Cardiac Surgery

Heart surgery including coronary bypass (CABG), valve replacement or repair, and other open-heart procedures.

Duration: 3–6 hours Hospital stay: 5–10 days Recovery: 6–12 weeks

What to expect

Your Journey

  1. Before surgery

    Preparation for cardiac surgery is thorough — you will attend a specialist cardiac pre-assessment clinic for blood tests, heart scans, and lung function tests. Your teeth may be reviewed by a dentist before surgery, as dental infections can be serious after open-heart procedures. Stopping smoking as early as possible and doing prehabilitation walking and breathing exercises are both particularly important for this operation.

  2. The day of surgery

    Cardiac surgery is performed under general anaesthesia by a specialist cardiac anaesthetic team. Most open-heart operations use a heart-lung bypass machine while your heart is temporarily stopped — surgery takes 3–6 hours. You will wake up in the cardiac intensive care unit (ICU), where you may briefly have a breathing tube and will have a chest drain and monitoring lines — your team will explain everything before you go to theatre.

  3. In hospital

    You will spend 1–2 days in the cardiac ICU before transferring to the cardiac ward, with a total stay of 5–10 days. A physiotherapist will start breathing exercises and gentle walking from day one. Your sternotomy wound (the cut down your breastbone) will be checked regularly, and you will begin cardiac rehabilitation in hospital before continuing it as an outpatient programme after discharge.

  4. Going home

    Follow your team's sternal precautions strictly for 6–8 weeks after surgery: do not lift anything heavier than 2kg, do not push or pull heavy objects, and do not drive. Cardiac rehabilitation outpatient sessions are an important part of your recovery — most patients find them extremely beneficial. Contact your team urgently for any chest pain, fever, fast or irregular heartbeat, wound oozing, or increasing breathlessness.

Get ready for surgery

Prehabilitation

Prehabilitation means getting your body as fit as possible before your operation. Research shows that patients who are fitter before surgery recover faster, have fewer complications, and spend less time in hospital. Even a few weeks of preparation makes a real difference.

Aim to start at least 4–8 weeks before your operation if you can.

Heart & lungs

Aerobic fitness improves how your body delivers oxygen. This reduces your anaesthetic risk and helps your lungs recover after surgery.

Muscle strength

Stronger muscles help you get out of bed sooner, move around the ward, and manage at home after discharge.

Lung function

Breathing exercises train your lungs and help prevent chest infections — one of the most common complications after major surgery.

Mental readiness

Understanding what to expect reduces anxiety and helps you engage with your recovery from day one.

Exercise programme

Aim for a mix of all three types of exercise, at least 5 days a week. You don't need a gym — everyday activities count.

Aerobic

Walking, cycling, swimming, or dancing. Start with 20 minutes and build up. You should feel slightly out of breath but still able to hold a conversation.

Aerobic exercise guide

Strength

Resistance band exercises, chair stands, wall press-ups, or light weights. Focus on legs and core. Aim for 2–3 sets of 10–15 repetitions.

Strength exercise guide

Breathing

Diaphragmatic breathing and incentive spirometry exercises help expand your lungs and clear secretions. Practise 10 slow deep breaths, 3–4 times a day.

Breathing exercise guide

If you have a heart or lung condition, significant joint pain, or any other health concern that limits your exercise, speak to your GP or physiotherapist before starting. They can tailor a safe programme for you.

Eating well before surgery

Nutrition

Good nutrition in the weeks before your operation helps your body prepare for the physical stress of surgery and supports faster healing afterwards.

  • Eat regular meals with a good source of protein at each one — meat, fish, eggs, dairy, legumes, or tofu.
  • Eat plenty of vegetables and fruit to provide vitamins and minerals that support healing.
  • Stay well hydrated — aim for 6–8 glasses of water per day. Limit sugary drinks and excessive caffeine.
  • Try to maintain a healthy weight. If you are significantly underweight or have lost weight recently, tell your surgical team — you may benefit from nutritional support before your operation.

Fasting before surgery reduces the risk of complications during anaesthesia. Follow the ERAS (Enhanced Recovery After Surgery) guidelines below, unless your team gives you different instructions.

