IS Case 331: Left renal artery stenosis, likely secondary to fibromuscular dysplasia
Imaging Sciences URMC 2009
Publication Date: 2009-09-15
Severe focal stenosis of the mid-segment of the left renal artery is seen on the CTA (Figs. 1-2). This finding is further confirmed on catheter angiogram (Fig. 3). Balloon angioplasty was performed with excellent result (Fig. 4).
Renovascular hypertension (RVHT) is hypertension caused by anatomic narrowing of the renal artery. It is estimated that 1-10% of Americans with hypertension have RVHT. It is a result of the renin-angiotensin-aldosterone system activation in response to the reduction of blood flow to the kidney. The important causes of the RVHT are atherosclerotic disease and fibromuscular dysplasia.
Atherosclerosis is usually diffuse and bilateral. Involvement of the aorta and other arteries is common. The disease affects the proximal third of the renal arteries. The typical patient is the older man.
Fibromuscular dysplasia (FMD) is angiopathy involving medium size arteries, most commonly renal (60-75%), carotid (25-30%), visceral (9%), and external iliac (5%). The disease predominantly affects women of childbearing age. The characteristic finding on the angiography is focal stenosis and dilation (string of beads appearance) of the mid to distal segment of the renal artery. FMD is classified histologically by the involvement of the arterial wall layer: intimal, medial, and adventitial dysplasia. Medial FMD is further classified into medial fibroplasia, perimedial fibroplasia, and medial hyperplasia. Medial fibroplasia accounts for 75-80% of all cases.
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- Khan AN, MacDonald S, Sohaib M, Saeed S. Renal artery stenosis/renovascular hypertension. Emedicine, June 6, 2008. http://emedicine.medscape.com/article/380308-overview