Coronary artery bypass surgery is a major heart operation that creates new pathways for blood to reach areas of the heart when arteries become blocked or narrowed. This procedure, commonly known as CABG or heart bypass surgery, is one of the most frequently performed heart surgeries in the world, helping thousands of people each year regain better heart function and reduce symptoms like chest pain and breathlessness.

Understanding Coronary Artery Bypass Surgery

Coronary artery bypass grafting is a surgical procedure designed to restore proper blood flow to the heart muscle. When the coronary arteries—the blood vessels that wrap around and supply blood to the heart—become blocked or narrowed by buildup of fatty deposits called plaque, the heart muscle can’t get enough oxygen-rich blood. This condition is known as coronary artery disease, and it can lead to serious problems like chest pain, heart attacks, or even death of heart muscle tissue.^[1]

During bypass surgery, surgeons take a healthy blood vessel from another part of your body and use it to create a detour around the blocked section of the coronary artery. This new pathway allows blood to bypass the blockage and reach the heart muscle that needs it. The blood vessels used for this purpose typically come from the chest, specifically the internal mammary artery, or from the leg, known as the saphenous vein. Sometimes arteries from the arm or wrist are also used.^[2]

The surgery doesn’t cure the underlying heart disease that caused the blockages in the first place, such as atherosclerosis—the hardening and narrowing of arteries. However, it can significantly reduce symptoms like chest pain and shortness of breath, improve heart function, and may reduce the risk of death from heart disease.^[1]

Epidemiology: Who Needs This Surgery and How Common Is It

Coronary artery bypass surgery is the most common heart surgery performed in the world. In the United States alone, almost 400,000 CABG surgeries are performed each year, making it the most commonly performed major surgical procedure. However, the number of these surgeries has been decreasing as alternative treatments like medications and less invasive procedures have become more widely available.^[7]

The average age of people who undergo CABG surgery is around 66 years old. Most people who have this procedure are male, though women also undergo the surgery when needed. The surgery is typically recommended for adults who have developed significant blockages in their coronary arteries that cannot be adequately treated with medication alone or with less invasive procedures.^[3]

People from various backgrounds and demographics may need this surgery, but it tends to be more common among those who have risk factors for coronary artery disease. These include individuals with high blood pressure, high cholesterol, diabetes, and those who have smoked or led sedentary lifestyles for many years.

Causes: Why Arteries Become Blocked

The main reason people need coronary artery bypass surgery is the buildup of plaque inside the coronary arteries. Plaque is made up of cholesterol, fatty substances, calcium, and other materials found in the blood. Over time, this sticky material accumulates on the inner walls of the arteries, making them narrower and stiffer. This process is called atherosclerosis, or hardening of the arteries.^[3]

When plaque builds up to the point where it significantly narrows or blocks an artery, less blood can flow through. This means less oxygen reaches the heart muscle. In some cases, a piece of plaque can break open, causing blood clots to form at that spot. These clots can completely block the artery, causing a heart attack. When areas of the heart don’t receive enough blood—a condition called ischemia—the heart muscle can become damaged or die.^[3]

The development of plaque and blockages in the coronary arteries doesn’t happen overnight. It’s usually the result of habits and conditions that develop over many years. Poor diet, lack of physical activity, smoking, high blood pressure, high cholesterol, and diabetes all contribute to the formation of plaque in the arteries.

Risk Factors: Who Is More Likely to Need Bypass Surgery

Certain groups of people and certain behaviors increase the likelihood that someone will develop coronary artery disease and potentially need bypass surgery. Understanding these risk factors can help people recognize their own level of risk.

High blood pressure is a major risk factor because it puts extra strain on artery walls, making them more likely to develop damage where plaque can build up. High cholesterol, particularly high levels of “bad” LDL cholesterol, directly contributes to plaque formation in the arteries. When there’s too much cholesterol in the blood, it gets deposited on artery walls.^[3]

Diabetes significantly increases the risk of coronary artery disease because high blood sugar levels over time can damage blood vessels and the nerves that control the heart. People with diabetes often develop heart disease at younger ages and may have more severe blockages.^[1]

Smoking is one of the most harmful risk factors. It damages the lining of arteries, raises blood pressure, reduces the amount of oxygen in the blood, and makes blood more likely to clot. All of these effects accelerate plaque buildup and increase the risk of blockages.

