Background: Initially based on histology, the diagnosis of renal artery fibromuscular dysplasia (FMD) is now based mostly on angiographic appearance because arterial tissue samples are rarely available. This retrospective cross-sectional study aimed to assess the clinical relevance of a binary angiographic classification of FMD lesions (unifocal or multifocal) based on computed tomographic or magnetic resonance angiography.
Methods and results: Adult patients diagnosed with FMD in a single tertiary care center for hypertension management were identified by screening of electronic files. FMD lesions were reviewed and classified according to computed tomography or magnetic resonance angiography as multifocal if there were at least 2 stenoses in the same arterial segment; otherwise, they were classified as unifocal. Of 337 patients with established renal artery FMD, 276 (82%) were classified as multifocal. Patients with unifocal and multifocal lesions differed significantly in median age at diagnosis of FMD (30 and 49 years) and hypertension (26 and 40 years), sex distribution (female:male ratio, 2:1 and 5:1), initial blood pressure (157/97 and 146/88 mm Hg), current smoking (50% and 26%), prevalence of unilateral renal artery lesions (79% and 38%), presence of kidney asymmetry (33% and 10%), renal revascularization procedures (90% and 35%), and hypertension cure rates in patients who underwent revascularization (54% and 26%).
Conclusions: A binary angiographic classification into unifocal or multifocal renal artery FMD is straightforward and discriminates 2 groups of patients with different clinical phenotypes.