CABG: understanding bypass surgery

When bypass surgery is recommended

Coronary artery bypass grafting (CABG), usually called bypass surgery, treats coronary artery disease — the narrowing of the heart's own arteries by fatty plaque (atherosclerosis) that can cause angina or heart attack. Rather than opening the narrowed artery from within, as angioplasty and stenting do, bypass surgery creates an entirely new route for blood to reach the heart muscle, using a healthy blood vessel taken from elsewhere in your own body to carry blood around ("bypass") the blocked section.

CABG is generally considered when coronary disease is extensive — several arteries significantly narrowed, an important blockage in a critical location, or disease not well suited to a stent — and especially when there is also reduced heart-pumping function or diabetes, both of which affect how well surgery is likely to work compared with other options. This decision is not made by one clinician alone: a heart-team of cardiologists and cardiac surgeons jointly reviews your angiogram, overall health and personal circumstances before recommending surgery over medicine alone or a stent procedure.

How bypass surgery works

A surgeon uses a length of healthy blood vessel — commonly an artery from inside the chest wall (the internal mammary artery), a vein from the leg (the saphenous vein), or sometimes an artery from the arm (the radial artery) — and connects one end beyond the blocked section of the diseased coronary artery and the other end to a healthy source of blood, most often the aorta. Blood then flows through this new graft, supplying the heart muscle beyond the blockage and bypassing the narrowed segment entirely. Depending on how many arteries are significantly narrowed, one or several grafts may be needed in the same operation.

Bypass surgery is performed through an incision in the chest, most commonly through the breastbone (sternum), which is carefully divided to reach the heart and is repaired and wired back together at the end of the operation. In many cases the heart is temporarily stopped and a heart-lung bypass machine takes over pumping blood and oxygenating it while the surgeon works; in selected cases, surgery can be performed on a beating heart instead. Your surgical team will discuss which approach is planned for your operation and why.

Before your operation

• ●CABG usually follows a coronary angiogram that has already mapped where your arteries are narrowed
• ●You will have a pre-operative assessment to check your fitness for surgery and anaesthesia
• ●The number of bypass grafts needed depends on how many arteries are significantly narrowed
• ●Recovery continues well beyond hospital discharge, over weeks to months

How to prepare for surgery

Good preparation helps reduce avoidable risk and sets up a smoother recovery:

• ●Complete all pre-operative tests and assessments requested, including blood tests, heart imaging and a general fitness review
• ●Bring a full list of your current medicines — some are paused before surgery on your team's specific advice, particularly certain blood thinners
• ●Stop smoking completely, and as early before surgery as possible — this meaningfully improves healing and reduces complications
• ●Treat any dental problems or infections beforehand if your team advises it
• ●Arrange practical support at home for the weeks after discharge, and plan time off work in advance
• ●Ask your team any questions you have before the day — understanding the plan reduces anxiety and helps recovery

What happens on the day

• 01
  Final heart-team assessment. A last review of your fitness, medicines and the surgical plan before you go to theatre.
• 02
  Pre-operative optimisation. Final checks, fasting instructions and preparation for general anaesthesia.
• 03
  Surgery in a dedicated cardiac theatre. Performed under general anaesthesia, so you are fully asleep and feel nothing during the operation itself.
• 04
  Cardiac intensive care. You wake in ICU, connected to monitors, with a breathing tube usually removed once you are stable enough to breathe comfortably alone.
• 05
  Ward care and early rehabilitation. As you stabilise, you move to the ward, with physiotherapy, breathing exercises and gradual mobilisation beginning within days.

How recovery feels in hospital

You will feel groggy and unaware of the operation itself as the general anaesthetic wears off. Chest and wound discomfort in the days afterward is expected and is actively managed with pain relief — tell your team if pain is not controlled, as good pain control helps you breathe deeply and move safely, both important for healing. Tiredness, reduced appetite and some emotional ups and downs are common in the early days and generally ease as you progress through recovery.

Follow-up and results

Your surgical and cardiology teams will review how the operation went, discuss any findings with you, and agree a follow-up plan before you leave hospital, including when to see your surgeon and cardiologist again, medicine changes, and when cardiac rehabilitation will begin.

Recovery and aftercare at home

• ✓Protect the chest wound as instructed, and keep it clean and dry
• ✓Increase activity gradually with the rehabilitation team, starting with short, regular walks
• ✓Avoid lifting anything heavy or driving until your team clears you to do so
• ✓Take preventive medicines consistently — antiplatelet medicines, statins and others protect the grafts and your heart going forward
• ✓Control blood pressure, diabetes and cholesterol, since bypass surgery treats existing blockages but does not stop new ones forming without ongoing risk-factor control
• ✓Attend cardiac rehabilitation — it meaningfully supports a full recovery

Preparing for your follow-up appointment

What to bring

• ✓Your discharge summary and any wound-care instructions
• ✓A list of all medicines you are currently taking
• ✓Your HMO card or payment details and a valid means of identification

Questions worth asking us

• ●How many grafts did I have, and how are they expected to last?
• ●When can I resume driving, lifting and exercise?
• ●What is my target for blood pressure, cholesterol and blood sugar now?
• ●When should I start cardiac rehabilitation?