A sedentary lifestyle and obesity contribute to many of the other risk factors. Lack of physical activity can lead to weight gain, high blood pressure, high cholesterol, and diabetes. People who don’t exercise regularly are more likely to develop heart disease than those who stay active.

Family history also plays a role. If close relatives have had coronary artery disease or heart attacks, especially at younger ages, your own risk increases. This suggests that genetics can influence how your body handles cholesterol and other factors related to heart health.

Symptoms: What Leads People to Need Bypass Surgery

The symptoms that lead someone to need coronary artery bypass surgery are usually related to the heart not getting enough blood. The most common symptom is chest pain, known as angina. This pain often feels like pressure, squeezing, fullness, or discomfort in the center of the chest. Some people describe it as feeling like an elephant is sitting on their chest. The pain may also spread to the shoulders, arms, neck, jaw, or back.^[4]

Shortness of breath is another common symptom. When the heart can’t pump blood effectively because it’s not getting enough oxygen itself, fluid can back up into the lungs. This makes it hard to breathe, especially during physical activity or even at rest in severe cases. People may find they can’t climb stairs or walk as far as they used to without becoming breathless.^[1]

Fatigue is often reported by people with coronary artery disease. When the heart struggles to pump enough blood throughout the body, you may feel tired all the time, even after resting. Simple daily activities that used to be easy may suddenly feel exhausting.

Some people experience heart palpitations, which feel like the heart is racing, fluttering, pounding, or skipping beats. Abnormal heart rhythms can develop when parts of the heart aren’t getting enough oxygen. Indigestion or nausea can also occur, sometimes making it difficult to distinguish heart problems from stomach issues.^[4]

It’s important to know that some people with coronary artery disease don’t have any symptoms at all. This is called silent myocardial ischemia, where the heart muscle isn’t getting enough blood but the person doesn’t feel any pain or discomfort. These individuals may still need surgery if tests show severe blockages.^[3]

In emergency situations, coronary artery bypass surgery may be needed to treat a severe heart attack when other immediate treatments aren’t working. During a heart attack, a coronary artery becomes completely blocked, and heart muscle begins to die rapidly. Quick action to restore blood flow is critical.^[4]

When Doctors Recommend Bypass Surgery

Before recommending bypass surgery, doctors usually try other treatments first. These might include lifestyle changes, medications to control blood pressure and cholesterol, or a procedure called angioplasty where a balloon is used to open up blocked arteries and a small mesh tube called a stent is placed to keep them open. If these approaches don’t provide enough relief or if the blockages are too severe, bypass surgery becomes the next option.^[4]

Your healthcare provider might specifically recommend coronary artery bypass surgery if you have a blockage in the left main heart artery, which supplies a large portion of blood to the heart muscle. Blockages in this artery are particularly dangerous because they affect so much of the heart. Surgery is also recommended when multiple coronary arteries are blocked, when you have diabetes along with multiple blockages, or when you have serious heart failure.^[1]

The decision to have bypass surgery depends on several factors: how severe your blockages are, where exactly they’re located in the coronary arteries, your overall health, and your personal preferences. Your medical team will consider all these factors when discussing whether surgery is the right choice for you.^[4]

Pathophysiology: What Happens in the Body

To understand why bypass surgery is necessary, it helps to know what’s happening inside the body when coronary artery disease develops. The heart is a muscular pump that works continuously throughout your life. Like any muscle, it needs a constant supply of oxygen and nutrients, which are delivered through blood flowing in the coronary arteries.

The heart’s blood supply comes from two major coronary arteries: the left main coronary artery and the right coronary artery. The left main artery quickly branches into two important vessels: the left anterior descending artery, which runs down the front of the heart, and the circumflex artery, which wraps around the side. The right coronary artery supplies the right side and often the bottom of the heart.^[7]

When plaque builds up inside these arteries, several mechanical and biochemical changes occur. The plaque deposits take up space inside the artery, making the channel narrower. This is similar to how mineral deposits inside old water pipes reduce water flow. As the opening gets smaller, less blood can flow through, especially during times when the heart needs more blood, like during exercise or stress.

