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Coronary Artery Bypass Grafting (CABG)

Coronary Artery Bypass Grafting (CABG) - What it is

Coronary artery bypass grafting (CABG), also known as heart bypass surgery, is an open heart surgery which is a major operation where the surgeon opens up the chest and uses veins and/or arteries to bypass blocked or narrowed blood vessels in the heart. It is an established operation, which is usually recommended to patients with coronary artery blockages to relieve the symptoms of
coronary artery disease.

Coronary artery bypass grafting is typically an open heart surgery

What is coronary artery disease?

Coronary artery disease is caused by hardening and subsequent blockage of the arteries that supply blood to the heart. The obstruction of the coronary arteries reduces the amount of blood reaching the heart muscle, resulting in chest pain called angina pectoris. In severe cases, this may cause a life-threatening heart attack, scarring of the heart or heart failure. 

The mainstay of treatment for coronary artery disease is medication, while some patients will require invasive intervention such as CABG.

How is coronary artery bypass grafting done?

A bypass graft vessel allows oxygenated blood to bypass the blocked arteries and restore blood flow to the heart

In a CABG operation, the patient will be given a general anaesthetic before the chest is opened through the breastbone. A new graft vessel, which is a healthy artery or vein is taken from the patient’s leg, arm or chest, is surgically removed and sewn around the areas of the blockage by the surgeon. 

The graft vessel supplies oxygenated blood to the part of the heart that needs it, thereby “bypassing” the blocked arteries and restoring blood flow to the heart muscle. The augmented blood flow improves symptoms, reduces the need for medications, and prolongs life in well-selected patients. More blood flow reduces angina and should also reduce the need for medication. The number of grafts needed will depend on the severity of the patient’s condition.

One or more plastic chest drains may be left in the chest temporarily to drain any fluid that may have collected during the surgery. If necessary, pacing wires may be temporarily left in the heart for heart rhythm control. The breastbone is then wired together and the skin wounds closed with self-dissolving sutures.
On-pump surgery
The traditional coronary artery bypass grafting (CABG) procedure involves connecting the patient to a heart-lung bypass machine which performs the function of the heart and lungs. The patient’s heart is then stopped with medication and the grafting process begins. Once the procedure is completed, the patient’s heart is restarted and the heart-lung machine is disconnected.

Who will need a coronary artery bypass surgery?

Coronary artery bypass grafting (CABG) is an established operation that is usually recommended to patients with coronary artery blockages to relieve the symptoms of coronary artery disease:

These symptoms include:
  • Chest discomfort (called angina pectoris), often described as ‘tight’, sometimes involving the jaw, left shoulder or arm. 
  • Pain in the neck, jaw, throat, upper abdomen or back.
  • Breathlessness on exertion or when lying down. 
  • Heart attack during which you may even be breathless, sweaty with cold and clammy peripheries.

However, it is important to note that some patients (especially diabetics) may have absolutely no pain. If a heart attack occurs, CABG can also be performed as an emergency procedure to restore blood flow to the heart. If blood flow is not restored to the affected area, the heart muscles die and become scarred causing the heart to fail as an efficient pump.

Possible complications of CABG 

Coronary artery bypass grafting (CABG) is considered a major surgery and in some cases might result in certain complications, including:
  • Infection: The incision sites can become infected. This can be treated effectively with antibiotics and special dressings. 
  • Bleeding: This is a complication that is often seen in major surgeries.
  • Irregular heartbeat: Arrhythmia can occur after a CABG though it is usually quickly treated with medication.
  • Kidney problems: Some patients might develop kidney problems after a CABG but this is often temporary.
  • Heart attack: Some patients might suffer a heart attack during or after the surgery. 

Other CABG techniques 

There are several other ways the CABG can be performed.

1) Off-pump surgery 

The heart is stabilised at various parts, allowing the surgeon to proceed with the surgery while the heart is still beating. This technique reduces the risks of certain complications during or after the surgery. However, this technique is more challenging than the conventional on-pump procedure and is performed in selected patients. 

2) Minimally invasive CABG methods 

Minimally invasive CABG (also known as a keyhole surgery) is where small incisions are made, allowing surgical instruments to be inserted into the body. This technique could also involve the use of robotics and a video feed. Such procedures often lead to quicker recovery due to the significantly smaller wound sizes.

Coronary Artery Bypass Grafting (CABG) - Symptoms

Coronary Artery Bypass Grafting (CABG) - How to prevent?

