Coronary artery bypass grafting (CABG) Is a form of heart surgery that restores blood flow to the heart when one or more coronary arteries have become narrowed or blocked, likely as a result of coronary artery disease.

Coronary artery disease (CAD) is the most common type of heart disease—affecting around 18 million Americans —and the leading cause of death in the United States. The condition is marked by a narrowing or blockage of the coronary arteries, which are responsible for delivering blood to the heart. Many people with the condition experience chest pain and are at increased risk of having a heart attack.

Fortunately, treatments are available for CAD, from lifestyle changes to medications to procedures like percutaneous coronary intervention (PCI) and CABG.

“CABG is one of the most common procedures performed in the U.S. When done for patients with complex coronary artery disease, it results in excellent outcomes, which prolongs patients’ lives and decreases the need for additional revascularization for the long term,” says Arnar Geirsson, MD, Chief of the Division of Cardiac Surgery at Yale Medicine.

Pronounced “cabbage” and sometimes referred to as heart bypass or bypass surgery, CABG is a surgical procedure that reroutes blood around narrowed or blocked coronary arteries, thereby improving blood flow to the heart.

To stay healthy and in good working order, the heart needs a constant supply of oxygen-rich blood, which is transported by the coronary arteries.

In people with CAD, plaque builds up within the walls of the coronary arteries over time, narrowing them and reducing—or even completely blocking—blood flow to the heart. This can lead to chest pain (known as angina) and heart attacks.

During a CABG procedure, a surgeon takes a healthy vein or artery from elsewhere in the body, then attaches one end to the aorta (the largest artery in the body) and the other end to the coronary artery (past the narrowed or blocked section). Oxygen-rich blood flows through the newly grafted blood vessel, around—or bypassing—the narrowed or blocked section of the coronary artery, to the heart.

Sometimes 2, 3, 4, or more coronary arteries need to be bypassed during a single surgery. In these cases, the surgical procedure is often referred to as a double, triple, or quadruple bypass, respectively.

CABG may be used to treat:

• People who have CAD with chest pain that doesn’t go away after taking medications
• People with CAD who have a heart attack that cannot be treated with percutaneous coronary intervention
• People with more than one narrowed or blocked coronary artery
• People with a life-threatening abnormal heart rhythm (arrhythmia)
• People with heart failure
• People who have CAD due to diabetes
• Patients who have undergone an unsuccessful percutaneous coronary intervention procedure

CABG can be done via open-heart surgery or using minimally invasive techniques.

At the start of a CABG procedure, patients are given general anesthesia, so they won’t be awake or feel pain during the surgery. 

• Open-heart CABG. The surgeon begins the procedure by making a long incision down the chest and through the center of the breastbone, which is separated, providing the surgeon with access the heart.
  
  In a traditional CABG procedure, drugs are used to stop the patient’s heartbeat; the heart is connected to a heart-lung bypass machine that takes over the circulation of oxygen-rich blood throughout the body during the surgery.
  
  The surgeon then takes part of a blood vessel—an artery or vein—from the leg, arm, or chest. This blood vessel is used to make a graft. One end is sewed to the blood vessel that connects to the aorta and the other end to the affected coronary artery. If more than one coronary artery is narrowed or blocked, the surgeon will perform bypass each of them using this technique.
  
  At the end of the procedure, the heart is restarted and removed from the heart-lung bypass machine. The surgeon will close the breastbone and wire it together, then stich up the chest incision. The wires remain in the patient’s body after the procedure.
• Minimally invasive CABG. In this version of the procedure, the surgeon makes an incision along the left side of the chest and accesses the heart, performing the bypass through the ribs. Sometimes, the surgery is performed robotically. With minimally invasive CABG, a heart-lung bypass machine is not usually required. Minimally invasive CABG is less invasive, involves smaller incisions, and typically has a shorter recovery period than open-heart CABG.

Like all surgeries, CABG comes with certain risks. Serious complications are rare.

Risks include:

• Bleeding
• Heart attack
• Stroke
• Irregular heartbeat (arrhythmia)
• Infection
• Kidney failure
• Failure of the graft

Before undergoing a planned CABG procedure, blood tests are usually necessary to ensure that the patient’s complete blood count (CBC), blood clotting factors, and other measures are at appropriate levels for CABG. The patient may also need to undergo imaging tests including a chest X-ray, electrocardiography (ECG), and coronary angiography before surgery.

Patients should let their doctor know about any medications they take. Use of some medications may need to be temporarily paused prior to the surgery.

Patients shouldn’t eat or drink anything for 8 or more hours (usually overnight) before the surgery.

Full recovery from the procedure may take a few months.

In most cases, patients spend around a week in the hospital following CABG surgery. Usually, the first day or two are spent in the intensive care unit where patients are closely monitored as they begin their recovery. Within a day or two after surgery, most people are able to walk a short distance.

Upon leaving the hospital, patients typically need to take medications to lower the risk of complications. Among others, these may include blood thinners to prevent blood clots, blood pressure-lowering drugs, and cholesterol-lowering drugs. Patients will also be taught how to care for their surgical wounds while they heal.

Cardiac rehabilitation programs are an important part of CABG recovery. These programs involve guided exercises designed to safely improve heart function. Patients are also encouraged to quit smoking, get high blood pressure and cholesterol under control, reduce stress, and follow a healthy diet.

Some people experience depression or mood changes following CABG surgery. Mental health treatment can help improve recovery in these cases.

For people with CAD and certain other heart problems, CABG can relieve chest pain and help them lead active, healthy lives. CABG cannot prevent coronary arteries or even grafts from narrowing or getting blocked in the future.

That’s why, after undergoing CABG surgery, it’s important for people to get regular exercise, follow a healthy diet, quit smoking, and take steps to keep high blood pressure, sugar, and cholesterol levels under control.

“Yale Medicine offers a multidisciplinary approach for patients with complex CAD in which interventional cardiologists and cardiac surgeons review and discuss cases such that the best intervention or surgery is tailored to each patient,” says Dr. Geirsson. “This provides the best care and best outcomes for both the short and the long term.“