Cardiac Bypass Surgery - "Bypass"

Cardiac bypass surgery is an operation that treats blocked coronary arteries. The surgery is also known as “bypass surgery” or Coronary Artery Bypass Grafting (CABG).

What is cardiac bypass surgery?

Cardiac bypass surgery is an operation that treats blocked coronary arteries, which are the blood vessels that supply your heart with blood. Cardiac bypass surgery doesn’t actually remove the blockages in the arteries - instead, it creates an alternate pathway (also known as a “bypass route”) allowing blood to flow around the blockage and into your heart. 

Why do I need cardiac bypass surgery?

Your coronary arteries can become narrowed or blocked by the build-up of a fatty substance, called “plaque”. This is known as atherosclerosis. Your doctor may recommend cardiac bypass surgery if you have multiple areas of atherosclerosis. Cardiac bypass surgery may be also recommended for you if you have:

Below, you can watch a short video from one of our surgeons explaining more about cardiac bypass surgery

Below, you can watch an animation explaining what happens during cardiac bypass surgery

What are the risks of cardiac bypass surgery?

As with any surgery, there are some risks associated with cardiac bypass surgery. Some of these risks might include:

Some patients may experience delirium shortly after their surgery, so it's important to be prepared.

The video below provides an overview of delirium.

These are usually temporary problems and your doctor will explain the risks to you before you agree to the surgery. It is important for you to ask questions and discuss any concerns with your medical team.

How do I prepare for cardiac bypass surgery?

Around two weeks before your surgery, you’ll need to:

  • Check with your doctor about taking your medications - some may need to be stopped before the surgery.  If you take SGLT2 medicine for diabetes, you will need to stop taking them at least 3 days before your surgery. Read our Patient Information Guide on SGLT2 inhibitors for diabetes.
  • Prepare your home for when you return from hospital - find someone to collect you from the hospital to help you return home after surgery and to help you with shopping, meals, cleaning and driving.
  • Plan your transport home - It is your responsibility to arrange how you will get home after surgery. For information, including guidelines and tips for travelling home by car or plane after heart surgery, you can visit our travel page.
  • Have some important tests - including an ECG, chest X-ray, blood tests, nose and groin swabs and carotid dopplers (which is an ultrasound of the blood vessels in your neck that supply the brain). The full range of investigations needed before having cardiac bypass surgery at St Vincent's Hospital Sydney can be found here
  • Shower with antibacterial soap - your doctor will recommend one for you

On the day before surgery, you’ll need to:

  • Ensure your bowels are opened – ask  for a laxative, if required
  • Pack a small bag of essentials, like toiletries and glasses - these will be taken to Intensive Care after your surgery
  • Stop eating and drinking - from midnight before your surgery

On the day of surgery:

  • Remember not to eat or drink anything - from midnight before surgery
  • A member of hospital staff will clip off any hair from your chest, arms, legs, groins – to reduce the potential of infection
  • Shower with antibacterial soap - this will be provided by the hospital
  • Wear a hospital gown - and remove any makeup, nail polish and jewellery (dentures can be left in)

You can read our Cardiac Surgery - Patient and Family Handbook to learn more.

What happens during cardiac bypass surgery?

Cardiac bypass surgery is performed under general anaesthetic, which means you will be given medications before your surgery to relax and make you fall asleep. As soon as you fall asleep:

  • A breathing tube is put down your throat -  to the lungs
  • A urinary catheter is passed up into your bladder -  so that you do not need to get to the toilet and the amount of urine can be assessed

Your doctor will:

  • Access your heart - by a cut through your breastbone (sternum)
  • Use veins cut from your leg, chest wall or your arm - to use as the bypasses on your heart
  • Stop your heart for a short time while the grafts are attached to your heart - your body may be connected to a heart-lung machine to maintain your blood circulation throughout your body during the surgery
  • Restart your heart and take you off the heart-lung machine - allowing blood to flow back to heart

The surgery usually takes 3-4 hours to complete.

What happens after cardiac bypass surgery?

After your cardiac bypass surgery, you’ll spend one or two days in  the Intensive Care Unit (ICU), where you will be connected to machines to assess your heart, blood pressure, body temperature and breathing.

Below, you can watch an animation explaining what happens after cardiac bypass surgery.

On the first day after your surgery, you should be able to sit out of bed in a chair and take a few steps - but it’s important not to rush your recovery. You’ll need to ease back to your regular movements and take time to recover well. When you’re ready to leave the ICU, you’ll go to the cardiac ward for another few days.

