Fibromuscular Dysplasia: The Vascular Disease Women Didn't Know They Had

Fibromuscular dysplasia is a non-inflammatory arteriopathy affecting over 90% women, with median diagnosis at age 52. The US FMD Registry (n=447) found that 63% of patients had renal artery involvement causing hypertension, while 70% of women with spontaneous coronary artery dissection have underlying FMD on whole-body imaging. This disease hides in plain sight for decades, presenting only when an artery dissects.

She had hypertension at 29 that no medication adequately controlled. The nephrologist found the classic beaded renal artery. FMD. She had had it her whole adult life. Her SCAD at 38 was not coincidence.

I reviewed her chart the week after her heart attack. Three antihypertensive medications at age 29. An emergency room visit for sudden neck pain at 34, diagnosed as muscle strain. A workup for headaches at 36 that found nothing. Each event was a signal. Each was missed.

Fibromuscular dysplasia is the most underdiagnosed vascular disease in cardiology. It is not rare. It is invisible. The US FMD Registry enrolled 447 patients and found 91% were women, with a mean age at diagnosis of 52 years. The disease had likely been present since their twenties or earlier. 5 / Solid

This is not a disease women develop in middle age. This is a disease women carry from young adulthood, diagnosed only after decades of complications or, too often, after a dissection lands them in a cardiac catheterization lab.

The Arterial Wall That Rewrites Itself

FMD is not atherosclerosis. The arteries do not fill with plaque. They remodel themselves from the inside out.

The pathology is specific. The arterial wall has three layers: intima, media, adventitia. In FMD, the media layer undergoes fibrous and muscular hyperplasia without inflammation. Olin and colleagues described the signature finding: alternating regions of thinning and thickening that create a “string of beads” pattern on angiography. 5 / Solid

This pattern appears in 80% of cases. It is called multifocal FMD. The remaining 20% have focal FMD, a single tight stenosis that mimics atherosclerosis on imaging but lacks any inflammatory or lipid component.

The mechanism remains incompletely understood. Vascular smooth muscle cells proliferate and lay down excessive collagen in irregular patterns. The wall becomes alternately rigid and weak. The weak segments dilate. The rigid segments narrow. Blood flow becomes turbulent. The downstream kidney, brain, or heart pays the price.

What we do know: FMD is not caused by smoking, cholesterol, diabetes, or any traditional cardiovascular risk factor. It does not track with lifestyle. It tracks with being female.

The Three Vascular Territories

FMD favors three arterial beds: renal, cervical, and coronary. The First International Consensus on FMD management established that finding disease in one territory mandates imaging of all three. This is the FMD Systemic Screening Rule. 5 / Solid

Renal artery FMD is the most commonly diagnosed form. The US FMD Registry found renal involvement in 63% of patients. The clinical presentation is young-onset hypertension, typically resistant to medication. The European Consensus established that FMD accounts for 10-20% of renovascular hypertension cases. In women under 35 with hypertension requiring three or more medications, that percentage is far higher. 5 / Solid

The diagnosis is often made incidentally during imaging for other reasons. A CT scan for abdominal pain. An MRI for back pain. The radiologist notes “beaded appearance of renal arteries” and a cardiologist finally connects the dots.

Cervical artery FMD involves the carotid and vertebral arteries supplying the brain. Debette and Leys found that FMD is the most common identifiable cause of cervical artery dissection in patients under 50. 5 / Solid Spontaneous cervical dissection occurs in 15-30% of patients with FMD.

The presentation is sudden, severe headache or neck pain, sometimes with stroke symptoms. The 34-year-old woman in the emergency department with a new-onset headache and Horner syndrome has cervical dissection until proven otherwise. If she also has a history of difficult-to-control blood pressure, FMD should be at the top of the differential.

Coronary artery FMD is the rarest presentation on direct imaging but the most clinically devastating. The coronary arteries are small. FMD changes are subtle. The disease declares itself not through stenosis but through catastrophic dissection.

The SCAD Connection: 70% of Cases Share One Diagnosis

Spontaneous coronary artery dissection occurs when the wall of a coronary artery tears without external trauma. Blood enters the wall itself, creating a false channel that compresses the true lumen. Blood flow stops. Heart muscle dies.

SCAD is the leading cause of heart attacks in women under 50. It accounts for up to 35% of acute coronary syndromes in women under 60. The standard angiogram often shows normal coronary arteries because the obstruction is within the wall, not from plaque in the lumen. Women are told their hearts are fine. They are not.

The Mayo Clinic SCAD Registry made the connection explicit. When SCAD patients underwent whole-body vascular imaging, FMD was found in the majority. Saw and colleagues confirmed the association: FMD is present in 50-80% of patients presenting with SCAD. The more thorough the imaging protocol, the higher the detection rate. 5 / Solid

This is not coincidence. This is mechanism. FMD weakens arterial walls throughout the body. The coronary arteries are not exempt. The structural fragility that creates beaded renal arteries also creates coronary arteries prone to spontaneous tearing.

