The heart is an organ which supplies oxygen and nutrients to itself and the entire body. Blood flows into the right atrium of the heart, through the tricuspid valve into the right ventricle where it is pumped into the pulmonary valve, which in turn sends the blood onto the lungs where it exchanges gases of oxygen and carbon dioxide with the air. Once the blood is oxygenated, it flows back through the left atrium, through the mitral valve and into the left ventricle, where it is pumped to the aorta which pumps blood to the heart first, and then the rest of the body.

The mitral and tricuspid valves control the direction and volume of blood that flows into the ventricles, by opening and closing so the heart does not get damaged by having to work too hard pumping blood. Sometimes, due to aging or other factors, the valves get diseased or don’t work efficiently. The cusps of the valves can become stiff or the valve can become relaxed, and not fit well onto the annulus of the ventricle and therefore not close properly. The aortic valve controls output of oxygenated blood. The pulmonary valve rarely needs repair or replacement, however repair or replacement of the aortic and mitral valves are commonplace. The tricuspid is less commonly replaced due to its lower pressure of blood flow.

The vessels that provide oxygenated blood to the heart and the rest of the body within the heart are called coronary arteries. Sometimes, due to age, amongst other factors, the walls of the coronary arteries narrow due to plaque build up. A blood clot can form in the narrowed artery, and cause a blockage which restricts blood supply to the heart and can lead to a heart attack.

Coronary arteries can be revascularised in a common procedure called coronary artery bypass grafting. Artery or vein from another site in the body is used to carry the blood from the site past the blockage to where it is supposed to go. The blockage does not get cut away. The graft is placed just past the blockage, so the flow of blood is not interrupted, and the other end of the graft is connected to its own blood supply. At times, a graft will have a smaller branch attached to it, that will connect the blood supply to another part of the heart if needed. Between one and six coronary grafts are commonplace in bypass surgery.

More About Coronary Artery Bypass Surgery

Where do the grafts come from?

The most common sites to retrieve what is known as conduit for bypass are:

  • Internal Mammary Arteries. The thoracic area has a blood supply in addition to the two internal mammary arteries that lie on either side of the sternum, which is why it can function very well without these arteries. When these arteries are used they normally remain attached to the blood supply of the heart, and the cut end is placed at a site after the blockage which is being bypassed, necessitating only one anastomosis (the incision and stitching required to attach the bypass graft).
  • Radial Artery. The hand is supplied with blood from the ulnar artery as well as the radial artery, so using the radial artery usually does not compromise the hand.
  • Saphenous Vein. The long saphenous vein travels down the leg. Although it is a vein, and not an artery, it is durable and strong enough for bypass grafting because of its function within the body.

Mr Pick will discuss with you which conduit he will be using in the surgery after a preoperative examination to determine quality of the conduit.

What is bypass?

With the exception of a single bypass, Mr Pick will perform the coronary surgery with the heart arrested. The heart will be cannulated and connected to a machine, which will pump the blood around the body and perform the function of the lung, whilst the procedure is taking place. At Mr. Adrian Pick MBBS FRACS’ Rooms, we pride ourselves on operating very efficiently and having the bare minimum time “on pump”, to optimise the patient’s recovery. The technician that looks after the oxygenation and pumping of blood is called a perfusionist. In exceptional circumstances, the femoral artery in the groin will be cannulated instead of the heart. Mr Pick will discuss this with the patient at the preoperative visit.

What happens during surgery?

The sternum (or breast bone) will be taken down with an incision (a very neat and straight, flat, faded result will be the ultimate look), the tissues divided through to the sternum which will be opened using an oscillating saw and retracted, so there is easy access to the heart. The heart has a cover called the pericardium, which is cut through and the heart is then operated on. At the completion of the procedure, the sternum is reapproximated with stainless steel wires, which remain in place and are not removed in the future.

What happens after surgery?

Heart surgery patients will spend the first night in the intensive care unit followed by 3-4 nights in the normal cardiac ward. Afterwards patients have the option of being discharged to cardiac rehabilitation for assist in their recovery. It generally takes three months to fully recover from heart surgery. Some patients will return to work in six weeks. Mr Pick will discuss resuming driving, heavy lifting and other activities at the post operative visit which takes place four weeks after the procedure.

More About Heart Valve Surgery

Heart valves fail or deteriorate with age, among other factors, and can calcify, become stiff or not fit as tightly as they need in order to function. Sometimes the valve can be repaired, in some circumstances the valve is beyond repair and needs replacement.

When a valve isn’t functioning the blood doesn’t flow in the direction it is supposed to entirely; when blood retreats in the direction of its origin, it is called regurgitation. Regurgitation can put pressure on the ventricle pumping the blood, due to increased volume, which over time can enlarge and damage the ventricle. Stiffness of the cusps of the valve is called stenosis. This prevents a coordinated, fluid functioning of the valve.

Valve Options for Replacement:

  • Bioprosthetic: These valves come from animals or humans (a tissue bank); they are processed to minimise rejection. The advantage of bioprosthetic valves is that there is no need for anticoagulation therapy in the future (eg. Warfarin). There could possibly be a need for reoperation in the future, as bioprosthetic valves have a lifespan.
  • Biomechanical: These valves are man made, and require some form of anticoagulation in the future. The benefit of these valves is they do not need replacement in the future.

The balance of advantages vs. disadvantages of a bioprosthetic and biomechanical valve will be discussed with the patient at their preoperative consultation. Mr Pick will make a recommendation after consideration of the patient’s opinions and preferences.

What is a Valve Repair?

The valve component of the heart is made up of the valve, and the annulus, which is where the valve attaches to the ventricle in the case of the mitral and tricuspid valve, and to the aorta in the case of the aortic valve. Valves have cusps which open and close, controlling the flow of blood in one direction. Sometimes the cusps need revising (trimming and suturing) to tighten them up, so they don’t leak when the valve is closed. The annulus can become slack and not perform the opening and closing effectively; in this case an annuloplasty band can be placed around the annulus, to repair the function of the annulus. The mitral and tricuspid valves are attached to the corresponding ventricles with string like structures called chordae, which attach to papillary muscles. The chordae can be replaced with a cord that resuspends the valve to the ventricle, correcting the problem. Mr Pick will discuss the nature of your valve repair at the preoperative visit.

How is valve repair/replacement performed?

The patient is placed on bypass and a sternotomy is performed. In certain circumstances, the valve repair is done minimally invasively (in the case of mitral and aortic valves). This obviates the need for a sternotomy, and the incision is a thoracotomy, which is a small incision through the ribs. The advantage is a less invasive procedure, with less down time for recovery.