Heart Bypass Surgery (CABG): Procedure, Side Effects, Benefits

Coronary Artery Bypass Graft Surgery, or CABG, is a surgical procedure to treat narrowed or blocked coronary arteries that supplies blood to the heart muscle. 

CABG surgery improves blood flow to the heart by bypassing the blocked or narrowed areas of the coronary arteries with a healthy blood vessel taken from another part of the body.

Anatomy and Physiology of the Human Heart

The heart is a muscular organ which is located in the thoracic cavity, behind the breastbone and slightly to the left. It pumps blood throughout the body. It is divided into four chambers. 

The anatomy of the heart includes the following structures:

1. Atria: It is the upper chambers of the heart. The right and left atrium receive blood from the body and lungs.
2. Ventricles: It is the lower chambers of the heart. The right ventricle and the left ventricle pump blood to the lungs and the body, respectively.
3. Valves: There are four valves which control the flow of blood through the chambers of the heart.
4. Coronary Arteries: They are blood vessels that supply the heart muscle with oxygen-rich blood.
5. Cardiac Muscle: The heart muscle, also known as the myocardium, contracts to pump blood through the heart.
6. Veins and Arteries: The blood vessels that carry blood to and from the heart.
7. Electrical System: It is composed of the sinoatrial (SA) node and the atrioventricular (AV) node, controls the heart's rhythm and ensures that the chambers contract correctly.

CABG surgery is recommended for patients with severe coronary artery disease (CAD) caused by plaque buildup in the coronary arteries. This buildup, known as atherosclerosis, can block or narrow the coronary arteries, reducing blood flow to the heart muscle. Conditions treated using CABG Surgery are:

1. Angina: Chest pain or discomfort caused by blocked or narrowed coronary arteries.
2. Myocardial infarction (heart attack): Damage or death of a portion of the heart muscle caused by blocked blood flow to the heart.
3. Heart failure: It is caused by narrowed or blocked coronary arteries. Due to this, the heart cannot pump blood adequately to the body.
4. Left Ventricular Dysfunction: Reduced pumping ability of the left ventricle, one of the four chambers of the heart, caused by narrowed or blocked coronary artery.
5. Cardiomyopathy: It makes the heart muscle harder to pump blood.

Who needs CABG Surgery?

Patients who may need CABG surgery have one or more of the following:

1. Angina (chest pain) that medications can't treat
2. A previous heart attack
3. Significant blockages in multiple coronary arteries
4. Heart damage or weakness that limits the ability of the heart to pump blood effectively
5. Blockages that cannot be treated with angioplasty

The entire procedure may take anywhere between 3-6 hours or sometimes more. Patient vitals are monitored during the entire procedure. The procedure starts with the following:

1. A urinary catheter is inserted.
2. CABG surgery is done under general anaesthesia given intravenously.
3. A breathing tube attached to a ventilator is inserted through the mouth. The ventilator breathes for the patient during and immediately after the surgery. 
4. The surgical site is cleaned with an antiseptic solution.
5. The surgeon will proceed with either one of the above based on your condition. CABG surgery procedure may be done in either of the following:
   1. On-pump procedure
   2. Off-pump procedure

On-pump & Off-pump CABG Surgery:

1. The surgeon will access the blood vessel to be used for the grafts by making an incision in either the leg(s) or wrist. After the removal of the blood vessel, the incision is closed. 

2. An incision is made from below Adam’s apple to just above the navel (i.e. incision from just below the neck till slightly above the belly button).

3. The sternum (breastbone is cut in half lengthwise, and halves are separated to expose the heart.

4. In the case of On-pump CABG Surgery: The heart is placed on a heart-lung bypass machine that pumps blood like an artificial heart. The heart is stopped temporarily by injecting a cold solution. 

In the case of Off-pump CABG Surgery: The heart is not stopped. Instead, a unique instrument is used to stabilize the area around the artery to be bypassed.

5. One end of the graft is sewn over a tiny opening made in the aorta, and the other end over a tiny space made just below the block. (If the internal mammary artery is used as a graft, the lower end of the artery is cut and sewn below the blockage. 

6. Depending on the number of arteries blocked, more than one bypass graft may be done. 

7. Grafts are checked as blood runs through them.

8. In the case of On-pump CABG Surgery: Blood circulating through the bypass machine is let into the heart. The heart may restart on its own, or a mild electric shock may be used to restart it. Temporary wires may be put in for pacing the heart.

9. The sternum is stitched with small wires.

10. To drain fluids from around the heart, tubes are inserted into the chest.

11. A tube is placed into the stomach through the mouth or nose to drain stomach fluids. 

12. To cover the surgical site, a sterile bandage is used.

Prior to the CABG surgery, the surgeon will discuss and prepare the patient for the surgery. These steps often involve:

Before CABG Surgery

1. Medical history (current and past drug prescriptions, smoking/alcohol habits, lifestyle habits, presence of other concurrent health conditions, surgical history), complete physical exam, necessary blood tests and other diagnostic tests are prescribed to determine the type of CABG procedure to be done
2. In case of elective surgery, the patient is admitted to the hospital a day prior to the scheduled procedure and provided with a unique identification number.
3. No food or drink is allowed 8 hours before the procedure
4. You may carry spare clothing, toiletries, comfortable slippers/shoes to the hospital. 
5. It is recommended to leave all the jewellery and other accessories at home before getting admitted to the hospital. 