  1. 8 hours before surgery

    Stop eating solid food. This includes all meals, snacks, and chewing gum. You may continue to drink clear fluids.

  2. 6 hours before surgery

    Stop all light meals — toast, crackers, or anything that isn't a clear fluid.

  3. 2 hours before surgery

    Stop all fluids, including water, black tea or coffee, and clear juice. No milk, smoothies, or fizzy drinks after 6 hours.

  4. Some hospitals provide a carbohydrate drink

    Your team may give you a carbohydrate loading drink (such as Preload or similar) to take 2 hours before surgery. This reduces thirst, hunger, and post-operative nausea. Follow your team's specific instructions.

Always follow the specific fasting instructions from your surgical or anaesthetic team. These take priority over the general guide above, particularly if you have diabetes or a condition affecting stomach emptying.

Protein is the building block your body uses to heal wounds, rebuild muscle, and fight infection. In the weeks before surgery, aim to eat more protein than usual.

  • Target: 1.2–1.5 grams of protein per kilogram of body weight per day. (For a 70kg person, that is 85–105g per day.)
  • Good food sources: chicken, fish, eggs, Greek yoghurt, cottage cheese, lentils, chickpeas, tofu, and nuts.
  • Protein supplement drinks (e.g., Fortisip, Ensure, Complan) can be helpful if your appetite is poor or you are struggling to eat enough. These are available from pharmacies without a prescription.

If your surgical team recommends specific nutritional supplements, take these as directed. Tell your team if you are finding it difficult to eat enough — nutritional support services are available.

Alcohol

Stop drinking alcohol at least 4 weeks before surgery. Alcohol increases bleeding risk, impairs wound healing, suppresses immune function, and affects how your body responds to anaesthesia and pain relief.

Smoking

Stop smoking as early as possible — ideally 8 weeks before surgery. Smoking significantly increases the risk of wound infection, chest complications, blood clots, and slower healing. Your GP can help with cessation support.

Herbal supplements

Stop all herbal and natural supplements at least 2 weeks before surgery. Many affect bleeding or interfere with anaesthetic drugs. This includes: garlic capsules, ginkgo biloba, ginseng, St John's Wort, kava, valerian, and high-dose fish oil.

Grapefruit

Avoid grapefruit and grapefruit juice in the week before surgery. Compounds in grapefruit block a liver enzyme that breaks down many medications, including some used in anaesthesia and pain management.

Understanding your anaesthetic

Anaesthesia

Anaesthesia means using medicines to block pain and keep you comfortable during your operation. There are several types — your anaesthetist will discuss which is most appropriate for you and your surgery.

General anaesthesia

You are completely unconscious for the operation. Medicine is given through a drip in your arm, and you breathe with the help of an airway device placed once you are asleep. You wake up in the recovery room when the operation is finished. This is the most common type for major surgery.

Spinal or epidural

An injection into your back numbs the lower half of your body. You stay awake or are given light sedation to keep you comfortable. This is commonly used for hip and knee replacement, some bladder surgery, and some bowel operations. The numbness wears off gradually over a few hours after surgery.

Nerve block

A targeted injection of local anaesthetic near a specific nerve numbs just one area — for example, your arm, shoulder, or leg. Nerve blocks are often used alongside general anaesthesia to reduce pain after the operation and reduce the need for strong opioid pain relief.

Sedation

You receive medication through a drip to make you relaxed and drowsy. You remain breathing on your own and can still respond. Used for some minor procedures, scopes, and operations under local anaesthetic where a degree of relaxation is helpful.

Common questions

Anaesthetic awareness — waking up or having any awareness during a general anaesthetic — is very rare. It occurs in fewer than 1 in 10,000 cases with modern techniques. Your anaesthetist monitors the depth of your anaesthetic continuously throughout the operation using dedicated monitoring equipment. If you are worried about this, please raise it at your pre-assessment appointment — your anaesthetist can discuss the precautions used.

Post-operative nausea and vomiting (PONV) is common after surgery but very manageable. Your anaesthetist will give you anti-nausea medication routinely during and after the operation. If you have a strong history of PONV, motion sickness, or have felt very sick after a previous anaesthetic, tell your team at your pre-assessment — they can plan extra precautions, including additional anti-nausea medications and changes to your anaesthetic technique.

