CORONARY ARTERY BYPASS SURGERY
The coronary artery bypass graft (CABG) is the gold-standard surgical treatment for coronary artery disease (CAD). This procedure is done if angioplasty proves to be unsuccessful and the physician is unable to place stents to open up the narrowed artery. CABG’s have been performed for nearly 30 years.
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During a CABG the sternum is separated and the ribs are spread apart to allow access to the heart. Often blood circulation and breathing functions will be taken over by a heart-lung machine. This surgery though, is now being done more frequently in a manner called off-pump where the heart-lung machine is not used. The surgeon uses a piece of vein or artery to form a bypass to enable blood to flow around the area of blockage. The goal of this surgery is not to repair the area of blockage but to detour the flow of blood around the area.
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Various vessels can be accessed and used for this grafting procedure. The most common vessel that has been used in the past is the saphenous vein from the leg. But the radial artery from the arm is now more commonly be accessed and used for the procedure. As long as the patient has adequate blood flow to the lower arm via the ulnar artery the use of the radial artery poses no problem for blood flow through the patients arm. Another artery that is sometimes used is the internal mammary artery from the chest.
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Occasionally an artery from the stomach (gastroepiploid artery) also may be used as bypass grafts.
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Depending on which blood vessel is used, one end is either sewn to the aorta or may remain connected to the larger artery where it originated. The other end is grafted beyond the area of blockage in a specific coronary artery.
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The day and night before surgery the patient is usually in the hospital. Usually a chest x-ray will be required prior to surgery. Usually blood is drawn to Type and Screen the patient’s blood in case they require blood transfusion during or after the surgery. Other tests are also routinely done such as a CBC, tests on the patient’s electrolytes, and coagulation studies such as a PT/PTT/INR, liver function tests, EKG, and a urinalysis. Often the evening before surgery the patient’s chest and legs are scrubbed with a bacterial-killing solution ordered by the surgeon. Also before surgery the chest and legs will be shaved.
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The patient should always be NPO after midnight the night before surgery which means that the patient should have nothing to eat or drink. Often the patient is put on a maintenance IV fluid drip during this time so that the patient does not become dehydrated.On the day of surgery, before the actual surgery is done, often a Swan-ganz catheter is inserted in order to measure heart function during the surgery. Obviously the patient will be intubated prior to the surgery and given anesthesia during surgery.
During surgery functions of the heart, including blood flow and oxygenation, are rerouted through a heart-lung machine. While the heart-lung machine is taking care of the functions of the heart, the heartbeat can be stopped by administering what is called a cardioplegic solution. Cardioplegic solutions protect and preserve the myocardium for extended time periods during open heart surgery and reperfusion by preventing ischemia. Usually the heart remains stopped for 30 to 90 minutes during the usual 4-5 hour surgery.
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The vessels that are going to be used for the bypass graft are removed before the patient is put on the heart-lung machine. After the grafting is completed and blood is flowing adequately around the blocked artery, the patient is taken off of the heart-lung machine. After the surgery is over the sternum is usually closed with wire and the surface area is closed with staples. Most of the time there are wires coming from the chest, usually atrial and ventricular, in order to be able to use a pacemaker in the event that the electrical activity of the heart is not adequate.
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After the surgery is completed the patient is usually transferred from the operating room to the cardiac intensive care unit where they are closely monitored by skilled cardiac intensive care unit nurses. These patients generally have chest tubes, due to the chest being opened; they are often are intravenous medications that are being administered in a drip to control blood pressure, heart rate, cardiac output, and other hemodynamic parameters. The patient remains intubated until the physician is confident that the patient can adequately breathe on their own. Patients though are extubated much more quickly now than they were a few years ago. There is a strong belief that the sooner the patient is up and about the faster they will recover. The nurse taking care of these patients must be very skilled and educated regarding the medications, chest tubes, monitoring of blood loss from chest tubes, Swan-ganz catheters, and respiratory care of these patients.
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There are complications that can arise from coronary artery bypass surgery. These include difficulty breathing, bleeding ( blood loss from the chest tubes need to be carefully monitored ), infection, hypertension, and arrhythmias, particularly atrial fibrillation. Most of these complications are short-term and are not life-threatening. More serious complications that may arise, usually from the use of the heart-lung machine, include kidney failure, heart attack, stroke, or even death. These risks are obviously higher in patients with diabetes, older patients, and patients with other major health problems
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Usually the patient needs to make some lifestyle changes after surgery. These include eating a healthy diet, quitting smoking, monitoring blood pressure, monitoring diabetes closely if they have that condition, be compliant with taking medications, and take part in regular exercise, generally begun during a cardiac rehabilitation program.
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A very important part of the patient’s recovery from coronary artery bypass surgery is patient education usually done by nursing personnel. Lifestyle changes need to be reinforced. Education regarding medications that the patient will be taking is important as it has been shown that patients that understand what medications they are taking, and the reason for taking them, are more compliant with taking these medications.
