Heart Attack Coming on You

MINOCA may account for up to 25% to 30% of all heart attacks in women (and less than 10% in men), according to C. Noel Bairey Merz, MD, director of the Barbra Streisand Women's Heart Center at Cedars-Sinai Medical Center in Los Angeles. The symptoms of MINOCA are the same as those of a classic heart attack that happens in someone with coronary artery disease. But because no blockages are found in the main coronary arteries, patients often leave the hospital unsure about what caused their MINOCA heart attack and how to prevent another one.

During the next 3 years, Conrad estimates she had 20 more episodes. None were as severe as the first one and, as far as she knows, none were heart attacks. She visited the ER three more times, but after being sent home as before, she stopped going.

Conrad consulted a cardiologist, who suspected spasms in the coronary artery wall and prescribed nitroglycerin for her chest pain (angina). She eventually quit her job as a local government finance director because she worried the stress might be contributing to her condition. "I thought, 'Well, this is something I'm just going to have to live with,'" she says.

Why Are MINOCA Cases Rising?

What we now call MINOCA was first described decades ago. Writing in the Archives of Internal Medicine in 1939, two New York doctors noted reports of autopsies of heart attack patients with minimal to no coronary artery disease. There are two main reasons why it's being discussed more now. 

First, new technologies such as high-sensitivity troponin tests are much better at detecting small heart attacks. But the imaging systems available in most hospitals haven't caught up. That can leave doctors puzzling over high troponin levels that indicate a heart attack and angiograms that show clear coronary arteries. 

Second, long-standing stereotypes about who gets heart disease have shifted. We now know it's the leading cause of death for men and women. Not long ago, heart attacks were incorrectly considered a male thing, and women seeking medical care for similar symptoms were often dismissed. They were told it was nerves and prescribed rest. Doctors and advocacy groups have been working to correct these misconceptions. And as more women get the message, more are coming to ERs at the sign of a possible heart attack, as health experts advise.

"When a woman comes into an ER today complaining of chest pain, she's more likely than 20 years ago to get an EKG and a blood troponin test," says Cedar-Sinai's Bairey Merz.

Researchers aren't sure why MINOCA and INOCA are more common in women than men. Reynolds and Bairey Merz suspect it could be due to hormones, hormone therapy, or the simple fact that women are physically smaller, on average, than men. Women's hearts and blood vessels are typically smaller, so arterial blockages and clots that may not show up on conventional imaging can do more damage.

But not all MINOCA and INOCA is caused by plaque buildup and rupture in the heart's small arteries. Everyone has some plaque. When it exists in small arteries, it takes up more of the available space. There are other potential causes. For example, the interior of an artery wall can tear and cause a blockage that feels like a classic heart attack. This is known as spontaneous coronary artery dissection, or SCAD.

Other times, blood vessels can spasm, which interrupts normal blood flow and produces heart attack-like symptoms. Still, other potential causes include myocarditis (an inflammation of the heart muscle) and stress cardiomyopathy (a reaction to a surge of adrenaline). Reynolds and Bairey Merz encourage doctors to consider all these possibilities when a patient of any gender with open arteries has a heart attack or chronic chest pain.

How to Protect Yourself

After years of being unable to get her condition diagnosed, Rita Conrad was watching a TV news interview with Purvi Parwani, MD, director of the Women's Heart Health Clinic at Loma Linda University Health in California.

"She described my symptoms exactly," Conrad says. She quickly made an appointment to see Parwani, who diagnosed her with MINOCA caused by vasospastic angina (an artery spasm) and prescribed medication (ranolazine) to manage it.

Conrad says she's reached "a much better place" with her heart health. Her MINOCA episodes are down dramatically. She's working again and traveling with her husband. "I have my life back. I'm not scared anymore."