Minimally invasive coronary artery bypass graft surgery (MI-CABG)
Coronary artery bypass graft (CABG) surgery treats coronary artery disease by restoring normal blood supply to the heart. In this procedure, new arteries or veins (bypass grafts) are connected to the coronary arteries to bypass blockages.
In Canada, the most common CABG surgery uses bypass grafts retrieved from the left side of the chest (an arterial bypass graft) and the leg (a vein bypass graft). In the long-term, arterial bypass grafts are considerably more durable than vein grafts.
Risks associated with a conventional CABG include:
- limited durability of vein grafts,
- adverse effects of using the heart-lung machine,
- infection of the incision post-surgery (common for diabetic patients).
The Peter Munk Cardiac Centre is one of a handful of centers in the world to offer minimally invasive CABG without the heart-lung machine, using only arterial bypass grafts. This technique was developed by Dr. Davierwala.
Dr. Davierwala offers three different types of minimally invasive CABG procedures:
1. Left-sided minimally invasive direct coronary artery bypass.
- Durable arterial bypass graft.
- No heart-lung machine.
- The entire procedure is done through the space between the fourth and fifth ribs on the left side of the chest.
2. Right-sided minimally invasive direct coronary artery bypass
- Durable arterial bypass graft.
- No heart-lung machine.
- The entire procedure is done through the space between the fourth and fifth ribs on the right side of the chest.
3. Minimally invasive multi-vessel total arterial coronary artery bypass
- Durable arterial bypass grafts.
- No heart-lung machine.
- The entire procedure is done through the space between the fourth and fifth ribs on the right side of the chest.
The aortic valve
The aorta is our largest artery, supplying blood to our organs and limbs. The aorta runs from the heart up towards the head (ascending aorta), curves towards the back and arches (aortic arch) to turn downward, running along the spine (descending aorta).
The aortic valve is located between the left ventricle (lower left chamber of the heart) and the aorta. It consists of three cusps or leaflets. When the left ventricle contracts (pumps), the leaflets open, allowing blood to pass from the left ventricle into the aorta. When the left ventricle relaxes, the cusps close, preventing blood from flowing back into the heart.
The aortic valve is attached to the crown-shaped junction between the left ventricle and the aorta called the aortic annulus, which includes three commissures (points where one cusp meets the adjacent cusp) that are attached to the aortic wall. The part of the aorta between the aortic annulus and the plane connecting the uppermost tips of the commissures is called the aortic root, which also gives rise to the left and right coronary arteries.
Aortic valve disease
Aortic stenosis is the narrowing of the aortic valve. This can occur due to a deposition of calcium or a thickening of the aortic valve cusps. Aortic stenosis is caused by a variety of factors such as age-related wear and tear, rheumatic heart disease, or a congenitally abnormal valve.
Patients with severe aortic stenosis almost always require aortic valve replacement. When medical therapy is no longer adequate or the patient develops signs and symptoms of heart failure, the entire aortic valve is replaced with a biological or mechanical valve prosthesis.
When the three cusps of the aortic valve are unable to close completely, blood flows backwards from the aorta into the left ventricle with every heartbeat. This is called aortic regurgitation.
Regurgitation can occur in combination with stenosis. In such cases, the valve needs to be replaced. In some instances, the cusps of the aortic valve remain pliable, but fail to meet in the midline, creating a gap. Such valves can be repaired with a variety of techniques.
