Susan L. Smith, MN, PhD

Disclosures

March 28, 2003

Determining Suitability of the Cadaveric Organ Donor

The next step after a potential organ donor has been identified is to determine his/her suitability for donation. All patients who are brain dead or whose brain death is imminent must be evaluated as a potential organ donor. The challenge facing donation and transplantation professionals is not to define ideal donors, but rather to define suitable donors. A suitable donor is an individual who has at least 1 organ that has a reasonable likelihood of functioning well posttransplantation.

Knowledge of the potential donor's reason for admission to the hospital and their current hospital course is crucial to successful multi-organ recovery. The assessment begins with a review of the emergency department admission and prehospital events, if applicable. A review of the physicians' and nurses' progress notes, the admission history and physical, as well as conversations with caregivers generally provide an overview of the patient's hospital course.

During this initial review, special emphasis should be placed on gathering information on periods of hemodynamic instability and other vital sign trends, use of vasoactive drugs, periods of hypoxia, oliguria, and trends in laboratory test values. If the potential donor has been hospitalized for several days, a comprehensive review can take several hours to complete. Next, a thorough physical examination is performed following the same guidelines as for any other patient in an ICU. The presence of tattoos, body piercing jewelry, or suspected prehospital needle track marks should be further investigated.

Obtaining a thorough and accurate medical and social history is one of the most important aspects of determining donor suitability. The OPO coordinator conducts a medical and social history interview designed to elicit information from family members and/or significant others about general health and lifestyle information (including risk factors for the transmission of HIV) pertinent to the potential donor. The person or persons responding to the questionnaire are first asked if they knew the deceased well enough to answer questions regarding their medical and social history.

Answers to these questions from the most knowledgeable historian can make the difference between acceptance or refusal of a particular organ or tissue for transplantation.[10] Although the donor's family and/or significant other will usually be able to provide this information, medical records must also be reviewed and discussions with physicians, nurses, friends and other healthcare agencies may be necessary to answer social and past medical history questions.

UNOS requires each OPO and transplant center to have guidelines for donor acceptance criteria. Regardless of what organs are to be donated, determining donor suitability must be performed in a systematic and comprehensive manner in order to recover as many organs as possible from each and every donor. Medical suitability of the organ donor is determined by an assessment of the following donor parameters:

 

  • Detailed medical and social history

  • Complete physical examination

  • Review of current hospital course

  • Organ-specific function

  • Age

  • Infectious disease status

  • Screen for malignancy (actual and history of)

 

Age Criteria

The age range of the potential donor is from term newborn to over 65 years, depending on the organ(s) being considered for donation, recipient needs, and quality of organ function in the potential donor. As the transplantable population ages, the upper limit for age of the organ donor has become more liberal and donor age is evaluated relative to organ function rather than in absolute chronologic terms. This practice is reflected in the significant change in donor age over the last decade. While the overall number of cadaveric donors has increased 30%, the number of donors older than 65 years of age has increased 535%.[10]

In spite of this trend, however, the ideal donor age is still considered to be 10 to 50 years, as grafts from older donors generally do not function as well as grafts from younger donors.[11] According to UNOS data, the 3-year graft survival rates for kidney and liver transplants from donors older than 65 years of age are 65.1% and 58.5% respectively, compared with 84.3% and 75.6% respectively, from donors 18-34 years of age.[8] The use of grafts from older donors however, is justified by some on the basis of the greater number of patients who will survive if transplanted compared with the number who will die on the waiting list if older donors are not utilized.

Evaluation for Infection

In today's environment, few medical contraindications to organ donation are absolute, with the exception of infectious and malignant diseases that are associated with poor transplant outcomes. All potential donors undergo a comprehensive evaluation for the presence of malignant tumors, sepsis, and other infectious diseases. The organ donor must be free of active infection as well. Donors with a recent history of infection documented by a positive blood, sputum, or urine culture must receive appropriate antibiotic coverage and have negative culture results to be considered for donation.

A primary concern is the presence of sexually transmitted disease. Serologic screening includes tests for syphilis, HIV, HTLV, and viral hepatitis. Absolute contraindications to organ donation include a donor who has:

 

  • a transmissible infectious disease that will adversely affect the recipient (ie, HIV, active hepatitis B virus (HBV) infection, West Nile virus, encephalitis of unknown cause, Jakob-Creutzfeldt's disease, malaria, or disseminated tuberculosis)

  • active visceral or hematologic neoplasm

  • clinical signs that indicate the organ is unlikely to function.

