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:

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:

• Fever
• Redness
• Swelling
• Drainage

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.