A heart-and-lung transplant prolongs the life of a patient who otherwise would die. The operation is done only when there is a very good chance of success. While long-term outcomes are unknown at this time, 5-year survival is approximately 40-50%.

As with all major organ transplants, the problems are finding a donor, preventing rejection, and the cost of the surgery and anti-rejection medications.

Finding a donor for heart-lung transplant can be difficult. The donated organs must come from a person who has been declared brain-dead, but is still on life-support, while the patient is still in healthy-enough condition to survive the surgery.

Preventing rejection is an ongoing process. The body's immune system considers the transplanted organs as invaders (much like an infection), and fights them.

To prevent rejection, organ transplant patients must take anti-rejection (immunosuppression) drugs (such as cyclosporine and corticosteroids) that reduce (suppress) the body's immune response and reduce the chance of rejection. These drugs also reduce the body's natural ability to fight off various infections.