What Is Coronary Artery Bypass?

 

Coronary artery bypass is a surgical procedure performed to relieve chest pain (angina pectoris) and prevent heart attacks (myocardial infarction), which are the primary cause of death in women and men in the United States. Everyday approximately 1400 people die of heart attacks in the US. Coronary artery bypass is done on a daily basis at the Inova Heart and Vascular Institute (since 1977), the Virginia Hospital Center and Inova Alexandria Hospital.

 

During the procedure, one or more blocked coronary arteries are bypassed using another blood vessel as a graft, or bridge, to carry blood around the obstruction. A healthy extra blood vessel from another part of the body is used as the bypass graft. The most frequently used bypass grafts are:

• arteries from the chest wall (internal mammary or internal thoracic arteries)

• arteries from the leg (saphenous vein)

• arteries from the forearm (radial artery)

 

The bypass graft serves as a bridge or conduit to carry blood to a point beyond the narrowing or complete block in the coronary artery on the outside surface of the heart.

 

Number of Bypasses

The terms single, double, triple, and quadruple bypass relate to the number of coronary arteries bypassed during the operation. There are only two major coronary arteries: right and left. However, their branches are often involved with the disease process (arteriosclerosis), hence multiple bypass grafts can be necessary.

While the operative plan and number of bypasses plan is created and determined before surgery, it may be modified in the operating room depending upon the actual findings.

 

Bypass Graft Selection

There are various types of blood vessels in the body which may be used as bypass grafts. The surgical decision concerning which graft(s) to use depends on vessel availability, the patient’s age, size, presence or absence of severe diabetes, and the degree of blockage in the coronary artery. The three most commonly utilized grafts are:

 

• Internal mammary (thoracic) arteries (IMA). IMAs are proven to exhibit superior long-term results with >90% patency more than 10 years after surgery. The IMA can be used with its origin left intact (in situ graft) or detached and then re-attached to another blood vessel as a T-graft or a free graft

• Using the Radial Graft

• Saphenous veins. The saphenous vein is one of a number of veins in the leg that carry blood back towards the heart. The vein may be removed and used as a bypass graft with little effect on the leg because other veins are able to augment its ability to return blood to the heart. The saphenous vein lies beneath the skin on the innermost portion of the leg from the ankle to the groin. It may be removed via a standard surgical incision or using a minimally invasive endoscopic technique.

 

What Is Endoscopic Saphenous Vein Removal?

Patients undergoing coronary artery bypass surgery often have their saphenous veins harvested, or removed, from their legs.

 

The body contains an extensive system of both superficial and deep veins. The saphenous vein, which is used during bypass surgery, is a superficial vein which courses underneath the skin from the ankle distally to the groin proximally. Once it is removed, blood is rerouted to the deeper venous system in the leg. For this reason, venous blood flow in the leg is not compromised in any way after removal of the saphenous vein.

 

After the vein is removed, it is used as a graft on the heart to bypass the blocked coronary arteries and to restore blood flow to the heart. In the past, removing the vein from the leg always required an incision that corresponded to the length of vein required. For multiple grafts, the incisions were often long, painful, swollen, and slow to heal.

 

Now, an innovative approach to harvest the saphenous vein exists for most patients. The vein can be removed endoscopically through a small 2-cm incision. To remove the vein with such a small incision, a camera is used to view the vessel on a video monitor. The vessel is carefully dissected from the surrounding tissue, and carbon dioxide gas (CO2) is injected to enlarge the area in order to create a “tunnel” in which to work.

 

This procedure reduces healing time and pain and makes it possible for patients to walk with less pain and to recover faster. In addition, the patients are left with only 2-cm scars on their legs.

To watch an actual video of endoscopic vein harvesting, click here.

Please note, this video contains footage of an incision being made and images from the camera showing the vein harvest inside the “tunnel” of the leg.

 

CORONARY ARTERY BYPASS: THE SURGICAL PROCEDURE

 

There are a variety of techniques used to perform coronary artery bypass. The choice depends on the patient’s general medical condition, the degree of prior damage to the heart, the number of coronary arteries involved in the disease (arteriosclerosis) process and the urgency of the operation.

The traditional approach involves a median sternotomy, which is a midline chest incision over the length of the sternum (breastbone). Cardiopulmonary bypass equipment (heart-lung machine) is used to provide the surgeon an ideal motionless, bloodless field to perform stitching of the bypass grafts to the delicate coronary arteries.

 

Beating heart surgery, also called off pump surgery coronary artery bypass (OPCAB) is an alternative technique used to perform coronary artery bypass surgery. Certain patients, such as those with aortic calcification, have increased risk of embolization and other complications with the cardiopulmonary bypass (heart-lung) machine. In OPCAB, the cardiopulmonary bypass machine is not used. Before surgery, the surgeon carefully studies the patient’s history, x-rays, and cardiac catheterization and then decides if the patient is a good candidate for OPCAB.

 

In OPCAB, a median sternotomy, or chest incision, is still required, and the bypass grafts—internal mammary arteries, radial arteries and saphenous veins—are harvested using standard techniques as previously described. Specialized surgical equipment is utilized to stabilize portions of the heart and the coronary arteries during the operation. The remainder of the heart continues to function and to perfuse the body. The cardiopulmonary bypass machine is standing by if needed.

 

The coronary artery to be grafted is then temporarily occluded proximally and the bypass graft is stitched between the bypass graft and the coronary artery. By avoiding the cardiopulmonary bypass machine in properly selected patients, surgeons hope to decrease blood transfusion requirements, decrease the incidence of postoperative cognitive dysfunction, and minimize the incidence of other complications.

 

 

RISK FACTORS FOR HEART DISEASE

Heart disease remains the primary cause of death for men and women in the United States. Approximately 79.4 million Americans live with some form of heart diseasse. While there are no rules that will invariably prevent a heart attack, there are known risk factors which may be controlled. All of the 8 listed risk factors, except the last one, may be managed by you and your physician.

• Tobacco use

• Elevated lipids in your blood (cholesterol, triglycerides)

• High blood pressure

• Diabetes

• Obesity

• Lack of exercise

• Stress

• Family history of coronary artery disease

 

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