CABG
WHAT IS CORONARY ARTERY BYPASS GRAFTING (CABG)?
Coronary artery bypass grafting or "CABG" (often pronounced "cabbage") is the most commonly performed "open heart" operation in the United States. Cardiothoracic surgeons perform the procedure to bypass blockages or obstructions of the coronary arteries. The coronary arteries are the blood vessels that supply the heart with oxygen and nutrients. The heart relies on these fuels as it works constantly to pump blood through the body. The heart never rests like the other muscles in the body, and it demands a constant supply of fuel day and night. The term ischemic heart disease refers to this condition, when the heart does not get these fuels. When the heart is sufficiently ischemic (when the shortage of fuel is critical enough), the muscle begins to die. This is a "heart attack" or myocardial infarction.
WHAT ARE THE INDICATIONS FOR SURGERY?
The indications for CABG were first defined by the results of the Coronary Artery Surgery Study or CASS. The study was performed by cardiothoracic surgeons and cardiologists in the early days of bypass surgery. It showed a survival advantage for patients undergoing surgery who had disease of the left main coronary artery and those with disease of all three major coronary arteries and abnormal function of the main pumping chamber of the heart, the left ventricle. CABG may also be indicated in other specific circumstances, or when an individual patient is experiencing severe angina pectoris that cannot be controlled with medicines alone. The most important thing to keep in mind is that coronary artery disease is complex and every patient's specific situation is different. You should therefore discuss your circumstances with your doctor.
HOW IS THIS OPERATION PERFORMED?
Coronary artery bypass grafting is a procedure performed exclusively by cardiothoracic surgeons. The traditional technique involves an incision down the front of the chest through the breastbone or sternum. This incision is called a median sternotomy. Through this incision the surgeon can see the heart and the aorta. The procedure as traditionally performed requires that the patient be connected to the heart lung machine while the bypasses are being performed. The heart can then be stopped using a special mixture of chemicals called cardioplegia. After the bypasses have been performed the patient is taken off of the machine and their own heart takes over once again. All bypasses were originally performed using saphenous vein from the leg to carry blood around the obstruction. The vein was attached at one end to the aorta and at the other end to the coronary artery beyond the blockage.
WHAT ARE THE CHANCES FOR LONG-TERM SUCCESS AFTER CABG?
The long term results of CABG are excellent. The majority of patients obtain excellent relief of their symptoms of angina after surgery. Some patients notice an increase in their energy level after recovery -- and will state that they had not realized how much they had been slowing down prior to surgery. Although symptoms may recur, most patients have sustained relief. A minority of patients will require repeat surgery , usually 10 or more years after their original operation. Because of a number of improvements in the procedure, most cardiothoracic surgeons feel that fewer and fewer patients will need reintervention in the future. In addition to the relief of symptoms, research shows that the expected survival (life-span) for specific subgroups of patients improves after CABG.
ARE THERE ANY ALTERNATIVES TO CABG?
Alternatives to surgery include aggressive medical therapy and balloon angioplasty for suitable candidates. Significant advances are constantly being made on both of these fronts. Patients and their families should ask their cardiologist or cardiothoracic surgeon about alternatives to surgery.
Credit: National Institute of Health.