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 2018, the most common procedure is to take a functioning heart, with or without both lungs, from a recently deceased organ donor (brain death is the standard) and implant 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).