Each year in the United States, nearly 30,000 people receive the opportunity to save, extend or enhance their lives through the human gift of organ donation. Of those, roughly three-fourths of the organs transplanted come from deceased donors.
Because every transplant involves a human donor, there is always a small risk of transmitting a disease present in the donor that might harm the recipient. Some potentially transmissible diseases, such as hepatitis or CMV, can be readily identified by a common lab test. Other diseases can't be positively determined in the short time frame that deceased donor organs must be recovered, transported and transplanted. Still other diseases have no specific screening test and may not become known unless symptoms occur in a recipient.
Transplant clinicians understand that the only way to avoid all risk of donor-transmitted disease is not to do a transplant at all, with the certain and catastrophic consequences of organ failure. At the same time, we want to take all reasonable measures first to prevent donor-transmitted disease and secondly to direct timely and effective interventions for those recipients who become ill despite our best efforts.
Since 1986, United Network for Organ Sharing (UNOS) has operated a national transplant network under federal contract. Known as the Organ Procurement and Transplantation Network (OPTN), it develops organ allocation policies and standards for all transplant centers and organ procurement organizations nationwide. The OPTN also collects detailed medical data on all donors, transplant candidates and transplant recipients throughout the United States.
The OPTN has always had policies requiring testing of living and deceased donors for potential disease risks, and for organ procurement organizations to communicate potential donor disease risks to transplant centers to consider along with other medical facts of an organ offer. In addition, the OPTN has long maintained "trackback" procedures in case one transplant recipient shows symptoms of a significant donor-transmitted disease; through linked data, we can identify all recipients from a particular donor and contact the respective transplant teams if other recipients might be affected.
In recent years, these efforts have intensified. In 2004, a work group was established to study all OPTN data and reports on donor disease transmission. It is now one of about 20 OPTN committees. The Ad Hoc Disease Transmission Advisory Committee (DTAC) has national representation including transplant physicians and surgeons, organ recovery specialists, and experts in fields including infectious disease, oncology and epidemiology.
The DTAC serves in multiple capacities. It seeks to estimate the prevalence and relative risk of donor-transmitted disease in transplantation. It makes recommendations for new practices and policies to prevent disease transmission through detection and communication among clinicians. It also assists UNOS staff and relevant health agencies in investigating and reporting incidents of donor-transmitted disease.
OPTN policies require certain disease screening to be performed for every potential donor. This includes both clinical testing and collection of information about the donor's medical and social history to identify any major risk factors for disease transmission. This information is conveyed to the transplant program considering an organ offer; in addition, if the donor is considered "high risk" for blood borne disease based on CDC guidelines, OPTN policies direct that the patient be notified of this risk. We believe the extensive programs for assessing transmission risk and communicating this rapidly with transplant programs has helped to minimize the risk of significant disease transmission.
Medical judgment must always supplement the OPTN's requirements, especially when considering rare diseases or conditions not readily identified through a standard test. The DTAC continues to assess new methods for screening and provides guidance to clinicians in instances where an individual judgment must be made. As an example, as concern rose in 2009 over the prevalence of H1N1 infection, DTAC provided resource information and advisories to donation and transplantation professionals considering potential donors known or suspected to have an H1N1 infection.
UNOS maintains a patient safety portal as part of the computer network used by all OPTN members. The portal provides a mechanism for transplant centers or organ procurement organizations to report issues or events that may affect the health and safety of living donors and transplant patients. The OPTN monitors these reports not only for tracking and assistance in potential transmission events, but to assess member compliance with OPTN policies and bylaws (addressed by other UNOS staff and OPTN committees).
It's important for people needing transplants to understand the risk of disease transmission and discuss it with the staff of their transplant program. A DTAC analysis of potential donor-derived transmissions reported to the OPTN in 2009 confirmed a disease transmission in 51 recipients (in some cases, one organ donor affected more than one recipient); of these known events, 16 recipients died. Reports included both infections (from bacteria, fungi, viruses, and parasites/protozoa) and malignancies. The majority of the reports did not confirm transmission. Any transmission of a significant disease may have consequences; in addition, the actual disease transmission rate is probably underestimated by the reports to DTAC. Even so, the reported rate is very low when compared with the nearly 28,500 transplants that occurred nationwide in the same year.
As centers and OPOs develop greater awareness of reporting potential disease transmissions to DTAC, the number of reports has increased annually, although the types of diseases reported have been similar from year to year. The increased reporting is not necessarily an indication that the risk of transmission is increasing. It may in fact be due to a growing awareness of the reporting process and a comfort level of transplant professionals in providing information to improve quality and care throughout our field.
The OPTN's direct authority addresses only vascular organs (often called "solid organs"). But many of the concerns with disease transmission from organs are shared with related fields, such as transplantation of tissues such as corneas, vasculature, skin and bone. Often a single deceased donor may provide both organs and tissue, and if "lookbacks" are needed for a potential transmission, it is important to identify all recipients in a timely and coordinated way.
Through our efforts and the shared commitment of all transplant professionals, our greatest hope is to minimize the risk of donor disease transmission. Knowing that the risk can never be entirely eliminated, we continue to learn from the reported events and apply these lessons both to improve care of affected recipients and to improve the donor screening process. Part of this process involves providing ongoing education to the transplant community. We have benefited greatly from the collaboration of many disciplines and professions with a role in this process, and we hope to continue and expand these efforts to create the safest possible environment for everyone who receives a transplant.
Dr. Emily Blumberg is a Professor of Medicine at the University of Pennsylvania, where she is also the Program Director for the Infectious Diseases Fellowship Training Program and the Director of Transplant Infectious Diseases. She is actively involved in the care of adults who are being evaluated for and/or have undergone heart, lung, liver, kidney, and pancreas transplants. She is the Chair of the DTAC.