PROgression of FIbromuscular LEsions

Background

Fibromuscular dysplasia (FMD) is a group of nonatherosclerotic, noninflammatory arterial diseases that usually involve renal and carotid arteries. Patients with FMD may present with renovascular hypertension and/or with cerebrovascular symptoms. The prevalence of FMD in hypertensive patients is estimated at 4/1000. Angiographic classification includes the multifocal type, with multiple stenoses and the 'string-of-beads' appearance that is related to medial FMD, and tubular and focal types which are not clearly related to specific histological lesions. FMD may affect one or more vascular beds and progress to more severe stenosis and to renal or cerebrovascular complications. FMD appears to be familial in 10% of cases (OMIM #135580).

Renal artery FMD may progress to more severe stenosis and to renal atrophy, and/or to stenoses affecting more arteries within or outside the renal vasculature. The risk of progression as assessed from available studies was probably overestimated because documentation of progression was obtained from angiography, a procedure which is not routinely undertaken in patients with favourable clinical and biological outcomes. The disease is progressive, however, and literature stated that patients with FMD should undergo yearly duplex ultrasonography to detect progression of disease, restenosis, or loss of kidney volume.

There are very few data on prognosis of patients with symptomatic carotid or vertebral artery FMD. The risk of arterial disease progression over time is unknown. The risk of ischemic stroke ranged from 0 to about 3% per year in the few studies which assessed that issue.

Objectives