Heart transplantation

A heart transplant, also known as a cardiac transplant, is a major surgical procedure. It is performed on patients suffering from end-stage heart failure. This condition occurs when the heart can no longer pump enough blood to meet the body's needs. Doctors use this surgery when other medical or surgical treatments have failed. It is important to note that transplantation is not a cure for heart disease. Instead, it is a life-saving treatment. The goal is to improve the quality and duration of a patient's life. On average, post-operative survival periods for recipients last about 15 years.

There are two primary methods used to implant a new heart. The most common method is the orthotopic procedure. In an orthotopic transplant, surgeons remove the patient's diseased heart and replace it with a donor heart. This new heart takes the exact position of the original one. A much less common method is the heterotopic transplant. This is sometimes called a "piggyback" transplant. In this version, the recipient's diseased heart is left in place. The donor heart is implanted alongside it to provide extra support.

The source of the new heart is often a recently deceased organ donor. Most commonly, these donors have experienced brain death. This type of transplant is called an allotransplant. An allotransplant involves moving an organ from one non-genetically identical individual to another of the same species. Because the organs come from different people, the body may try to fight the new heart. This is known as rejection. To manage this, doctors use specific medicines. A major breakthrough occurred in 1983 with the widespread use of cyclosporine. This drug helped prevent rejection and allowed doctors to use fewer corticosteroids.

Scientists have explored different ways to source hearts throughout history. One method is xenotransplantation. This is the technical term for transplanting an organ or tissue from one species to another. In 1964, James D. Hardy performed a xenotransplant using a chimpanzee heart. The heart beat in the patient's chest for 60 to 90 minutes before the patient died. In 2022, surgeon Bartley P. Griffith performed the first successful pig-to-human heart transplant. More recently, in January 2022, David Bennett became the first person to receive a gene-edited pig heart. This was done at the University of Maryland Medical Center because he could not receive a human heart.

The history of human-to-human transplantation is marked by several major milestones. American researcher Simon Flexner first suggested that replacing human organs might be possible in 1907. The first successful human-to-human heart transplant was performed by Christiaan Barnard. He used techniques developed by American surgeons Norman Shumway and Richard Lower. This historic event took place in Cape Town, South Africa, on December 3, 1967. Shortly after, Adrian Kantrowitz performed the first pediatric heart transplant in New York on December 6, 1967. In 1968, Norman Shumway performed the first adult heart transplant in the United States. That same year, a team in the United Kingdom completed their first transplant.

Today, heart transplantation is a significant global medical practice. Approximately 5,000 heart transplants are performed every year worldwide. More than half of these procedures take place in the United States. There is a large gap between the number of people needing hearts and the number of available organs. About 800,000 people suffer from advanced heart failure symptoms. Because of this need, researchers are studying non-human hearts and artificial hearts. One major center is the Vanderbilt University Medical Center in Tennessee. In 2024, they completed 174 transplants, though the title of largest volume center often changes.

Not every patient is a candidate for this surgery. Certain medical conditions are considered absolute contraindications, meaning they make the surgery too risky. These include irreversible disease in the kidneys, lungs, or liver. Active cancer or life-threatening diseases like systemic lupus erythematosus also prevent transplantation. Other factors, called relative contraindications, include severe obesity or being over the age of 65. Doctors must evaluate each person individually. They also look at factors like recent strokes or insulin-dependent diabetes. The goal is always to ensure the best possible outcome for the patient's long-term health.