of medium-sized arteries. There are no described radiological characteristics pathognomonic of aortic FMD but pathological documentation of aortic FMD has been occasionally reported. The aims of this study were to investigate the characteristics of abdominal aorta in patients with FMD versus controls and to review the relevant literature. Design and method: We measured centreline abdominal aortic diameters on 136 patients with FMD (22 with focal disease) enrolled in the ARCADIA-POL study, 60 patients with carotid dissections but no evidence of FMD and 136 healthy controls. Results: The median abdominal aortic diameter did not differ between patients with FMD, patients with carotid dissections and no evidence of FMD and healthy controls. However, aortic diameter at the level of the diaphragm was smaller in patients with focal FMD compared to patients with multifocal FMD, patients with carotid dissections and healthy controls (ANOVA 0.015). Six patients with mid-aortic syndrome (MAS) were reported separately. All had radiological evidence of FMD in medium-sized aortic branches. In one in whom a sample of aortic wall was obtained, histology confirmed focal aortic FMD. A literature review found a further 31 reports of aortic histology with features of FMD. Conclusions: We found no difference in aortic diameters between individuals with or without FMD. Nevertheless, patients with focal FMD had smaller aortic diameters than those with multifocal FMD and controls. This represents another phenotypic difference between multifocal and focal FMD. Focal renal artery stenosis associated with MAS may represent an extreme presentation belonging to the same disease spectrum.