Who can donate?
There are three types of organ donors:
Cadaveric donors
This is the most usual form of donation. Suitable donors are those who are diagnosed braindead, usually following brain haemorrhage or severe head injury.
Potential donors are individually assessed for suitability. Age is a consideration and, in most countries, donors up to the age of approximately 75 are considered suitable kidney and liver donors.
Non-heart beating cadaveric donors
In these donors, brain death is accompanied by cardiac arrest. Time elapsed between cardiac arrest and perfusion of the organs must be very short. The kidneys can only survive up to 30-45 minutes before perfusion is started; for other organs, this time is even shorter. This procedure requires a very high degree of organization since it involves cooling of the organs "in situ" and then their removal as soon as possible after the start of perfusion. Organs that have been donated after cardiac death are kidneys, liver, lungs, and pancreas.
Living donors
Nobel prize winner Dr. Joseph Murray performed the first living-related kidney transplant between identical twins in 1954 in Boston. The recipient lived eight years before dying from a heart attack.
The most common type of living donation is a kidney. These are mostly performed between blood relatives and, in some countries, also between emotionally related peoples, such as husbands and wives.
The success of this type of transplantation is better than with cadaveric donors as shown in a study by Terasaki et al (New England Journal of Medicine, August 10, 1995). This showed that after three years, 85% of transplanted kidneys donated by a spouse (emotionally related) survived, compared with 90% for grafts from identical siblings and 81% from blood related living donors. In this study, the survival rate for kidneys taken from cadaveric donors was 70% after three years.
Living (un)related liver transplantation has increased in popularity. In this technique, which is used mainly in children, a small lobe of liver is transplanted from a parent to a child. Results have been encouraging.
Occasionally, combined heart-lung transplants have made living donation of hearts possible. In patients with cystic fibrosis, for example, the lungs are diseased but their heart may be unaffected. In what is known as a "domino" procedure, a heart-lung transplant is given to an individual with cystic fibrosis, and his/her healthy heart is then transplanted in another recipient.
Further developments in living donation are investigating the possibilities with lung, pancreas and small bowel.
