Fibromuscular Dysplasia (FMD)

Updated:Jul 12,2017
FMD is a blood vessel disease that has no unique symptoms and can only be diagnosed with advanced imaging techniques. The first accurate description of FMD occurred in 1958, according to Dr. Jeffrey Olin. Dr. Olin is a professor of medicine at Mount Sinai School of Medicine and Director of Vascular Medicine and the Vascular Diagnostic Laboratory in the Zena and Michael A. Wiener Cardiovascular Institute of The Mount Sinai Medical Center in New York City.

Pam Mace of Rocky River, Ohio, was diagnosed with FMD in 2001, many months after having a transient ischemic attack (TIA) at age 37. She joined the Fibromuscular Dysplasia Society of America (FMDSA) soon after to raise awareness of this disease. “FMD causes the arteries to narrow, blocking blood fl ow,”she said. “It often affects arteries to the kidneys, causing the sudden onset of high blood pressure, or blocking blood flow and causing the destruction of kidney tissue. If FMD affects the carotid or vertebral arteries, people may experience dizziness and chronic headaches or even neurological symptoms such as stroke or TIA. My symptoms were caused by bilateral carotid artery dissections (tears or rips).”

“The name ‘fibromuscular dysplasia’ refers to the fact that the fibrous tissue and muscle layers in the middle of the artery wall grow in an abnormal manner and deform the artery,” said Dr. Richard Hughes, an associate professor in the neurology department at the University of Colorado Health Science Center in Denver. “This makes the normally smooth tube a bumpy tube.”

The most common forms of FMD produce this bumpy tube, which in the angiography produces the characteristic “string of beads” appearance. This is due to changes in the architecture of the artery wall that cause the arteries to alternatively become narrow and dilated. A less common but more aggressive form of FMD may cause the vessels to become severely narrowed without the “string of beads” appearance. 

Read the full feature from Stroke Connection March/April PDF format and see the March 2014 update below.

(Online extra for Stroke Connection magazine Spring 2014 article Uncommon Causes of Stroke, available in e-Zine or PDF format)

We have learned a great deal about fibromuscular dysplasia (FMD) due in large part to the creation of a U.S. Registry for Fibromuscular Dysplasia in 2008. There are currently 921 patients enrolled in the U.S. Registry for Fibromuscular Dysplasia at 14 participating registry centers.

Findings from the U.S. Registry include:
  • Ninety percent of patients with FMD are women, but it does occur in men and children. FMD still falls under the rare disease category, but many feel the disease is under diagnosed.
  • In the U.S. Registry, only 7 percent of patients have a family member with diagnosed with FMD. However, it is noted that among first and second degree relatives of patients with FMD, stroke occurred in half, aneurysm in a quarter and sudden death in 20 percent. Clearly this needs further investigation to determine the relationship of these findings to patients with FMD. It occurs in the renal arteries and the carotid/vertebral arteries approximately 70-75 percent of the time. In the US Registry, the most common presenting signs or symptoms are hypertension, headache, pulsatile tinnitus (swooshing or whooshing sound in the ears) and dizziness.
  • Fortunately, less than 7 percent of patients suffer from a stroke on initial presentation. However, about one in five FMD patients has an arterial aneurysm, and one in five has experienced an arterial dissection. Because of this, imaging is now recommended from the head to the pelvis for every patient with FMD to exclude the presence of an aneurysm.
  • Dr. Esther Kim has shown that women have more cerebrovascular signs/symptoms and men are more likely to have aneurysm or dissection.
  • There is still no known cause or cure for FMD and no standardization for evaluating and treating patients with this disease.
Drs. Jeffrey W. Olin and Heather L. Gornik co-chaired a writing committee put together by the American Heart Association that produced “Fibromuscular Dysplasia: State of the Science.” This is a detailed, multidisciplinary document with expert recommendations on the evaluation and treatment of FMD published in Circulation.

In May 2014, Fibromuscular Dysplasia Society of America (FMDSA) medical advisory board members Gornik and Olin will co-chair the First International Fibromuscular Dysplasia Research Network Symposium, bringing together key researchers in the field of FMD from the U.S. and Europe. Leaders in the field of clinical care, genetics, epidemiologists, interventional specialists, imaging specialists and basic scientists will gather and exchange scientific ideas. The goal of the meeting is to establish a multidisciplinary collaborative FMD Research Network to determine what research is needed and determine how best to fund and complete such research. Details and findings of the Research Symposium will be shared at the FMDSA annual meeting May 17, 2014 in Cleveland, Ohio.

The good news is that several centers are actively participating in research looking for the gene(s) associated with FMD and ultimately its cause. Only then can a cure be found. A further description of this research can be found on the FMDSA website under ‘research studies’.

For more information on FMD:

Cardiology Patient Page, Circulation, 2012

Bringing Awareness to an Under-Recognized Medical Conundrum

Fibromuscular Dysplasia: State of the Science and Critical Unanswered Questions: A Scientific Statement From the American Heart Association

Fibromuscular Dysplasia Society of America

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