Coronary artery bypass surgery

Why it is done

The coronary arteries supply the heart muscle with blood. When they become narrowed by fatty plaques (atherosclerosis), the heart muscle may not get enough blood, causing angina or breathlessness, or a heart attack. Coronary artery bypass grafting (CABG) is recommended when narrowings are severe, affect several arteries or the main left coronary artery, or are not well suited to stents. The decision is usually made by a heart team of surgeons and cardiologists, who weigh surgery against stents and medical treatment for each patient.

What happens during the operation

The operation is done under general anaesthetic and usually takes three to five hours. Most operations are done through the breastbone (a sternotomy). Grafts are taken from your own blood vessels:

• Internal mammary artery from inside the chest wall, usually joined to the most important artery at the front of the heart. This graft has the best long-term results.
• Long saphenous vein from the leg.
• Radial artery from the forearm, in selected patients.

Most operations use the heart–lung (bypass) machine, which takes over the work of the heart and lungs while the grafts are stitched in place.

After the operation

You will wake up in intensive care, usually staying there for a day or two before moving to the ward. Most people go home after about a week. The breastbone takes about 14 to 16 weeks to knit together fully, although most people feel much better well before then. A cardiac rehabilitation programme helps you rebuild fitness safely.

Risks

Every operation carries risks, including bleeding, infection, irregular heartbeat (atrial fibrillation, which is common and usually temporary), stroke, kidney problems and, rarely, death. Your own risk depends on your age, general health and heart function, and your surgeon will discuss it with you before you consent.

This guide is general information and does not replace advice from your own clinical team, who will explain the plan and risks for you individually. Last reviewed November 2026.