Coronary Artery Bypass Grafting (CABG) - Causes and Risk Factors

Coronary Artery Bypass Grafting (CABG) - Diagnosis

Coronary Artery Bypass Grafting (CABG) - Treatments

Coronary Artery Bypass Grafting (CABG) - Preparing for surgery

Our Patient Journey

Learn more on what to expect on the actual day of your coronary artery bypass graft (CABG) surgery at NHCS: [Same Day Admission – SDA]

Patient journey for Coronary Artery Bypass Graft (CABG)

Preparation before coronary artery bypass grafting surgery

You are usually admitted to the hospital one or two days before surgery to allow the doctor to assess your general condition and conduct some pre-operative tests. Some patients are suitable for same day admission (SDA).

Please remember to bring your medication to the hospital when you are admitted. This allows the medical team to perform medication reconciliation.

No Smoking
You are strongly advised to stop smoking before your operation. Smoking makes it difficult for you to clear your secretions after surgery and is dangerous to your health and recovery. Smoking also decreases the durability of bypass grafts.

Preoperative physiotherapy training is essential for you because of the potential post-operative chest complications. Your co-operation is much needed.  

The physiotherapist will assess your breathing and teach you techniques such as slow, deep breathing, limb exercises and supported coughing with a small pillow. These will help you after your surgery.

Consent for Surgery
The surgeon will explain to you and your family members the nature of heart problems and the type of operation you are undergoing. He will tell you the date of your surgery and the approximate duration of the operation. He will also obtain your written consent for the surgery. You should feel free to discuss your concerns with the doctors.

Pre-medication (for elective admissions, non-SDA)
The anaesthesiologist will see you on the evening before your surgery. He will explain to you how you will be anaesthetised during the operation. Sedation may be ordered to help you sleep better before the operation.

Bowel Preparation
A laxative (suppository) will be given on the evening before your operation to clear your bowels. 

No Food Consumption
You are not allowed to consume any food or drink at least six hours before surgery. This is to prevent any vomiting and subsequent inhaling of the vomitus into your lungs during surgery, which can be life threatening.

Personal Items & Valuables
Personal items such as spectacles, dentures, watches and other valuables should be given to your family members for safekeeping.  

Day of coronary artery bypass grafting surgery

Skin Preparation
On the morning of surgery, you will need to shower with an antibacterial solution to minimise the risk of infection. Talcum powder and body sprays are not allowed after your bath.

Before you are sent to the operating theatre, the nurse will inform you to do the following:
  • Empty your bladder
  • Remove any personal items e.g. dentures, spectacles, watch.
  • Change into a gown

An injection will be given just before you are taken to the operating theatre. The medication will cause dryness in your mouth, make you sleepy and less anxious. You are advised to remain in your bed after the injection.

Family Visit
Your family may visit you before you are wheeled to the operating theatre.

Transfer to Operating Theatre
The ward nurse will accompany you to the operating theatre on a trolley.

In the Operating Theatre
Once you have arrived at the operating theatre, the nurse will countercheck your identity and the type of surgery you are scheduled for. You will then be transferred to the operating theatre. The anaesthesiologist will administer medication to induce sleep and eliminate pain during the operation. 

After a coronary artery bypass grafting surgery

Once the operation is completed, you will be transferred to the post-anaesthesia care unit (PACU) or Intensive Care Unit (ICU) where you will be monitored closely. You will regain consciousness after the anaesthesia wears off. There will be a number of tubes and small electrodes that will be taped to your chest to monitor your heart rate and rhythm.

A breathing tube will be inserted through the mouth into the windpipe. It will be connected to a breathing machine, which will assist you to breathe. From time to time, the nurse will remove the secretions from your mouth. 

While this tube is in place, you will not be able to talk since the tube passes through your voice box. The nurses are specially trained and will be able to anticipate your needs. 

The breathing tube will be removed when you do not require breathing assistance. You will receive oxygen through a face mask or nasal cannula for the next few days.

A flexible plastic tube is passed through your nose into the stomach, to drain out any fluid or air. It is usually removed after a few days or when the breathing tube is taken out. You will not be able to drink orally because of the danger of water entering your lungs and causing you to choke. However, your mouth will be cleansed frequently and your lips moistened to prevent dryness.

In addition, you will have several small tubes in your veins to administer fluid, blood and medication. There will be a small tube inserted in your wrist artery to measure blood pressure and/or for withdrawing blood samples. A urinary catheter will drain urine from your bladder continuously and enable the nurse to keep an accurate record of your urine output. 

