Meet SCAD, a Major Cause of Heart Attacks in Women 50 and Under
If someone asked you to picture a heart attack patient, you might imagine an older man clutching his chest. In reality every year an estimated 445,000 U.S. women 35 and older will experience a new heart attack, recurrent heart attack, or fatal outcome of coronary heart disease (which, in addition to heart attack, can cause issues like heart failure). A major cause of heart attacks in women is SCAD, or spontaneous coronary artery dissection. And the strangest thing about SCAD: It most commonly affects otherwise healthy women in their 40s and 50s.
In this article, we'll be discussing how SCAD is known to be more prevalent in people who were assigned female at birth. We do not have data on whether or not hormonal or surgical transitioning has any effect on SCAD risk, but it is likely that this elevated risk also extends to trans men. While we refer to women throughout this article (particularly because gender bias is a known factor when it comes to diagnosing and treating heart attacks), it's important to remember that you do not necessarily need to identify as a woman to be at a greater risk of SCAD.
How SCAD causes a heart attack
First the basics: A heart attack occurs when one or more of the coronary arteries—blood vessels that have the all-important task of delivering oxygen to the heart—become blocked, according to the National Institute on Aging. This causes the part of the heart that doesn’t have enough oxygen to start to die.
In most cases that blood vessel blockage happens because of a disease called atherosclerosis, or a buildup of plaque in your arteries that eventually hardens and constricts blood flow, the National Heart, Lung, and Blood Institute (NHLBI) explains. But other times it occurs because of SCAD.
SCAD happens when a tear in an artery wall leads the inner layers of that wall to fill with blood and swell, according to the Mayo Clinic. This swelling compresses the lumen (the hollow part in the center of your artery through which blood travels) until adequate levels of blood can no longer stream through. That lack of blood flow can lead to a medical emergency like a heart attack.
Experts know SCAD is rare, but they aren’t sure exactly how often it happens. It has historically been underdiagnosed, mainly because heart attacks aren't often suspected in younger, healthy women. Providers may also be less familiar with it as a cause of heart attack. In the general population, SCAD is estimated to cause just 1 to 4 percent of all incidents of acute coronary syndrome (a range of conditions that suddenly prevent blood flow to the heart), according to a 2018 scientific statement on SCAD from the American Heart Association (AHA). But its impact on women is shockingly disproportionate.
As a 2019 piece of research called the Canadian SCAD Study noted, women are estimated to comprise over 90 percent of SCAD patients. Many women with SCAD don’t have most of the risk factors you see in other cardiovascular diseases, like high blood pressure or diabetes, the Mayo Clinic explains. What’s more, SCAD affects many people who haven’t yet reached the average heart attack age, which is over 70 for women. These patients often haven’t even yet reached the age at which heart attack risk typically starts to rise, which is 55 in women.
“If you look at studies of SCAD, the mean age is anywhere between mid-40s to 50s,” cardiologist Marysia S. Tweet, M.D., assistant professor of medicine at the Mayo Clinic College of Medicine and Science and senior associate consultant in the department of cardiovascular medicine within the Division of Ischemic Heart Disease and Critical Care, tells SELF.
In fact SCAD could be responsible for up to 35 percent of heart attacks in women 50 years or younger, the AHA concluded in their scientific statement. The others largely tend to be due to atherosclerosis. This distinction is really important—even though the number of female heart attack patients with SCAD is significant, they sometimes don’t receive proper diagnosis and treatment because they don’t have those typical heart disease risk factors.
Reading that is naturally a little scary, but remember that SCAD is a rare occurrence overall. It’s also not usually fatal; SCAD is thought to be at fault for around 0.5 percent of sudden cardiac deaths. Getting help as soon as you notice symptoms no matter your age is a critical part of surviving SCAD.
Symptoms of heart attacks caused by SCAD
Chest pain or chest pressure are the major symptoms of a heart attack for people of any sex, says Suzanne Steinbaum, D.O., a cardiologist at the Mount Sinai Hospital and volunteer medical expert for the AHA’s Go Red for Women. That includes heart attacks that happen due to SCAD.
