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. At CVTSA, we're proud that our outcomes continue to exceed the national average.
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.
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. The heart-lung machine is run a perfusionist, someone specially trained to ensure that blood and oxygen continue to move through the body while the heart is stopped.
Off Pump Coronary Artery Bypass (OPCAB) is when coronary artery bypass surgery is performed without the use of the cardiopulmonary bypass (heart-lung) machine.
Off-pump, or beating heart surgery, was originally developed as a safer alternative to the bypass machine. The use of cardiopulmonary bypass can sometimes be associated with potentially harmful side effects following heart surgery. While technological advances over the last several years have made the routine use of cardiopulmonary bypass very safe for most patients, there are some groups in particular which continue to do better if its use can be avoided. These include older patients wtih calcification (plaque) in their aorta and those with bad lung or kidney disease.
When a patient undergoess off-pump surgery, 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. Because the heart continues to beat, specialized surgical equipment stabilizes portions of the heart and the coronary arteries while the surgeon works. The remainder of the heart continues to function and to perfuse the body.
There is always the chance that patients who undergo off-pump surgery will be converted to on-pump during the operation (on average less than 5% of the time). For this reason, there is always a cardiopulmonary bypass machine on stand-by in the operating room.
TEST TEST TEST
When you meet with your surgeon, he will assess your medical history and review your cardiac and pulmonary function and cardiac catheterization films to help him determine if you are a candidate for off-pump surgery.
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
• Lack of exercise
• Family history of coronary artery disease