You will also find drainage tubes inserted in the lower end of your chest incision. These tubes are for draining fluid that may accumulate during and after the operation. These tubes may be uncomfortable but will be taken out as soon as possible, usually a few days after surgery.

After your breathing tube is removed and depending on your condition, you may be able to drink a small amount of water, progressing from liquids, to a soft diet, depending on your tolerance.

The physiotherapist will continue to see you through your progress. If necessary, you will need to practise frequently on the incentive spirometer to help you in your lung expansion. 

We recommend early ambulation to prevent complications. You will be propped up in bed and turned from side to side to facilitate chest drainage. 

While you are in the PACU/ICU, it is important that you receive plenty of rest. As such, visitors will be limited. Please refer to our latest Visitor Policy here (

The use of handphones may interfere with the functioning of some electrical equipment. Hence, visitors are advised not to bring it into the ICU or to switch off the handphone before entering the ICU. 

The average stay in the ICU for most patients is two to three days, though this will vary with individuals. Your surgeon will explain to you the need for any extended stay.

Transfer to the ward
When your condition is stable, you will be transferred to the Intermediate Care Area (ICA) or High Dependency (HD) unit for further convalescence. You may be nursed in the HD area for one to two days, depending on the progress of your recovery. Your doctor will decide when to transfer you to the general ward.  

In the HD area, you will see some monitoring equipment by your bedside. These are used to monitor your heart, blood pressure, pulse and respiratory rate. 

From the second or third day after surgery, you may be assisted from your bed to an armchair. Your activity level will slowly be increased; from taking short walks in the room to walking around the ward, then progressing to longer walks and stairs climbing, in preparation for discharge.

The physiotherapist will continue to see you through your progress. If necessary, you will need to practise frequently on the incentive spirometer to assist in deep breathing and lung expansion. The physiotherapist will assist you in coughing techniques during the day.

Deep breathing and coughing exercises will help clear your secretions. The coughing exercises will not harm your incision but may cause some pain and discomfort. Taking pain medication and holding a small pillow against your chest to splint your chest incision will make you more comfortable when you cough. Limb exercises help to promote and improve blood circulation and strengthen muscles.

Relief of Post-operative Pain
You will experience some pain after surgery. The severity of pain varies from one person to another and depends on the extent of the surgery. Pain medications will be given orally or by injections to relieve your pain. 

Wound Care
The nurses will clean and check your incision wound. Once the wound is dry, it will not be covered with dressing unless ordered by your doctor. It will be exposed to air, which allows it to become dry. The wound can be cleansed with a mild soap. Do not apply any talcum powder, lotion or ointment onto your wound.

Coronary Artery Bypass Grafting (CABG) - Post-surgery care

Recovering from heart surgery

Coronary artery bypass surgery (CABG) aims to return patients to gainful employment, or active retirement with a restored sense of well-being. Generally, most people will see improvements in their symptoms such as chest pain and breathlessness after CABG. However, you should adopt positive lifestyle changes to sustain these improvements. You must comply with your prescribed medication, stop smoking, control your weight and adhere to a diet low in salt, fat and cholesterol. 

Patients recovering from heart surgeries such as CABG should take note of the following for quicker recovery:

1) Engage in light physical activity

You can start with light activities such as doing chores and taking strolls. This can be beneficial to patients who face difficulties with sleeping after the surgery. However, within the first two months, you should avoid:

  • Lifting, pushing or pulling heavy objects (depending on your level of fitness)
  • Driving a car  
If it is possible, patients going back to work should start with reduced working hours and workloads before gradually increasing these back to normal. This prevents excessive strain on the body.

2) Care for your wound(s)

Keep the wounds and the surrounding areas dry. Clean the wound using soap and warm water only. Please visit your doctor immediately if you notice any signs of infection such as:
  • Pus 
  • Fever more than 38º C
  • Tenderness and redness around the wound 
  • Opening up of the wound

3) Take note of cognitive and emotional changes

Patients might experience slight decreases in their cognitive functions though this is usually temporary. To cope with this, patients should avoid any stressful or mentally taxing tasks within the first few weeks of surgery. 

Some patients might also experience an onset of low moods or even depression after the surgery. However, patients’ moods should generally improve over the period of recovery. Patients could also speak with their family and friends to cope with these emotions. 