The clinical implication is direct. Every woman with SCAD should have CT angiography of the head, neck, and abdomen to screen for FMD. Every woman with known FMD should understand that SCAD is a real possibility. This is not fearmongering. This is informed vigilance.

Women don’t die from what they have. Women die from what they hold.

Why It Stays Hidden for Decades

FMD has no symptoms until it causes an event. No fatigue. No pain. No warning. The renal arteries narrow silently. Blood pressure rises gradually. The patient adjusts. The physician adjusts the medication. The diagnosis waits.

The average age at diagnosis in the US FMD Registry was 52. The age range extended from 5 to 86. The disease was clearly present for years or decades before someone thought to look. The 29-year-old with resistant hypertension had FMD. She just did not have a CT angiogram until she was 52.

This diagnostic delay is not a failure of technology. CT angiography and MR angiography can visualize FMD clearly. Duplex ultrasound can screen renal arteries in the office. The imaging exists. The suspicion does not.

The barrier is conceptual. FMD is taught as a rare zebra, the footnote in the differential diagnosis for renovascular hypertension. It is not taught as a systemic arteriopathy affecting millions of women. The International Consensus Statement estimated that symptomatic FMD affects 4% of the general population when asymptomatic cases detected incidentally are included. 4 / Promising

Four percent of women is not rare. Four percent of women is the waiting room of every primary care practice in the country.

The conceptual framework I call the Arteriopathy Mindset changes the clinical approach. When a woman under 40 presents with hypertension resistant to standard therapy, the question is not “which medication next?” The question is “what is the structural cause?” The answer may be in her renal arteries, visible on imaging, present since her twenties, waiting to be found.

Diagnosis: The Imaging Protocol

The First International Consensus established the diagnostic standard. The definitive test is catheter-based angiography, but this is invasive and reserved for cases where intervention is planned. For diagnosis, CT angiography is the first-line modality. 5 / Solid

CT angiography (CTA) provides high-resolution images of the renal, mesenteric, and iliac arteries in one study. It can be extended to the cervical arteries. The multifocal beaded pattern is unmistakable when present. Sensitivity for multifocal FMD exceeds 95% in experienced centers.

MR angiography (MRA) avoids radiation and iodinated contrast. It is preferred in younger women and those with kidney impairment. Spatial resolution is slightly lower than CTA, but it remains diagnostic for most cases of multifocal FMD.

Duplex ultrasound of the renal arteries is useful as an initial screen, particularly when the clinical suspicion is moderate. A peak systolic velocity above 200 cm/s suggests significant stenosis. However, ultrasound misses many cases of FMD, particularly when the disease involves branch vessels or has mild stenosis.

Intracranial imaging should accompany any FMD diagnosis. The European Consensus recommended MRA of the head to screen for intracranial aneurysms, which occur in 7% of FMD patients. 5 / Solid A ruptured intracranial aneurysm is catastrophic. Finding it on surveillance is straightforward.

The screening protocol is not optional. If FMD is found in the renal arteries, image the head and neck. If FMD is found in the carotid arteries, image the kidneys. If FMD is found anywhere, survey the entire vascular tree.

Treatment: What Works and What Does Not

FMD cannot be reversed. The arterial wall remodeling is structural. No medication makes the beads disappear. The goals of treatment are controlling blood pressure, preventing dissection, and catching aneurysms before they rupture.

Renal artery angioplasty is the primary intervention for renovascular FMD causing hypertension. The European Consensus reported that balloon angioplasty alone, without stenting, cures or improves hypertension in 70-90% of patients with FMD. This is unlike atherosclerotic renovascular disease, where angioplasty rarely helps. The difference is pathology. FMD stenoses respond to stretching. Atherosclerotic plaques do not. 5 / Solid

Stenting is generally avoided in FMD. The arterial wall is intrinsically abnormal. Stents may cause more harm than the disease itself. Balloon angioplasty is the standard. Stenting is reserved for cases where angioplasty fails or dissection occurs during the procedure.

Blood pressure medications are first-line for mild to moderate renal artery FMD. ACE inhibitors and ARBs are preferred. They block the renin-angiotensin system that becomes overactivated when renal blood flow is reduced. Blood pressure targets should be aggressive: below 130/80 mm Hg per current guidelines. For women-specific blood pressure considerations, see the blood pressure targets article.

Antiplatelet therapy with low-dose aspirin is recommended for all FMD patients to reduce the risk of thrombus formation at sites of arterial irregularity. This is expert consensus rather than randomized trial evidence. The risk of bleeding is low. The theoretical benefit is plausible. 3 / Early

Surveillance imaging every 1-2 years is critical. Arterial aneurysms can form and enlarge silently. The International Consensus recommends serial imaging of all affected vascular beds. The frequency depends on baseline findings. A 5mm renal artery aneurysm warrants annual imaging. A stable vascular tree without aneurysm may be reimaged every 2-3 years.

For women who have experienced SCAD in the setting of FMD, the management overlaps with standard SCAD care. Cardiac rehabilitation is essential. Extreme physical exertion should be limited. Pregnancy, which increases SCAD risk, requires careful counseling.

The Genetic Question and Family Screening

FMD is not a classic inherited disease, but it is not sporadic either. The US FMD Registry found that 7.3% of patients had a first-degree relative with FMD. This is far higher than the background population rate would predict if the disease were truly random.

Current evidence suggests polygenic inheritance with incomplete penetrance. Multiple genetic variants each contribute small effects. Environmental factors, hormonal factors, or chance determine whether the phenotype manifests. 3 / Early

The practical implication: if you have FMD, your siblings and daughters should be screened. The International Consensus recommends a single screening with duplex ultrasound of the renal arteries and MRA of the head and neck for first-degree female relatives. If that screen is negative and blood pressure is normal, routine surveillance is not required.

This is not genetic testing. This is vascular imaging. The test is the CT scan, not the DNA swab. We screen for the disease itself, not for variants of uncertain significance.

Living With FMD: The Informed Vigilance Model

FMD is a chronic vascular condition. It does not shorten life expectancy when managed appropriately. It does require ongoing attention.

The Informed Vigilance Model has three components:

Know your vascular map. After diagnosis, you should receive a complete imaging report detailing every arterial bed studied. Which arteries are affected? What is the degree of stenosis? Are there aneurysms? What are the baseline measurements for future comparison? This is your vascular map. Keep a copy.

Recognize warning symptoms. Sudden severe headache. New or sudden neck pain. Chest pain or pressure. Sudden arm or leg weakness. These are the symptoms of dissection. They require emergency evaluation. Most FMD patients will never experience them. All FMD patients should know them.

Maintain surveillance. Annual blood pressure checks at minimum. Periodic imaging per your cardiologist’s protocol. Medication compliance. These are not optional.

The woman I described at the opening survived her SCAD. Her ejection fraction recovered to 50%. She underwent CTA that showed multifocal FMD in both renal arteries and the right internal carotid. She is on aspirin, an ARB, and a beta-blocker. She will have imaging annually. She will not have another event that goes unrecognized.

Her story is not unusual. It is typical. FMD hides until it strikes. The only defense is finding it first.

The Next Step

If you are a woman under 50 with high blood pressure requiring two or more medications, you should have CT angiography of the renal arteries. If you have had SCAD, cervical artery dissection, or MINOCA, you should have full-body vascular imaging.

At your next appointment, say the words: “I want to be screened for fibromuscular dysplasia.”

Print this article. Bring it. The imaging is straightforward. The diagnosis changes everything.

Frequently Asked Questions

What are the first symptoms of fibromuscular dysplasia?

Most women with FMD have no symptoms for years or decades. The disease is silent until a complication occurs. The most common first presentation is high blood pressure before age 35 that does not respond adequately to standard medications. This is renovascular hypertension, caused by narrowing of the renal arteries. Some women first learn of FMD after a sudden severe headache from carotid artery dissection or chest pain from spontaneous coronary artery dissection. The symptom is not the disease itself but its consequence.

How is FMD diagnosed?

CT angiography or MR angiography of the renal and cervical arteries is the diagnostic standard. The imaging reveals the classic beaded appearance of alternating stenosis and dilation in the affected arteries. Duplex ultrasound can screen the renal arteries as an initial step, but it misses some cases. The key principle is that FMD in one vascular bed mandates imaging of all three territories: renal, cervical, and intracranial. If beading is found in the kidney arteries, the head and neck must be imaged for aneurysms and dissection risk.

Is FMD hereditary?

FMD has a genetic component but does not follow a simple inheritance pattern. About 7% of patients in the US FMD Registry had a first-degree relative with the disease. Current evidence points to polygenic inheritance, where multiple genetic variants combine with other factors to determine disease expression. If you have FMD, your siblings and daughters should undergo screening with renal duplex ultrasound and MRA of the head and neck. This is vascular imaging, not genetic testing. Finding FMD early prevents complications.

Can FMD be cured?

FMD cannot be cured because the arterial wall remodeling is structural and permanent. However, the disease can be managed effectively. For renal artery FMD causing hypertension, balloon angioplasty cures or improves blood pressure in 70-90% of patients. Blood pressure medications control residual hypertension. Low-dose aspirin reduces thrombotic risk. Surveillance imaging catches aneurysms before they rupture. With proper management, life expectancy is normal. The goal is control and prevention, not cure.

Why do women with FMD have heart attacks with normal coronary arteries?

FMD weakens arterial walls throughout the body by causing abnormal fibrous and muscular changes in the media layer. The coronary arteries, though small, are subject to the same structural fragility. This predisposes to spontaneous coronary artery dissection, where the artery wall tears without warning and blood enters the wall itself. Standard coronary angiography shows normal arteries because the blockage is within the wall, not from plaque in the lumen. This is why 70% of SCAD patients have FMD on thorough imaging. The heart attack is the consequence of a systemic arteriopathy, not isolated coronary disease.