Understanding Heart Transplant Rejection

Your immune system’s job is to find and destroy things in the body that may cause harm. This includes bacteria and viruses. The immune system works to help keep you healthy. But in some cases, the immune response can be a problem. After a heart transplant, your immune system sees your new heart as a threat. It can start to attack the heart. This is called rejection.

Rejection is a normal reaction by the body. You will need to take medicine for the rest of your life to help prevent it. But rejection can still happen. It’s common even in people who take all of their medicine as prescribed.

Types of heart transplant rejection

There are a few types of rejection. These include:

• Acute cellular rejection. This is the most common type. It happens when immune system cells called T-cells attack your new heart. It happens most often in the first 3 to 6 months after a transplant.

• Humoral rejection. This is a less common type. It’s also known as acute antibody rejection. It happens when antibodies injure your blood vessels. This can cause problems with the blood flow to the heart. This type of rejection can develop during the first month after transplant surgery. Or it can happen months or years later.

• Coronary artery vasculopathy. This is a form of ongoing (chronic) rejection. The coronary arteries send oxygen and nutrients to the heart. This type of rejection causes the inner lining of these blood vessels to thicken. This can reduce the bloow flow to the heart.

What causes heart transplant rejection?

Heart transplant rejection is caused by a normal immune system. Not taking antirejection medicines as prescribed can cause transplant rejection. But many people who take their medicines still have rejection. No one knows for sure why this happens.

Certain factors can increase the risk for acute rejection. These include:

• A genetic mismatch between the heart donor and heart recipient.

• Having a recent transplant. The risk is highest in the weeks right after transplant. Then it starts to decrease.

• Getting a heart from a female donor.

Your risk is also higher if you are female, younger, or African-American.

Factors that can increase the risk for chronic rejection include:

• A genetic mismatch between the heart donor and heart recipient.

• Certain health problems in the donor. These include high cholesterol, cytomegalovirus (CMV) infection, and insulin resistance.

• Getting a heart from an older donor.

• Having a transplant at a younger age.

• History of acute rejection.

• Coronary heart disease in the donor or the recipient.

Symptoms of heart transplant rejection

Rejection may not cause symptoms. The problem may only be found during follow-up tests after the surgery. It’s important to go to all your follow-up appointments.

When symptoms of rejection occur, they can include:

• Feeling tired or weak.

• Fever or chills.

• Shortness of breath.

• Fast or uneven heartbeat.

• Drop in blood pressure.

• Swelling of your feet, hands, or ankles.

• Sudden weight gain.

• Flu-like aches and pains.

• Reduced amounts of urine.

• Dizziness or fainting.

• Nausea or loss of appetite.

Chronic rejection often has no symptoms. The first symptom may be a heart attack.

Diagnosing heart transplant rejection

Your healthcare provider will ask about your health history and your symptoms. You’ll have a physical exam. You’ll also have tests such as:

• Heart biopsy. A small piece of tissue will be taken and tested. You may have several biopsies over time after a heart transplant. They often show signs of rejection before you have any symptoms. Finding a rejection early increases the chances it can be treated.

• Blood tests. These tests check for genes linked to transplant rejection.

• Heart function tests. You will have tests to check how well your heart is working. These may include an electrocardiogram (ECG) and echocardiogram.

• Blood vessel tests. These tests may be needed to check for chronic rejection. Your provider can tell you more about these tests.