Bypass (CABG)

Coronary artery bypass grafting is a surgical procedure which aims to improve blood flow to heart muscle. It can relieve symptoms such as angina as well as reduce cardiac breathlessness and reduce the chance of a heart attack.

The coronary arteries are vessels that supply blood directly to the heart muscle. If these vessels become narrowed or blocked from coronary artery disease, the supply of oxygen-rich blood to the heart muscle is reduced and can cause tissue damage and symptoms.

During bypass surgery, a new disease free blood vessel is taken from your body and used to bypass the diseased heart vessel in order to supply blood to your heart muscle. This new blood vessel can be created from lengths of vein taken from your leg or from an artery in your arm, or by redirecting the ‘internal mammary artery’ from inside the chest wall to your heart. The removed vessel is called a graft.

A careful assessment for potential veins/arteries to be used as grafts will be made before your operation. It is important to note that no harm is caused to your leg/arm/chest wall by removing the vein or artery as these areas have a double blood supply and can exist with fewer blood vessels. By the end of the operation, the new graft will be attached to the heart, enabling the blood flow to bypass the old narrowed or blocked vessel and replenish the heart tissues. Most people have several grafts done during one operation

Bypass surgery does not cure coronary artery disease, so it is possible for narrowing and blockages to reoccur in both the grafts and other vessels

Consequently, overall current evidence favour CABG as the revascularization modality of choice for patients with diabetes and multivessel disease. When patients present with a comorbidity that increases surgical risk, the choice of revascularization method is best decided by multidisciplinary individualized risk assessment.

The use of bilateral internal mammary arteries (BIMA) should be considered in all patients with a reasonable life expectancy and a low risk of sternal wound complications.

The radial artery constitutes an alternative as the second arterial graft in patients in whom BIMA grafting is not feasible, patients with a high risk of sternal wound complications, or as a third arterial graft.

Bilateral IMA (BIMA) and radial artery have been shown to provide better patency rates than saphenous vein grafts (SVG), particularly for the left coronary artery system.

How is it performed:

The operation lasts approximately three hours and usually requires a hospital stay of 5-7 days. It is performed under general anaesthesia, which means you will be asleep during the procedure, and will feel no pain.

First the arteries or veins that are to be used for your grafts, will be removed and prepared. Your surgeon will then make a cut (traditionally about 25cm long, mini sternotomy about 10-12cm long) down the middle of your breastbone (sternum) and open the ribcage to reach the heart.

Next, the movement (beat) of the heart is temporarily stopped using medication and the blood re-directed to a heart-lung (bypass) machine (full bypass or mini bypass). This machine takes over the pumping action of the heart and lungs, adding oxygen to the blood and maintaining the blood circulation. With the heart now bloodless and not moving, the new grafts can be attached. Once completed, the blood is re-directed from the machine back to your heart, and the heart restarted. CABG can also be performed whilst the heart is still beating (‘off-pump’), your surgeon will discuss with you the technique that they are planning to use for you.

The breastbone is re-joined using wires and the skin on your chest is sealed using dissolvable stitches. Tubes are put into small holes in your chest to drain blood and fluid that collects as part of the normal healing process.

Off pump coronary artery bypass surgery

Off-pump coronary artery bypass surgery differs from traditional coronary artery bypass surgery, because the heart-lung machine is not used. Rather than stopping the heart, technological advances and new kinds of operating equipment now allow the surgeon to hold stabilize portions of the heart during surgery. With a particular area of the heart stabilized, the surgeon can go ahead and bypass the blocked artery in a highly controlled operative environment. Meanwhile, the rest of the heart keeps pumping and circulating blood to the body.

Off-pump coronary artery bypass surgery may be performed in certain patients with coronary artery disease. With present technology, all arteries on the heart can be bypassed off-pump.

It may be ideal for certain patients who are at increased risk for complications from cardiopulmonary bypass, such as those who have heavy aortic calcification, carotid artery stenosis, prior stroke, or compromised pulmonary or renal function.

Not all patients are a candidate.