Coronary Artery Bypass Grafting (CABG)

Contents

In this article we will look at:

• What is coronary artery bypass grafting (CABG)?
• Eligibility for CABG
• How is CABG performed?
• On-Pump CABG procedure
• Off-Pump CABG procedure
• Risks of undergoing the CABG procedure
• Benefits of undergoing the CABG procedure
• Alternatives to CABG
• Pre-procedure guidelines of CABG
• Possible complications of CABG
• Post-procedure guidelines of CABG
• Recovery period after undergoing a  CABG procedure
• Are the results of CABG permanent?
• Is the CABG a success?
• More Cardiology Related Topics
• References

You can click on any of the links above to navigate to the section of your interest.

What is coronary artery bypass grafting (CABG)?

Coronary artery bypass grafting is a procedure performed on people who are suffering from severe heart conditions, such as coronary atherosclerosis or acute coronary syndrome. 

This condition results from plaque build-up overtime on the inner artery walls. The hardened arteries are not able to expand to their fullest capacity to let the blood flow through into the heart.

In the CABG procedure, a healthy artery or vein from the body is connected, or grafted, to the blocked coronary artery. The grafted artery bypasses the blocked portion of the coronary artery. The grafted artery thus becomes a new path for the oxygen-rich blood to flow to the heart muscle.

During a single surgery, the surgeons can bypass multiple coronary arteries.

CABG is performed under general anesthesia and the cost of the procedure in India can vary from Rs. 2,00,000 to Rs. 5,00,000 depending on the patient’s medical condition, the hospital amenities, and the surgeon’s fees. The entire procedure generally takes 3 to 6 hours to complete.

Am I eligible for coronary artery bypass grafting?

You are eligible for coronary artery bypass grafting if you suffer from severe coronary artery disease which cannot be corrected with balloon angioplasty, laser angioplasty or stent placement. The surgery may be risky for you if you:

• have other chronic health conditions, including peripheral artery disease, diabetes, high blood pressure, kidney or lung disease

• consume a lot of alcohol

Please Note: Eligibility criteria for various medical procedures differs from patient to patient and depends on their general health, medical history, and medical conditions. Please consult a doctor to know more about your eligibility or ineligibility for any medical procedure. 

How is coronary artery bypass grafting performed?

There are two different methods of performing CABG:

1. On-pump CABG which is the traditional way and time honoured way of performing CABG

2. Off-pump CABG which is the newer way. 

On-Pump CABG Procedure

On-Pump Coronary Artery Bypass Grafting involves the following steps:

1. At the outset, you are administered general anesthesia by an anesthetist. 

2. A breathing tube is inserted into your throat to help you breathe. 

3. A catheter is placed in your bladder to drain your urine. 

4. Once the anesthesia takes effect, the cardiac surgeon makes an incision over the breastbone called the sternum.

5. He then saws (cuts) through the breastbone (sternum). This procedure is called a median (middle) sternotomy (cutting of the sternum).

6. Once the sternum is cut, the surgeon proceeds to open the rib cage to get to the heart. 

Please Note: In the on-pump CABG procedure, your circulatory system is connected throughout to a cardiopulmonary bypass pump (or a heart-lung machine). This machine temporarily takes over the function of your heart and lungs through the course of the surgery, allowing your heart to be stopped while your surgeon performs the procedure of sewing the grafts into place. 

7. The doctor takes a healthy artery or vein from your leg or chest.

8. He now grafts or connects one end of the healthy artery above the blocked artery in your heart and the other end below the block. The grafts are sewn in place.
   This way, the blood flows through the newly grafted artery and goes around or bypasses the blocked part of the coronary artery to reach the heart.

9. With the graft securely in place, your surgeon uses electrical signals to restore your heartbeat and attaches a temporary pacemaker (a small device placed in the chest to control abnormal heart rhythms) to the heart.

