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 condition 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

• FMD is a systemic disease that can affect multiple vascular beds, making it essential to consider possible involvement of the carotid, coronary, and other major arteries 1.
• Patients with FMD are at risk of dissection if blood pressure is not controlled, highlighting the importance of medical therapy to reduce blood pressure in the first instance 1.
• Regular monitoring with vascular imaging is recommended to detect any changes in disease severity or the development of complications such as dissection or aneurysm rupture.

Management

• PTRA without stenting is the preferred treatment for FMD, as it can restore renal perfusion pressure and lower blood pressure 1.
• Medical therapy, including blood pressure control and antiplatelet therapy, is also essential in managing FMD, particularly in patients who are not candidates for PTRA or have significant atherosclerotic renal artery stenosis 1.
• RAS blockers can be used as an alternative treatment, but require careful monitoring of renal function over time, as they can cause acute renal failure in patients with tight bilateral stenoses or a stenosed solitary functioning kidney 1.

From the Research

Definition and Pathogenesis of Fibromuscular Dysplasia

• Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease that may involve medium-sized muscular arteries throughout the body 2.
• The pathogenesis of FMD remains poorly understood, but a combination of genetic and environmental factors may be involved 2.
• FMD is a non-inflammatory, non-atherosclerotic disease that has been reported in almost every arterial bed and primarily affects women aged 15-50 years 3.

Clinical Manifestations and Diagnosis

• The majority of FMD patients are women, but men may have a more progressive disease, especially when smoking 2.
• Arterial hypertension and neurological symptoms are the most frequent clinical presentations, as renal and cerebrovascular arteries are the most commonly involved 2.
• Diagnosis is based on CT-, MR-, or conventional catheter-based angiography during work-up of clinical manifestations, but clinically silent lesions may be found incidentally 2.
• FMD can lead to several complications, such as hypertension, headaches, dissections, aneurysms, myocardial infarctions, and cerebrovascular accidents 4.

Management and Treatment

• The management of FMD depends on the vascular phenotype as well as the clinical picture 2.
• Treatment consists of antiplatelet therapy for asymptomatic individuals and percutaneous balloon angioplasty for patients with indications for intervention 3.
• Patients with macroaneurysms should be treated with either a covered stent or surgery 3.
• Anti-platelet agents were administered to 72.9% of patients, and factors associated with a greater likelihood of anti-platelet agent use were older age, CAD, cerebrovascular artery FMD involvement, and a history of previous intervention for FMD 5.

Research and Consensus

• Ongoing FMD-related research will elaborate in depth the current progress in improved understandings of the disease's clinical manifestations, epidemiology, natural history, and pathogenesis 2.
• A comprehensive review of current literature on epidemiology, etiology, diagnosis, treatment, and long-term surveillance and FMD management is necessary 4.
• The First International Consensus on the diagnosis and management of fibromuscular dysplasia provides updated data from the US Registry for FMD and proposes future research directions for understanding this multifaceted arterial disease 6.