Heart and lung transplants will inevitably come from a recently deceased donor. The demand for donor heart and lungs outweighs the supply.
Indications
The most common indiction for a heart transplant is congestive heart failure, which can be secondary to:
- Ischaemic heart disease
- Cardiomyopathy
- Congenital heart disease
The most common indications for a lung transplant are:
- Chronic obstructive pulmonary disease (COPD)
- Pulmonary fibrosis
- Cystic fibrosis
- Pulmonary hypertension
Variations
There are several ways heart and lungs can be transplanted:
- Single lung transplant
- Double lung transplant
- Heart transplant
- Heart-lung transplant
A double lung transplant can be performed as a bilateral single lung transplant (one lung, then the other), or an “en bloc” transplant where both lungs are implanted together. Bilateral single lung transplants are generally preferred.
Incisions
A lateral thoracotomy incision may be used for single lung transplants.
A midline sternotomy incision may be used for heart transplants.
A clamshell incision may be used for bilateral lung transplants.
Procedure
The time between the death of the donor and the transplant needs to be as short as possible (under 6 hours). In the meantime, the organ is cooled to reduce the damage during transportation. This is referred to as the cold ischaemic time. Usually, the operation will begin before the donated organ has arrived, so that the transplant can take place immediately on arrival of the organ.
Heart or lung transplantation requires a cardiopulmonary bypass, to bypass the circulation in the organ(s) that will be removed and transplanted. The bypass machine takes blood from the vena cava or right atrium, pumps it through a machine that adds oxygen and removes carbon dioxide from the blood, then pumps it back into the ascending aorta. This way, blood bypasses the heart and lungs and is artificially oxygenated. Heparin is used to prevent blood clotting. The clinical perfusionist is responsible for operating and monitoring the cardiopulmonary bypass equipment.
After a donor heart is implanted, the heart is reperfused with blood and warmed. The treatment that prevents the heart from beating (cardioplegia) is stopped. The heart will then spontaneously start beating. Cardioversion or temporary pacing may be used to treat arrhythmias that occur.
Patients will be transferred to the intensive care unit after surgery.
Post Transplant
Organ rejection is a major risk with any organ transplant. Patients will require life-long immunosuppression to reduce the risk of transplant rejection.
Immunosuppressants have a long list of complications, particularly:
- Side effects of steroids (e.g., diabetes, osteoporosis and Cushing’s syndrome)
- Severe or unusual infections
- Skin cancer
- Post-transplant lymphoproliferative disorder (a form of non-Hodgkins lymphoma)
A key complication after a heart transplant is cardiac allograft vasculopathy (CAV), which involves narrowing of the coronary arteries in the donor heart. The donor heart is not innervated, meaning the patient will experience symptoms of ischaemia in the heart tissue. This means they will not have any symptoms of angina or myocardial infarction. Patients have regular follow up coronary angiograms to monitor for this.
The key complications after a lung transplant are:
- Primary graft dysfunction (PGD), which usually occurs within 3 days, with acute pulmonary oedema, alveolar damage and hypoxia
- Bronchiolitis obliterans syndrome (BOS), which usually occurs within 1 year, with damage to the bronchioles
- Dehiscence of the bronchial anastomosis, which causes air leakage into the mediastinum and is life-threatening
Survival is approximately:
- 85% at 1 year for heart or lung transplants
- 75% for heart transplants at 5 years
- 50% for lung transplants at 5 years
Last updated May 2021