What is Bypass Surgery?
Coronary artery bypass graft surgery (CABG, pronounced “cabbage”) is the most commonly performed type of heart surgery. In the year 2003 there were 467,000 bypass surgeries performed in the United States, and 26% of these were performed on women.
During bypass surgery, a healthy artery or vein is removed from another part of your body and used to re-route blood flow around a blocked or narrowed coronary artery. The healthy vein or artery is called a bypass graft. One end is sewn to the aorta (the largest artery that comes out of your heart) and the other end is attached to the coronary artery just below the blockage. A vein in the leg (the saphenous vein) or an artery in the chest (the internal mammary artery) is usually used to create the bypass graft. More rarely, an artery from the arm or the stomach may be used. Removing these healthy vessels is harmless since there are many other arteries and veins that can take over for them.
Heart Before Bypass
Heart After Bypass
Who should have bypass surgery?
Most patients with coronary artery disease do not require surgery. Bypass surgery is usually reserved for women with severe blockages in two or more arteries. Women with narrowings in only one coronary artery are usually treated with balloon angioplasty or stents. If you have other conditions, such as diabetes, bypass surgery may be the best treatment option. You may require one, two, three, or more bypass grafts depending on how many arteries are blocked.
Bypass surgery may be recommended if you have blockages in several arteries of the heart, a severe narrowing in the largest coronary artery (on the left side of the heart), severe chest pain, or blockages that have not responded to other treatments (such as medication or balloon angioplasty). Your doctor will recommend bypass surgery based on your symptoms and the results of diagnostic tests including cardiac catheterization.
Bypass Surgery – Risks
What are the risks associated with bypass surgery?
As with any medical procedure, bypass surgery is associated with certain risks. However, these risks are usually outweighed by the fact that bypass surgery can lengthen life and greatly improve quality of life by alleviating symptoms such as chest pain and shortness of breath. Complications that may occur during or after bypass surgery include bleeding, infection, high blood pressure, abnormal heart rhythms (arrhythmias), and breathing difficulties. These complications are relatively rare, usually not serious, and resolve within a few weeks. However, more serious complications such as heart attack, stroke, or death can occur.
Bypass surgery has become safer as techniques improve. One database of more than 1 million bypass patients found that the death rate fell from 3.9% in 1990 to 3.0% in 1999. This was despite the fact that the average patient undergoing surgery in 1999 was older and sicker than the average patient in 1990.
Women with certain conditions such as high blood pressure, diabetes, obesity, or peripheral vascular disease (blockages in arteries outside the heart, usually the legs) are at increased risk for complications after bypass surgery. If you have already had bypass surgery, you are also at higher risk, and the risk of surgery is generally higher for women over 70 years of age.
Are women more likely to die after bypass surgery?
Women are more likely to die in the hospital than men after bypass surgery. In 1999, the overall death rate for bypass surgery was about 3%. Between 1% and 8% of women who undergo bypass surgery die within 30 days, compared with 1% to 3% of men. This is largely because, compared with men, women who undergo bypass are older and are more likely to have additional health problems including heart failure, diabetes, high blood pressure, and high cholesterol. In addition, women have smaller blood vessels than men, which makes surgery more difficult and puts women at a higher risk of complications after surgery. Being female itself does not necessarily mean you will have a worse outcome, but if you are petite or have additional risk factors, you should consider yourself at higher-than-average risk.
Women and men fare equally well in the long-term after surgery; approximately 13% of patients die within 5 years. One large trial even found that women were less likely than men to have died 5 years after surgery. Some studies find that women have a slightly higher death rate as much as 18 years after bypass surgery, but any difference seen was small and probably due to their older age.
Heart disease is relatively rare in women younger than 50 years. However, when younger women develop heart disease, they are 2 to 3 times more likely to die than men of the same age. Younger women who require bypass surgery have higher death rates than young men, even after their smaller body size and other health conditions are taken into account. The reason for the high mortality rate in young women is not clear, and is also seen in younger women undergoing balloonangioplasty and stenting.
Do women have to stay in the hospital longer after surgery?
