Heart transplantation is the removal of a healthy heart from a recently deceased person and then its transfer into the body of a person who has a severe heart disorder that can no longer be treated effectively with drugs or other types of surgery.
(See also Overview of Transplantation.)
Heart transplantation is reserved for people who have one of the following disorders if the disorder cannot be treated effectively with drugs or other forms of surgery:
Severe heart failure
Irregular heart rhythms (arrhythmias)
Other severe heart disorders
Heart transplantation alone cannot be done if people have severe pulmonary hypertension (high blood pressure in the arteries of the lungs) that has not responded to drug treatment. These people would likely be candidates for combined heart-lung transplantation.
In some medical centers, heart machines can keep people alive for weeks or months until a compatible heart can be found. Also, implantable artificial hearts (called ventricular assist devices or VADs) that pump blood to the rest of the body are being used to tide people over until a heart is available or are used in people who are not candidates for heart transplantation. These devices are increasingly being used as a long-term replacement. As a result, the need for heart transplantation has somewhat decreased.
About 95% of people who have had a heart transplant are substantially better able to exercise and do daily activities than they were before the transplantation. Over 70% return to full-time employment. About 85 to 90% of heart transplant recipients survive for at least 1 year.
Wafadhili
All donated hearts come from someone who has recently died. Donors must be under 60 years old and have not had coronary artery disease or other heart disorders. Also, the blood type and heart size of the donor and recipient must match.
Donated hearts must be transplanted within 4 to 6 hours.
Taratibu ya Upandikizaji wa Moyo
Both donors and recipients undergo pretransplantation screening. This screening is done to be sure that the organ is healthy enough for transplantation and the recipient does not have any medical conditions that would prohibit transplantation.
Through an incision in the chest, most of the damaged heart is removed, but the back wall of one of the upper heart chambers (atria) is left. The donated heart is then attached to what remains of the recipient’s heart.
Heart transplantation takes about 3 to 5 hours. The hospital stay after this operation is usually 7 to 14 days.
Drugs to inhibit the immune system (immunosuppressants), including corticosteroids, are started the day of transplantation. These drugs can help reduce the risk that the recipient will reject the transplanted heart.
Matatizo ya Upandikizaji wa Moyo
Transplantation can cause various complications.
Most deaths that occur after heart transplantation are due to rejection soon after the operation or to infections.
Kukataliwa
Even if tissue types are closely matched, transplanted organs, unlike transfused blood, are usually rejected unless measures are taken to prevent rejection. Rejection results from an attack by the recipient's immune system on the transplanted organ, which the immune system recognizes as foreign material. Rejection can be mild and easily controlled or severe, resulting in destruction of the transplanted organ.
Immunosuppressants are drugs that block or slow the immune system and must be taken to prevent rejection of a transplanted heart.
Rejection, if it occurs, may cause weakness and a rapid or other abnormal heart rhythm. When rejection occurs, the transplanted heart may not function well, causing low blood pressure and accumulation of fluid in the legs and sometimes the abdomen, resulting in swelling—a condition called edema. Fluid may also accumulate in the lungs, causing difficulty breathing. However, rejection is often mild. In such cases, no symptoms may occur, but electrocardiography (ECG) may detect changes in the heart’s electrical activity.
If doctors suspect rejection, they usually do a biopsy. A catheter is inserted through an incision in the neck into a vein and is threaded to the heart. A device at the end of the catheter is used to remove a small piece of heart tissue, which is examined under a microscope. Because effects of rejection can be serious, doctors also routinely do a biopsy once a year to look for rejection that has not yet caused symptoms.
Atherosklerosisi inayohusiana na upandikizaji
About one fourth of people who have a heart transplant develop atherosclerosis in the coronary arteries.
Treatment includes drugs to lower lipid (fat) levels in the blood and diltiazem (a drug that can help prevent blood vessels from narrowing).
