Coronary artery bypass graft (CABG) surgery is performed to detour blood flow around blocked arteries. It's used for patients who haven't responded to therapy with medication and who aren't good candidates for angioplasty procedures, generally because they have significant narrowing in multiple coronary arteries.

There are a number of different forms of CABG surgery, but they all involve removing a blood vessel from a different part of the patient's body for use as a graft. The graft is connected to areas before and after the blocked area of the coronary artery so that blood flows around (bypasses) the blockage. This restores blood flow to the affected part of the heart and relieves chest pain and other symptoms.

Types of CABG Surgery:

• Traditional Open-Chest. This surgery has been performed for decades. The breastbone, or sternum, is split in two (a technique called a sternotomy) to gain access to the heart. The heart is stopped, and a heart-lung bypass machine is used to oxygenate and circulate blood during surgery. It is performed on patients with stronger hearts and immune systems. This is a very invasive procedure and requires a 5-10 day stay in the hospital after the operation and 4-8 weeks of recovery time.
• Beating-Heart (Off-Pump) Open-Chest, often called Off-Pump Coronary Artery Bypass (OPCAB). As in the traditional surgery, a sternotomy is performed and the chest opened, but the heart remains beating during the operation. About 20% of CABG surgeries are off-pump. It is preferred for patients who have weak hearts. Recovery takes 4-8 weeks.
• Minimally Invasive Surgery, often referred to as Minimally Invasive Direct Coronary Artery Bypass (MIDCAB). This term refers to a variety of techniques used to perform bypass surgery through smaller incisions, about 3-5 inches (8-13 cm) across. A sternotomy is not performed. Often robotics and video imaging are used to assist the surgeon in operating in a small area. This type of bypass surgery is often used for patients with weak hearts and/or immune systems. Patients typically stay in the hospital 2-3 days after the operation, and recovery usually takes 7-10 days.

Risks of CABG Surgery:

• Death. Overall mortality related to CABG is 3-4%.
• Heart attacks. Heart attacks occur in 5-10% of patients during and shortly after CABG surgery and are the main cause of death.
• Bleeding. This occurs in about 5% of patients.
• Stroke. Stroke occurs in 1-2% of patients, primarily the elderly.
• Arrythmia
• Infection
• Problems with memory, comprehension, and concentration

Heart-Lung Machine
The conventional technique in coronary bypass surgery requires stopping the patient's heart. This is done so that the surgeon can have a quiet (nonbeating) heart and a bloodless field in order to do the delicate work of stitching the graft to the coronary artery. Coronary arteries can be tiny; some have the circumference of a round toothpick.

The heart-lung machine, frequently called "the pump," is used in open-chest heart surgery to do the work of the heart and lungs while the heart is stopped. Patients are referred to as being "on-pump" or "off-pump," meaning the heart-lung machine is being used or not.

The heart-lung machine is connected to the patient by two connections. One is to a large artery, and the other is to a major vein. The oxygen-depleted blood from the vein is rerouted into a chamber in the machine. The blood is then pumped through an oxygenator, which removes carbon dioxide and adds oxygen, a function normally performed by the lungs. The newly oxygenated blood is then pumped back into the body via the artery. Throughout the surgery a technician monitors the heart-lung machine, carefully watching the temperature of the blood, the pressure at which it is being pumped, its oxygen content, and other measurements. When the surgeon nears the end of the procedure, the technician increases the temperature of the heat exchanger in the machine to allow the blood to warm. This restores normal body heat to the patient before he or she is taken off the machine. At the end of the operation, the surgeon gradually allows the patient's heart to resume its normal function, and the heart-lung machine is "weaned off."

Minimally Invasive Technique
Minimally invasive technique, or MIDCAB, isn't new to cardiac surgery, having first been used in the 1950s. But the technology used to quiet the heart during the operation has become more sophisticated, and advances in robotics have made it possible for the surgery to be done remotely.

Because minimally invasive surgery utilizes only a 3-5 inch (8-13 cm) incision between the patient's ribs or several smaller cuts, not everyone is eligible for the procedure. It is generally used for:

• Patients who are otherwise healthy but have a blockage in one or two coronary arteries located on the front side of the heart
• Patients who have a blockage in one or two coronary arteries on the front side of the heart, but who are considered too high-risk for traditional open-chest bypass surgery

Robotic assistance is the latest advance in heart surgery. In it, the surgeon has no direct contact with the patient. He or she sits at a computer console controls pencil-sized robotic arms that perform the actual surgery. The robotic arms hold specially designed surgical instruments that perform the intricate movements, mimicking the movements of the surgeon's hands. An endoscope is inserted into the patient's chest so that the surgeon is able to view the operation on a monitor. As the technology becomes more advanced, surgeons may be able perform coronary artery bypasses remotely, whether from another room or from hundreds of miles away.

Benefits
Minimally invasive heart surgery is expected to result in a shorter hospital stay (2-3 days as compared to 5-10 days for traditional bypass surgery), less pain, lower rates of infection, and a faster return to normal activity (usually about 2 weeks).

Risks
The risks for minimally invasive surgery are similar to those for traditional CABG surgery (minus the risks of sternotomy). Some studies have shown that incidence of stroke, arrhythmia, and need for blood transfusions are greatly reduced. However, minimally invasive surgery can result in a higher rate of restenosis (recurrence of narrowing of the arteries) than traditional coronary artery bypass grafting.

More on this topic

What is Coronary Bypass Surgery? (VIDEO)
Restoring Flow
Stiff & Narrow
The Consequences of Clots
Testing & Diagnosis
Bypass Background
The Way to Your Heart
New Connections
Recovery from Bypass
Lifestyle for a Healthy Heart

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