Over half of all women who have a heart attack have clear arteries—another challenge to the outdated “blocked pipe” theory of heart disease, says Bryan Hubbard
No, it’s not breast cancer: The number one killer of women is heart disease, but you might not recognize it as such because it doesn’t follow the classical pattern. For women, a heart attack (myocardial infarction) is often nothing to do with a blocked artery; their arteries are completely clear, and yet they still suffer a heart attack.
They also don’t always suffer the usual symptoms of a heart attack. Sometimes there’s not a crushing feeling in the chest or sensations down one arm, and yet a heart attack it is.
The same is true for men, but to a lesser extent. Around a third of men have a heart attack that’s nothing to do with a blocked artery restricting the oxygen supply to the heart, and again the symptoms don’t follow the classic pattern.
The phenomenon has been recognized for years by cardiologists, who collate these cases under the broad umbrella term of MINOCAs (myocardial infarction with non-obstructive coronary arteries). Nonetheless, health agencies still promote the blocked pipe theory of coronary heart disease (CHD).
Everyone over age 50 is urged to start taking a cholesterol-lowering statin drug that targets the “bad” LDL (low-density lipoprotein) cholesterol that blocks the arteries. When people aren’t popping a statin, they’re eating low-fat foods that are also designed to keep their LDL levels in check.
Despite these heroic efforts, heart disease stubbornly remains the world’s main killer, claiming around 20 million victims worldwide every year—suggesting something is very wrong with the whole idea of heart disease.
According to the blocked pipe theory shaped by medical science from the 1950s, our arteries narrow as “bad” LDL cholesterol sticks to the sides, causing them to stiffen (atherosclerosis). Eventually they close up and restrict the oxygen supply to the heart, which triggers a heart attack.
But a new study is another reminder that the theory tells only part of the story. A research team at the Mayo Clinic discovered that over half of female participants who had suffered a heart attack had clear arteries. It was also true—although less so—in men, of whom 25 percent had no blockages.
The researchers analyzed 1,474 heart attack cases that happened in a Minnesota county between 2003 and 2018 and discovered that fewer than 47 percent of the women and 75 percent of the men had blocked arteries.1
Heart attacks often look very different in women than in men, but that’s partly because medical science has seen CHD as a problem that afflicts more men. Some of the keynote studies of the 1970s almost exclusively recruited men, and the researchers were seeing plaque formation around arteries, so confirming the blocked pipe theory.
But for women a heart attack is more likely to happen because of anemia or an infection, and when either of these is the culprit, it’s classified as a supply/demand mismatch secondary myocardial infarction (SSDM). In the Mayo study, SSDM was the common culprit in women younger than 45.
Another common cause among women is a sudden tear in the artery wall, known as spontaneous coronary artery dissection (SCAD), which creates a “false channel” in the artery that restricts blood flow. It’s nearly six times more common in women than in men.
Women are also more likely to suffer from Takotsubo syndrome, quite literally a broken heart. This happens when a sudden surge of stress hormones stuns the heart muscle, producing symptoms and changes that mimic a heart attack.2
These MINOCAs challenge the blocked pipe theory and the origins of heart disease. Even by the 1990s, researchers were recognizing that CHD is an inflammatory disease and that blocked arteries—if they happen at all—are a byproduct of other processes.
One key insight that seemed to support the blocked pipe theory was the discovery that heart attacks often occur when plaques rupture and not just when they fully block an artery. Cardiologists described these plaques as “vulnerable.”
The plaques may not be large enough to significantly obstruct blood flow, but they have thin, fragile caps which, when they rupture, cause the body to treat the site like an injury and form a blood clot. This clot can suddenly block the artery, even if it was previously only mildly narrowed. In other words, the danger is not always how big the plaque is but how unstable it is.
But this insight still didn’t answer the fundamental question: Why were the plaques forming in the artery in the first place?
Plaques are not just passive accumulations of cholesterol. They are active, inflamed areas involving immune cells and chemical signals. Although LDL is a healing agent, it can also damage the lining of blood vessels, known as the endothelium, making arteries less able to function properly.
Despite this, LDL cholesterol isn’t, on its own, a warning flag of an impending heart attack—but inflammatory markers are, as a major review has underlined. Researchers from the Brigham and Women’s Hospital in Boston tracked the heart health of 31,245 people who were taking a statin because they either had atherosclerosis or were at high risk. The researchers assessed the patients’ levels of C-reactive protein (CRP), an inflammatory marker, and LDL to see which more closely predicted a heart attack or death.
Surprisingly, those suffering from inflammation were at far greater risk. They were twice as likely to die from their heart condition and indeed from any health problem, suggesting they were sicker. By comparison, high LDL levels had a “neutral” influence on the progression of heart disease.
Don’t treat heart issues only with statins, the researchers concluded—even though the study was partly funded by statin manufacturer AstraZeneca—but look to tackle inflammation as well.3
Even the conservative American College of Cardiology, a vital voice in setting CHD treatment, has recently gotten the memo. Its latest position statement, sent to all cardiologists in America last year, states that there is strong evidence that CVD (cardiovascular disease) is an inflammatory condition.
“There is now compelling evidence of adverse CVD outcomes in the setting of elevated markers of inflammation and that targeting inflammation significantly reduces recurrent CVD events,” it says. In other words, stop looking to reduce LDL levels and focus on bringing down inflammation.4
So, if CHD and CVD are diseases of inflammation, and if LDL cholesterol is an agent that is attempting to shore up damage in the arterial wall caused by the inflammation, what kick-starts this process in the first place?
Heart disease became the number one killer in America as far back as 1921. Although rates have dropped significantly, it is still ahead of cancer in the number of victims it claims. It is now less deadly than it was 70 years ago, partly because of advances in heart surgery and the use of stents, although the numbers living with CHD and CVD are rising and today stand at around 500 million worldwide.
Low-grade, chronic inflammation is the real culprit, and this has been the result of our modern lifestyle that started to emerge after the First World War. Processed food, refined sugars, a sedentary lifestyle, pollution and stress have all contributed to the problem, and their part in the development of heart disease was emphasized by a study that looked at the rate of heart disease among the Tsimane people of Bolivia.
Around 85 percent over age 40 had no signs of heart disease, and obesity, hypertension, high blood sugar, and regular cigarette smoking were rare, New Mexico University researchers found. “Coronary atherosclerosis can be avoided in most people by achieving a lifetime with low glucose, normal body-mass index, no smoking, and plenty of physical activity,” the researchers concluded.5
The whole issue of heart disease can be summarized in two words: insulin resistance, meaning cells don’t take in the sugars from carbohydrates when insulin signals them to. So sugar levels stay high in the blood. As the precursor of type 2 diabetes and, beyond that, of heart disease itself, insulin resistance is part of the spectrum of metabolic diseases that plague modern living.
When we step back and see the complete picture, the theory of the blocked pipe is inadequate. Statins and a low-fat diet play, at best, a marginal role in preventing and managing heart disease.
For a healthy person with no history of heart disease, statins reduce the risk by just 1 percent—an insignificant reduction that is easily bettered by eating a fresh whole-food diet. And, unlike food, the drugs come with a range of side effects, including muscle pain and weakness that on rare occasions can lead to fatal kidney failure.
Statins and low-fat products may be part of an approach that’s off the mark, but they’re still being promoted by industries that earn billions of dollars every year from them. As the American College of Cardiology makes clear, it’s time to shift the focus to inflammation—but where’s the money in that?
What do you think? Start a conversation over on the... WDDTY Community
Great news! Discounts are available based on your cart total. Check the details below:
