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The University of Maryland Heart Center offers all variations of coronary artery bypass grafting (CABG) techniques, many of which are performed using minimally invasive techniques. The heart bypass operation is tailored to the patient’s needs.
In a CABG operation, the blockages on the coronary arteries are bypassed by blood vessels, which are taken from the patient's chest, arm or leg. This allows more blood to flow into the coronary arteries, which ensures adequate blood supply to the heart. It also relieves chest pain and angina, will prevent the occurrence of a heart attack (myocardial infarction), and will prevent sudden cardiac death.
In many cases a traditional or classic CABG operation will be performed.
|Photo 1: A bypass vessel and coronary arteries measure two to three millimeters in diameter. Coronary surgery is fine work which requires loupe magnification and micro-instrumentation.|
|Photo 2: The heart-lung machine is a high-tech device that maintains the blood circulation while micro-surgery is performed on the heart.|
|Photo 3: In a classic CABG operation the surgeon has access to all parts of the heart. Up to five or even six bypass vessels can be connected to the coronary arteries. The durability of the internal mammary artery graft, which the surgeon inspects on this photo, is counted in decades.|
The traditional or classic CABG procedure was developed in the late 1960s and is therefore a well established and very mature form of treatment for coronary artery disease. For patients with multiple blockages of the coronary artery system, it is clearly the best option.
Most recently, large studies have shown that in these patients, CABG has survival advantages as compared to catheter-based interventions with balloon dilation and stenting. Most striking is the long-term durability of the grafts, which is counted in decades. The patient who undergoes a classic CABG operation will very likely be symptom free for years and will most likely not undergo any further invasive treatment.
CABG procedures were originally carried out using vein grafts from the leg. These days second- and third-generation operations are performed where arteries rather than veins are implanted. It has been repeatedly demonstrated that arteries, primarily the internal mammary arteries, which can be harvested from the thoracic wall inside the chest, stay patent or secure for many years. The patency rate at 10 years is above 90 percent.
Therefore, our team aims to implant these arteries in order to achieve this long-term benefit. Operation techniques involve fine, delicate work using loupe magnification and the finest surgical instrumentation. Perfect connection between the bypass graft and the coronary artery is a clear goal.
A team of seven to eight professionals takes care of the patient during this operation.
This operation is performed under general anesthesia. The best access to the heart is gained by dividing the breastbone (sternotomy). This incision is less painful than many patients would expect. It is clearly less painful than an incision on the lateral thorax or incisions in abdominal surgery.
The internal mammary artery is harvested from the inside of the chest and additional bypass conduits may be harvested from the arms or the legs. The surgeon exposes the heart. Through the sternotomy, the surgeon can easily access all parts of the coronary artery system.
The heart-lung machine or extracorporeal circulation is then connected to the heart. This machine is a highly sophisticated tool that can keep up the blood circulation while the surgical team works on the heart. Heart-lung machine technology is more than 50 years old and has saved the lives of thousands of patients. The advantage of using this device is that the heart can be arrested and kept completely still while the delicate suturing maneuvers on the coronary arteries are carried out.
In order to achieve a complete heart arrest, the surgeon places a clamp on the ascending aorta; thereby the blood flow to the heart is interrupted. For protection of the heart muscle during this phase, potassium solution (cardioplegia), is infused into the aortic root. The heart is then well prepared for implantation of the bypass grafts.
The coronary arteries are opened downstream from the blockages. The bypass vessels are sutured to the coronary artery with a fine polypropylene thread. This suture will not resolve. No leaks are tolerated. If the coronary bypass connections are perfect, the clamp on the ascending aorta is removed and the heart usually regains a normal rhythm.
Some bypass grafts need to be connected to the ascending aorta. The surgeon places another clamp and sews them to the aorta, again using very fine suture material. Finally, the heart-lung machine is disconnected and the chest is closed. The CABG operation usually takes three to four hours.
After the operation the patient will be brought to the cardiac surgery intensive care unit. This is a ward where specially trained personnel will observe all vital functions. The electrocardiogram (ECG), blood pressure and the amount of blood the heart ejects are carefully watched. Sometimes application of medication is necessary, which supports the contractions of the heart or makes the heart beat faster or more slowly.
For a few hours the patient will be kept on the ventilator, but the tracheal tube will be removed as soon as good spontaneous breathing is reached. Infusions will be given for regulation of blood pressure and adequate fluid balance. The surgeon has placed tubes into the chest during the operation and the intensive care team watches for the amounts of blood or air, which are drained.
Laboratory tests are taken frequently in order to get an overview if all organ systems are functioning correctly. Urine output is monitored through a urinary catheter.
Transfer to a step-down unit will usually take place on the first day after the operation. Most of the lines and catheters will be removed early and drinking, eating and walking will usually be started on the first postoperative day. The patient will have to use an oxygen mask to breathe. Medication that regulates blood pressure and heart rate may be necessary; all patients will receive drugs for stomach protection and proper bowel function.
Pain is not a major issue in this type of operation, but painkillers will be given if necessary. The chest tubes will be removed depending on how much fluid is drained. Discharge home or to a rehab center can be expected in the middle or end of the first postoperative week.
After discharge the patient will resume normal activities step by step. Because of the midline incision, which needs to heal, there are restrictions concerning weightlifting for eight weeks. After that, regular activites can be resumed. These activities will be tailored to the patient's condition and will be discussed with the surgical team and the cardiologist.
Medication is necessary long term. This medication will include platelet inhibitors like aspirin, which protect the bypass grafts and the native coronary arteries from further narrowing or occlusion. Other medication primarily consists of beta blockers and drugs that treat risk factors for atherosclerosis.
Advantages of the traditional or classic CABG operation include the following:
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