The news that you need bypass surgery usually comes as a shock, especially if you have been trying to lead a healthy lifestyle. While high blood pressure, high cholesterol levels and other factors contribute to your risk of heart disease, the ultimate marker of heart disease is atherosclerosis, which is a hardening of the blood vessels on the surface of the heart called the coronary arteries.
When plaque builds up inside these normally flexible arteries, blood flow is restricted or stopped and the heart muscle may die. Sometimes the body gives hints that the heart muscle is becoming compromised, by causing pain in the chest, arm or jaw.
Cardiologists can look for coronary blockage in the arteries that supply the heart muscle with tests such as coronary angiography, where an X-ray dye is injected into the arteries, so that they can be viewed on a screen. Depending on what the doctor finds, you may be referred to a heart surgeon for coronary bypass surgery or other some other potentially lifesaving procedure that will open up your arteries. Below, Miguel A. Gomez, MD, a cardiothoracic surgeon and chairman of the department of surgery in the Memorial Hermann Hospital System in Houston, Texas, explains how bypass surgery works and why new approaches to it may be safer for patients.
What is coronary bypass surgery?
In bypass surgery, we use either arteries or veins from the patient's own body to create a bypass around blockage in the artery, so blood can flow beyond the blockage to the heart muscle that's being supplied by that artery. It's like new plumbing. We're creating a new avenue for blood to go to the heart muscle.
When is bypass surgery recommended?
Bypass surgery is recommended to people with coronary artery disease. Nowadays, it's offered to people with three or more coronary arteries that have blockages and evidence that their heart is not pumping properly. If somebody has a blockage of the left main coronary artery, which supplies most of the blood to the majority of the heart, bypass surgery is the first and the only option. It also recommended to people with heart disease and diabetes.
If the blockage is located at a bifurcation, that may require bypass surgery. A bifurcation is when you have an artery that comes down to a fork in the road and divides and becomes two arteries. Bypass surgery may also be recommended because of the anatomy of the blockage, such as if the blockage is a very long, or if the coronary arteries are very small.
Usually, when people have only blockages of one or two vessels, the cardiologist does procedures that are performed though the skin, such as a balloon angioplasty or putting in a stent, which is a wire coil that is left in place to keep the inside walls of the artery open.
What is an angioplasty?
A balloon angioplasty is where you put a catheter across the blockage and you blow up a balloon and that dilates the artery and compresses the plaque, so that the blockage is minimized and the artery tunnel size is made greater. Nowadays, most people will not just do a balloon angioplasty, but also put in stents to support the artery wall. Some of the stents are coated with drugs that prevent re-growth of the blockage.
There is less risk involved in these procedures. These are performed in the hospital in the cardiac catheterization lab with local anesthesia. Cardiologists access the coronary arteries in the heart through the groin artery. The cardiologists thread catheters all the way up into the heart and down to the coronary arteries.
Why are the different approaches to bypass surgery?
The conventional approach, which has been around for the last 30 to 40 years, is where the patient's breastbone is divided in half, which is called a sternotomy, and the chest is spread open. Then the heart surgeon places the patient on the heart-lung machine, which circulates the blood and oxygenates it while the heart and lung are stopped. The surgeon stops the heart with a high-potassium solution that arrests the heart and allows us to work on it. The surgeon does the bypasses and then the arresting solution wears off and the heart starts pumping again. The surgeon slowly weans that patient off the heart-lung machine and then you close their chest.
The newer off-pump bypass procedure is where you still divide the breastbone with a sternotomy and spread the chest, but you don't stop the heart and you don't put the patient on the heart-lung machine. Instead, we use a device that stabilizes the portion of the heart where the coronary artery has the blockage, and we are able to sew the bypasses while the heart's still beating.
What are the benefits of the off-pump bypass?
The benefits of that option is that this is a more normal physiological state for the patient because you don't stop the patient's heart, and you don't have his blood circulating outside of his body through a machine and getting pumped back into the patient.
There are several studies that have shown that the patients' death rate during surgery is lower. There are fewer postoperative complications. The patients spend less time on the respirator after the operation and less time in the hospital. There's also less chance of brain deficits and less of a need for a blood transfusion.
Mortality rates after bypass surgery appear higher in women than they are for men. Do you have a sense of why that might be?
That's something that people are working on: to find out why women have a higher mortality. I would lean towards thinking that it is because their coronary arteries tend to be smaller in diameter than men's coronary arteries. The bigger the arteries you're sewing, the more likely that the operation's going to be successful and the grafts that you do are going to stay open.
How would you describe recovery from bypass surgery?
Following the conventional bypass, most patients are in the intensive care unit for a couple of days. Their entire hospital length of stay is usually five or six days. After the off-pump bypass procedure, most patients are in the intensive care unit just overnight, and they're in the hospital for three or four days. I refer all patients to cardiac rehabilitation programs, which involve diet and exercise training, following their hospitalization.
Why do people still need to work on reducing their heart disease risk factors after bypass surgery?
The same blockages that you had in your native arteries will occur in the bypasses, unless you take good care of yourself. If you are able to change your dietary habits, your sedentary lifestyle and take the medicines, such as statin therapy to lower cholesterol, hopefully, the bypasses will stay open for a longer period of time. If patients block their bypasses, they're going to be looking at having heart surgery again.
What is the future of bypass surgery?
The next step that people are trying is not performing a sternotomy and trying to do bypasses through small incisions between the ribs. This procedure is in its early stages and only a few heart surgeons are doing it. And the next step in bypass surgery, which is still experimental, is where we do bypass with a robot. In these procedures, tiny incisions, about a centimeter in size, are made through the chest and then the robot sews the bypasses. The surgeon sits at a console that controls the robot's arms. I would guess that in five to 10 years this approach will be adopted by more surgeons and will be found to be a very effective way of treating our patients.
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