A heart transplant is an open-heart surgery in which a severely diseased or damaged heart is replaced with a healthy heart from a recently deceased person. It may be a treatment option for heart failure due to conditions such as coronary artery disease, cardiomyopathy, congenital heart disease or valve disease.
About heart transplants
A heart transplant is an open-heart surgery in which a severely diseased or damaged heart is replaced with a healthy heart from a recently deceased person. Heart transplants have been successfully performed since 1967.
Unfortunately, the number of people waiting for a heart transplant is higher than the number of available organs. A patient generally becomes eligible for a heart transplant when diagnosed as having end-stage heart disease, all other medical interventions have failed and the patient is stable enough to sustain a major surgery.
Coronary artery disease and cardiomyopathy are the most common heart conditions that may lead to a heart transplant. Other diseases include congenital heart disease (the most common reason for heart transplant in children), failure of a previous bypass or heart transplant and valvular heart disease. These conditions can lead to heart failure, in which the heart is unable to meet the body's demand for blood.
How is heart transplant performed?
Heart transplants are sometimes performed along with lung transplants for individuals with end-stage lung disease due to conditions including:
- Primary pulmonary hypertension. High blood pressure in the blood vessels of the lungs. This is considered a contraindication for a straight heart transplant, making a lung transplant necessary.
- Eisenmenger syndrome. Any type of congenital heart disease that involves severe pulmonary hypertension. The condition accounts for nearly half of all heart-lung transplants.
- Cystic fibrosis. A genetic disease that causes thick mucus to build up in the lungs.
- Bronchiectasis. Destruction and widening of the lungs' large airways.
Who needs a heart transplant?
Every year in the India, there are about 4,000 people who could benefit from a heart transplant. Unfortunately, there are only about 2,000 donor hearts available. Therefore, there is a careful selection process in place to assure that hearts are distributed fairly and to those who will benefit most from the donor heart. The heart is just a pump, although a complicated pump. Most patients require a transplant because their hearts can no longer pump well enough to supply blood with oxygen and nutrients to the organs of the body. A smaller number of patients have a good pump, but a bad "electrical conduction system" of the heart. This electrical system determines the rate, rhythm and sequence of contraction of the heart muscle. There are all kinds of problems that can occur with the conduction system, including complete interruption of cardiac function causing sudden cardiac death.
While there are many people with "end-stage" heart disease with inadequate function of the heart, not all qualify for a heart transplant. All the other important organs in the body must be in pretty good shape. Transplants cannot be performed in patients with active infection, cancer, or bad diabetes mellitus; patients who smoke or abuse alcohol are also not good candidates. It is not easy to be a transplant recipient. These patients need to change their lifestyle and take numerous medications. Hence, all potential transplants patients must undergo psychological testing to identify social and behavioral factors that could interfere with recovery, compliance with medications, and lifestyle changes required after transplantation.
Moreover, needing a heart and being a suitable candidate are not enough. The potential donor heart must be compatible with the recipient's immune system to decrease the chance of problems with rejection. Finally, this precious resource, the donor organ, must be distributed fairly. is in charge of a system that is in place to assure equitable allocation of organs to individuals who will benefit the most from transplantation.
Before the heart transplant procedure
Patients waiting for a donor heart will generally carry a pager and be "on call." When a suitable donor heart becomes available, the patient will be paged and told to come to the hospital immediately.
If the donor heart is in the same hospital as the recipient, then the surgery will be done as soon as all preparations have been made. If the donor heart is being transported by ambulance or by air, then the surgical team responsible for the transfer will keep the hospital team informed of its progress.
The hospital team will require about 20 minutes to prepare the donor for removal of the heart. Time is critical, because the donor heart can survive for only four to six hours outside the body.
After arriving at the hospital, the patient will be given specific preoperative medications and prepped for surgery. First, the chest area is shaved (if necessary). Next, the surgical team creates a sterile environment by swabbing the patient's chest with an antiseptic solution and covering the area in sterile surgical drapes. An intravenous (IV) line will be started, usually in the forearm or back of the hand.
When the time is right, the patient is given general anesthesia through the IV line. The patient will continue to breathe a mixture of oxygen and anesthetic gas to remain asleep throughout the surgery.
Schematic of a transplanted heart with native lungs and the great vessels. Once the donor heart has passed its inspection, the patient is taken into the operating room and given a general anesthetic. Either anorthotopic or a heterotopic procedure is followed, depending on the condition of the patient and the donor heart.
The orthotropic procedure begins with the surgeons performing a median sternotomy to expose the mediastinum. The pericardium is opened, the great vessels are dissected and the patient is attached to cardiopulmonary bypass. The failing heart is removed by transecting the great vessels and a portion of the left atrium. The pulmonary veins are not transected; rather a circular portion of the left atrium containing the pulmonary veins is left in place. The donor heart is trimmed to fit onto the patient's remaining left atrium and the great vessels are sutured in place. The new heart is restarted, the patient is weaned from cardiopulmonary bypass and the chest cavity is closed.
