Heart Transplantation Health Article

Definition

Heart transplantation, also called cardiac transplantation, is the replacement of a patient's diseased or injured heart with a healthy donor heart.

Purpose

Heart transplantation is performed on patients with end-stage heart failure or some other life-threatening heart disease. Before a doctor recommends heart transplantation for a patient, all other possible treatments for his or her disease must have been attempted. The purpose of heart transplantation is to extend and improve the life of a person who would otherwise die from heart failure. Most patients who have received a new heart were so sick before transplantation that they could not live a normal life. Replacing a patient's diseased heart with a healthy, functioning donor heart often allows the recipient to return to normal daily activities.

Demographics

Patients are not limited by age, sex, race, or ethnicity. In 1999, the primary diagnoses of adult patients receiving cardiac transplantation include coronary artery disease, cardiomyopathy, congenital diseases, and re-transplantation associated with organ rejection. Characteristics of patient presentation include cardiomegaly, severe dyspnea, and peripheral edema.

Adults with end-stage heart failure account for 90% of heart transplant recipients. Pediatric patients make up the remaining 10%, with 50% of those going to patients under the age of five. In the United States, patients that receive heart transplant are 73% male, 77% are white, 19% are ages 35–49, and 51% are ages 50–64.

Because healthy donor hearts are in short supply, strict rules dictate criteria for heart transplant recipients. Patients who may be too sick to survive the surgery or the side effects of immunosuppressive therapy would not be good transplant candidates.

These conditions are contraindications for heart transplantation:

• active infection
• pulmonary hypertension
• chronic lung disease with loss of more than 40% of lung function
• untreatable liver or kidney disease
• diabetes that has caused serious damage to vital organs
• disease of the blood vessels in the brain, such as a stroke
• serious disease of the arteries
• mental illness or any condition that would make a patient unable to take the necessary medicines on schedule
• continuing alcohol or drug abuse

Description

Patients with end-stage heart disease unresponsive to medical treatment may be considered for heart transplantation. Potential candidates must have a complete medical examination before they can be put on the transplant waiting list. Many types of tests are done, including blood tests, x rays, and tests of heart, lung, and other organ function. The results of these tests indicate to doctors how serious the heart disease is and whether or not a patient is healthy enough to survive the transplant surgery.

Organ waiting list

A person approved for heart transplantation is placed on the heart transplant waiting list of a heart transplant center. All patients on a waiting list are registered with the United Network for Organ Sharing (UNOS). UNOS has organ transplant specialists who run a national computer network that connects all the transplant centers and organ-donation organizations.

When a donor heart becomes available, information about the donor heart is entered into the UNOS computer and compared to information from patients on the waiting list. The computer program produces a list of patients ranked according to blood type, size of the heart, and how urgently they need a heart. Because the heart must be transplanted as quickly as possible, a list of local patients is checked first for a good match. After that, a regional list and then a national list are checked. The patient's transplant team of heart and transplant specialists makes the final decision as to whether a donor heart is suitable for the patient.

The transplant procedure

When a heart becomes available and is approved for a patient, it is packed in a sterile cold solution and rushed to the hospital where the recipient is waiting. The recipient will be contacted to return to the hospital if chronic care occurs outside of the hospital.

A description of the procedure follows:

• General anesthesia is provided by an anesthesiologist experienced with cardiac patients.
• Intravenous antibiotics will prevent bacterial wound infections.
• The patient is put on a heart/lung machine, which performs the functions of the heart and lungs by pumping the blood to the rest of the body during surgery. This procedure is called cardiopulmonary bypass.
• Once the donor heart has arrived to the operating room, the patient's diseased heart is removed.

• The donor heart is attached to the patient's blood vessels, including the atrium(s), pulmonary artery, and aorta.
• After the blood vessels are connected, the new heart is perfused with the patient's blood and begins beating. If the heart does not begin to beat immediately, the surgeon may use defibrillation to gain a productive rhythm.
• The patient is taken off the heart-lung machine.
• The new heart is stimulated to maintain a regular beat with medications and/or a pacemaker for two to five days after surgery, until the new heart functions normally on its own.

Heart transplant recipients are given immunosuppressive drugs to prevent the body from rejecting the new heart. These drugs are usually started before or during the heart transplant surgery. Immunosuppressive drugs keep the body's immune system from recognizing and attacking the new heart as foreign tissue. Normally, immune system cells recognize and attack foreign or abnormal cells such as bacteria, cancer cells, and cells from a transplanted organ. The drugs suppress the immune cells and allow the new heart to function properly. However, they can also allow infections and other adverse effects to occur to the patient.

Because the chance of rejection is highest during the first few months after the transplantation, recipients are usually given a combination of three or four immunosuppressive drugs in high doses during this time. Afterwards, they must take maintenance doses of immunosuppressive drugs for the rest of their lives.