Heart-lung transplant
|
|
A heart-lung transplant is a procedure carried out to replace both heart and lungs in a single operation. Due to a shortage of suitable donors it is rarely done, and only about 100 such transplants are performed each year in the USA.
| Contents |
Qualifying Conditions
Most candidates for heart-lung transplants have life-threatening damage to both their heart and lungs. In the US, most prospective candidates have between 12 and 24 months to live. At any one time, there are about 250 people on the United Network for Organ Sharing (UNOS) in the USA - about 40 of those will die before a suitable donor is found.
Conditions which may necessitate a heart-lung transplant include:
- Congenital problems (defects present at birth) affecting the heart and lungs (48%)
- Pulmonary hypertension (20%)
- Cystic Fibrosis (2%)
- A second transplant after the first transplant failed to 'take' or was rejected (4%)
Candidates for a heart-lung transplant are usually required to be:
- Under 55 years old
- Have no other medical conditions (eg. AIDS, Diabetis, Hepatitis)
- Mentally sound
- Capable of following a post-op regiment of exercise and immunosuppressant drugs
History
Dr. Norman Shumway laid the groundwork for heart lung transplantation with his experiments into heart transplantation at Stanford in the mid-1960s. Shumway conducted the first adult heart transplant in the US in 1968.
Building on his research at Stanford, Dr. Bruce Reitz performed the first successful heart-lung transplant on Mary Gohlke in 1981 at Stanford Hospital. The transplant team at Stanford is the longest continuously active team performing these transplants.
The Procedure
The patient is anesthetised. When the donor organs arrive, they are checked for fitness - any organs that show signs of damage are discarded and the operation cancelled. Some patients are concerned that their organs will be removed and the donor organs not suitable. Since this is a possibility, it is standard procedure that the patient is not operated on until the donor organs arrive and are judged suitable, despite the time delay this involves.
Once suitable donor organs are present, the surgeon makes an incision starting above and finishing below the sternum, cutting all the way to the bone. The skin edges are retracted to expose the sternum. Using a bone saw, the sternum is cut down the middle. Rib spreaders are inserted in the cut, and spread the ribs to give access to the heart and lungs of the patient.
The patient is connected to a heart-lung machine, which circulates and oxygenates blood. The surgeon removes the failing heart and lungs. Most endeavour to cut blood vessels as close as possible to the heart to leave room for trimming, especially if the donor heart is of a different size than the original organ.
The donor heart and lungs are positioned and sewn into place. As the donor organs warm up to body tempreature, the lungs begin to inflate. The heart may fibrillate at first - this occurs because the cardiac muscle fibres are not contracting synchronously. Internal paddles can be used to apply a small electric shock to the heart to restore proper rhythm.
Once the donor organs are functioning normally, the heart-lung machine is withdrawn, and the chest is closed.
Post-operation
Most patients spend several days in intensive care after the operation. If there are no complications (eg infection, rejection), some are able to return home after just 2 weeks in hospital. Patients will be given anti-rejection drugs, and antibiotics to prevent infection. A schedule of frequent follow up visits is necessary.
Statistics
- One month survival rate - 79%
- One year survival rate - 66%
- Three year survival rate - 54%
Further information
National Heart, Lung and Blood Institute (NHLBI) (http://www.nhlbi.nih.gov)