Beyond chest discomfort, heart attack symptoms can be nuanced and surprising, especially for women. “In women, symptoms of heart attacks can be much more subtle,” Dr. Steinbaum tells SELF. These symptoms can include pain in the jaw, stomach, back, neck, and arms; nausea; lightheadedness; and shortness of breath severe enough to be “unignorable,” Dr. Steinbaum says. “If that’s what you’re feeling, that’s when you need to get help,” she adds.
At this point you have a fair amount of background information about SCAD. But one of the biggest questions you may have—it’s certainly one of the most pressing questions troubling SCAD experts—is why this condition so disproportionately affects women.
How hormones and pregnancy play a role in SCAD
Experts believe that the hormones estrogen and progesterone could play a part in SCAD, the AHA’s 2018 scientific statement on SCAD explains. Estrogen and progesterone have been shown to weaken blood vessel walls, which could leave them more vulnerable to the kind of tear that results in SCAD.
With that said, researchers are still trying to narrow down the exact mechanism behind this potential cause and effect. Experts are also still investigating how much, if at all, external hormones like those in birth control or hormone therapy may contribute to weakened blood vessel walls. As of now there’s no established evidence that these external hormone sources are clear SCAD risk factors. They only really become a concern in someone who already has a history of SCAD, at which point doctors want to really carefully weigh the benefits of hormone-containing contraception and hormone therapy against the theoretical (but unproven) risks.
Now that you know the hormone connection with SCAD, a few of the other risk factors will make a lot more sense. Pregnancy, for instance, increases a person’s odds of SCAD, especially having had four or more pregnancies (known as multiparity).
Before we explain why, it’s really important to remember that the vast majority of people will not have any kind of heart attack while pregnant or postpartum. A 2018 study in Mayo Clinic Proceedings analyzed 55,402,290 pregnancy-related hospitalizations that occurred from 2002 through 2014, finding that heart attacks happened in 8.1 per 100,000 of these hospital visits (some of which happened postpartum). Those are already really unlikely odds, even more so when you consider that this study looked at pregnant people who went to the hospital, not the total number of pregnant people in the country, many of whom wind up being completely fine.
However, of those heart attacks that happen during or right after pregnancy, a significant number involve SCAD. Some experts believe SCAD may even be the number one cause of heart attack in pregnancy and the postpartum period. A 2016 BMJ study the AHA referenced in their scientific statement on SCAD found 1.81 SCAD events per 100,000 pregnancies, up to and including six weeks after delivery. That’s still uncommon, but prevalent enough to get researchers’ attention.
Experts believe the significant hormonal changes that come with pregnancy and giving birth could be largely to blame here. Since most cases of pregnancy-associated SCAD actually occur in the postpartum period—which is when you see a significant drop in estrogen and progesterone—Dr. Tweet explains that fluctuating hormone levels (rather than the hormones themselves) could contribute to SCAD.
“There are receptors for hormones on the vasculature [i.e., blood vessels], including the coronary arteries, so we’re still trying to tie it together,” Dr. Tweet tells SELF.
Other physiological elements of pregnancy and birth can contribute to SCAD, such as increased blood volume shunting around the body. Pushing during vaginal labor can also be a factor because it’s what’s known as a Valsalva maneuver, or essentially bearing down while holding your breath. This extreme physical exertion can be one of many things that coalesce to trigger SCAD. (We’ll explore that a bit more down below.)
Though it’s generally quite rare, researchers are keen to raise awareness about the risk of SCAD in pregnancy and the postpartum period because SCAD can be more serious at this time. “When it is a pregnancy-related or postpartum SCAD, those patients do tend to present more severely…which means usually they’re also sicker,” Dr. Tweet says.
How stress and mental health play a role in SCAD
SCAD patients commonly report having mental health conditions like chronic stress, depression, and anxiety, and notably at higher rates than other heart attack patients. On the flip side, having SCAD can bring about or exacerbate these conditions in the recovery period.
A more sudden type of stress could also trigger SCAD. Intense stress (like the type that comes with the sudden news of a death) can cause an adrenaline surge that increases blood pressure and heart rate, which can lead to an arterial tear, Malissa J. Wood, M.D., codirector of the Corrigan Women's Heart Health Program, director of the SCAD program at the Massachusetts General Hospital Heart Center, and associate professor of medicine at Harvard Medical School, tells SELF.