Cardiovascular Rehabilitation & Preventive Cardiology (CVR & PC) Programme

You are encouraged to attend the Cardiovascular Rehabilitation & Preventive Cardiology Programme that will enable, encourage and assist you on the road to recovery.

Cardiovascular rehabilitation is a process to enable, encourage and assist you to make the transition from a state of illness back to a state of health and normal function. It is a lifelong process and begins from the time of diagnosis. The four basic features of the programme are behavioural counselling, aggressive risk factor modification, health education and exercise training.

Various members of the health team will be available to teach, guide and encourage you. The team comprises of physicians, nurses, physiotherapists, psychiatrist, dietitians and pharmacists. But the effort to achieve the goal of optimal rehabilitation depends solely on you.

Cardiac Rehab Programme


Coronary Artery Bypass Grafting (CABG) - Other Information

Frequently Asked Questions

How many incisions will I have?
Generally, there will be a midline incision on the chest, with forearm and leg incisions, though this might vary depending on the extent of the surgery. Newer techniques such as the ‘key hole’ surgery are available for selected patients.

Once the wounds are dry, they can be cleansed with mild soap and will not be covered with dressing. 

Can coughing and deep breathing pull apart the incision?
No, your breast-bone will be securely closed with surgical steel wire and the incision will be closed with sutures. Coughing and deep breathing will not affect the closure or healing process of your chest wound.

You may notice an occasional “clicking noise” or sensation in your chest in the first few days after surgery. This should occur less often with time and go away completely within the first few weeks. If it gets worse, consult your doctor.

How do I care for the incision?
During the healing process, you may feel sore due to the incisions and muscle spasms. It can be relieved by good posture and frequent movements of the arms and shoulders. The wound is also exposed to air, which allows it to become dry. After a few days, the wound can be cleansed with a mild soap. Do not apply any talcum powder, lotion or ointment onto your wound.

If an artery in your chest, called the mammary artery, was used during your surgery, you may experience numbness to the left of your incision. This is normal.      

External stitches or staples are removed from the chest about a week after the operation and a few days later from the legs, if the stitches or staples are present. It takes about six weeks for complete healing of these wounds. It is advisable to avoid lifting heavy objects for 3 months while the wound is healing.

Leg incisions will first be cleansed with an antiseptic solution, and then with mild soap and water. There may be some tendency for the ankles to swell or the presence of a burning sensation felt when standing up. Elastic support stockings and walking will help to improve blood circulation and reduce the swelling. Avoid crossing your legs.

What is the recommended diet after the surgery?
The doctor, dietician and nursing staff will advise you on your diet. It is wise to reduce the risk factors of heart disease as much as possible by cutting down on salt, cholesterol and saturated fats in your diet. Increase your vegetables and fruits intake to prevent constipation. It is also important to keep your weight under control as extra weight will place strain on your heart. 

Moderation and wise judgement are usually the best guides in maintaining a healthy diet. Refrain from drinking alcohol. Refer to diet instructions given.

What is the average length of stay for patients undergoing CABG Surgery?
Depending on the surgery and how well you have recovered, the average length of stay for patients undergoing CABG Surgery is six to eight days. However, the length of stay may vary with each individual. Patients with multiple pre-existing medical conditions may require a longer stay.

How long is the period of convalescence (or recovery) for CABG?
An uncomplicated hospital stay may last a week, whilst your surgical wounds will completely heal between six weeks to two months.

What can be done to help recovery?
Deep breathing and coughing exercises will help clear your secretions. You should use the incentive spirometer diligently and perform deep breathing exercises. The physiotherapist will assist you in coughing techniques. Taking pain medication and holding a small pillow against your chest to splint the incision will make you more comfortable when you cough. Changing positions in your bed also helps in the recovery process. Lying on your back for a long period of time causes secretions to collect in the lungs.

How long will I be off work?
It depends on the nature of your work. An office worker can return to his/her desk-job after four to six weeks. Those performing manual labour, especially work that requires upper body strength, could return to work after three months. Some may not be able to return to their former jobs.

CABG is well-established in Singapore and worldwide. It is undoubtedly the most well studied operation in the realm of surgery, and has an excellent track record of over 50 years. Furthermore, the effects of CABG last an average of 10 years which is much longer than the alternative, coronary angioplasty (also known as percutaneous coronary intervention, or PCI). However, the procedure has a higher risk for complications than coronary angioplasty. It also requires a longer hospital stay (one week) and longer recovery (one to two months).

The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

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