Adventitial Fibromuscular Dysplasia of the Renal Artery
Management Challenges of Nonatherosclerotic Renal Artery Stenosis
A 19-year-old healthy woman presented with new onset of severe migrainous headache. She did not take medications or use illicit drugs. There was no personal or family history of hypertension. Physical examination revealed a blood pressure of 220/130 mm Hg in both arms. There was no fourth heart sound. She had full and symmetric pulses in the upper and lower extremities with no radial/femoral delay. There were no carotid, subclavian, or abdominal bruits. Fundoscopic examination revealed normal retinal arteries without hypertensive retinopathy. Renal function and serum potassium were normal. Renal artery duplex ultrasonography revealed elevated peak systolic and end-diastolic velocities in the mid to distal portion of the right renal artery, consistent with severe right renal artery stenosis. The left renal artery was normal. The right kidney measured 8.8 cm with atrophy of the right cortical margin. The left kidney was 11.5 cm. There were normal renal resistive indexes bilaterally.
She had persistent headache, labile blood pressure, and intolerance to her oral antihypertensive medications and was referred for renal arteriography. Selective angiography demonstrated a severe stenosis in the mid right renal artery (Figure 1A). Intravascular ultrasound identified a normal distal right renal artery reference segment (Figure 2A). At the area of stenosis in the mid vessel, there was a marked decrease in the minimum luminal diameter (Figure 2B). The lesion was fibrocalcific and appeared to involve the adventitia. Percutaneous transluminal renal angioplasty with a 3.0×20-mm balloon (Quantum Maverick, Boston Scientific Corp, Natick, Mass) was performed. Significant residual stenosis and flow-limiting dissection were seen (Figure 1B). A 3.5×28-mm Cypher sirolimus-eluting balloon-expandable stent (Cordis, A Johnson & Johnson Co, Miami Lakes, Fla), which was the ideal diameter for the vessel, was deployed. The stent was postdilated with a 4.5-mm balloon with an excellent angiographic result (Figure 1C). Intravascular ultrasound revealed adequate stent apposition, no residual dissection, and an increased minimum residual luminal diameter (Figure 2C). The patient was discharged the next day on lisinopril, aspirin, and clopidogrel. At the 1-month follow-up, she did not require antihypertensive agents, and her headaches have resolved.
Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory vascular disease that may affect any artery, most commonly the renal and internal carotid arteries.1 The pathological classification scheme for FMD is based on the arterial layer—intima, media, or adventitia—in which the lesion predominates.2 Medial fibroplasia, characterized by the classic “string of beads” appearance, is the most common, affecting 75% to 80% of all patients. This patient had adventitial (periarterial) hyperplasia, the least common type, for which limited angiographic information is available.3 FMD occurs in the middle or distal arterial segments in younger patients with few cardiovascular risk factors. In contrast, atherosclerotic renal artery stenosis generally occurs at the ostium and proximal portions of the artery in older patients with typical cardiovascular risk factors.4 It is also important to distinguish FMD from vasculitis.
Revascularization for FMD is considered in young patients with new-onset refractory hypertension. Angioplasty is typically sufficient therapy for medial FMD. Stenting is reserved for failure of percutaneous transluminal renal angioplasty, when there is residual stenosis or flow-limiting dissection, as in our patient. The adventitial type of FMD in this patient may explain why angioplasty was unsuccessful and a stent was required.
In our practice, after endovascular revascularization, patients undergo surveillance duplex ultrasonography within 1, 6, and 12 months to detect restenosis. It can be repeated thereafter annually or if there is worsening hypertension. This case demonstrates the importance of recognizing unusual secondary causes of hypertension, particularly in young patients with no atherosclerotic risk factors.
Dr Rosenfield has served as a consultant to Abbott Vascular, BARD, Baxter, Boston Scientific, Cordis Endovascular, EV3, The Medicines Co, Medical Ventures/B-Balloon, Angioguard, Lumen Biomedical, Xtent, CardioMind, and Medical Simulation Corp. Dr Rosenfeld also has equity investment in Angioguard, Lumen Biomedical, Xtent, CardioMind, Medical Simulation Corp, and CardioMEMS. Dr Jaff has served as a consultant to Cordis Corp; has served on the scientific advisory boards for Abbott Vascular and Nexeon Medical Systems; has equity investment in Square One, Inc; and belongs to VIVA Physicians (not-for-profit 501c3 physician education and research organization). The other authors report no conflicts.