After bypass surgery, women generally have to stay in the hospital longer than men. They are also more likely to require blood transfusions during and after surgery than men, and when transfusions are given women require more units of blood. In one study, 65% of women and only 19% of men required blood transfusions. This difference is seen even when risk factors such as older age and other health conditions are taken into account. Most other complications (such as heart attack, difficulty breathing, wound infection, and irregular heart rhythms) occur as rarely in women as in men.
Do women recover more slowly than men after surgery?
Recovery after bypass surgery typically takes 4 to 8 weeks. Depression is common in the weeks immediately following surgery, during the most intense phase of recovery. However, these symptoms usually resolve as the patient begins to resume normal activities.
Women have a slower physical recovery, experience more physical symptoms, and have more severe adverse mood effects after surgery than men. Starting at about 6 weeks after surgery, both women and men are less anxious and less depressed than they were before surgery. One study found that even though both women and men improve after surgery, after 1 year women have more depressive symptoms and score lower on tests of physical and social functioning than men. However, there was no gender difference in anxiety, life satisfaction, or the time it took to return to work. Another study reported that women were twice as likely to be readmitted to the hospital (22% of women vs. 13% of men) and more often reported chest pain, constipation, and nausea or lack of appetite.
Why do women recover more slowly after bypass surgery?
This may be related to the different social roles of women and men. Traditionally, women have more responsibilities in caring for the home and family than men, and may therefore experience a greater disruption when they are unable to perform these roles while recovering from surgery. Women undergoing bypass surgery are more likely to be unmarried or widowed and have less social support than men, which may contribute to a more difficult recovery. Despite having a harder recovery than men, women who have bypass surgery experience improved quality of life, fewer symptoms, and feel better physically and emotionally after surgery.
What neurological complications can occur?
As the population undergoing bypass surgery ages, the risk of neurological complications related to the heart-lung machine and stopping the heart increases. In a 1996 study, 3% of patients experienced serious neurological events within a week of surgery, including stroke or coma. In a 2001 study, 53% of patients had a decline in intellectual function at discharge from the hospital, and 42% of patients experienced such mental decline at 5 years after surgery. Patients who experience these problems have a higher risk of death and worse long-term function than those who do not. Several studies have found that women are at a greater risk for adverse neurological and cognitive outcomes after surgery than men. Women undergoing bypass are more likely than men to have other risk factors for stroke such as high blood pressure, diabetes, and being older than 75 years. Surgery without the use of the heart-lung machine (performed on a beating heart) may reduce these complications, and therefore be of particular benefit to women.
Bypass Surgery – Emergency Bypass
Emergency Bypass Surgery?
In most cases, you are told in advance that you need to have bypass surgery and the surgery is scheduled ahead of time. However, sometimes emergency bypass surgery is required during a heart attack, for example, or if a procedure such as balloon angioplasty goes wrong and bypass is required to correct the problem.
Studies suggest that women are more likely than men to undergo emergency bypass. This may be because women with heart disease often present with different symptoms than men, which may make diagnosis more difficult. There is also research showing that women consider themselves less likely than men to have a heart attack, and therefore may delay seeking treatment. When bypass is performed in emergency circumstances, it is a riskier procedure than if the surgery is planned in advance.
Sometimes balloon angioplasty or stenting fails and the patient has to undergo emergency bypass surgery. This is referred to as rescue bypass. Today, this occurs rarely; its use decreased from 1 out of 70 patients in 1992 to 1 out of 700 in the year 2000. Women are more likely than men to require rescue bypass and the procedure is associated with higher rates of death and complications than elective bypass surgery. Exactly why women more often require rescue bypass is not clear, although it may be because their smaller blood vessels make them more likely to experience complications during balloon angioplasty.
Bypass Surgery – Comparison with Other Treatments
Bypass vs Medication Alone
Medication alone is most often used to treat low-risk patients who have heart disease that is unlikely to cause serious damage. In addition to recommending lifestyle modification to lower your heart disease risk, your doctor will give you medications to slow the progression of coronary artery disease and relieve symptoms like chest pain and shortness of breath.
Compared with taking medication alone, bypass surgery improves long-term outcomes in high-risk patients, especially patients with multivessel disease. If only one vessel is narrowed or blocked, medical treatment and bypass surgery produce similar results. In the case of low-risk patients, bypass surgery doesn’t save more lives than medical therapy. Therefore, the procedure is aimed at improving physical function and providing symptom relief.
