CHD is a disease in which a waxy substance called plaque (plak) builds up inside the coronary arteries. These arteries supply oxygen-rich blood to your heart.
Over time, plaque can harden or rupture (break open). Hardened plaque narrows the coronary arteries and reduces the flow of oxygen-rich blood to the heart. This can cause chest pain or discomfort called angina (an-JI-nuh or AN-juh-nuh).
If the plaque ruptures, a blood clot can form on its surface. A large blood clot can mostly or completely block blood flow through a coronary artery. This is the most common cause of a heart attack. Over time, ruptured plaque also hardens and narrows the coronary arteries.
During CABG, a healthy artery or vein from the body is connected, or grafted, to the blocked coronary artery. The grafted artery or vein bypasses (that is, goes around) the blocked portion of the coronary artery. This creates a new path for oxygen-rich blood to flow to the heart muscle.
Surgeons can bypass multiple blocked coronary arteries during one surgery.
CABG isn't the only treatment for CHD. A nonsurgical procedure that opens blocked or narrow coronary arteries is percutaneous (per-ku-TA-ne-us) coronary intervention (PCI), sometimes referred to angioplasty (AN-jee-oh-plas-tee).
During PCI, a thin, flexible tube with a balloon at its tip is threaded through a blood vessel to the narrow or blocked coronary artery. Once in place, the balloon is inflated to push the plaque against the artery wall. This restores blood flow through the artery.
During PCI, a stent might be placed in the coronary artery to help keep it open. A stent is a small mesh tube that supports the inner artery wall.
If both CABG and PCI are options, your doctor can help you decide which treatment is right for you.
Transmyocardial (tranz-mi-o-KAR-de-al) laser revascularization (re-VAS-kyu-lar-ih-ZA-shun), or TMR, is surgery used to treat angina.
TMR is most often used when no other treatments work. For example, if you've already had one CABG procedure and can't have another one, TMR might be an option. For some people, TMR is combined with CABG.
If TMR is done alone, the procedure may be performed through a small opening in the chest.
During TMR, a surgeon uses lasers to make small channels through the heart muscle and into the heart's lower left chamber (the left ventricle).
It isn't fully known how TMR relieves angina. The surgery may help the heart grow tiny new blood vessels. Oxygen-rich blood may flow through these vessels into the heart muscle, which could relieve angina.
For the heart to work well, blood must flow in only one direction. The heart's valves make this possible. Healthy valves open and close in a precise way as the heart pumps blood.
Each valve has a set of flaps called leaflets. The leaflets open to allow blood to pass from one heart chamber into another or into the arteries. Then the leaflets close tightly to stop blood from flowing backward.
Heart surgery is used to fix leaflets that don't open as wide as they should. This can happen if they become thick or stiff or fuse together. As a result, not enough blood flows through the valve.
Heart surgery also is used to fix leaflets that don't close tightly. This problem can cause blood to leak back into the heart chambers, rather than only moving forward into the arteries as it should.
To fix these problems, surgeons either repair the valve or replace it with a man-made or biological valve. Biological valves are made from pig, cow, or human heart tissue and may have man-made parts as well.
To repair a mitral (MI-trul) or pulmonary (PULL-mun-ary) valve that's too narrow, a cardiologist (heart specialist) will insert a catheter (a thin, flexible tube) through a large blood vessel and guide it to the heart.
The cardiologist will place the end of the catheter inside the narrow valve. He or she will inflate and deflate a small balloon at the tip of the catheter. This widens the valve, allowing more blood to flow through it. This approach is less invasive than open-heart surgery.
Researchers also are testing new ways to use catheters in other types of valve surgeries. For example, catheters might be used to place clips on the mitral valve leaflets to hold them in place.
Catheters also might be used to replace faulty aortic valves. For this procedure, the catheter usually is inserted into an artery in the groin (upper thigh) and threaded to the heart.
In some cases, surgeons might make a small cut in the chest and left ventricle (the lower left heart chamber). They will thread the catheter into the heart through the small opening.
The catheter has a deflated balloon at its tip with a folded replacement valve around it. The balloon is used to expand the new valve so it fits securely within the old valve.
Currently, surgery to replace the valve is the traditional treatment for reasonably healthy people. However, catheter procedures might be a safer option for patients who have conditions that make open-heart surgery very risky.
An arrhythmia (ah-RITH-me-ah) is a problem with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.
Many arrhythmias are harmless, but some can be serious or even life threatening. If the heart rate is abnormal, the heart may not be able to pump enough blood to the body. Lack of blood flow can damage the brain, heart, and other organs.
