A human heart transplant is a surgery that involves the replacement of a severely damaged heart with a healthy donor heart. Heart transplants are reserved as a life-saving measure, used only when all other treatments or surgeries have failed. According to the National Heart, Lung and Blood Institute, survival rates for heart transplants have improved, with 72 percent of recipients surviving for five years or more; however, there remain significant risks associated with the surgery.
Primary Graft Dysfunction and Rejection
According to the National Heart, Lung and Blood Institute (NHLBI), primary graft dysfunction--the failure of the new donor heart to function--is the most frequent cause of death during the first 30 days after a transplant. While medicine, including nitric oxide and intravenous nitrates, may be used to treat this condition, narrowed blood vessels in the transplant recipient's lungs and shock or trauma in the donor heart are common barriers to successful functioning after transplantation.
The newly implanted heart may also fail to function over time if the same problems that damaged the transplant recipient's old heart reappear. For example, according to the University of Southern California (USC) Keck School of Medicine, certain forms of heart disease may reappear in the new heart, leading to the risk of having to have another transplant (called a retransplant).
Rejection of the new heart is a risk that never goes away because of the body's natural tendency to attack any object or substance it does not recognize as its own. The risk of rejection is highest in the first six weeks after surgery, and risk decreases over time. Approximately 25 percent of heart transplant recipients experience at least one sign of rejection during the first year, according to the NHLBI.
Infection and Cancer
Medications that are administered to reduce the risk of rejection of the new heart also suppress the body's immune system, increasing the risk of infection, according to the USC Keck School of Medicine. Fever, general malaise or spreading pains throughout the body may occur as a result of infection. The NHLBI reports that infection is a common cause of hospital admission and a leading cause of death during the first year after transplant.
Suppression of the immune system also puts heart transplant patients at increased risk of developing certain cancers, particularly cancers of the skin, lips and lymph system. Malignancies account for 25 percent of late deaths (those occurring three years post-transplant), according to the NHLBI.
Risk Due to Medications
Medicines used to treat infection and other heart-transplant complications can damage the kidneys, leading to fluid retention and swelling of the extremities. Anti-rejection medications can also provoke the onset of diabetes, even among individuals with no history of problems processing blood glucose. These medications can also induce blood cholesterol levels to rise and cause high blood pressure.
Commonly used immunosuppressant medications such as the corticosteroid prednisone can cause damage to the eyes and increase the likelihood of developing cataracts---cloudy or darkly pigmented spots on the lens of the eye(s) that require surgical removal.
A thinning or weakening of the bones, or osteoporosis, may also occur as a result of medications or a combination of drugs and lifestyle factors such as reduced activity level or poor diet.