During your stay in the cardiac ward, you’ll need to be aware of:

  • Wound care – your nurse will help to make sure your wound is clean and healing well. When a leg vein is used in bypass surgery it is common to feel prickling and numbness along the wound and around the ankle. This is due to the nerve healing and may take several months to settle down. Your leg and ankle may become swollen. This usually gets better after about 3 months when other blood vessels take over the work of the missing vein. Being active helps the circulation and wearing support stockings may reduce the swelling in your leg. Try keeping your leg up when you are sitting.
  • Bowel function –  it is easy to become constipated after a big operation. It may be due to your tablets or because you are less active than usual. Drinking fluids and eating foods such as fruit, vegetables and grains may help. There is also medication available to help, so discuss any concerns with your nurse
  • Stitches and wires – your medical team will let you know when any stitches and wires will need to be removed, and this will happen before you leave the hospital
  • Discomfort – you might feel tightness in your chest and shoulders, and changing your position frequently to maintain good posture can help. Use painkillers regularly so that you can move, take deep breaths and sleep comfortably. Taking painkillers regularly will keep pain under control. If your mammary artery was used for your bypass you may feel discomfort, numbness or tingling over the left side of your chest. These feelings may last for 6 months or more. You may also find that your skin very sensitive in this area. This is quite normal and is due to the nerves healing in your chest. You can learn more tips about managing chest discomfort here
  • Fever – some people find that they are sweaty - especially at night in the early days after surgery. Others may find it hard to keep warm. This will improve as your body gets back to normal after the operation. You may have a slight fever in the first few days after your  operation which is completely normal, and there is medication to help with this
  • Muffled hearing or thumping sensations in your chest, head or ears - this will settle down in a few weeks as your heart recovers after the operation. If this happens in bed, try changing your position
  • Palpitations - you may feel extra heartbeats after surgery. This is due to the heart being sensitive after the operation. It usually settles down in the first 4 weeks after the operation. If you experience palpitations, contact your doctor
  • Poor memory and concentration - it is quite common to be forgetful and have poor concentration in the early stages of your recovery. This should improve over the first few months
  • Vivid dreams and sleeping problems - it may take a few weeks to get back to your normal sleeping pattern. In the early days, you may find that a brief day time nap may help. Try to follow you usual bedtime routine and take pain relief shortly before attempting to sleep. Avoid sleeping on your stomach for the first 6 weeks
  • Poor appetite and changes in taste - you may notice that you have a poor appetite and find that food has lost its flavour. Your sense of smell may change and you may also experience a strange metallic taste in your mouth. This can be caused by the operation or your medication and can take 3 months to fully recover. Try to eat frequent small amounts of cold and simple foods - not spicy or rich in flavour

Your medical team will help you with some of the physical aspects of your recovery, including:

  • Physiotherapy routine – you can start to work on your activity levels while still in hospital
  • Breathing exercises – you’ll be shown breathing exercises and coughing techniques that don’t harm your recovery
  • Mobility – it will take 6-8 weeks for your breastbone to heal, and your nurse will show you the safest ways to lift and move your body, including rolling and sitting in bed. You can learn about protecting your breastbone after cardiac surgery in our Sternal Precautions brochure

Below, you can watch a video explaining how to look after your breastbone after cardiac surgery.


It’s completely normal to feel a range of different emotions during this time. You may have up and down days, strange dreams and changed sleeping habits - but none of this means your body is having trouble recovering. It’s very important to talk about your feelings with your family and friends so they can support you as you recover. Keeping a diary is a good way for you to understand your range of emotions.

When it’s time to leave the hospital, you’ll need to arrange for a family member or friend to collect you and take you home (please advise the nursing staff of who you have arranged to pick you up and transport you home). For information, including guidelines and tips for travelling by car or plane after heart surgery, you can visit our travel page.

When you are ready to leave the hospital, try and find someone whom you can rely on to help you at home during those first few weeks. If you need assistance with this, let your medical team know. Please advise the nursing staff of who you have arranged to pick you up and transport you home.

As you prepare to return to your normal way of life, you’ll be given detailed instructions for exercise, medications, ongoing wound care and resuming normal activities. We also encourage you to book in to a cardiac rehabilitation program.  Doing this will help you to recover as best you can and live a healthy, fulfilling life.

Before you leave hospital, you will be given contact details for your closest cardiac rehabilitation program. In your program, you’ll be supported every step of the way as you heal, recover and get back to your normal, everyday life.

Remember to follow your doctor’s advice about medications and any recommended lifestyle changes after your surgery, and attend your regular appointments. If you start to feel unwell or would like to discuss your follow-up care at any time, make an appointment with your doctor.