 

Bacterial infection. If the donor has been hospitalized for more than 72 hours, blood and urine cultures are done. An active systemic bacterial infection at the time of the donor's death introduces the risk of transmitting infectious disease from donor organs to the recipient. In spite of the risks, however, donor infection must be evaluated on an individual basis in order to avoid excluding suitable organs. For example, donors with meningococcal or pneumococcal sepsis who have had 24-48 hours of appropriate antibiotic coverage should be considered for organ recovery. An infectious process localized outside the abdominal cavity does not preclude abdominal organ recovery, and lung recovery may be possible when the donor has a unilateral pneumonia.

Cytomegalovirus (CMV) Infection. The CMV serologic status of the donor is also tested, but not as an exclusionary criterion. Positive CMV serology in the donor does not appear to have adverse effects on patient and graft survival.[12] Although historically, studies demonstrated decreased patient and graft survival when a CMV-positive graft was transplanted into a CMV-negative recipient, many of these studies predated the development of effective antiviral agents for prevention and control of CMV infection. An additional factor in favor of transplanting organs from CMV-positive donors is the high prevalence of CMV-positive individuals (potential recipients) in the general population. The incidence of CMV among donors and recipients ranges from 40% to 80%.

Syphilis. Serologic tests for syphilis include the venereal disease research laboratory (VDRL) and rapid plasma reagin circle card test (RPR). The detection of the antibody to syphilis via either test is not a contraindication to organ donation, however, because there is no documented evidence of transmission of syphilis from a donor to a recipient. This test is performed so that the recipient of an organ from a donor positive for the antibody to syphilis can be prophylactically treated with an appropriate course of antibiotics.

HIV infection. Serologic tests for HIV I and II antibody and HTLV I antibody are performed on all potential donors. According to UNOS policy, detection of the HIV I and II or HTLV I antibody is an absolute contraindication to donation unless subsequent confirmatory testing indicates that the original test results were falsely positive. Due to the risk of transmitting HIV to blood, tissue, and organ recipients, the Centers for Disease Control (CDC) developed guidelines for prevention of spreading HIV to recipients.[13] Regardless of potential donors' HIV antibody status, donors who meet the CDC criteria listed in Table 1 should be excluded from donation of organs and tissues unless the risk to the recipient of not performing the transplant is deemed to be greater than the risk of HIV transmission and disease. In such cases, organs may be recovered without restrictions, but the transplant center is required to inform the recipients of the potential risk of transmission of HIV infection from the donor.[14]

Even though HTLV I has been transmitted via blood transfusions, the transmission of HTLV I by solid organ transplantation has not been clearly demonstrated and, therefore, some OPOs and transplant programs do not reject donors who are HTLV I antibody-positive. Thus, depending on a potential recipient's severity status, he/she may have little alternative but to accept an organ from such a donor.[14]

Hepatitis B virus (HBV) infection. The debate continues regarding the transplantation of organs from donors who test positive for HBV infection. The implications vary depending on the specific marker(s) present in the donor and the recipient. The hepatitis screen for HBV includes the following markers: HBV surface antigen (HbsAg), HBV core antibody (anti-HBc), and HBV surface antibody (anti-HBs). Table 2 summarizes HBV serologic markers and associated risks of HBV transmission to recipients.[14,15]

Hepatitis C virus (HCV) infection. As with HBV infection, there is lack of consensus within the transplant community about transplanting organs from HCV-positive donors. Fifty percent of such recipients become HCV-antibody positive, 24% become HCV-PCR positive, and up to 35% develop liver disease.[16]

All potential donors are tested for HCV antibody (anti-HCV) either to rule out donation or to establish a basis for initiation of treatment in the recipient at centers where positive HCV serology is not a contraindication to donation. Several programs advocate that HCV-positive donors be used in recipients with a history of HCV-positive antibody. A liver graft from an HCV-positive donor to an HCV-positive recipient does not appear to be associated with increased morbidity or mortality compared with HCV-positive recipients of HCV-negative donor livers. Additional recommendations include that HCV-positive organs be reserved for cases with urgent need and patients who have a limited chance of being transplanted (ie, the highly sensitized patient waiting for a kidney transplant).[14,15]

Evaluation for malignancy. Given the impact of donor-transmitted malignancy on the outcome of organ transplantation, detection of malignancy is an important measure of donor suitability. Not all malignancies, however, constitute an absolute contraindication to donation. Low-grade skin cancers, low-grade solid organ tumors with a greater than 5-year documented tumor-free interval, and primary brain tumors that have not undergone previous surgery usually do not preclude organ donation. As with other donor selection criteria, the acceptance of organs from donors at risk of transferring a malignancy to recipients must be weighed against the urgency of the transplant, and the recipient and/or the recipient's family must be informed of the potential risks.

Evaluation for Severe Systemic Disease

The ideal organ donor is relatively young, and is free of and with no history of end-organ disease. Each organ system is evaluated separately. Other than carcinoma (except primary brain tumor), no disease by itself should be considered a contraindication to organ donation.

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