Most regular medications should be taken as usual on the morning of surgery with a small sip of water, even if you are fasting. However, some medications — particularly diabetes medications, blood thinners, and certain newer drugs — need specific adjustments. Your surgical and anaesthetic team will give you written instructions. See the Medications section on this page for a detailed guide. If in doubt, contact your pre-assessment clinic or GP.

Feeling anxious before surgery is completely normal — most patients do. The most effective thing you can do is talk about your concerns with your anaesthetist at your pre-assessment appointment. Understanding exactly what will happen often helps significantly. On the day, a mild sedative can be given before you go to theatre if you need it. If your anxiety is significant, ask your GP or surgical team about additional support options.

A pre-assessment appointment happens a few weeks before your operation. A specially trained nurse or anaesthetist will review your general health, current medications, and any test results. You may have blood tests, an ECG, or other checks done at this appointment. It is also your opportunity to ask questions about your anaesthetic and what to expect on the day. Completing the pre-assessment questionnaire on this website before your appointment will save time and help your team prepare.

Managing your medications

Medications

Getting your medications right before surgery is important for your safety. Use this as a general guide, but always follow the specific written instructions from your surgical or anaesthetic team — these take priority.

Usually continue

Take these on the morning of surgery with a small sip of water, even if you are fasting:

  • Blood pressure tablets (antihypertensives)
  • Heart rhythm medications
  • Thyroid medications
  • Inhalers (asthma, COPD)
  • Antidepressants and antipsychotics
  • Anti-epileptic medications
  • Acid reflux medications (PPIs, H2 blockers)

Special instructions

These medications need individual planning — your team will give you a specific plan:

  • Diabetes medications and insulin: Doses almost always need adjusting on the day of surgery. Do not assume your usual dose is safe — wait for written instructions from your team.
  • GLP-1 agonists (Ozempic/semaglutide, Victoza/liraglutide, Trulicity/dulaglutide): These slow stomach emptying, which increases the risk of regurgitation under anaesthesia. You may need to stop these 1 week before surgery. Confirm with your team.
  • SGLT-2 inhibitors (Jardiance/empagliflozin, Forxiga/dapagliflozin): Stop these 3 days before surgery. They can cause a serious condition called euglycaemic diabetic ketoacidosis around the time of surgery, even if your blood sugar appears normal.

Usually stop before surgery

Discuss timing with your surgical team — do not stop without advice:

  • Anticoagulants (warfarin, rivaroxaban/Xarelto, apixaban/Eliquis, dabigatran/Pradaxa, enoxaparin): Stopping timing depends on your surgery and your clot risk. Some patients need bridging therapy. Your team will give you a written plan.
  • Anti-inflammatory pain relief (ibuprofen, diclofenac, naproxen): Stop 5–7 days before surgery. These increase bleeding risk.
  • Aspirin taken for pain relief (not cardiovascular prevention): Stop 7 days before. If you take aspirin for heart or stroke prevention, check with your team — it is often continued.
  • Herbal supplements: Stop all 2 weeks before (see Nutrition section).
  • Combined oral contraceptive pill: Discuss with your team. For major surgery involving the abdomen or pelvis, you may be advised to stop 4 weeks before to reduce blood clot risk.

Always tell your team about

Make sure your surgical and anaesthetic team knows about all of the following:

  • Allergies — especially to medications, latex, iodine, or any previous reactions to anaesthesia
  • All supplements and vitamins, including things you might not think of as medications
  • Over-the-counter medications — antihistamines, cold remedies, sleeping tablets, pain relief
  • Recreational drug use — this information is confidential and is essential for safe anaesthetic planning
  • Previous anaesthetic problems — including nausea, awareness, prolonged emergence, or any family history of anaesthetic reactions (particularly malignant hyperthermia)
  • Dental work — loose teeth, crowns, caps, veneers, or a bridge in the front of your mouth

Pre-Assessment Questionnaire

Complete this at home before your pre-assessment appointment. When you reach the end, you can print your summary or email it directly to your clinic.

Start questionnaire