10. Once your heart is beating normally, the heart-lung machine is disconnected.

11. Your surgeon then positions the rib cage back in place and wires the breastbone together.

12. Finally, he sutures the incision. 

13. A temporary drainage tube is inserted through the skin beneath the incision, which is hooked to a machine to help drain out extra air and blood. The tube is taken out in about a day or when the drainage is stopped.

Off-Pump CABG Procedure

Off-Pump Coronary Artery Bypass Grafting involves the following steps:

1. At the outset, you are administered general anesthesia by an anesthetist. 

2. The doctor makes an incision to remove a vessel. Often this is a vessel taken from your chest wall or your leg.

3. If you are undergoing traditional off-pump CABG, your doctor makes an incision down the middle of your chest to separate your breastbone.

4. If you are undergoing a minimally invasive off-pump CABG, your doctor may make a small incision down the middle of your chest and separate part of your breastbone. Sometimes doctors use special instruments and a camera to do the surgery. In this approach, your doctor makes several small holes in your chest, between the ribs. Some doctors use robot-controlled arms to perform the surgery.

5. Your heart will keep beating throughout the surgery, unlike on-pump CABG procedure where your heart stops functioning and the heart-lung machine takes over its function.

6. Your doctor now grafts or attaches the removed vessel to the aorta, the main blood vessel going out to the body and the other end of the vessel to the blocked coronary artery, to bypass the blockage.

7. Once the grafting is complete, the doctor wires your breastbone back together (if necessary).

8. Finally, he sutures the incision. 

The off-pump CABG procedure is generally preferred for :

• patients with aortic disease precluding bypass

• patients at a higher risk of complications from the on-pump procedure, such as:

  • those suffering from ventricular dysfunction

  • those suffering from renal insufficiency

  • those suffering from diabetes

  • those who are of advanced age

  • those suffering from chronic lung disease

What risks will I face while undergoing the coronary artery bypass grafting procedure?

Some possible surgical risks for coronary artery bypass surgery include:

• High fever

• Infection

• Bleeding or infection at the site of the incision

• Reaction to the anesthesia

• Blood loss

• Developing a blood clot that could affect the lungs

• A sudden heart attack or stroke

• Death during the surgery

• Abnormalities with heart rhythm called arrhythmia

• Chronic pain in sternum or breastbone (wound site) 

• Pneumonia

• Difficulty in breathing

• Kidney failure

• Impairment of cognitive functions

• Pain in the chest and fever for up to six months

What are the complications of a coronary artery bypass grafting procedure?

Complications can arise during or after coronary artery bypass surgery, which include:

• No proper blood flow to the heart due to bypass not functioning properly.

• Blocking of the new bypass blood vessel.

• Death during surgery due to heart not functioning or responding.

• Nerve damage in the leg from where the graft (blood vessel) was taken.

• Pain and swelling in the legs.

How will I benefit after undergoing a coronary artery bypass grafting procedure?

The benefits of coronary artery bypass surgery are:

• Relief from chest pain or angina.

• A decreased risk that the coronary arteries will become completely occluded, which decreases the risk of a heart attack.

• Results last longer as a surgical revascularization is long lasting than a stent procedure.

What are my alternatives to coronary artery bypass grafting?

Alternatives to coronary artery bypass grafting include:

• Medications that dilate your blood vessels to allow normal blood flow. The doctor may prescribe medications, such as beta-blockers, nitrates, calcium channel blockers, and lifestyle changes, such as to quit smoking, eating a more heart-healthy diet and exercising. These changes can effectively alleviate your heart condition. 

• Balloon Angioplasty

• Coronary Stenting

• Laser Angioplasty

What are the pre-procedure guidelines I should follow for coronary artery bypass grafting? 

The pre-procedure guidelines you need to follow before undergoing a coronary artery bypass grafting are:

• You need to discuss your complete medical history with your doctor prior to the surgery and let him/her know of any other medical conditions that you suffer from, apart from the heart-related conditions. You also need to mention if you are allergic to any substances.

• Prior to the surgery, the following tests will be performed:

• chest x-ray

• urine test

• electrocardiogram (ECG)

• blood tests

• You will be advised to stop taking drugs containing blood thinners such as aspirin for at least 5 days before the surgery, since these medicines may lead to severe bleeding during and post the surgery. 

