What is fibromuscular dysplasia (FMD)?

From the Guidelines

Percutaneous transluminal renal angioplasty (PTRA) without stenting is the treatment of choice for fibromuscular dysplasia, as it can restore renal perfusion pressure and lower blood pressure. Fibromuscular dysplasia (FMD) is a non-inflammatory, non-atherosclerotic vascular disease that affects multiple vascular beds, including the renal and carotid arteries, and can lead to significant morbidity and mortality if left untreated 1. The disease is characterized by abnormal cell growth in artery walls, resulting in narrowing, aneurysms, or tears, and can present with symptoms such as hypertension, headaches, pulsatile tinnitus, and stroke.

Key Considerations

• Patients with FMD should receive medical therapy to reduce blood pressure in the first instance, and PTRA without stenting is recommended for those with significant artery narrowing causing symptoms or organ damage 1.
• Regular follow-up with a vascular specialist is essential, and patients should be screened for associated aneurysms and other vascular involvement, as FMD is now recognized as a systemic disease affecting multiple vascular beds 1.
• The use of RAS blockers is recommended for patients with FMD, but requires careful monitoring of renal function over time, as they can cause acute renal failure in those with tight bilateral stenoses or a stenosed solitary functioning kidney 1.

Management and Treatment

• Antiplatelet therapy with aspirin (81-325 mg daily) may be recommended to prevent clot formation and reduce the risk of cardiovascular events.
• Comprehensive vascular imaging is necessary to identify all affected vessels and guide treatment decisions.
• Patients with significant atherosclerotic renal artery stenosis are at high risk of cardiovascular and renal events, and PTRA and stenting should be performed in experienced centers due to the high risk of restenosis 1.

From the Research

Definition and Prevalence of Fibromuscular Dysplasia

• Fibromuscular dysplasia (FMD) is a generalized vascular disease that may affect all vascular beds, resulting in arterial stenosis, occlusion, aneurysm, or dissection 2.
• FMD is an under-recognized non-atherosclerotic, non-inflammatory arteriopathy that occurs most commonly in middle-aged women, but may affect individuals of all age groups 3.

Clinical Manifestations and Diagnosis

• Clinical manifestations of FMD often reflect the vascular territory affected and can include hypertension, headaches, pulsatile tinnitus, myocardial infarction, transient ischemic attack, and stroke 3.
• The gold standard for diagnostic evaluation of FMD remains catheter-based angiography, but noninvasive imaging such as duplex ultrasound, computed tomographic angiography, and magnetic resonance angiography may be used for diagnosis 3.
• Angiography of renal arteries with FMD often displays "beaded" luminal abnormalities, but may not accurately reflect the severity or precise location of the intraluminal obstruction 4.

Treatment and Management

• Treatment of FMD depends on symptoms as well as the nature and location of arterial lesions, and may include both medical (blood pressure control, antiplatelet agents) and interventional (angioplasty, stents, coils, surgery) therapies 3.
• Percutaneous transluminal angioplasty can be an effective treatment for FMD affecting the renal arteries, especially when guided by pressure wire measurements and intravascular ultrasound 5, 4.
• European consensus recommends up-to-date guidelines for the diagnosis, evaluation, and management of FMD, emphasizing the importance of raising awareness about the disease and its potential consequences 6.

Systematic Evaluation and Impact on Clinical Decisions

• Systematic and multidisciplinary evaluation of patients with FMD, including whole-body computed tomography angiography, can have a significant impact on clinical management and may lead to the detection of previously undetected FMD lesions and vascular complications 2.
• The ARCADIA-POL study demonstrated that one out of every four evaluated patients with FMD qualified for interventional treatment due to newly diagnosed FMD lesions or vascular complications, highlighting the necessity of systematic evaluation of all vascular beds in patients with FMD 2.