If one or more of your coronary arteries (the vessels that carry blood to your heart muscle) are blocked, blood can’t flow to the heart muscle. In this case, the heart muscle may die (heart attack) or become weakened and damaged and cause chest pain (angina). Problems like shortness of breath, increasing fatigue, leg swelling, or feeling run down may occur. Coronary artery bypass surgery creates a path for blood to flow around a blockage and helps reduce the risk of further damage to your heart from lack of sufficient blood flow.
Preparing the Bypass Graft
First, a healthy blood vessel (graft) is taken from another part of the body. Taking this graft usually doesn’t affect blood flow in that body part. There are several types of bypass grafts used for heart bypass surgery. The surgeon decides which graft(s) to use, based on the location of the blockage, the amount of blockage, and the size of the patient’s coronary arteries.
- Internal mammary arteries (also called thoracic arteries). These are the most common bypass grafts used, as they have been shown to have the best long-term results. In most cases, these arteries can be kept intact at their origin since they have their own oxygen-rich blood supply. During the procedure, the arteries are sewn to the coronary artery below the site of blockage. This artery is located in the chest and can be accessed through the primary incision for the bypass surgery.
- Saphenous veins. These veins are removed from your leg, and then sewn from your aorta to the coronary artery below the site of blockage. Minimally invasive saphenous vein removal may be performed and results in less scarring and a faster recovery.
- Radial artery. There are two arteries in the lower part of the arm, the ulnar and radial arteries. Most people receive adequate blood flow to their hand from the ulnar artery alone and will not have any side effects if the radial artery is removed and used as a graft. Careful preoperative and intraoperative tests determine if the radial artery can be used. If you have certain conditions (such as Raynaud’s, carpal tunnel syndrome, or painful fingers in cold air) you may not be a candidate for this type of bypass graft. The radial artery incision is in your forearm, about 2 inches from your elbow and ending about 1 inch from your wrist. Some people report numbness in the wrist after surgery. However, long-term sensory loss or numbness is uncommon.
- The gastroepiploic artery to the stomach and the inferior epigastric artery to the abdominal wall are less commonly used for grafting.
It is common for three or four coronary arteries to be bypassed during surgery. A coronary artery bypass can be performed with traditional surgery (see below) or with minimally invasive surgery (see below). Your surgeon will review your diagnostic tests prior to your surgery to see if you are a candidate for minimally invasive bypass surgery.
Reaching the Heart
While one member of the bypass team is harvesting the graft(s), another member works to expose your heart. First, an incision is made in the chest. Then the breastbone (sternum) is opened down the middle and then pulled apart. The breastbone is held open throughout surgery. This puts pressure on the nerves of the chest. This is why you may have soreness and muscle spasms in your chest, shoulders, and back during recovery.
Attaching the Graft
A small opening is made in the coronary artery, past the blockage.
If a saphenous vein or radial artery is used, one end of the graft is sewn onto this opening. The other end is typically sewn on to the aorta. The diseased artery is not removed. If a stent is present, it is not removed either, as will have grown into the artery already.
If the internal thoracic (mammary) artery is used, one end of the graft is sewn onto this opening. The other end is already attached to a branch of the aorta.
Once the graft has been attached, blood will start flowing through this new pathway to bypass the blockage. If you have multiple blockages, more than one bypass may be done. Then your breastbone is rejoined with wires. These wires will stay in your chest permanently. Rarely do they cause a problem, and they are safe around microwaves and airport metal detectors. The incision is closed, and you are taken to the intensive care unit to begin your recovery.
Using a Heart-Lung Machine
Coronary artery bypass surgery can be done with the heart still beating (off pump) or with the heart still (on pump.) Your surgery team can tell you more about which type of procedure you will have.On-pump procedure.
A machine does the work of your heart and lungs during surgery. Blood is circulated through a heart-lung machine. The machine supplies the blood with oxygen and pumps it back through the body. In these cases, the heart may be stopped temporarily before the graft is attached. Your own heart and lungs start working again after the bypass is completed.
The heart-lung machine is not used and the heart is not stopped. This is sometimes called a “beating heart” procedure.
There are advantages and disadvantages to each technique. If you have a question about why your doctor is using one technique, instead of the other, do not be afraid to ask.
Risks and Complications
You and your surgeon can discuss the risks and possible complications of coronary artery bypass surgery. They may include:
- Excessive bleeding, sometimes requiring a transfuion or a trip back to the operating room
- Infection of the incision sites
- Pneumonia (lung infection)
- Fast or irregular heartbeat, which is almost always temporary
- Nerve injury or muscle spasms
- Breathing problems
- Memory problems or confusion
- Heart attack, stroke, or death
- Damage to other parts or organs of your body due to problems with blood circulation