On the Day of the CABG Surgery

1. A unique identification number as a wristband is assigned after admission 
2. A consent form granting permission to the surgeon to do the procedure and not holding the hospital or surgeon and their team liable for complications (including death) is sought from the patient. 
3. The patient is helped to change into a hospital gown, and all jewellery and accessories are removed. 
4. Hair near the genital area (for urinary catheter) and the surgical site may be trimmed if required.
5. Vitals are monitored

CABG surgery usually takes 3-6 hours. The patient can go home within a couple of days after the procedure. The patient may expect the following after the surgery:

The recovery process at the hospital

1. Monitoring: The vital signs will be closely monitored to ensure that they are stable and that the surgery was successful.
2. Pain management: Pain and discomfort are common after CABG surgery. Medication will be prescribed to manage pain, prevent infection, and lower the risk of blood clots.
3. Drainage: Patients may have a tube placed to remove any excess fluid from the chest area.
4. Breathing exercises: Deep breathing exercises would be taught to help clear the lungs and prevent pneumonia.
5. Discharge planning: Patients will receive discharge instructions and information on post-operative care, including follow-up appointments, medications, and lifestyle changes.

The recovery process after hospital discharge

1. Rest and relaxation: Patients will need to rest and avoid strenuous activities for several weeks after surgery to allow the body to heal properly.
2. Medications: Patients will continue to take medications as prescribed by their surgeon to manage pain, prevent infection, and lower the risk of blood clots.
3. Physical activity: Patients will be encouraged to slowly increase their physical activity as they recover. They will be advised to start with light walking and gradually increase their activity level as they feel ready.
4. Diet: Patients will be advised to eat a healthy diet that is low in saturated fat and cholesterol to promote healing and reduce the risk of further cardiac issues.
5. Lifestyle changes: Patients will be advised to make lifestyle changes such as quitting smoking, reducing stress, and exercising regularly to reduce the risk of further cardiac issues.

First follow-up appointment

1. Medical evaluation: The surgeon will perform a medical evaluation, including a physical examination and review of the patient's vital signs.
2. Discussion of recovery: The surgeon will discuss the patient's recovery process and answer any questions the patient may have.
3. Review of medication regimen: The surgeon will review the patient's medication regimen and make any necessary adjustments.
4. Review of activity level: The surgeon will assess the patient's activity level and provide guidance on increasing physical activity as the patient recovers.
5. Review of incision site: The surgeon will examine the incision site to ensure that it is healing properly.
6. Review of lab results: The surgeon will review any lab results, such as blood tests, that were performed during the recovery process.

Coronary Artery Bypass Graft surgery provides several benefits for patients with severe coronary artery disease (CAD), including:

1. Improved blood flow to the heart: Bypassing the blocked or narrowed areas of the coronary arteries with a healthy blood vessel improves blood flow to the heart muscle, reducing symptoms such as chest pain (angina) and shortness of breath.
2. Reduced risk of heart attack: Bypassing the blocked coronary artery reduces the risk of a heart attack by improving blood flow to the heart muscle.
3. Relief of angina: CABG can relieve angina by improving blood flow to the heart muscle and reducing chest pain and discomfort.
4. Improved heart function: It can improve heart function by increasing blood flow to the heart muscle, which can help to reduce the risk of heart failure.
5. Long-term benefits: CABG has been shown to provide long-term benefits, with studies showing that patients who have had the surgery have a lower risk of dying from heart disease.
6. Reduced need for medication: After coronary artery bypass surgery, many patients can reduce or stop taking medications for angina, high blood pressure, and other cardiac issues.

Complications and risks associated with CABG surgery are generally higher in comorbidities (i.e. presence of one or more additional medical conditions) such as diabetes, kidney disease, emphysema and others. Other risks include:

1. Bleeding during or after the bypass surgery
2. Blood clots that may cause heart attack, lung problems, or stroke
3. Infection at the incision site
4. Pneumonia
5. Breathing problems
6. Kidney failure
7. Abnormal heart rhythms
8. Failure of the graft

the delay in the surgery may be a result of the patient's overall health and the complexity of the surgery. In these cases, the delay is done in order to minimize the risks and to ensure the best outcome. If CABG surgery is delayed, the following risks can occur:

1. Progression of disease: The blockages in the coronary artery may become more severe over time, leading to more damage to the heart muscle, and making the surgery more complex and risky.
2. Increased symptoms: The patient's symptoms of chest pain (angina), shortness of breath, and fatigue may become more severe as the blockages in the coronary artery become more severe.
3. Increased risk of heart attack: The risk of a heart attack increases as the blockages in the coronary artery become more severe.
4. Reduced quality of life: The patient's quality of life may be reduced as the symptoms of CAD become more severe.
5. Greater risk of death: The risk of death from CAD may increase as the blockages in the coronary artery become more severe.

The cost of CABG surgery ranges from ₹140000 - ₹ 350000. The cost varies based on the following factors:

1. Type of CABG surgery
2. Age of the patient
3. The medical condition of the patient
4. The type of hospital facility availed - individual room or shared