Fibromuscular dysplasia: an uncommon cause of secondary hypertension

Abstract

Fibromuscular dysplasia is a noninflammatory vascular disease that commonly affects the distal two thirds of the renal artery and branch vessels, but occasionally involves other arteries. Progression of stenosis occurs in 16%-38% of renal arteries. Although the etiology is unknown, genetic studies suggest a relationship to the angiotensin-converting enzyme I allele. Thin, young Caucasian women without a family history of hypertension are most commonly affected. An abdominal or flank systolic-diastolic bruit is an important clue for the diagnosis. Most noninvasive screening tests are not sensitive or reproducible to be used to rule out renal artery stenosis, but digital subtraction renal angiography usually confirms the diagnosis. Percutaneous renal artery angioplasty is the treatment of choice, but may not result in normalization of blood pressure if diagnosis is delayed. Since restenosis occurs, continued follow-up is necessary.

Figure 1

Fibromuscular dysplasia of the renal artery showing alternating constrictions and saccular aneurysms, described as a “string of beads.” The top panel is the renal arteriogram and the bottom panel is the digital subtraction image.

Figure 2

Prevalence of renovascular hypertension according to etiology and age. Fibromuscular dysplasia most commonly occurs among patients younger than 50 years; whereas, atherosclerotic renovascular hypertension occurs in older patients. Derived from Anderson et al. ²