It’s a well-known fact that women have higher rates of many mental health conditions than men do. According to numbers cited by the National Institute of Mental Health (NIMH), 23.4 percent of women reported having any type of anxiety disorder in the past year compared with 14.3 percent of men. When it comes to depression, 8.7 percent of women reported at least one major depressive episode in the past year as opposed to 5.3 percent of men, the NIMH says. These health conditions can contribute to stress and vice versa.
There’s a host of reasons why women can be more vulnerable to certain mental health conditions, the World Health Organization (WHO) explains. Women are more likely to experience things like gender-based violence, lower socioeconomic status, a lack of societal power, and pressure to care for others over themselves. But one major complicating factor in estimating gender-based differences in mental disorder prevalence is that women may be more likely to seek help for conditions like depression than men, the NIMH explains.
Other known risk factors for SCAD
Having certain conditions that affect the blood vessels can make someone more susceptible to SCAD. Fibromuscular dysplasia (FMD) is the arterial disease most strongly linked to SCAD, and it happens when irregular cell growth causes arteries to alternately swell and narrow, ultimately constricting blood flow. This can impact arteries all over the body but when it happens to arteries leading to the heart, it can cause SCAD.
FMD symptoms can change depending on which arteries it affects, but overall it doesn’t tend to cause any major signs. “Unfortunately, [FMD] tends to be silent with most cases,” Jacqueline Saw, M.D., clinical associate professor in the division of cardiology at the University of British Columbia in Canada and principal investigator of the Canadian SCAD Study, tells SELF. That is, until it becomes severe enough to lead to something like SCAD.
Some research suggests that as many as 60 to 70 percent of SCAD patients have underlying FMD, which tends to be vastly more prevalent in women. Estimates suggest that over 90 percent of people with FMD are women, according to the Cleveland Clinic. Again, hormones are a big contributing factor here though experts aren’t sure how. Smoking (which damages arteries) and a family history of FMD are additional risk factors, according to the Mayo Clinic.
Since blood vessel problems are central to SCAD, other health conditions that affect this part of the circulatory system may also play a role. For instance, lupus (which more commonly affects women) causes bodily inflammation that can affect the blood vessels, the Mayo Clinic explains.
It's also possible that SCAD can be triggered by excessive physical exertion, Dr. Wood says, like “doing something that is much more vigorous than one has done previously or routinely, such as going out and running very, very hard in a race or lifting something extremely heavy.” In addition to FMD, physical exertion happens to be a major SCAD risk factor in men.
Finally, genetic connective tissue disorders like Marfan, Ehlers-Danlos, or Loeys-Dietz syndromes also seem to be associated with SCAD. However, since these conditions are already considered rare and not everyone who has them will experience SCAD, these represent a minority of cases, Dr. Wood tells SELF.
Taking SCAD symptoms seriously
If you experience any SCAD symptoms, call 911. “A lot of women—young women in particular—ignore their symptoms,” Dr. Saw says. But getting treatment ASAP “[increases] the likelihood that you will not damage your heart muscles further,” Dr. Tweet explains. “People [with SCAD] can go on to live very well, particularly since they usually don’t have a whole lot of other medical problems.”
Treatment for SCAD can be really varied depending on the specifics of the case, but the point is to repair the tear so blood can flow to the heart in normal amounts. SCAD can actually heal on its own in many people, the Mayo Clinic explains, in which case doctors might prescribe medications to relieve symptoms like chest pain while allowing your heart to mend and monitoring whatever may have caused the SCAD.
If more conservative treatments like watchful waiting and medication haven’t been effective enough, surgery to repair the tear may be recommended. However, Dr. Wood says, this isn’t always necessary. Getting the right diagnosis is crucial when it comes to treating SCAD, so if you’re younger than expected for a heart attack, have any of the above risk factors, and your doctors diagnose you with atherosclerosis, ask them if they’ve considered SCAD as a cause.
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Originally Appeared on Self
