Understanding Coronary Artery Disease

“In the American lifestyle, the largest contributors are being sedentary and what we eat,” says Dr. Rory Weiner, a cardiologist at Massachusetts General Hospital and an assistant professor of medicine at Harvard Medical School.

When we eat a lot of foods high in unhealthy fats, such as red meat and processed foods, and don’t exercise, the arteries that feed the heart blood and oxygen become lined with plaque, Weiner says. When plaque builds up, it causes a condition called atherosclerosis, and blood has trouble flowing through the arteries. This decreases the amount of oxygenated blood to your heart.

Plaque is made up of cholesterol, cells and other materials, and it’s dangerous because it causes narrowing of arteries and can even rupture. A rupture can be fatal because the soft inside of the plaque is released, causing a clot that can block blood flow. Partial blockage can cause angina, which is pain or pressure commonly in the chest, back or shoulders. Complete blockage causes a heart attack.

Warning Signs

Coronary artery disease presents in two ways, Weiner says: either angina or “exercise intolerance,” meaning, for example, someone who used to be able to run or climb stairs easily but suddenly can’t. “It’s someone who is running slower, getting winded easily,” Weiner says.

How do we confirm it’s coronary artery disease? And how would we know we have plaque build-up when we don’t have any symptoms? It takes decades for coronary artery disease to develop, and it can be a silent condition, meaning most people don’t know they have it until it causes a problem.

By middle age, it’s fairly common to have at least some build-up. In fact, autopsies performed on U.S. military members who died in the Iraq and Afghanistan wars – a generally young, fit population – showed that about 1 in 9 had plaque in their arteries, though none had been diagnosed with heart disease.

The study, a 2012 report in the Journal of American Medical Association, noted that autopsies performed on service members in prior wars showed even more heart disease. They attributed the drop, in part, to declining rates of smoking and other risk factors. The mean age of the troops studied in the more recent report was 26, and most were men.

Dr. Daniel Levy of the National Heart, Lung, and Blood Institute wrote in an accompanying editorial in JAMA that prevention should start in childhood with maintaining a healthy weight. “Autopsy studies have demonstrated that coronary disease begins at a young age,” he wrote. “Consequently, primary prevention campaigns to address obesity and related risks should begin in childhood.”

For the general population, high blood pressure and high cholesterol are risk factors for coronary artery disease, along with family history, diabetes, obesity and cigarette smoking, says Dr. Ross Van Dorpe, cardiovascular disease specialist at the Northwestern Medicine Bluhm Cardiovascular Institute West in Illinois. He notes that cholesterol is both produced by our bodies and ingested in food we eat.

Van Dorpe recommends talking to your primary care physician about risk factors, even if you’ve never had chest pain, shortness of breath or discomfort. “Many times people come in having a heart attack, and when you ask about their medical history they say they don’t have one,” Van Dorpe says. “They haven’t been to a doctor’s visit in 20 years. Those are preventable outcomes.”

With treatment, plaque can be stabilized so it’s at less risk for rupture, and the progression of the disease can be halted.

Van Dorpe says there are various tests a doctor can perform to analyze blood flow through the arteries and to the heart. These include non-invasive tests such as an exercise stress test, an echocardiogram or a coronary CT angiogram. A more invasive but potentially beneficial test is a cardiac catheterization, where a catheter is inserted and run into the cardiac arteries to test their function.

If you have risk factors but no symptoms, the first step to treatment beyond exercise and a healthy diet is for a doctor to prescribe a daily baby aspirin or possibly a statin medication, which acts to reduce levels of fats in the blood.

If a patient has significant plaque build-up – say, 70 percent of an artery is blocked – doctors often recommend a stent, which is a surgical procedure to place a tube in the artery to open it up and let the blood flow more freely. In the most severe cases, doctors will perform a bypass surgery, which diverts blood around a section of a blocked artery.

Prevention

But the very best thing you can do, doctors say, is prevent it from happening in the first place. You can maximize your heart health by exercising, eating lots of fresh fruits and vegetables, and minimizing red meat, sugar and processed foods.

People who live in more remote areas of the world, such as indigenous populations in the rainforest, have low cholesterol and very little build-up in their arteries, which reflects their hunt-and-gather lifestyle, says Dr. Pamela S. Douglas, Ursula Geller Professor of Research in Cardiovascular Diseases in the Department of Medicine at Duke University and director of the Multimodality Imaging Program at Duke Clinical Research Institute. “Eating a normal western diet gives us cholesterol [and average of] five to 10 times higher than what is normal for humans in a less industrialized environment,” she says.

In fact, a study published earlier this year in the Lancet examined the heart health of the Tsimane, a hunter-gatherer Bolivian tribe in the Amazon. Using CT scans, the study showed that for participants 40 years and older, 85 percent had no risk of heart disease, 13 percent had low risk and 3 percent had moderate risk. “Heart disease can be prevented with healthy behaviors,” Douglas says.