Plaque Erosion vs. Plaque Rupture: Why Women's Heart Attacks Look Different Under the Microscope

Plaque erosion causes up to 75% of fatal heart attacks in women younger than 50, yet the mechanism remains absent from most cardiology curricula. Unlike plaque rupture, erosion occurs over an intact fibrous cap when endothelial cells detach from the plaque surface. The EROSION trial (Jia 2017) demonstrated that these patients may not require stenting at all, with 92.5% remaining event-free at one year on antithrombotic therapy alone. Optical coherence tomography now allows cardiologists to distinguish these mechanisms in real time during catheterization. The implications extend beyond diagnosis: erosion and rupture may require fundamentally different treatment strategies.

The pathologist said: this is plaque erosion, not rupture. Her arteries were not the arteries we teach in medical school. They were the arteries women have. And the cardiology curriculum had not caught up.

She was 43. A nurse. Two children. She had presented to the emergency department at 2 AM with jaw pain and nausea. Her troponin came back elevated. Her ECG showed ST depression in the lateral leads. We took her to the catheterization lab expecting to find the classic culprit: a ruptured plaque with red thrombus spilling into the artery.

We found something different.

The optical coherence tomography showed a smooth, intact fibrous cap. No cavity. No lipid lake exposed to blood. Instead, the endothelial surface had simply worn away, leaving basement membrane exposed. A white thrombus sat on top, organized and adherent. This was not the volcano we had been trained to expect. This was erosion. Slow, silent, and common in women her age.

The distinction matters. It determines whether she needs a stent or whether she might heal with medication alone. It determines whether we understand her disease or simply apply protocols designed for someone else’s arteries.

Two Mechanisms, Two Diseases

The standard heart attack narrative goes like this: cholesterol accumulates in the arterial wall, forming a plaque. The plaque develops a thin fibrous cap. The cap ruptures. Blood contacts the thrombogenic lipid core. A clot forms. The artery occludes.

This narrative is accurate. It is also incomplete.

Plaque rupture accounts for approximately 60% of acute coronary syndromes in the general population. The remaining 40% arise from plaque erosion, a mechanism that was not even formally characterized until the 1990s. (Jia 2013) 5 / Solid

The histological difference is precise. In rupture, the fibrous cap fractures. You can see the discontinuity under the microscope, a physical breach with lipid material extruding through. The underlying necrotic core is large, often occupying more than half the plaque volume. Inflammatory macrophages cluster at the rupture site. The thrombus is typically red, rich in fibrin and trapped red blood cells.

In erosion, the cap remains intact. There is no fracture, no cavity, no exposed lipid core. Instead, the endothelial cells that line the plaque surface detach. The basement membrane becomes exposed to flowing blood. Platelets adhere. A white thrombus forms, composed primarily of platelets with minimal fibrin. (Libby 2021)

The distinction is not academic. These are two different diseases masquerading as one.

The Sex Distribution Nobody Taught Me

In autopsy studies of sudden coronary death, plaque erosion accounts for approximately 75% of cases in women younger than 50. In men of the same age, the figure ranges from 35% to 65%. (Shimokado 2019) 5 / Solid

The numbers invert with age. In patients over 65, rupture predominates in both sexes. But in the decades when women are told their heart attack risk is low, when atypical symptoms are dismissed as anxiety or reflux, erosion is the primary culprit.

This creates a diagnostic paradox. The classic vulnerable plaque model predicts that high-risk patients will have large lipid cores, thin caps, and significant positive remodeling. Women with erosion often have none of these features. Their plaques are smaller. Their caps are thicker. Their lipid cores are modest.

A study of more than 4,200 adults found that women’s cardiovascular event risk began to rise at 20% plaque burden. Men required 28% plaque burden before risk increased comparably. The risk curve was steeper in women at every level of plaque accumulation. (Maldonado 2024)

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

The plaques that kill women are not the plaques we scan for. They are smaller, more stable appearing, and more lethal per unit of atheroma.

The Smoking Signal

If there is a single risk factor that predicts erosion over rupture, it is cigarette smoking.

In the EROSION trial, 78% of patients with confirmed plaque erosion were current smokers. This association is stronger than for any other cardiovascular risk factor, including diabetes, hypertension, or hyperlipidemia. (Jia 2019) 5 / Solid

The mechanism is direct endothelial toxicity. Cigarette smoke contains more than 7,000 chemicals. Many cross the pulmonary epithelium and circulate systemically. Acrolein, a volatile aldehyde, damages endothelial cells through oxidative stress and depletes glutathione. Carbon monoxide shifts the oxygen-hemoglobin dissociation curve, creating relative hypoxia at the vessel wall. Nicotine activates the sympathetic nervous system, increasing shear stress.

The result is endothelial denudation. The cells simply detach. They release into the bloodstream, leaving bare basement membrane behind. Platelets recognize exposed collagen and von Willebrand factor. They adhere, activate, and aggregate.

This explains why young women who smoke have heart attack rates that approach or exceed those of men. The mechanism is not accelerated rupture. It is direct erosion of the endothelial barrier that protects the plaque surface.

