The heart is the organ that makes life possible. That’s why doctors and surgeons will do anything they can to keep your heart beating—even if it means replacing it. A heart transplant is a surgical procedure in which a patient’s diseased heart is replaced with a healthy one from a donor who has died recently. The first heart transplant procedure was performed in 1967. Since then, doctors have learned much more about transplants. That knowledge, in combination with advancements in technology and anti-rejection drugs have dramatically improved survival. While they are still considered a treatment of last resort, heart transplants are now the gold standard therapy for end-stage heart failure.

Today, around 3,700 heart transplants are performed each year in the United States. Most heart transplant recipients are adults, though children and adolescents may also need them. In 2020, for instance, there were 465 pediatric heart transplants in the U.S.

“Heart transplant is considered when doctors determine that the heart is damaged beyond repair by usual means, including medications, stents, bypass procedures, or drugs to boost heart function,” says Yale Medicine cardiac surgeon Pramod Bonde, MD. “Usually, this starts a countdown to find a substitute for the failing heart.

Heart transplants are used to treat people who have end-stage heart failure or other severe heart conditions that cannot be adequately treated with medications or other treatments. When heart failure occurs, the heart is unable to pump enough blood to meet the needs of the body. Heart failure does not mean that the heart has stopped working. It’s a serious condition that progresses over time. People with severe heart failure have a hard time doing even routine physical tasks and a poor prognosis.

Heart failure may be caused by a number of conditions including coronary artery disease, heart valve disease, irregular heartbeat (arrhythmia), and structural heart disease, among others.

Doctors perform a thorough examination of patients with advanced heart disease to determine whether they are eligible to receive a new heart and are healthy enough to undergo heart transplant surgery. Tests include bloodwork, imaging studies of the chest and heart, and an electrocardiogram (ECG) to evaluate heart function, as well as other tests to evaluate how well the heart and lungs are working.

People may not be eligible for a heart transplant if they have one or more of the following conditions, among others:

• Current or recent history of cancer
• Severe pulmonary hypertension
• Severe cerebrovascular disease
• Advanced kidney, liver, or lung disease
• Use of tobacco, alcohol, and/or drugs within previous 6 months
• History of not taking medications as prescribed by doctors
• Aged 70 or over
• Current infection such as HIV or hepatitis C
• Obesity (having a body mass index [BMI] of 35 or higher)
• Poorly controlled diabetes

People with advanced kidney, liver, or lung disease may be candidates for multi-organ transplantation surgery, such as a heart-kidney, heart-liver, or heart-lung transplant. 

People deemed eligible for a heart transplant will be added to a waiting list for a donor heart. Unfortunately, the demand for heart transplants exceeds the supply of available hearts. There are currently about 3,800 people in the United States on the waiting list for a donor heart, and many will wait more than six months.

Because the people on the heart transplant waiting list have severe heart problems, many of them need to be treated until a donor heart becomes available. In some cases, this involves implantation of mechanical devices such as a ventricular assist device (VAD) or a total artificial heart (TAH) that help pump blood throughout the body while patients wait for a donor heart.   

United Network for Organ Sharing (UNOS), a private, non-profit organization that manages the nation’s organ transplant system under contract with the federal government, allocates hearts to compatible recipients based on several factors including:

• Biological factors. The recipient’s blood type needs to match that of the donor heart. Other factors, such as the recipient’s body size, are also taken into account. Smaller hearts may be reserved for children on the waiting list.
• Medical urgency. In general, patients in more urgent need of a transplant are prioritized on the waiting list.
  
• Distance. Donor hearts cannot be preserved for long periods, so distance between the transplant center and donor is an important consideration.

A heart transplant is a major, carefully orchestrated procedure. A heart can become available at any time, so a prospective patient must be available 24 hours a day and have a suitcase packed. When a heart becomes available, a retrieval surgeon travels to the hospital where the donor heart is stored, makes sure it is suitable, and brings it to the transplant center. Because the heart will last only four to six hours once it is removed from the donor’s body, the recipient must go to the hospital immediately where they are prepped for surgery.

Before surgery begins, the transplant team will administer general anesthesia and connect the patient to a ventilator for breathing support. The surgeon will make an incision in the patient’s chest and divide the breastbone to access the heart and major blood vessels. Patients will be connected to a heart-lung bypass machine, which will take over the function of the heart while the diseased heart is removed. Then, the surgeon will sew the donor heart into place and connect it to the blood vessels. Once blood flow is restored, the transplanted heart will start to beat, and the patient is gradually weaned from the heart-lung bypass machine.

Heart transplant surgery takes about four hours, but complicated cases can take seven, eight, or nine hours—and even longer. The surgeon may need extra time to remove a LVAD (left ventricular assist device) before transplanting the heart, or to remove scar tissue from previous heart surgeries. In some cases, the surgeon will need to adapt the surgery to a patient’s particular anatomy (sometimes heart disease causes a heart to be abnormal or unusual).

While time in the hospital varies, most patients spend a few days in the intensive care (ICU) unit where they will be closely monitored to ensure the transplanted heart is working properly. During the first days after surgery, doctors will order frequent blood tests to ensure that the heart and other organs are working as they should. After leaving the ICU, patients may need to spend up to three more weeks recovering in the hospital.

After a donor heart is implanted, there is a chance that the recipient’s immune system will recognize it as a foreign tissue and react by attacking and destroying it. This is known as transplant rejection. To prevent this from happening, after receiving a donor heart, patients must take medications to suppress the immune system for the rest of their lives. Unfortunately, people who take immunosuppressive drugs are at increased risk for infections.

Before leaving the hospital, patients may begin a cardiac rehabilitation program that involves exercise and education about living with a transplanted heart. A lifelong follow-up care plan is key to survival and quality of life for heart transplant patients. It includes frequent tests to make sure the new heart is functioning properly, that there are no infections, and that the body isn’t rejecting the transplanted heart.

Heart transplant surgery comes with certain risks, including:

• Bleeding
• Infection
• Blood clots
• Heart attack
• Stroke
• Abnormal heart rhythm (arrhythmia)
• Rejection of the transplanted heart
• Primary graft dysfunction—when the donor heart doesn’t work properly
• Increased risk of infections and other side effects (high blood pressure, high cholesterol, kidney problems, diabetes, and increased risk for some cancers) due to use of immunosuppressive drugs
• Cardiac allograft vasculopathy (CAV)—when blood vessels that supply the heart with blood become narrowed or blocked

Heart transplant surgery is a life-saving procedure. Getting a donor heart allows recipients to live longer, healthier lives. Nearly 90% of heart transplant recipients are alive 1 year after surgery, around 75% at the 5-year mark, and 55% after 10 years.

To prevent rejection of the donor heart, heart transplant recipients must take drugs that suppress their immune system for the rest of their lives. People whose immune system rejects the donor heart may be eligible for a second heart transplant, though this is not common.

Heart transplant recipients should also see their doctor regularly to monitor heart function and their overall health. Follow-up visits may involve a physical exam, bloodwork, and imaging tests.

Periodic biopsies of heart tissue to check for rejection of the transplant are also part of follow-up care.

“Yale medicine is one of the largest heart transplant centers in New England and has accumulated vast experience with a very experienced multidisciplinary team to ensure excellent outcomes and survival,” says Dr. Bonde.