A SCAD heart attack happens when the wall of a coronary artery tears or bleeds internally, blocking blood flow to the heart. Unlike a typical heart attack caused by cholesterol plaque buildup, SCAD (spontaneous coronary artery dissection) occurs in arteries that are otherwise healthy. It accounts for a small but significant share of heart attacks, particularly in women under 60 who have few or no traditional heart disease risk factors.
How SCAD Differs From a Typical Heart Attack
In a conventional heart attack, a fatty plaque inside an artery ruptures and forms a clot that blocks blood flow. SCAD works through an entirely different mechanism. The coronary artery wall itself develops a problem: either a tear in its inner lining lets blood seep between the layers, or tiny blood vessels within the artery wall bleed spontaneously, forming a pocket of trapped blood called an intramural hematoma. Either way, this pocket of blood expands, compresses the artery from the outside in, and chokes off blood flow to the heart muscle.
The separation typically occurs in the outer third of the artery’s middle layer. Whether the tear comes first or the internal bleeding comes first is still debated. Some cases show a clear entry tear, while in others the bleeding appears to start on its own from tiny vessels that nourish the artery wall. The end result is the same: the heart muscle downstream is starved of oxygen, producing a true heart attack.
Who Gets SCAD
About 90% of SCAD patients are women. In a study of over 1,100 SCAD patients, only 10.5% were men. Women with SCAD are typically diagnosed around age 52 on average, while men tend to be slightly younger, around 49. This stands in sharp contrast to atherosclerotic heart attacks, which skew heavily toward older men with high cholesterol, high blood pressure, or diabetes.
More than half of SCAD patients also have fibromuscular dysplasia (FMD), a condition where the walls of medium-sized arteries develop abnormally, becoming thicker or narrower in spots. FMD itself often goes undiagnosed because it can be silent for years, so many people discover they have it only after a SCAD event triggers broader vascular screening.
There is also a genetic component. A variant on a gene called PHACTR1/EDN1 appears in about 72% of SCAD patients compared to 56% of the general population. Each copy of this variant raises the risk of SCAD by roughly 67%. The same genetic region is linked to migraines and other types of arterial dissection, suggesting a shared vulnerability in blood vessel structure.
Common Triggers
SCAD often strikes during or shortly after extreme physical or emotional stress. Intense exercise, labor and delivery, severe emotional distress, and heavy straining have all been reported as precipitating events. Some patients describe the onset during activities they had done many times before without problems.
Pregnancy-associated SCAD deserves special mention. It most commonly occurs during late pregnancy or within 30 days after delivery. Compared to non-pregnancy SCAD, it tends to be more severe, with higher rates of the most dangerous type of heart attack (STEMI), higher levels of heart damage markers in the blood, and a greater risk of cardiogenic shock. The good news is that if diagnosed and treated promptly, survival rates are comparable to non-pregnancy SCAD.
Symptoms
SCAD produces the same symptoms as any heart attack: chest pain or pressure, shortness of breath, pain radiating to the arm, jaw, or back, nausea, and sweating. The challenge is that SCAD frequently strikes younger women who neither they nor their doctors would consider high risk for a heart attack, which can delay recognition. Pregnancy-associated cases are particularly tricky because the symptoms can mimic other pregnancy complications.
How Doctors Diagnose SCAD
Standard coronary angiography, the test where dye is injected into the arteries and X-ray images are taken, can suggest SCAD but is not reliable enough on its own. It shows the inside of the artery but cannot visualize the layers of the artery wall where the dissection actually happens. In one study, when angiography-diagnosed SCAD cases were re-examined with more advanced imaging, only 11 out of 17 were confirmed. The remaining six turned out to be severe atherosclerosis or blood clots mimicking a dissection.
Optical coherence tomography (OCT) is the preferred tool for confirming SCAD. It uses light waves to produce images with roughly ten times the resolution of ultrasound-based imaging, making it possible to see the intramural hematoma, identify tears in the artery lining, measure how much the true channel is compressed, and determine the exact length of the affected segment. When OCT is unavailable, intravascular ultrasound can serve as a backup, though its lower resolution means some details may be missed.
Treatment: Why Less Is Usually More
This is where SCAD treatment diverges most sharply from standard heart attack care. For a typical heart attack, the default response is to open the blocked artery immediately with a stent or balloon. For SCAD, that approach can actually make things worse by extending the tear.
The majority of SCAD dissections heal on their own. The artery wall reabsorbs the trapped blood and the channel reopens over time. Because of this, the general approach is conservative management: monitoring in the hospital, controlling blood pressure, managing pain, and waiting for natural healing. Even finding residual dissection on follow-up imaging is not a reason to intervene, as long as the patient is not experiencing ongoing symptoms of reduced blood flow.
Invasive procedures are reserved for high-risk situations: a completely blocked artery feeding a large area of heart muscle, ongoing chest pain with continued reduction in blood flow, dangerously low blood pressure, dangerous heart rhythms, or dissection of the left main coronary artery (the largest and most critical). When intervention is needed, stenting is attempted first. Bypass surgery is considered if stenting fails or if the dissection involves the left main artery or multiple vessels.
Pregnancy-associated SCAD poses additional challenges. Invasive procedures have higher failure rates in these patients, likely because the hormonal and structural changes of pregnancy make the artery walls more fragile and less predictable to work with.
Recovery and Cardiac Rehabilitation
Recovery from SCAD involves a more cautious approach to exercise than recovery from a standard heart attack. Cardiac rehabilitation programs for SCAD patients typically start at a moderate intensity, targeting 50 to 70% of heart rate reserve based on an exercise stress test performed before the program begins. Systolic blood pressure during exercise is generally kept below 130 mmHg to avoid putting excess pressure on healing artery walls.
This can be a significant adjustment for patients who were previously very active. The restrictions are not permanent, but the timeline for returning to high-intensity exercise is longer and more individualized than for atherosclerotic heart attack survivors. Gradual progression under medical supervision is the standard approach.
Long-Term Outlook and Recurrence
Most people survive their first SCAD event with good outcomes, but recurrence is a real concern. About 11% of patients experience another SCAD episode within two to three years, and that number rises to roughly 29% over ten years. Recurrences can happen in the same artery or in a completely different one.
There is no proven medication to prevent recurrence. Blood pressure control is emphasized because lower arterial pressure reduces stress on vulnerable vessel walls. Many SCAD survivors are screened for FMD in other arteries, since the underlying vascular fragility is not limited to the heart. Regular follow-up with a cardiologist familiar with SCAD is important, as management strategies continue to evolve and differ meaningfully from post-heart-attack care for atherosclerotic disease.