The plaque itself is unstable. It consists of a fatty core covered by a thin cap. If this cap breaks or ruptures, the body’s clotting system springs into action, forming a blood clot at that spot. This clot can quickly block the already narrowed artery, suddenly cutting off blood flow. When blood flow stops or is severely reduced, the heart muscle cells in that area don’t get the oxygen they need and begin to die within minutes. This is a heart attack.

Even before a complete blockage occurs, reduced blood flow causes problems. The affected heart muscle doesn’t work as well, becoming weak and less able to contract properly. This can lead to areas of the heart that don’t pump effectively, reducing the heart’s overall ability to circulate blood throughout the body. The remaining healthy heart muscle has to work harder to compensate, which can eventually wear it out.

Bypass surgery addresses these problems by creating new routes for blood to flow. Instead of trying to remove the plaque or widen the narrowed artery, surgeons connect a healthy blood vessel to the coronary artery above and below the blockage. Blood then flows through this new vessel, completely avoiding the blocked section. This restores normal blood flow to the heart muscle, allowing it to receive the oxygen and nutrients it needs to function properly again.^[2]

Prevention: Reducing Your Risk

While some risk factors for coronary artery disease, like family history and age, cannot be changed, many others can be controlled or improved through lifestyle choices. Preventing or slowing the progression of coronary artery disease can reduce the likelihood of needing bypass surgery.

Eating a heart-healthy diet is one of the most important steps. This means choosing foods low in saturated fats, trans fats, and cholesterol, which contribute to plaque formation. Instead, focus on eating plenty of fruits, vegetables, whole grains, and lean proteins. Fish rich in omega-3 fatty acids, like salmon and mackerel, are particularly beneficial for heart health. Limiting salt intake helps control blood pressure, and reducing sugar helps manage weight and prevent diabetes.^[16]

Regular physical activity strengthens the heart and improves circulation. Most adults should aim for at least 150 minutes of moderate-intensity aerobic exercise per week. This could be brisk walking, cycling, swimming, or any activity that gets your heart rate up and makes you slightly breathless. Exercise helps control weight, lowers blood pressure, improves cholesterol levels, and helps manage blood sugar.^[16]

If you smoke, quitting is absolutely critical. Smoking is one of the most damaging things you can do to your heart and blood vessels. It accelerates plaque buildup and significantly increases your risk of heart attack. Many resources and medications are available to help people quit smoking, and your doctor can guide you to appropriate support programs.^[16]

Maintaining a healthy weight reduces strain on your heart and helps prevent conditions like diabetes, high blood pressure, and high cholesterol. If you’re overweight, even modest weight loss can make a significant difference in your heart health.

Managing stress is also important, though often overlooked. Chronic stress can raise blood pressure and may lead to behaviors that harm heart health, like overeating, smoking, or drinking too much alcohol. Finding healthy ways to manage stress—through exercise, meditation, hobbies, or talking with friends and family—benefits your heart.

Regular health screenings allow your doctor to detect and treat risk factors early. Having your blood pressure, cholesterol, and blood sugar checked regularly means problems can be addressed before they lead to serious heart disease. If you have conditions like high blood pressure, high cholesterol, or diabetes, following your treatment plan and taking prescribed medications as directed is essential for preventing complications.

Preparing for Surgery

If bypass surgery is recommended, proper preparation can help ensure better outcomes and smoother recovery. Before the surgery, you’ll undergo several tests to help your healthcare team assess your heart and overall health. These may include an electrocardiogram to check your heart’s electrical activity, an echocardiogram to see how your heart is pumping, stress tests to see how your heart performs during exertion, and cardiac catheterization where a thin tube is inserted into blood vessels to directly visualize blockages. Blood and urine tests check your overall health.^[3]

Your doctor will review all medications you’re taking and tell you which ones to continue and which to stop before surgery. Some medications, especially blood thinners, may need to be stopped several days before the procedure to reduce bleeding risk during surgery. You’ll need to fast—stop eating and drinking—for several hours before the surgery.^[3]

If you smoke, your surgeon will strongly encourage you to quit before surgery. Smoking increases the risk of complications during and after the procedure. Your dental health may also be checked, as infections in the mouth can potentially spread through the bloodstream and cause problems with healing after heart surgery.