In some cases it may be too risky for you to undergo bypass surgery or angioplasty. For example if you have a severe medical conditions such as chronic obstructive pulmonary disease or heart failure, or if your heart disease is too diffuse and extensive. In these patients, medical therapy may be the only treatment option.
Bypass vs. Angioplasty and Stenting
Angioplasty with or without stent placement is a procedure in which a catheter is fed through an artery in the groin to the heart, and a balloon is used to clear the blocked arteries. A stent (a tiny wire mesh tube) may be left in place to prop open the artery. These treatments have the advantage of being less invasive than surgery: your chest cavity is not cut open, the heart beats normally during the procedure, and there is only mild anesthesia. The procedure usually takes less than 2 hours, and patients are discharged from the hospital in 1 to 2 days, compared with 7 to 10 days for bypass surgery. Typically this approach is used in patients with a single blocked artery, although recently the procedure’s use has been expanded to some patients who have blockages in more than one coronary artery.
The decision to undergo bypass or angioplasty is based on both the physician’s evaluation of your disease and your personal preference. When an artery is totally blocked (known as a total occlusion), bypass may be your only option. Bypass surgery is generally preferred if you have blockages in 2 or more arteries, blockage in the left main coronary artery, or if angioplasty has failed to provide adequate relief from symptoms. People with diabetes fare better with bypass surgery than angioplasty. When considering which option is best, the advantages and disadvantages of each procedure must be taken into account. Angioplasty is much less invasive and you can leave the hospital the following day. However, the artery is more likely to become blocked again after angioplasty than after bypass, which means you may need another angioplasty in the near future. Bypass grafts generally last 10 to 15 years and provide better relief from angina, but these benefits must be weighed against the fact that it’s a more serious operation with a long recovery period.
Bypass Surgery – Other Types of Bypass Surgery
Are there other types of bypass surgery?
Standard bypass surgery involves stopping the heart for 30-90 minutes while the functions of the lungs and heart are performed by a heart-lung machine. The heart is accessed by splitting the breastbone (sternum) and opening the chest cavity to fully expose the heart. For some patients, less invasive forms of bypass surgery may be performed to avoid some of the complications associated with traditional bypass surgery.
What is off-pump bypass surgery?
Beating heart, also known as off-pump, bypass surgery is performed without stopping the heart, making the heart-lung machine unnecessary. The parts of the heart muscle where the healthy vein or artery is sewn are held motionless by stabilizing devices, allowing the heart to continue to pump blood during the surgery. The off-pump approach is an important advance because use of the heart-lung machine increases the risk of complications such as stroke, heart attack, and kidney damage, and increases the need for blood transfusion. In 2002, 22% of bypass surgeries were performed using beating heart techniques. Off-pump surgery may also reduce the risk of death following surgery; a study of nearly 17,000 women found that those who underwent off-pump surgery had a 42% lower risk of death compared with those who had standard bypass surgery. In addition, off-pump surgery helps reduce the time spent in the hospital. This is especially important for women, who tend to require longer hospital stays than men after traditional bypass. Some studies also suggest that women who undergo off-pump surgery are less likely to experience mental confusion, memory loss, and stroke.
What is MIDCAB?
Minimally invasive direct coronary artery bypass surgery (MIDCAB) is another method to reduce the trauma associated with bypass surgery. In MIDCAB, surgeons access the heart through small incisions between or under the ribs. This type of surgery is also performed without stopping the heart. Smaller incisions mean that patients can recover more quickly after surgery. However, not all parts of the heart can be accessed using these small incisions, so patients who have many blockages or blockages on hard-to-reach areas of the heart may not be eligible for this type of surgery.
What is hybrid surgery?
Blockages in certain arteries of the heart, especially the large artery on the left side of the heart, are best treated with bypass surgery to ensure good long-term blood flow. However, in other areas of the heart, angioplasty or stenting may work as well as bypass. To provide the fastest recovery while ensuring the best results for the patient, a new technique called hybrid revascularization is being developed that combines bypass surgery with angioplasty. In hybrid surgery, a bypass graft (a vessel from another part of your body) is used to re-route blood around the blockage in the largest artery, and the other blockages are treated with angioplasty or stents. Although this procedure is still considered experimental, preliminary studies suggest that it may provide the same results as bypass surgery while reducing recovery time and postoperative pain.
