What causes coronary heart disease? How to know your risk factors for the leading cause of death in the US

• Coronary heart disease occurs when the arteries build up with cholesterol and become clogged, which increases the risk of heart attack and heart failure.
• The main risk factors for coronary heart disease include smoking cigarettes, a lack of regular exercise, being overweight or obese, and eating a diet high in trans fats.
• To treat coronary heart disease, it's important to adopt lifestyle changes such as regular exercise and a heart-healthy diet — and in more severe cases, bypass surgery may be necessary.
• This article was medically reviewed by Jason R. McKnight, MD, MS, a family medicine physician and clinical assistant professor at Texas A&M College of Medicine.

Coronary heart disease, also known as ischemic heart disease or coronary artery disease, is the most common type of heart disease, and the leading cause of death in the US.

It is largely preventable with proper treatment, but if untreated, it is associated with a higher risk of heart attack or heart failure.

Here's what causes coronary heart disease, how to know if you're at risk, and the best ways to treat it effectively.

What causes coronary heart disease?

Coronary heart disease occurs when low-density lipoprotein (LDL) cholesterol builds up in the arteries near the heart.

This is what causes high cholesterol, and the scientific process is known as atherosclerosis. High cholesterol can clog the arteries — preventing the heart from getting vital nutrients and oxygen — and lead to a heart attack.

There are a few lifestyle factors that increase your risk for developing coronary heart disease, including:

• Smoking cigarettes
• Lack of physical activity
• Being overweight or obese
• Eating a diet high in trans fats — found in fast food and junk food

How to recognize coronary heart disease

Coronary heart disease doesn't come with obvious symptoms, and you may not know you have it. That's why it's important to have routine check-ups with your doctor, to calculate your cholesterol levels and check blood pressure readings.

Along with these measurements of heart health, you should be extra vigilant if you have one or more risk factors for coronary heart disease. For example, if you smoke cigarettes frequently and don't exercise often, it's worth checking in with your doctor to talk about how to prevent heart disease.

According to Nicholas Amoroso, MD, a cardiologist at the Medical University of South Carolina, it's also vital to look out for chest pain — called angina — and other signs of a heart attack.

Sometimes, these symptoms can be very subtle, or present as a silent heart attack, so it's important to check with your doctor if you're experiencing any symptoms out of the ordinary.

And, if you know you're at risk for coronary heart disease, or know you have it, you should especially take these signs seriously.

"It's important that patients with known coronary artery disease pay particularly close attention to their symptoms, and they should have a lower threshold to seek evaluation with their cardiologist," Amoroso says.

How to treat coronary heart disease

It's imperative to treat coronary heart disease and follow your doctor's recommendations.

Nearly all heart attacks in older men stem from coronary blockages, along with 80% of heart attacks in young adults. Coronary heart disease is also the most common cause of heart failure, or when the heart can no longer pump blood throughout the body.

While Amoroso recommends a heart-healthy lifestyle for everyone, he says it's especially important for those with or at risk of coronary heart disease.

Here's how you can treat coronary heart disease and prevent further health risks:

• Lifestyle changes. Eat a low-sodium and low-trans-fat diet — like the DASH diet — exercise regularly, and quit or avoid smoking cigarettes.
• Medication. Some people might have to take medications like statins, which can lower LDL cholesterol levels. Research has found that taking some types of these drugs can decrease the risk of coronary heart disease by 27%.
• Surgery. Bypass surgery, or coronary artery bypass grafting (CABG), is the most common type of open-heart surgery in the US. This procedure takes healthy arteries from the chest, or veins from the legs, to bypass clogged arteries in the heart. It's usually recommended when someone has multiple blocked arteries as a result of coronary heart disease.

The bottom line

While coronary artery disease is the leading cause of death in the US, it is also largely preventable with the right treatment.

"We need to make sure that we're staying on top of it and helping prevent future problems from their coronary disease, not just dealing with it after it's already occurred," Amoroso says.

Related articles from Health Reference:

• How to lower cholesterol with the right diet and exercise regimens
• What causes high blood pressure and how to know if you have hypertension
• How to lower blood pressure with a heart-healthy diet and exercise
• How hypertension, heart disease, and stroke are related
• What is a good resting heart rate, for adults and kids