What is transplant rejection? How is it detected? How is it treated?

Your body possesses a natural defense mechanism, called the immune system, that under normal circumstances acts to protect you against injury due to such things as infection and trauma. After your transplant, the immune system perceives the transplanted heart as a “foreign” material and attempts to destroy it. If the immune system is able to attack the transplanted heart, it is called rejection. To suppress this response, you must take certain antirejection drugs (immunosuppressant medications) for life.

Rejection must be detected and treated quickly to prevent damage to the transplanted heart. It is not possible to predict who rejects, how frequently, or how severely, but almost all patients experience one or more rejection episodes at some time after their heart transplant. Your transplant doctors will teach you how to watch carefully for any symptoms of rejection.

Potential symptoms of heart transplant rejection are

• Sudden unexplained fatigue

• Decreased exercise tolerance

• Worsened shortness of breath

• Fluid retention, swollen ankles, feeling bloated

• Recurrence of your previous heart failure symptoms

• Palpitations or an irregular heartbeat

• Increased or high blood pressure

• Fever

• Flu-like symptoms or malaise

Acute transplant rejection is the leading cause of death in the first month after transplantation. It is essential to detect and treat acute rejection as early as possible, preferably before the injury is sufficient to cause symptoms to appear. For this reason you will undergo a series of routine examinations and testing at set intervals. These tests are carried out frequently during the first 6 months after your transplant, because this is when rejection most commonly occurs. Half of all possible rejections occur in the first 6 weeks, and most happen within the first 6 months of surgery.

The best method of checking your new heart to detect any signs of rejection is to perform a heart muscle biopsy (endomyocardial biopsy), described in Question 88. Small specimens of heart muscle tissue (endomyocardium) are taken from the heart and are examined under the microscope for any signs of damage to the heart.

Another way to check the transplanted heart for rejection is to perform an echocardiogram (cardiac ultrasound) to assess the pumping function of the heart. A heart that is experiencing some rejection may show signs of temporary weakening.

The treatment of rejection depends on the severity of the rejection, as determined by biopsy results and how well you are doing clinically. Most episodes of rejection are mild and can be treated at home with intravenous steroids and/or adjustment of your immunosuppressant medications. If there is evidence of more severe rejection, you may be admitted to the hospital for close monitoring and to receive other intravenous antirejection medicines.