…… some frequently asked questions about CABG
Two terms refer to two different things:
One is method of doing heart surgery and the other is a specific operation. Any method of operation on the heart that is done using a heart – lung machine has traditionally been called an open heart surgery. A heart lung machine takes over the functions of the heart and lungs while the operation is being done. The heart is stopped during this period. Once the operation is completed, the heart – lung machine is removed and the patient’s own heart and lungs start working again. So, an operation that involves the use of a heart – lungs machine is an open heart surgery. It could be for closure of holes, replacement of valves or bypass grafting of coronary arteries. The heart may or may not be opened.
A block in an artery of the heart is bypassed by a new channel. The objective of this operative is to improve the blood flow to those of the heart muscle that are getting a deficient blood supply owing to completely or partially blocked coronary arteries. The increased blood flow relieves angina and improve heart function.
A conduit or a tube (left or right internal mammary artery, radial artery or a segment of saphenous vein from the leg) is grafted onto the coronary artery beyond the block and the other of the conduit is attached to a source of blood supply, usually the aorta, and sometimes the mammary artery and rarely the axillary artery. Most often the left internal mammary artery is attached to the main artery of the heart, the left arterior descending artery and the radial artery and vein grafts are attached to other vessels. By and large, one tries to put more arterial grafts, as these are likely to stay open for longer.
Diagram showing two partially blocked arteries of the heart with bypass grafts attached beyond the obstruction. Arrows indicate blood flow through these new channels. The graft on right is a vein (light colour) and its other end is attached to the aorta and the other graft is the internal mammary artery, a branch of the artery to the shoulder.
The blockage is usually not disturbed and it remains there, while the rest of the artery receives blood from the bypass graft. In some situations, the block may have to be removed before the new graft can be attached.
It has been observed that patients may have a slightly more prolonged post-operative recovery if their bypass surgery has been done using a heart lung machine (Scientist attribute this to the effect of blood circulation through artificial tubing’s, filters and reservoirs of a heart – lung machine). Also, the incidence of post operative problems is more if the patient s has other co – existing disease like renal failure, lung disease etc. With modern and more advance equipment, the incidence of such post operative complications is much less than before but the problem is not totally eliminated. Now, if one were to avoid using a heart lung machine altogether, obviously the recovery would be much better. And this is possible in the procedure of beating heart surgery where the bypass grafting is done without using the heat lung machine or stopping the heart. Though more and more centers are offering this type of surgery (including my hospital), one must remember that many patients, because of technical difficulties, can be operated upon only by the conventional method.
Yes, ballooning or PTCA (Percutaneous Transluminal Coronary Angioplasty)is a validoption and usually preferred when the blockages are few and short in length. But this procedure is not advisable for all patients. For more than one or two blockage, forlong segment of blocks, for calcified deposits, for block at bends in the artery or for situations technically difficult for angioplasty, surgery is a better option. As a general rule, the procedure of PTCA allows the patient to be discharge earlier, and there is less discomfort associated with the procedure. But long term results of the procedure are not as good as in surgery. Surgery on the other hand needs longer hospitalizations and is associated with somewhat more morbidity, but the long term results of surgery are far superior.
No, laser technology is not used to clear the blockage. It is used in situations of diffuse disease with ungraftable arteries where neither PTCA nor surgery is possible. Laser rays are used to drill fine tunnels through the heart muscle in the hope that these will directly carry blood to the muscle. There is conflicting evidence to support this hypothesis however, and as of today, there is no consensus among doctors about the utility of laser treatment.
How safe is bypass surgery
Done by an experienced surgical team, in a busy center, operation is quite safe today. Overall, I would say the risk to life in this operation is 1-3%. However, the risk increase with age (esp. over 70 years), in females, in patients with co-existing disease of lungs, kidneys, brain etc., in patients where operation has been advised as an emergency, in patients coming for repeat surgery and in patient who have suffered a heart attack and have a reduced left ventricular function. The risk increases to a high of 25-30% in patients who have suffered a surgical complication of a heart attack. On the other hand, the risk may be less than 1% in a young male who is a non-smoker, has no diabetes or hypertension and has a normal ventricular function.
Yes, this operation is not a cure, and with time the grafts tend to close. Vein grafts are likely to close earlier than arterial grafts. About 50% vein grafts would block off by 10 year while 85-90% arterial grafts would still be open in this period. But the type of grafts used is not the only thing that influences results. The other more important determinants of a long term benefit are life style modifications (cessation of smoking, exercise, healthy diet), regular intake of aspirin and other anti- platelet medicines, use of an arterial graft the main coronary artery of the left ventricle (the left anterior descending artery) and the status of the heart function before surgery (poorer ventricle fare less well than those normal function).