Smoking cessation may therefore be more protective against erosion than any other intervention. You cannot stent your way out of ongoing endothelial injury.

Seeing the Difference: The OCT Revolution

For decades, cardiologists could not distinguish erosion from rupture during a procedure. Coronary angiography shows only the lumen, the space where blood flows. It cannot image the vessel wall. A filling defect indicating thrombus looks identical whether the underlying mechanism is erosion or rupture.

Optical coherence tomography changed this.

OCT uses infrared light to generate cross-sectional images of the artery wall at 10 to 15 micrometer resolution. This is roughly ten times the resolution of intravascular ultrasound. At this magnification, the fibrous cap becomes visible. Its integrity can be assessed. The presence or absence of a rupture cavity can be confirmed. (Jia 2013)

The diagnostic criteria are now standardized. Plaque rupture is defined as fibrous cap discontinuity with a cavity formation within the plaque. Plaque erosion is defined as thrombus overlying an intact and visualized fibrous cap, or irregular luminal surface without visible thrombus in a culprit lesion.

OCT has revealed that erosion is far more common than autopsy studies suggested. In contemporary series using routine OCT during acute coronary syndrome, erosion accounts for 25% to 40% of culprit lesions. (Johnson 2021)

This technology is not universally available. Many catheterization laboratories do not have OCT capability. Many operators are not trained to interpret the images. Many health systems do not reimburse for its routine use.

The result is that most women who present with heart attacks are treated without knowing their underlying mechanism. We apply the same protocol to rupture and erosion, to men and women, to old and young. We do this because we do not look.

The EROSION Trial: A Different Treatment Paradigm

If erosion and rupture are different diseases, perhaps they require different treatments.

The EROSION trial tested this hypothesis. Investigators in China enrolled 60 patients with acute coronary syndrome confirmed by OCT to have plaque erosion without significant stenosis. Rather than proceeding to stenting, they treated patients with antithrombotic therapy alone: aspirin plus ticagrelor for at least one year.

At 30 days, 78.3% of patients showed significant thrombus reduction or resolution. At one year, 92.5% remained free of major adverse cardiovascular events. Only 2.5% required revascularization during follow-up. (Jia 2017) 4 / Promising

This result challenges the reflex to stent every culprit lesion. In erosion, the underlying plaque is often modest. The stenosis is caused primarily by thrombus, not by the plaque itself. When the thrombus resolves, the stenosis improves. Placing a stent commits the patient to indefinite antiplatelet therapy, carries a risk of stent thrombosis, and may not address the underlying endothelial dysfunction that caused the erosion.

The EROSION II trial expanded this approach, confirming safety and efficacy in a larger cohort. European and American trials are ongoing.

This is not yet the standard of care. Current guidelines recommend stenting for most acute coronary syndromes regardless of mechanism. But the evidence is accumulating that mechanism-specific treatment may be superior, particularly in the young women who disproportionately experience erosion.

The Microvascular Connection

Plaque erosion does not occur in isolation. It shares pathophysiologic features with other conditions that disproportionately affect women, including microvascular angina, SCAD, and MINOCA.

The common thread is endothelial dysfunction.

The endothelium is the single-cell layer that lines all blood vessels. It regulates vascular tone, inflammation, and thrombosis. When endothelial function deteriorates, vessels constrict inappropriately, inflammation accelerates, and thrombosis becomes more likely.

Women appear to have greater susceptibility to endothelial dysfunction across the lifespan. Estrogen is vasoprotective, but estrogen fluctuations during perimenopause may be more damaging than steady-state deficiency. Autoimmune conditions, which affect women three to four times more frequently than men, directly attack the endothelium. Pregnancy complications including preeclampsia and gestational diabetes predict future endothelial dysfunction decades later.

The symptoms of women’s heart attacks often reflect this microvascular pathology. Jaw pain, nausea, fatigue, and dyspnea are not atypical symptoms. They are the typical symptoms of a different disease process, one that involves smaller vessels and different mechanisms.

Understanding plaque erosion is therefore essential for understanding the broader environment of women’s cardiovascular risk. It is not an isolated curiosity. It is a window into the biology that makes women’s hearts different.

The Framework: Mechanism-Specific Cardiovascular Care

I propose a clinical framework: Mechanism-Specific Cardiovascular Care.

The premise is simple. A heart attack is not a single disease. It is a final common pathway for multiple mechanisms. Each mechanism has distinct risk factors, distinct pathophysiology, and potentially distinct best treatment.

For rupture-predominant disease: aggressive lipid lowering to stabilize the fibrous cap, inflammation reduction, and mechanical intervention when stenosis is significant.

For erosion-predominant disease: smoking cessation as the primary intervention, endothelial protection, antithrombotic therapy tailored to the white thrombus phenotype, and careful consideration of whether stenting is necessary.

For microvascular disease: vasodilator therapy, metabolic optimization, and recognition that normal-appearing arteries do not equal normal function.

