Introduction to lung transplantation

Lung transplantation is a surgical treatment similar to heart transplantation where your lung or lungs are replaced by that of a donor. Although the first human lung transplant took place in 1963 it was not till the early 1980s that survival figures became encouraging. In 1981 a heart and lung transplant was performed to treat pulmonary vascular disease (disease of the blood vessels that supply the lung), this was quickly followed in 1983 by a single lung transplant for pulmonary fibrosis and in 1986 a double lung transplant for obstructive lung disease. The successes of these operations led to the resurgence of lung transplantation in recent years. In Australia the first single lung transplant at St Vincent’s hospital in Sydney took place in 1990 followed by the first double lung transplant the following year.

How many people are receiving lung transplants?

About 100 lung transplants are performed annually in Australia at four centers. This represents about 6% of all transplants performed worldwide. Over the years while the need for the procedure has increased this has not been matched by an increase in the supply of lungs available for transplantation. In 2004 for example the mean waiting time for a transplant was about a year, this has been a fairly constant figure over the past decade with patients dying or becoming too sick for transplant while on the waiting list.

What criteria must be met for a lung transplant/who gets a lung transplant

Generally patients with end-stage lung disease who meet the following criteria are considered for transplantation:

  • Untreatable end-stage lung disease due to any cause
  • Absence of other significant medical diseases
  • Substantial limitation of daily activities
  • Limited life expectancy
  • Satisfactory psychosocial profile and emotional support system

Absolute contraindications to lung transplantation include:

What examinations are involved?

The doctor will perform a complete physical examination of the whole body. This may involve getting undressed for inspection and doing some exercises in the doctor’s room. The doctor will listen to the chest and back and may ask for a sputum sample.

What tests or evaluation is involved in preparing for a lung transplant

A battery of tests is needed before a transplant. These will include:

  1. Blood tests
  2. Tissue typing
  3. Electrocardiogram (ECG) – a test that records the heart’s activity by measuring electrical currents through the heart muscle.
  4. CT – a type of x-ray that uses a computer to make pictures of the inside of the lungs.
  5. Echocardiogram – a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart.
  6. Pulmonary function tests – tests that measure the function of the lungs.
  7. Ventilation-perfusion lung scan – a test that examines the movement of blood and air through the lungs.
  8. Cardiac catheterization – a tube-like instrument inserted into the heart through a vein or artery (usually in the arm or leg) to detect problems with the heart and its blood supply.
  9. Psychological assessment
  10. Referral to other practitioners such as physiotherapy, occupational health and safety and a dietician.

Prognosis after a lung transplant

In spite of the poor state of patients prior to surgery the one and five year survival rates for unilateral and bilateral transplants are 80% and 50% respectively with the majority having a dramatic improvement in lung function.

Common complications

Common complications include:

  1. Infection
  2. Rejection of the donor lung
  3. Pneumonia
  4. Excessive bleeding
  5. Anesthesia-related problems
  6. Cancer related to taking immunosuppressant medications
  7. Death

What happens before the transplant?

On the day a lung or lungs become available you will probably be in hospital or you will be called to come in. usually there will be two teams involved with you on the day. One will harvest the available lung and the other will perform the operation, sometimes the same team does both. You will be informed that a lung has become available by one of the doctors. From here things happen very quickly. You will be changed into a gown and taken to the preoperative waiting area until the surgical team is ready for you.

During this waiting period you will have an interview with the anaesthetist who will ask you questions about your past medical history and then put you to sleep as this procedure is carried out under general anaesthesia. It is possible that you may already have had this interview at some point in which case you will quickly be put to sleep and the surgery begun.

What questions can be asked before a transplant

Any and all questions that are on the patients mind should be asked before the operation and the medical team should be more than happy to answer these.

What happens during the transplant?

