Coronary Artery Bypass Graft (CABG) Surgery

What is coronary artery bypass graft (CABG) surgery?
Coronary artery bypass graft surgery is a surgical procedure in which one or more blocked coronary arteries are bypassed by a blood vessel graft to restore normal blood flow to the heart. These grafts usually come from the patient’s own arteries and veins located in the chest, leg, or arm. The graft goes around the blocked artery (or arteries) to create new pathways for oxygen-rich blood to flow to the heart.

coronary artery bypass grafts

The goals of the procedure are to relieve symptoms of coronary artery disease (including angina), enable the patient to resume a normal lifestyle and to lower the risk of a heart attack or other heart problems.

Coronary artery bypass graft surgery is widely performed in the United States. It is estimated that more than 800,000 coronary artery bypass graft surgeries are performed worldwide every year.

The American Heart Association reports that 467,000 coronary artery bypass graft surgeries were performed on 268,000 patients in the United States in 2003.

Who is eligible to receive coronary artery bypass graft surgery?
The decision to prescribe medical treatment, invasive procedures or surgery depends on several factors including the extent of cardiovascular disease, the severity of symptoms, your age and other medical conditions. The cardiologist (heart specialist) and surgeon will determine the best method of therapy for each patient.

What happens during the surgery?
The surgery generally lasts from three to five hours, depending on the number of arteries being bypassed. After general anesthesia is administered, the surgeon removes the veins or prepares the arteries for grafting.

Graft Preparation

There are several types of bypass grafts. The surgeon decides which graft(s) to use, depending on the location of the blockage, the amount of the blockage and the size of the patient’s coronary arteries. Note – somehow insert - Due to research on longevity of bypass grafts, arterial grafts are the graft of choice

Internal mammary arteries (also called IMA grafts or thoracic arteries) are the most common bypass grafts used, as they have shown the best long-term results. In most cases, these arteries can be kept intact at their origin because they have their own oxygen-rich blood supply, and then sewn to the coronary artery below the site of the blockage. If the surgeon removes the mammary artery from its origin, it is called a “free” mammary artery. Over the last decade, more than 90% of all patients received at least one internal artery graft. Because of the success of mammary arteries, other arterial grafts are used.

The radial (arm) artery is another common type of arterial graft. There are two arteries in the arm, the ulnar and radial arteries. Most people receive blood to their arm from the ulnar artery and will not have any side effects if the radial artery is used. Careful preoperative and intraoperative tests determine if the radial artery can be used. If the radial artery is used as the graft, the patient may be required to take a calcium channel blocker medication for several months after surgery. This medication helps keep the artery open. Some people report numbness in the wrist after surgery. However, long-term sensory loss or numbness is uncommon.

Saphenous (leg) veins can be used as bypass grafts. Minimally invasive saphenous vein removal does not require a long incision. One to two incisions are made at the knee and a small incision is made at the groin. This results in less scarring and a faster recovery. Your surgeon will decide if this method is a good option for you. Traditionally, removing the vein requires several small incisions on the leg.

The gastroepiploic artery to the stomach and the inferior epigastric artery to the abdominal wall are less commonly used for grafting.

Surgical Procedure

To bypass the blockage, the surgeon makes a small opening just below the blockage in the diseased coronary artery. If a saphenous (leg) or radial (arm) vein is used, one end is connected to the coronary artery and the other to the aorta. If a mammary artery is used, one end is connected to the coronary artery while the other remains attached to the aorta. The graft is sewn into the opening, redirecting the blood flow around this blockage.

The procedure is repeated until all affected coronary arteries are treated. It is common for three or four coronary arteries to be bypassed during surgery.

After surgery, the surgeon closes the breastbone with special sternal wires. Then the chest is closed with internal stitches or traditional external stitches. Before the patient leaves the hospital, the doctor or nurse will explain the specific bypass procedure that was performed.

Heart-Lung Machine

During traditional CABG surgery, a surgeon makes a 6- to 8-inch incision down the center of the sternum (breastbone) to get direct access to the heart. During surgery, the heart-lung bypass machine (called “on-pump” surgery) is used to take over for the heart and lungs during surgery, allowing the circulation of blood throughout the rest of the body. The heart’s beating is stopped so the surgeon can perform the bypass procedure on a “still” heart.

Off-pump or beating heart bypass surgery allows surgeons to perform surgery on the heart while it is still beating. The heart-lung machine is not used. The surgeon uses advanced operating equipment to stabilize (hold) portions of the heart and bypass the blocked artery in a highly controlled operative environment. Meanwhile, the rest of the heart keeps pumping and circulating blood to the body.

Traditional incision

Minimally invasive incision

Minimally Invasive Technique

Minimally invasive coronary artery bypass (MIDCAB) surgery is an option for some patients who require a left internal mammary artery (LIMA) bypass graft to the left anterior descending (LAD) artery. A small incision (only about 3 inches instead of the 6 to 8 inches required for traditional bypass surgery) is used. The benefits of minimally invasive bypass surgery include a smaller incision (and a smaller scar), reduced risk of infection, decreased recovery time and shorter hospital stay.

Some patients also are candidates for surgery using new robotic techniques, allowing surgeons to perform bypass surgery in a closed chest, beating-heart environment through small keyhole incisions.

Recovery
Full recovery from coronary artery bypass graft surgery takes around two months. Most patients are able to drive in about three to eight weeks after surgery. For those who have robotic or minimally invasive surgery, these time frames may be shorter. Your doctor will provide specific guidelines for your recovery and return to work, including specific instructions on activity and how to care for your incision and general health after the surgery.

Coronary artery bypass graft surgery does not prevent coronary artery disease from recurring, therefore lifestyle changes and prescribed medications are strongly recommended to reduce this risk. Lifestyle changes include:

Quitting smoking
Treating high cholesterol
Managing high blood pressure and diabetes
Exercising regularly
Maintaining a healthy weight
Eating a heart-healthy diet
Controlling stress and anger
Taking prescribed medications as ordered
Participating in a cardiac rehabilitation program, as recommended
Following up with your doctor for regular visits

References:
1. Heart Disease and Stroke Statistics—2006 Update: A Report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation, January 2006. 113(1):85-151. (http://www.americanheart.org/presenter.jhtml?identifier=1200026)
2. Cardiovascular Procedures – Statistics, 2004 (http://www.americanheart.org/presenter.jhtml?identifier=3000958)

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