Another important reason for patients getting symptoms again is appearance of disease in those vessels of the heart that were normal at the time of the operation.
The operation may not be a cute but it definitely helps in the relief of angina pain and other symptoms of reduced blood supply to the heart muscle like choking, breathlessness, “ghabrahat” etc. With surgery, the need for medication comes down and the patient feels less tied down because of his disease, and is able to live a fuller life at home and at work. In other words, bypass surgery improves the quality of day to day life. In addition several scientific studies have clearly shown that bypass surgery patients are likely to live longer than comparable patients who are only on medicines.
The basic disease (viz. atherosclerosis) that caused blockages in the heart vessels remains there (that explains why the surgery is not a cure); bypass surgery helps overcome the effect of these blockages, it does nothing to the atherosclerosis.Even then, I believe that with proper medical management, good diet control and strict lifestyle changes after the operation, one can enjoy the benefits of bypass surgery for a long time.
Yes, aspirin is known to improve the long term outcome of surgery, and is usually continued lifelong. Some centers advise additional antiplatelet agents to enhance the benefit obtained by aspirin alone. More recently, a greater understanding of the mechanism of atherosclerosis (the disease that cause blockage in coronary arteries, and also the bypass grafts) has led many doctors to prescribe in addition to above, antioxidants and statins (usually used for lowering of cholesterol but also thought to act on the inner lining of grafts and the coronary vessels). Treatment for diabetes, hypertension and impaired heart function has to continue.
The patient has make sure that the known risk factors for coronary artery disease are kept in check. These are smoking, hypertension, diabetes, obesity, lack of exercise, intake of saturated fats and tension or stress. The importance of these risk factors is particularly evident in patients with a strong family history of coronary artery disease.
It usually depends on one’s type of work, the demands of the job, level of physical stamina in the patient and other medical report obtained from the post operative check up. By and large, after an uncomplicated operation, most patients should be able to go back to work in 4 to 6 weeks.
One concern that bothers many patients but is usually not addressed easily relates to sex life after surgery.
This appears to be a real problem, much more common than usually thought of, but few patients have the courage to bring it up with their doctor. There is no bar to having sex after surgery but one should follow common sense in such matters. The patients should not feel tried or tense, and should wait will the discomfort around the chest incision is less. It one feels recovered completely from surgery and is confident enough to carry out one’s full routine at home and office, one should be able to enjoy sex too.
One the most important associations of atherosclerosis is that the disease runs in families. This means that the immediate blood relations of a patients have a higher chance of developing the disease than the normal population. Unfortunately we cannot change this fact. However we can certainly try to reduce the chances of getting heart disease even if one has a strong family history. This is possible by modifying our lifestyle esp. complete avoidance of smoking, regular exercise, a healthy diet, losing weight if one is obese, and if possible, yoga and meditation. If one has diabetes and hypertension, these need to be under total control. One may still develop heart disease despite all these precautions, but perhaps its appearance will be more delayed, and its intensity less severe.
The fact that a patient has had a heart attack usually indicates underlying atherosclerosis in one or more of the heart vessels. Appearance of a blood clot in such a diseased artery cuts of totally the blood supply to the area of the heart supplied by that artery: this is what we call an acute myocardial infraction (acute MI) or a heart attack. Even when a patient recovers from an attack, it is important to know the extent of the underlying disease and whether the patient is at a risk for a repeat heart attack. He may not be having symptoms but there may still be a serious blockage of other arteries. A coronary angiogram is very useful in getting this information. Unfortunately, many people avoid getting and angio. Done out of an irrational fear. They are worried that the angio. Period may show disease and doctors may then suggest angioplasty or CABG. But if these procedures are actually needed, not getting an angio. Will not obviate their need, it will only delay the benefits that should follow the procedure. I do advise you to do as your doctors has suggested.
If the patient is admitted with chest pain and continues to have symptoms or ECG changes despite treatment or if the angiogram reveals very critical disease, surgery is advised in the same admission or as soon as possible.
For patients with stable angina (symptoms well controlled with medicines) or those with less severe blockages , sufficient time is usually available to allow financial and other arrangements to be made or important deadlines to be honoured (social functions, court dates, examinations etc.) But even here, the sooner the surgery is done, the better it is. Waiting beyond a reasonable period does no good the patient.
The operation has become fairly common now and is being offered at many places in North India though the volume of cases done outside Delhi is much less at present. In Delhi too there are several centers where it can be done and our hospital is among the foremost names for this purpose. For an average surgery, the approximate expenditure here is Rs. 1,55,000/- Rates are less for CGHS sponsored patients or those from the army. For patients who find it difficult to arrange for all the money, we encourage them to seek assistance from several central and state government agencies. Some NGOs and private institutions also can help at times.