The CABG procedure generally takes 3 to 6 hours, depending on the number of grafts required. Below is a detailed step-by-step explanation of the CABG procedure:

Step 1: Preoperative Preparation

The patient undergoes comprehensive medical evaluation, including blood tests, chest X-rays, ECG (electrocardiogram), echocardiogram, and coronary angiography to assess the severity of artery blockages.

Medications such as blood thinners or beta-blockers may be adjusted before surgery.

The surgical team provides instructions on fasting before the procedure.

General anesthesia is administered, ensuring the patient is completely unconscious. A breathing tube (endotracheal tube) is inserted to support ventilation.

Step 2: Incision and Chest Opening

A median sternotomy (cutting the breastbone) is performed, where the surgeon makes an 8 to 10-inch incision down the center of the chest.

The sternum (breastbone) is divided to provide access to the heart.

In minimally invasive CABG or robotic-assisted CABG, smaller incisions are made instead of a full sternotomy.

Step 3: Harvesting the Graft Vessel

A healthy blood vessel is harvested from another part of the body to serve as a bypass graft. The most used vessels are:

Internal Mammary Artery (IMA) – from the chest wall (preferred due to long-term patency).

Saphenous Vein – from the leg (commonly used for multiple grafts).

Radial Artery – from the forearm (used when additional grafts are needed).

Step 4: Connecting the Heart-Lung Machine (For On-Pump CABG)

In on-pump CABG, the heart is temporarily stopped using a cardioplegic solution, and the patient is connected to a heart-lung machine (cardiopulmonary bypass). This machine takes over heart and lung function, ensuring oxygenated blood continues circulating.

In off-pump CABG (beating-heart surgery), the heart continues to beat, and special stabilising devices hold the affected artery in place for grafting.

Step 5: Graft Attachment (Bypassing the Blockage)

The surgeon sews one end of the graft to the aorta (or a major artery) to receive oxygenated blood.

The other end is attached beyond the blockage in the coronary artery to restore blood flow.

Grafts can be attached without touching the aorta when required.

If multiple arteries are blocked, multiple grafts are placed accordingly.

Step 6: Restarting the Heart (For On-Pump CABG)

Once the grafts are securely in place, the heart is restarted by allowing the blood flow to return and mild electrical stimulation if required.

Once the heart takes over the heart-lung machine is gradually weaned off.

Step 7 (Final Step): Closing the Chest

The sternum is wired back together using stainless steel wires to ensure stability.

The chest incision is closed with sutures or staples.

A drainage tube is placed to remove excess fluid from the chest cavity.

A temporary pacing wire may be attached to regulate heart rhythm if needed.

Coronary Artery Bypass Grafting (CABG)