Bypass Surgery – Removing the Graft Vessel
Endoscopic Vein Harvesting
Endoscopic vein harvesting (EVH) is a minimally invasive procedure to remove the saphenous vein(which is used as a bypass graft) from the leg.
Saphenous Vein Removal
Normally, the surgeon makes a long incision from the ankle to the groin to remove the vein. However, endoscopic vein harvesting allows the vein to be removed with only 1 to 3 small, 1-inch incisions, resulting in less muscle and tissue damage than the standard procedure. This reduces the risk of complications of the leg wound, the need for blood transfusions during surgery, postoperative pain, and results in less scarring and a faster recovery.
Patients who have diabetes or peripheral vascular disease have a higher-than-average risk of leg wound complications, so these patients may particularly benefit from EVH. In most cases, this method can be used successfully, but in some patients the surgeon may decide that the traditional vein harvesting technique is more appropriate.
Does the vessel used to create the bypass graft make a difference?
The two vessels that are most commonly used to construct the bypass graft are the internal mammary artery (IMA) from inside the chest wall, and the saphenous vein (SVG) from the leg. Which one of these grafts is used in a particular patient depends on several factors, and affects the long-term outcome of the surgery. In the past, the saphenous vein was most commonly used, but it was later discovered that IMA grafts stay open longer, improve survival, and reduce the likelihood of future problems such as chest pain and heart attack. Because you have only two internal mammary arteries, if you have more than two blockages, both the IMA and SVG will be used. The SVG may also be used if the surgeon thinks your IMA is unsuitable for use as a graft; this could be because the IMA is blocked, too small to use, or is so delicate that removing it from the chest wall would damage the vessel.
Is an internal mammary artery (IMA) graft better than a saphenous vein graft (SVG)?
Both women and men have improved survival when at least one IMA graft is used, compared to patients who receive only SVGs. This is true in patients who have one, two, or three coronary arteries bypassed. Women who receive IMA grafts also spend on average 1 day less in the hospital than women who receive only SVGs. Although both women and men do better after surgery when they receive IMA grafts, in women the grafts are more likely to become blocked because women in general have smaller arteries than men.
Are women less likely to receive IMA grafts?
Despite the fact that both women and men benefit from the use of IMA grafts, women who undergo bypass surgery are less likely to receive an IMA graft than men. In one large trial, 85% of men and only 72% of women received them. This difference could not be explained by factors such as age or other health problems.
Use of IMA grafts also varies greatly by hospital: one study reported that in some hospitals, only 54% of women received grafts, and in others 93% did. In some patients, the grafts may not be suitable for use in bypass surgery, but in most women the IMA is the graft vessel of choice.
Bypass Surgery – Choosing a Hospital & Doctor
Choosing a Hospital & Surgeon
The Joint Commission on Accreditation of Healthcare Organizations (JCAHO) surveys hospitals and other care facilities to determine whether they meet the quality standards for accreditation. You can look up a hospital’s accreditation status at http://www.qualitycheck.org/.
An important aspect of choosing a hospital and doctor for elective CABG is how often your particular procedure is done. A recent study found that although hospitals that perform a certain procedure more often have better outcomes, there is a wide range of variability. If possible, you should try to find out not just the number, but also the outcome of bypass surgeries performed at the hospital you are considering. Even more important than the number of bypass surgeries the hospital performs is how many your surgeon performed. In general, the more often your surgeon performs your specific procedure, the lower your risk. You should look for a hospital that performs at least 500 bypass surgeries per year, and a doctor who performs at least 100.
You should talk to the doctor who referred you for bypass surgery about your options in choosing a surgeon and hospital. Choice of hospital is greatly influenced by your choice of physician, as most doctors are affiliated with one or two hospitals to which they typically admit patients. Also be sure to check with your health plan about which hospitals you can go to for care.
Bypass Surgery – The Bypass Procedure
How do I prepare for bypass surgery?
In the weeks before surgery, you will be advised to stop smoking if you smoke. Tell your healthcare provider all the medications you are currently taking. If you take an anticoagulant, such as warfarin(Coumadin), aspirin, or clopidogrel (Plavix), you may be asked to stop or to reduce your dosage before the procedure. If you have diabetes, you should discuss your medications with your doctor for the day of surgery.
