A heart transplant, or a cardiac transplant, is a surgical transplant procedure performed on patients with end-stage heart failure or severe coronary artery disease when other medical or surgical treatments have failed. As of 2016, the most common procedure is to take a functioning heart, with or without transplanting one or both lungs at the same time, from a recently deceased organ donor (brain death is the standard) and implanting it into the patient. The patient's own heart is either removed and replaced with the donor heart (orthotopic procedure) or, much less commonly, the recipient's diseased heart is left in place to support the donor heart (heterotopic, or "piggyback," transplant procedure).
Approximately 3500 heart transplants are performed every year in the world, more than half of which occur in the US. Post-operation survival periods average 15 years. Heart transplantation is not considered to be a cure for heart disease, but a life-saving treatment intended to improve the quality of life for recipients. Post-operative complications include infection, sepsis, organ rejection, as well as the side-effects of the immunosuppressive medication. Since the transplanted heart originates from another organism, the recipient's immune system typically attempts to reject it. The risk of rejection never fully goes away, and the patient will be on immunosuppressive drugs for the rest of his or her life, but these may cause unwanted side effects, such as increased likelihood of infections or development of certain cancers. Recipients can acquire kidney disease from a heart transplant due to side effects of immunosuppressant medications. Many recent advances in reducing complications due to tissue rejection stem from mouse heart transplant procedures. Surgery death rate is 5-10% in 2011