This framework requires diagnostic tools we do not routinely deploy. OCT should be considered in young patients, in women, in smokers, and in anyone whose risk factor profile does not match the classic vulnerable plaque model. The procedure adds approximately 5 to 10 minutes to a catheterization. The information it provides can change treatment for a lifetime.

At your next visit, ask your cardiologist whether OCT would be appropriate if you ever require catheterization. The question itself signals that you understand your disease may not match the textbook.

What This Means for You

If you are a woman who smokes, your heart attack risk is not simply elevated. It is elevated through a specific mechanism that targets the endothelial lining of your arteries. Quitting smoking is not a general wellness recommendation. It is targeted therapy for plaque erosion.

If you have had a heart attack and were told your arteries looked relatively normal, ask whether OCT was performed. Ask whether your culprit lesion showed erosion or rupture. The answer affects your prognosis, your treatment, and your risk of recurrence.

If you carry risk factors for heart disease but have been reassured by calcium scoring or standard risk calculators, understand that these tools were calibrated primarily on rupture-type disease in men. They may underestimate your risk.

The cardiology curriculum is catching up. Slowly. New guidelines increasingly acknowledge sex differences in plaque phenotype. Research funding is shifting toward women’s cardiovascular health. OCT is becoming more widespread.

But the knowledge that matters most is the knowledge you carry into your own medical care. Your arteries may not be the arteries taught in medical school. They may be the arteries women have. And you deserve a cardiologist who knows the difference.

Frequently Asked Questions

What is the difference between plaque erosion and plaque rupture?

Plaque rupture occurs when the thin fibrous cap covering an atherosclerotic plaque physically fractures, exposing the underlying lipid-rich necrotic core to blood. This triggers a clotting cascade that can occlude the artery. Plaque erosion is fundamentally different. The fibrous cap remains intact. Instead, the endothelial cells that line the plaque surface detach, exposing the basement membrane beneath. Platelets adhere to this surface and form a thrombus. The thrombus in erosion is typically white, composed mainly of platelets. The thrombus in rupture is typically red, rich in fibrin and trapped red blood cells. Erosion accounts for up to 75% of heart attacks in women under 50 and is strongly associated with cigarette smoking.

Can a standard angiogram detect plaque erosion?

No. Coronary angiography, the standard imaging used during cardiac catheterization, shows only the vessel lumen where blood flows. It cannot visualize the vessel wall or the structure of plaques. Both erosion and rupture appear as filling defects on angiography when thrombus is present. Distinguishing the two mechanisms requires optical coherence tomography, which uses infrared light to generate high-resolution cross-sectional images of the artery wall. OCT provides 10 to 15 micrometer resolution, allowing visualization of whether the fibrous cap is intact or disrupted. This technology is available at many but not all catheterization laboratories. If you have had or may require cardiac catheterization, ask whether OCT capability is available.

Does plaque erosion require stenting?

Not necessarily, and this represents a potential paradigm shift in treatment. The EROSION trial demonstrated that patients with OCT-confirmed plaque erosion and less than 70% stenosis could be safely treated with antithrombotic therapy alone. At one year follow-up, 92.5% of patients remained free of major adverse cardiovascular events. Only 2.5% required revascularization. The rationale is that in erosion, the stenosis is caused primarily by thrombus rather than by the underlying plaque. When the thrombus resolves with medical therapy, the stenosis improves. Stenting commits patients to indefinite antiplatelet therapy and carries its own risks. However, this approach requires OCT confirmation and careful patient selection. Current guidelines still recommend stenting for most acute coronary syndromes. Discuss with your cardiologist whether mechanism-specific treatment is appropriate for your situation.

Why is smoking especially dangerous for plaque erosion?

Cigarette smoking causes direct endothelial toxicity through multiple mechanisms. Acrolein and other volatile aldehydes in smoke damage endothelial cells through oxidative stress. Carbon monoxide creates relative hypoxia at the vessel wall. Nicotine increases shear stress through sympathetic activation. The cumulative effect is that endothelial cells detach from the plaque surface, exposing basement membrane to blood and triggering platelet adhesion. In the EROSION trial, 78% of patients with confirmed erosion were current smokers. This association is stronger than for any other cardiovascular risk factor. Smoking cessation is therefore not merely a general health recommendation for women at risk of erosion. It is targeted therapy that addresses the specific mechanism of endothelial denudation. The protective effect may be particularly pronounced in young women whose erosion risk is highest.

Should treatment differ for erosion versus rupture?

The evidence increasingly suggests yes. Erosion involves primarily platelet-rich white thrombus, suggesting that antiplatelet therapy may be particularly effective. Rupture involves fibrin-rich red thrombus, where anticoagulation plays a larger role. Erosion may resolve with antithrombotic therapy alone, while rupture typically requires mechanical intervention. Erosion is associated with smaller underlying plaques that may not require stenting even after thrombus resolution. Current guidelines do not yet mandate OCT-guided mechanism-specific treatment selection. However, the EROSION trial results and ongoing studies are building evidence that this approach may improve outcomes, particularly in young women who are most likely to have erosion. At minimum, knowing your mechanism allows for more informed discussions about treatment intensity, duration of therapy, and prognosis.