What Happens During Surgery

Coronary artery bypass surgery is major surgery that typically takes several hours. You’ll be given general anesthesia, which puts you into a deep sleep so you won’t feel anything during the procedure.^[3]

In traditional bypass surgery, the surgeon makes a cut down the center of your chest and divides your breastbone to access your heart. This approach, called a sternotomy, allows the surgeon to see and work on your heart directly. In many cases, the heart is stopped temporarily during the surgery, and a heart-lung bypass machine takes over the job of pumping blood and providing oxygen to your body. This is called “on-pump” surgery.^[2]

However, newer techniques allow some surgeries to be performed while the heart continues beating. This is called “off-pump” surgery and doesn’t require the heart-lung machine. Some patients may also be candidates for minimally invasive approaches, where smaller incisions are made between the ribs instead of opening the entire chest. In rare cases, robotic-assisted surgery may be an option.^[4]

During the surgery, the surgeon takes a healthy blood vessel from another part of your body. Most commonly, this is the internal mammary artery from inside your chest wall, or the saphenous vein from your leg. Sometimes arteries from the arm or wrist are used. The surgeon then attaches one end of this blood vessel above the blocked area of the coronary artery and the other end below the blockage. This creates a new pathway—a bypass—for blood to flow around the obstruction.^[1]

If you have multiple blocked arteries, the surgeon may create several bypasses. These are described as double (two bypasses), triple (three bypasses), or quadruple (four bypasses) depending on how many new pathways are created.^[3]

After the grafts are in place and working properly, the surgeon will restart your heart if it was stopped, close your chest by wiring your breastbone back together, and close the skin incision with sutures or staples.^[3]

Recovery After Surgery

After bypass surgery, you’ll typically spend time in the intensive care unit for close monitoring before being moved to a regular hospital room. Most people stay in the hospital for about a week after surgery.^[15]

You’ll have pain and discomfort at first, particularly where incisions were made in your chest and where blood vessels were removed from your leg or arm. Pain medication will be provided to help manage this. You may have brief, sharp pains in your chest, and your chest, shoulders, and upper back may ache. These sensations usually improve over four to six weeks.^[15]

Nurses and physical therapists will help you start moving around beginning the day after surgery. Early movement is important for preventing complications like blood clots and pneumonia. You’ll be encouraged to do breathing exercises to keep your lungs clear and strong.

Once you go home, recovery continues for several weeks to months. You’ll feel tired easily at first and will need to rest often. It may take one to two months to get your energy back fully. You’ll be able to do many usual activities after four to six weeks, but you’ll need to avoid heavy lifting and activities that strain your chest or upper arms for at least six weeks while your breastbone heals.^[15]

Driving is typically not allowed for at least four weeks to allow your breastbone to heal enough that you could safely use a seatbelt and control the vehicle without risk of injury. Your doctor will tell you when it’s safe to resume driving and return to work, which depends on the type of work you do and how you’re recovering.^[15]

Many people notice they’re more emotional after surgery. You may cry more easily or feel more sensitive than usual. This is common and can last up to a year. Some people experience depression after heart surgery. If you feel persistently sad or anxious, talk to your doctor, as treatment and support can help.^[15]

You may be referred to a cardiac rehabilitation program, which provides supervised exercise, education about heart-healthy living, and support for making lifestyle changes. These programs have been shown to improve recovery and long-term outcomes after bypass surgery.^[4]

Long-Term Outlook

Many people live long, healthy lives after coronary artery bypass surgery. Patients who successfully get through the first month after surgery have a survival rate similar to the general population. The surgery can significantly improve quality of life by reducing or eliminating chest pain, improving the ability to be physically active, and allowing people to return to activities they enjoy.^[23]

After surgery, many people remain symptom-free for years. However, it’s important to understand that new blockages can form over time. The grafted blood vessels can develop plaque buildup just like the original coronary arteries did. Blockages can also form in coronary arteries that weren’t blocked before. This is why continuing to follow a heart-healthy lifestyle and taking prescribed medications is so important after surgery.^[4]

Some people may eventually need additional procedures or even another bypass surgery if new blockages develop. However, by making healthy lifestyle choices, managing risk factors like high blood pressure and cholesterol, and taking medications as prescribed, you can significantly reduce the likelihood of needing further interventions.^[16]