Expanded criteria donors: attempts to increase the renal transplant donor pool.

There is a growing disparity between the demand for and the supply of kidneys for transplantation. The demographics of the donor pool are also changing. The average potential cadaveric organ donor is now more likely to be older, at greater risk for co-morbid conditions such as hypertension or viral infections, and more likely to die from cerebrovascular disease. These factors have led to an expansion of the criteria that defines the suitable organ donor. Expanded criteria donors are defined as the following: (1) at the upper and lower extremes in age; (2) having a history of hypertension or diabetes; (3) hemodynamically unstable; (4) non-heartbeating (cardiopulmonary death rather than brain death); (5) seropositive for hepatitis B or C; (6) having systemic infections; (7) having displayed high-risk social behavior for HIV infection; (8) having a history of malignancy; (9) having abnormal organ function; or (10) with renal anatomic anomalies or injuries. Use of kidneys from these "expanded criteria donors" is a two-edged sword. While they provide more organs for transplantation, the risk of suboptimal recipient outcome is increased. A rational approach to the use of each of these types of kidneys and proper selection of recipients is essential to obtain acceptable results. The article reviews the factors that have contributed to the successful transplantation of kidneys procured from expanded criteria organ donors and how these organs can be allocated most efficaciously to the appropriate recipients.