It is an operation that can take up to 12 hours and may require a bypass machine to help with circulation while the lungs are being replaced. For a single lung transplant, the surgeon makes an incision on your side, about six inches below your underarm. A horizontal incision across the lower chest is made for a double lung transplant. The bypass machine takes over the functions of the heart and lungs during the operation and a ventilator maintains your breathing. A small section of rib is permanently removed to allow access to your lung. The old lung is cut away from the main blood vessel and bronchus (large airway), and the new lung is inserted. The blood vessels and bronchus are attached to the new lung.

What happens after the transplant?

After the surgery you will be taken to the intensive care unit where your recovery will be monitored by the doctors and nurses. There will be a tube in your mouth and some tubes coming out of your sides. As a result you will not be able to talk and you will be in pain. The tubes will eventually be removed and you may feel uncomfortable for some time after this. Once the tubes have been removed you will be moved to a regular transplant room for further recovery.

You may expect to take up to five days in the intensive care unit and a few weeks in the hospital after this before being discharged.

After discharge you will make frequent trips to the medical centre and have a prescribed home based rehabilitation program including physical activity, breathing exercises, nutrition and taking medications especially immunosuppressive drugs. Immunosuppressant therapy is needed to suppress the solid-organ transplantation induced recipient immune response that eventually leads to graft destruction.

Graft rejection is classified into three types:

  1. Hyperacute rejection, marked by activation of complement and coagulation cascades in response to binding of preformed host antibodies to endothelial cells of the graft. This is more likely in patients with previous exposure to foreign peptides such as blood transfusion recipients, pregnant women, or prior transplant recipients.
  2. Acute rejection which histologically defined as a mononuclear leukocyte infiltrate of small airways and blood vessels. If left untreated acute rejection may progress to chronic allograft rejection.
  3. Chronic rejection.

Walking is recommended to restore strength and prevent lung complications.  More strenuous activity can resume when one is comfortable.

References

  1. Doershuk, C. F. and R. C. Stern (1999). “Timing of Referral for Lung Transplantation for Cystic Fibrosis: Overemphasis on FEV1 May Adversely Affect Overall Survival.” Chest 115(3): 782-787.
  2. Kanasky, W. F., Jr., S. D. Anton, et al. (2002). “Impact of Body Weight on Long-term Survival After Lung Transplantation.” Chest 121(2): 401-406.
  3. Glanville, A. R. and M. Estenne (2003). “Indications, patient selection and timing of referral for lung transplantation.” Eur Respir J 22(5): 845-852.
  4. Mannes, G. P. M., W. J. de Boer, et al. (1996). “Three Hundred Patients Referred for Lung Transplantation: Experiences of the Dutch Lung Transplantation Program.” Chest 109(2): 408-413.
  5. Marshall, S. E., M. R. Kramer, et al. (1990). “Selection and evaluation of recipients for heart-lung and lung transplantation.” Chest 98(6): 1488-1494.
  6. Maurer, J. (1998). “International guidelines for the selection of lung transplant candidates.” The Journal of heart and lung transplantation 17(7): 703-709.
  7. Snell, G. (1998). “Body mass index as a predictor of survival in adults with cystic fibrosis referred for lung transplantation.” The Journal of heart and lung transplantation 17(11): 1097-1103.
  8. Fiser S.M.,  Tribble C.G.,  Long S.M., (2002)  “Ischemia-reperfusion injury after lung transplantation increases risk of late bronchiolitis obliterans syndrome”. Annals of thoracic surgery 73:1041-1047.
  9. Duncan A.J.,  Dummer J.S.,  Paradis I.L.(1991),  Cytomegalovirus infection and survival in lung transplant recipients.Journal of heart and lung transplantation 10 : pp 638-644
  10. Arcasoy S.M.,  Hersh C.,  Christie J.D.(2001),  “Bronchogenic carcinoma complicating lung transplantation”. Journal of heart and lung transplantation 20: 1044-1053
  11. Trindale,AJ,Palmer,SM (2004). “Current concepts and controversies in lung transplantation”  Respiratory care clinics of North America;10(4):427-47