Quiz Page May 2007
Article Outline
Clinical Presentation
A 59-year-old previously healthy woman was referred to our hospital with recent onset of hypertension. On admission, her blood pressure was 179/94 mm Hg. No other abnormalities were found, and blood urea nitrogen and serum creatinine levels were within normal limits. An additional renal duplex ultrasound showed moderate velocity elevations (up to 2.4 m/s) throughout the mid- and distal right renal artery. Abdominal aortography was performed, and a selective arteriogram of the right renal artery was obtained (Fig 1).
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Figure 1.
Selective digital subtraction angiogram of the right renal artery.
■What is your diagnosis based on the arteriogram of the right renal artery?
Discussion
What is Your Diagnosis Based on the Arteriogram of the Right Renal Artery?
As seen in Fig 1, the midportion of the right renal artery shows a characteristic “string-of-beads” appearance, consistent with fibromuscular dysplasia (FMD) of the right renal artery (Fig 1). Abdominal aortography and selective catheterization of the left renal artery showed normal-caliber vessels and did not show additional locations of FMD. The lesion in the midportion of the right renal artery was treated successfully with percutaneous transluminal angioplasty using a 6 × 20-mm balloon, resulting in a patent vessel on the arteriogram and a significant decrease in pressure gradient between the renal artery and aorta to less than 5 mm Hg. Clinically, blood pressure normalized to 120/78 mm Hg and has been stable for a year.
Depiction of the classic string-of-beads sign on arteriograms of the renal artery is considered pathognomonic for the diagnosis of renal artery FMD and was described first by McCormack et al1 in 1967. The string-of-beads sign is caused by areas of web-like stenoses alternating with small aneurysms of the artery. Contrary to atherosclerotic disease of the renal artery, which usually involves the ostium, FMD typically involves the distal main renal artery, with extension into first-order branches in 25% of patients.2
The cause of FMD is unknown. Renal FMD represents a group of fibrotic disorders of the intima, media, or adventitia of the renal artery wall. The most frequent subtype of renal artery FMD is medial fibroplasia, occurring in 90% of cases. FMD accounts for approximately 10% of all cases of renovascular hypertension and tends to affect young women between 30 and 50 years of age. Clinically, patients present with uncontrolled hypertension caused by obstructed blood flow in the renal artery.
Endovascular treatment for patients with renal artery FMD is reserved for symptomatic individuals in whom hypertension cannot be controlled medically. Percutaneous transluminal angioplasty is considered the first line of therapy for patients with symptomatic renal artery FMD, with technical success rates ranging from 83% to 100%. Percutaneous transluminal angioplasty has excellent long-term results, with 5-year primary patency rates greater than 90%.1, 3
Final Diagnosis
Fibromuscular dysplasia of the right renal artery.
References
Case Provided By Maurice A. van den Bosch, MD, PhD, Daniel Y. Sze, MD, PhD, and Lawrence V. Hofmann, MD, Division of Interventional Radiology, Stanford University Medical Center, Stanford, CA.Support: None.Potential conflicts of interest: None.
PII: S0272-6386(07)00255-7
doi:10.1053/j.ajkd.2007.02.261