In the heterotopic procedure, the patient's own heart is not removed before implanting the donor heart. The new heart is positioned so that the chambers and blood vessels of both hearts can be connected to form what is effectively a 'double heart'. The procedure can give the patients original heart a chance to recover, and if the donor's heart happens to fail (e.g. through rejection), it may be removed, allowing the patient's original heart to start working again. Heterotopic procedures are only used in cases where the donor heart is not strong enough to function by itself (due to either the patient's body being considerably larger than the donor's, the donor having a weak heart, or the patient suffering from pulmonary hypertension).
After the heart transplant procedure
Continuous monitoring will follow the surgery. During this critical time, the cardiac surgeon, cardiologist and other members of the hospital staff will watch closely for any signs of heart rejection or infection. These are the two leading causes of death immediately after a heart transplant. Medications that suppress the body's natural immune system will be administered to counter the body's tendency to reject the new heart. These medications have dramatically reduced the number of rejections. Patients are unlikely to be very active in the next couple of days, but should be able to walk around in just three or four days. The total length of a hospital stay after a heart transplant is about 10 days to two weeks. Once patients are discharged from the hospital, the cardiologist and primary physician will provide regular medical support, including biopsies and other diagnostic tests several times a year.
The new heart will beat significantly faster than the original heart and will not respond as promptly to increased physical stress (e.g., when exercising). This is because the new heart lacks the nerve connections that help a normal heart respond to changes in activity.
Many unexpected adjustments may face heart transplant patients. Depression is not uncommon during this time, and the support of families and friends is very important. Most transplant centers have social workers and/or psychiatrists who can provide some assistance for heart transplant patients and their families.
Benefits and risks of heart transplants
Even considering that patients are in a life-threatening situation at the time of transplant, about 87 percent of those who receive heart transplants survive for more than one year, according to the United Network for Organ Sharing (UNOS). Additionally, 73 percent live at least five years after the procedure.
Today's heart transplant recipients live longer after surgery than those who received heart transplants just 10 years ago. Many transplant recipients return to work and many participate in moderately strenuous activities, such as walking, swimming and even running. Studies have shown that exercise is a valuable tool for recovery during the healing period and beyond.
The improved life expectancy of patients after a heart transplant is largely due to immunosuppressive drugs, which reduce the body's tendency to reject the new organ. Rejection is a major risk associated with transplant surgery. When it occurs, the immune system sends out antibodies to destroy the new heart, which is perceived as foreign or "invading" tissues. Left unchecked, this rejection can result in extensive damage to, and imminent failure of, the transplanted heart.
The many possible side effects of immunosuppressants include trembling, elevated cholesterol levels and elevated blood pressure (hypertension). Patients taking some immunupressants are cautioned to avoid grapefruit juice and grapefruit. This combination increases blood levels of the drug and can cause nausea, lightheadedness and abdominal pain.
Certain tests can help predict whether the heart is likely to be rejected. These tests include -
- Biopsies to monitor the body's response to the transplanted heart tissue. This involves using a thin tube to remove a small piece of heart tissue. The tube is inserted through a vein either in the groin or side of the neck. Biopsies are outpatient procedures that can be performed in less than an hour. They are performed often in the first four months after transplantation and less frequently in the months and years after that.
- Blood tests (e.g., an enzyme test). Studies have found that the risk of transplant failure is three times greater among recipients with high levels of troponin I than those with normal levels of this enzyme
Patients can do much to monitor themselves, as some symptoms may signal rejection.
They include -
- Dizziness, nausea or vomiting
- Chest pain
- Shortness of breath
- Flu-like symptoms (e.g., chills, sore throat)
- Fever over 100 degrees F
Rejection, however, is not necessarily an irreversible event. In fact, cardiac transplant patients experience an average of two to three episodes of rejection in the first year after transplantation. Up to 80 percent of patients will experience at least one episode of rejection. It could be that a patient needs different doses or timing of medication. This is why it is recommended that patients immediately contact their transplant center or team should any of the above symptoms occur.
The second risk is that of infection. Patients are urged to immediately report to their physician any of the following signs of infection:
When patients receive a new heart, they also receive new coronary arteries on the surface of that heart. Although these new coronary arteries may have less plaque buildup than their original coronary arteries, heart transplant recipients are more likely to develop coronary artery disease (CAD). This disease is thought to be part of the slow rejection process in the transplanted hearts. About 50 percent of heart transplant patients develop CAD. Therefore, patients must undergo a cardiac catheterization test periodically to check for the disease.
Researchers have been investigating ways to lower the risks of CAD in transplant patients. In one study, 40 heart transplant patients were given daily doses of antioxidant vitamins C and E in addition to cholesterol-lowering statins. Results showed only minimal thickening in artery walls compared to greater thickening among patients taking only cholesterol drugs. Further studies involving a larger number of heart transplant patients will need to demonstrate similar outcomes before this treatment can be offered.
Promising early results have also been seen with sirolimus, an immunosuppressive used since 1999 to help prevent kidney transplant rejection. In limited studies of human patients, sirolimus showed significant ability to slow down coronary artery disease.