What all women should know about MINOCA heart attacks

December 5, 2018

Providence Health Team

[7 MIN READ]

Myocardial infarction with nonobstructive coronary arteries (MINOCA) makes up about 5% to 10% of all heart attacks. What’s striking is that about 40% to 60% of MINOCA sufferers are women. It is different than a typical heart attack in many ways, says Lori Tam, MD, a cardiologist and the medical director of the Providence Women’s Heart Program in Oregon.

“This is a type of heart attack in which there is less than 50% blockage in the arteries of heart. So it’s not due to a severe blockage in the arteries, which is typical of the kind of heart attack we’ve seen over the years.”

Types of MINOCA heart attacks

Dr. Tam says there are many kinds of MINOCA heart attacks, with some being more common in women:

Spontaneous coronary artery dissection (SCAD)

This is caused by a tiny tear in the inner lining of a blood vessel. “When that happens, a blood clot can form in the lining that disrupts blood flow and can cause a heart attack,” Dr. Tam says.
She adds that this is a condition seen much more commonly in women, even if they are healthy and don’t have the typical risk factors for heart disease.

“There is some hormonal relation, we think, because we see it more often in women who are on hormone replacement therapy or birth control pills, or during pregnancy when there is more estrogen in a women’s system,” Dr. Tam says. “It also can occur during the early period after delivery because we think some of the same hormonal processes that prepare our body for delivery make the body tissues more relaxed and can predispose a woman to getting tears in the blood vessels.”

Dr. Tam offers insights on SCAD:

Coronary artery vasospasm

As the name implies, the blood vessels of the heart spontaneously spasm and obstruct blood flow just as a blockage of coronary plaque would.
“The spasm can come and go,” Dr. Tam says. “Sometimes it can be triggered by certain over-the-counter stimulants such as Sudafed or certain migraine medications such as triptans. When that happens, blood flow is cut off and it feels and acts just like a heart attack.”
To treat vasospasm, medications such as nitroglycerin are used to relax the blood vessels and restore blood flow.

Microvascular disease

In typical heart attacks, the focus is on the artery that is narrowed or blocked. Microvascular disease, however, centers on the tiny blood vessels of the heart that can spasm intermittently. This type of spasming is called endothelial dysfunction and it can slow down blood flow in the microvascular system. In severe cases, it may also decrease blood flow to the arteries, which could trigger chest pain called angina, or even a heart attack. This endothelial dysfunction appears to be more common in women.

Muscle issues

Other types of MINOCA are caused by problems in the heart’s muscular structure. For instance, in myocarditis, the muscles in the heart are inflamed, perhaps due to a virus, and that produces an abnormal cardiac enzyme. It can cause heart muscle damage or change the movement of the heart. “But until you look at the arteries you can’t be sure that’s the cause because it can look very much like a heart attack caused by a blockage,” Dr. Tam says.

Stress cardiomyopathy

This condition is also known as “broken heart syndrome” or Takotsubo cardiomyopathy. Before this syndrome was discovered, patients would come to hospitals and their heart attacks would show up on labs and tests, but angiograms would reveal the arteries weren’t blocked. It turned out that some of these heart attacks were essentially caused by a surge of adrenaline.

“Any sort of stress reaction can cause a surge of adrenaline and that can transiently stun the heart, and people can get heart failure related to this as well,” Dr. Tam says. “There have been many case reports of psychological or emotional stressors that trigger these attacks. It’s also been known to occur with surprise birthday parties or after a death of a family member, where someone gets a surge of adrenaline they don’t expect.”

This condition is also common for patients under physiological stress stemming from a serious illness or medical issue. The good news is that the vast majority of patients recover completely with medication.

MINOCA Symptoms

An important thing MINOCA attacks have in common with traditional heart attacks is the symptoms. “A lot of women don’t even describe their heart attacks as painful; they say there is pressure, burning, or tightness in the chest. So most of these MINOCA symptoms are associated with chest discomfort,” Dr. Tam says.

MINOCA symptoms may also include:

shortness of breath
pain radiating to areas such as the arm, neck, or jaw
cold sweats
nausea, vomiting, or gastrointestinal trouble

“Sometimes they will say they have a general feeling of being unwell, like a general sense of impending doom,” Dr. Tam says.

It is critical to pay attention to those symptoms because in most cases there aren’t steps women can take to prevent MINOCA.

“If they are getting chest pain issues that aren’t well-explained, women should be evaluated for any of these conditions. Sometimes the symptoms are a sign of something minor that can become a major heart attack later on,” Dr. Tam says. “I’ve had patients come in with heart attacks and I ask if they’ve had pain before. They say, ‘Not as severe, but a week ago I felt pain during a run, so I slowed down and it went away.’ A week later they come in with a serious heart attack because that was their warning.”

When to seek medical help

Dr. Tam urges women who experience sporadic chest discomfort to see their primary care doctor for a checkup; if the pain is constant and active, they should get immediate emergency medical help.

“We tend to think of heart disease as a man’s disease, but in reality, it’s a women’s disease,” Dr. Tam says. “In the last 30 years, for most of those years, more women have died from heart disease than men. It’s the number-one killer of women in the United States and it kills more women than all types of cancers combined.

“Knowledge is empowerment. If we make sure women understand their risks and pay attention to their symptoms — whether it’s a typical heart attack from obstructive coronary disease or a MINOCA heart attack — we can really make a difference and help women survive.”

Know your numbers:

Women and heart disease:

Find a doctor

Heart issues are a leading cause of illness and death among women. If you experience any of the symptoms listed or chest discomfort, see a doctor right away. For more information on cardiac-related issues, check out a Providence Heart & Vascular Institute near you. If you need a cardiologist, find one in our physician directory. Through Providence Express Care Virtual, you can also access a full range of healthcare services.