Medicine usually is the first line of treatment for arrhythmias. If medicine doesn't work well, your doctor may recommend surgery. For example, surgery may be used to implant a pacemaker or an implantable cardioverter defibrillator (ICD).
A pacemaker is a small device that's placed under the skin of your chest or abdomen. Wires connect the pacemaker to your heart chambers. The device uses low-energy electrical pulses to control your heart rhythm. Most pacemakers have a sensor that starts the device only if your heart rhythm is abnormal.
An ICD is another small device that's placed under the skin of your chest or abdomen. This device also is connected to your heart with wires. An ICD checks your heartbeat for dangerous arrhythmias. If the device senses one, it sends an electric shock to your heart to restore a normal heart rhythm.
Another arrhythmia treatment is called maze surgery. For this surgery, the surgeon makes new paths for the heart's electrical signals to travel through. This type of surgery is used to treat atrial fibrillation, the most common type of serious arrhythmia.
Simpler, less invasive procedures also are used to treat atrial fibrillation. These procedures use high heat or intense cold to prevent abnormal electrical signals from moving through the heart.
An aneurysm (AN-u-rism) is a balloon-like bulge in the wall of an artery or the heart muscle. This bulge can occur if the artery wall weakens. Pressure from blood moving through the artery or heart causes the weak area to bulge.
Over time, an aneurysm can grow and burst, causing dangerous, often fatal bleeding inside the body. Aneurysms also can develop a split in one or more layers of the artery wall. The split causes bleeding into and along the layers of the artery wall.
Aneurysms in the heart most often occur in the heart's lower left chamber (the left ventricle). Repairing an aneurysm involves surgery to replace the weak section of the artery or heart wall with a patch or graft.
A heart transplant is surgery to remove a person's diseased heart and replace it with a healthy heart from a deceased donor. Most heart transplants are done on patients who have end-stage heart failure.
Heart failure is a condition in which the heart is damaged or weak. As a result, it can't pump enough blood to meet the body's needs. "End-stage" means the condition is so severe that all treatments, other than heart transplant, have failed.
Patients on the waiting list for a donor heart receive ongoing treatment for heart failure and other medical conditions. Ventricular assist devices (VADs) or total artificial hearts (TAHs) might be used to treat these patients.
A VAD is a mechanical pump that is used to support heart function and blood flow in people who have weak hearts.
Your doctor may recommend a VAD if you have heart failure that isn't responding to treatment or if you're waiting for a heart transplant. You can use a VAD for a short time or for months or years, depending on your situation.
A TAH is a device that replaces the two lower chambers of the heart (the ventricles). You may benefit from a TAH if both of your ventricles don't work well due to end-stage heart failure.
Placing either device requires open-heart surgery.
Surgeons can use different approaches to operate on the heart, including open-heart surgery, off-pump heart surgery, and minimally invasive heart surgery.
The surgical approach will depend on the patient's heart problem, general health, and other factors.
Open-heart surgery is any kind of surgery in which a surgeon makes a large incision (cut) in the chest to open the rib cage and operate on the heart. "Open" refers to the chest, not the heart. Depending on the type of surgery, the surgeon also may open the heart.
Open-heart surgery is used to do CABG, repair or replace heart valves, treat atrial fibrillation, do heart transplants, and place VADs and TAHs.
Surgeons also use off-pump, or beating heart, surgery to do CABG. This approach is like traditional open-heart surgery because the chest bone is opened to access the heart. However, the heart isn't stopped, and a heart-lung bypass machine isn't used.
Off-pump heart surgery isn't right for all patients. Work with your doctor to decide whether this type of surgery is an option for you. Your doctor will carefully consider your heart problem, age, overall health, and other factors that may affect the surgery.
For minimally invasive heart surgery, a surgeon makes small incisions (cuts) in the side of the chest between the ribs. This type of surgery may or may not use a heart-lung bypass machine.
Minimally invasive heart surgery is used to do some bypass and maze surgeries. It's also used to repair or replace heart valves, insert pacemakers or ICDs, or take a vein or artery from the body to use as a bypass graft for CABG.
One type of minimally invasive heart surgery that is becoming more common is robotic-assisted surgery. For this surgery, a surgeon uses a computer to control surgical tools on thin robotic arms.
The tools are inserted through small incisions in the chest. This allows the surgeon to do complex and highly precise surgery. The surgeon always is in total control of the robotic arms; they don't move on their own.
Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Heart Surgery, visit www.clinicaltrials.gov.
November 20, 2013
Gary H. Gibbons
New NHLBI Program Trains Scientists to Bring More Science Out of the Lab and into the Patient Care Marketplace
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.