A few days before surgery, you will undergo a series of tests including an X-ray and an ECG, and your urine will be tested. You are not allowed to eat or drink after midnight the night before surgery.
What happens during the procedure?
The place where the healthy vein will be removed will be shaved if necessary and an antibacterial solution applied to both it and the chest. You will be given a sedative through an intravenous (IV) line. You may feel the needle prick when the IV line is inserted into your arm.
Throughout the procedure, you will be under general anesthesia; a breathing tube and machine will ensure you are breathing, and medicine in your IV will make sure you are asleep for the entire procedure. It will be constantly monitored by your anesthesiologist. A small catheter will monitor your heart function and pressure in the heart and lungs. A urinary catheter is also inserted in your bladder.
The blood vessels that are being used to bypass the blocked artery are first removed from their original location. If the saphenous vein in the leg is used, an incision is made from the ankle to the groin. If an artery in the chest is used, it can be accessed through the main bypass incision without making a separate incision. The surgeon makes an 11- to 12-inch incision in your chest and opens the breastbone to access your heart.
In traditional bypass surgery, your heart will be stopped for about 30 to 90 minutes and a heart-lung machine takes over the functions of the heart. Bypass surgery may also be performed off-pump where your heart remains beating (see Off-Pump Bypass Surgery).
The healthy blood vessel from the leg or chest is sewn into place to provide a detour around the blockage. It is referred to as the “graft.” Once the blood is successfully flowing around the blockage, your heart is restarted and you will be taken off the heart lung machine. The breastbone is closed by wire, and the chest incision is closed with staples or stitches.
Bypass surgery can take from 3 to 6 hours, depending on how many blockages you have, and therefore how many arteries are being bypassed.
What happens after bypass surgery?
After surgery, you will be moved to a bed in the cardiac surgical intensive care unit. Your heart rate and blood pressure are continuously monitored for 12 to 24 hours; family can visit periodically. You will continue to get medications through an IV line.
Once you are awake and able to breathe on your own, the breathing tube will be removed. Your throat will feel dry and sore. You may feel groggy and disoriented, and the incision sites may hurt. Painkillers are given as necessary. On the first day, you will be fed through an IV line, but by the second and third days, you will be encouraged to sit up, walk a bit, and eat regular food. You may stay in the hospital for 4 days to a week or more; during this time, tests will be conducted to assess and monitor your condition.
What does the MIDCAB procedure entail?
There are a few differences between the traditional bypass surgery procedure and the MIDCAB procedure. One is that an incision about 4 to 6 inches long will be made on the left side of the chest; through this incision, your surgeon will retrieve the healthy vessel to be used for the graft, though sometimes the saphenous vein from the leg will be used. As in traditional bypass surgery, if the saphenous vein in the leg is used, an incision is made from the knee or ankle to the groin.
Instead of the breastbone being opened, various types of incisions are then made between or under the ribs so that the surgeon can reach different areas of the heart through these spaces.
MIDCAB can be performed on-pump, meaning with the use of a heart-lung machine, or off-pump. In on-pump MIDCAB, the heart will be stopped for about 30 to 90 minutes while a heart-lung machine takes over the functions of the heart. In off-pump surgery, special stabilizers, which are a bit like mini suction devices, are used so that the heart can still beat while the surgeon sews on the healthy blood vessel. The stabilizers restrict the heart’s motion and create a stable and nearly still work area for the surgeon.
Once blood is flowing freely to the heart muscle, the chest incisions are stitched.
MIDCAB usually lasts an average of 2 hours.
You will stay in the ICU for about 24 hours after the procedure where normal breathing, circulation, and movement will be restored. Pain medication may be given, and if you feel up to eating, you are allowed to do so. The average hospital stay after MIDCAB is about 3 days.
What does the OPCAB procedure entail?
Except for the use of the heart-lung machine, the procedure is the same as that of traditional bypass surgery. Instead of the heart-lung machine, heart stabilizers and positioners, which are a bit like mini suction devices, are attached to the heart. The heart continues to beat, but the stabilizers keep the target area of the heart nearly motionless while the surgeon operates.
The entire procedure will take 2 to 5 hours, depending on how many arteries are blocked and how many grafts are needed.