Coronary Artery Bypass Grafting (CABG)

Coronary artery bypass grafting (CABG) is open-heart surgery that creates a new route for blood to flow around a blocked or narrowed coronary artery (the blood vessel that feeds the heart muscle).

The heart muscle needs a steady supply of oxygen-rich blood to keep pumping. When fatty deposits called plaque build up inside a coronary artery, that supply can slow to a trickle or stop entirely, causing chest pain or a heart attack. During CABG, a surgeon takes a healthy blood vessel — usually from the chest wall, leg, or forearm — and sews one end above the blockage and the other end below it. This detour, called a graft, carries blood past the narrowed section so the heart muscle gets the oxygen it needs again.

CABG is recommended when one or more coronary arteries are so narrowed or blocked that medications and less invasive procedures are unlikely to restore adequate blood flow to the heart muscle. A heart specialist (cardiologist) and a heart surgeon review imaging results together before recommending this surgery.

• Severe narrowing of the left main coronary artery, which supplies a large part of the heart
• Significant blockages in multiple coronary arteries at the same time (multivessel coronary artery disease)
• Coronary artery disease combined with weakened heart pumping function (reduced ejection fraction)
• Blockages whose shape or location makes them unsuitable for a stent (a small metal tube inserted to prop an artery open)
• A stent placed earlier that has become blocked again (in-stent restenosis) not responding to further stent treatment
• Ongoing severe chest pain (unstable angina) that does not respond to medication
• As part of emergency treatment after a serious heart attack when a large area of heart muscle is at risk

CABG is generally not suitable in certain situations. The surgical team will weigh each patient's overall health carefully.

• Coronary arteries that are too small or too diseased throughout their entire length to accept a graft
• Very poor overall heart function where the risk of surgery is considered too high
• Severe kidney, liver, or lung disease that makes recovery from open-heart surgery unlikely
• Patient preference for a less invasive approach when one is medically appropriate

CABG is major surgery and carries real risks; the surgical team discusses each patient's individual risk level before proceeding.

• Irregular heartbeat (arrhythmia), especially atrial fibrillation, which is common in the first few days after surgery and is usually managed with medication
• Bleeding during or after the operation, sometimes requiring a return to the operating theatre
• Wound infection at the chest incision or at the site where the graft vessel was taken
• Fluid around the heart (pericardial effusion) causing pressure or discomfort
• Stroke (damage to the brain caused by a blood clot or reduced blood flow during surgery)
• Heart attack during or shortly after the procedure
• Kidney injury due to reduced blood flow during the operation, which may be temporary or, rarely, require dialysis (a machine that filters the blood)
• Cognitive changes (memory problems or difficulty concentrating) in the weeks after surgery, which usually improve over time
• Incomplete relief of symptoms if new blockages develop in the grafts over time
• Adverse reaction to general anaesthesia (the medicine that keeps the patient fully asleep during surgery)
• Death — a rare outcome that is more likely in patients who are older, have had a recent heart attack, or have other serious health conditions

Preparation for CABG usually begins days before the surgery and involves changes to diet, medications, and daily habits. Your medical team will give specific instructions based on your situation; the points below describe what is typically required.

Fasting and lifestyle adjustments: Patients are usually asked to eat and drink nothing — including water — for several hours before the operation. Smoking greatly slows wound healing and increases lung complications, so the medical team typically advises stopping as early as possible before surgery. Alcohol should be avoided in the days leading up to the procedure.

Medication adjustments: Some medicines are paused before surgery. Blood thinners are often stopped several days in advance to reduce bleeding risk. Diabetes medicines may need to be adjusted. The care team will review every medicine the patient is taking and give clear guidance on which to continue and which to pause.

Pre-operative tests: Before surgery, the team usually orders a range of tests to map the blockages and assess the patient's overall health.

• Coronary angiography (a dye-and-X-ray test that shows exactly where the arteries are blocked)
• Echocardiogram (an ultrasound of the heart to measure pumping strength and valve function)
• Electrocardiogram — EKG (a recording of the heart's electrical activity)
• Chest X-ray to check the lungs and heart size
• Blood tests including full blood count, kidney function, blood sugar, and clotting ability
• Lung function tests in some patients, especially those who smoke or have breathing problems
• Carotid artery ultrasound (USG of the neck arteries) to check for blockages that could raise stroke risk during surgery

What happens during the procedure: The exact steps vary depending on the surgical technique chosen (for example, whether a heart-lung bypass machine is used), but the typical sequence is as follows.

• 1. The patient is given general anaesthesia and falls into a deep, painless sleep.
• 2. The surgical team places monitoring lines and a breathing tube.
• 3. The surgeon makes an incision down the centre of the chest and opens the breastbone (sternum) to reach the heart.
• 4. In most cases, a heart-lung bypass machine temporarily takes over the job of pumping and oxygenating blood so the surgeon can work on a still heart. In some techniques the heart continues to beat throughout (off-pump CABG).
• 5. The surgeon harvests (removes) the graft vessel — commonly the internal mammary artery from inside the chest wall, the saphenous vein from the leg, or the radial artery from the forearm.
• 6. Each graft is sewn carefully above and below each blockage to create a new bypass route.
• 7. The heart-lung machine is switched off and the heart is restarted, or, in off-pump surgery, the bypass grafts are completed while the heart keeps beating.
• 8. The breastbone is closed with metal wires, and the skin is stitched or stapled closed.
• 9. The patient is moved to the intensive care unit (ICU) for close monitoring as the anaesthesia wears off.

Recovery from CABG is a gradual process that takes place in stages — first in the ICU, then in a regular hospital ward, and finally at home over a period of weeks to months. The pace of recovery varies considerably from person to person depending on age, overall health, and the number of grafts performed.

• ICU monitoring: Patients typically spend one to several days in the ICU with continuous heart monitoring, a breathing tube (removed once the patient can breathe independently), and close observation of blood pressure, fluid balance, and heart rhythm.
• Hospital ward stay: After leaving the ICU, patients move to a cardiac ward for several more days. Nurses help with gradually increasing movement, breathing exercises, and wound checks.
• Chest wound care: The sternotomy (breastbone incision) and graft harvest sites need to be kept clean and dry. Signs of infection — redness, warmth, discharge, or fever — should be reported to the medical team promptly.
• Activity restrictions: Lifting heavy objects and strenuous activity are restricted for several weeks while the breastbone heals. Driving is usually not permitted until the medical team confirms that the sternum is stable and reflexes are unaffected by pain or medication.
• Medications after surgery: Most patients are prescribed blood thinners, medicines to lower cholesterol (statins), blood pressure medicines, and sometimes heart rhythm medicines. These should be taken exactly as directed by the prescribing doctor.
• Cardiac rehabilitation: A structured exercise and education programme (cardiac rehab) is widely recommended after CABG. It helps patients safely rebuild fitness, manage risk factors, and reduce the chance of future heart problems.
• Diet and lifestyle: A heart-healthy diet low in saturated fat and salt, no smoking, limited alcohol, regular gentle exercise, and stress management all support long-term graft function.
• Follow-up appointments: Regular outpatient visits are scheduled to check wound healing, blood results, heart function, and medication. The first follow-up is usually within a few weeks of discharge.
• When to seek urgent help: Patients should seek emergency care immediately for new chest pain, sudden shortness of breath, a rapid or very irregular heartbeat, signs of stroke (sudden weakness, speech difficulty, or vision changes), or any wound that looks infected.