• Your doctor will advise you to stop smoking for at least two weeks prior to the surgery. Smoking will interfere with the healing process as people who smoke tend to have more mucus in their lungs, which is difficult to remove after surgery.

• You will be advised not to take anything orally (food, liquids or tablets) at least 12 hours prior to the surgery. You may be given special instructions from your doctor if you are a diabetic. 

• The day before surgery, you may be asked to scrub your abdomen and legs several times with a special soap to kill germs. This procedure may vary in different medical facilities.

• You need to let the doctor know about the different medications you are currently taking, including herbal supplements.

• You need to sign a consent form prior to the surgery. 

• An anesthesiologist will explain about the anesthesia dosage that will be given to you and the side effects that may occur from it, prior to the procedure. 

• It will be wise to ask your cardiologist about the side effects of the surgery and if you need to take any precautions in advance.

What are post-procedure guidelines I need to follow after undergoing a coronary artery bypass grafting procedure?

The post-procedure guidelines after undergoing a coronary artery bypass grafting are: 

• You will be taken to the Cardiac Surgery Intensive Care Unit where you will be constantly monitored for 2 days approximately. 

• You will have a breathing tube in your windpipe. The nurse may use a small tube to remove mucus from your lungs and mouth, to prevent a mucus build-up in your lungs. The procedure can cause pain, make you cough and make it hard to breathe, but you may be given drugs to treat these symptoms.

• Once you become conscious, you are weaned from the machine that is helping you to breathe. Then, the tube in your windpipe is taken out. A mask is fitted on your nose and mouth area through which you can breathe in oxygen. 

• Later the mask is removed and a small tube under your nose is placed to provide oxygen.

• You will be advised to take deep breaths and cough 10 to 20 times an hour to prevent fluid build-up in your lungs. 

• If the blood vessel for the bypass was taken from your leg, you may have some swelling in your legs. Raise your legs above your heart when sitting and do not cross your legs. Ask the doctor or the attending health staff about the sitting posture.

• Some tests such as chest x-ray, ECG, and blood tests will be done on you to rule out any form of complications.

• You may feel frequently tired after the surgery, as you may suffer from anemia. This is quite normal.

• After a day or two, the dressings over your chest and leg wounds is taken off.

• Most of your stitches are inside and will dissolve over time. The staples are taken out five to seven days after surgery. 

• You will be advised by a dietician about the kind of foods you should and should not eat.

• You will be advised to do simple exercises to help you heal. You will also be advised to avoid strenuous exercises for a few days. 

• You need to abstain from taking tub baths for a few weeks after the surgery. 

• You need to avoid sexual activities for eight to nine weeks following the surgery, or till your doctor advises you to.

• You will be asked to come for follow-up visits to the hospital. 

• You should refrain from driving till your doctor says it is okay for you to drive.

What is the recovery period after undergoing a coronary artery bypass grafting procedure? 

The recovery period from coronary artery bypass grafting varies from patient to patient. It usually takes six to twelve weeks. The healing of the breastbone alone takes six weeks. 

Are the results of coronary artery bypass grafting permanent? 

The results overall seem to be good in patients who have undergone the surgery, though if performed as an emergency surgery, the risk of complication increases. The results can also vary from patient to patient depending on each patient’s overall health condition. Your doctor may also recommend a cardiac rehab program that can act as a supplement to improve your overall health and well-being.

How do I know if the coronary artery bypass grafting procedure I underwent is a success? 

The imaging and x-ray tests taken during follow-up visits, post the procedure, will clearly show whether the procedure has been a success and the blood flow to the heart has returned to normal. If not, further treatment may be required. 

More Cardiology Related Topics

People interested in this topic also read:

Angioplasty Overview: Meaning, Procedure, & Risks

• Balloon Angioplasty
• Balloon Angioplasty with Stent Insertion
• Laser Angioplasty

Related Topic 

Coronary Artery Bypass Grafting (CABG)

References