BASIC CHECKS TO ENSURE A DONOR ORGAN IS SUITABLE

The process of organ donation and transplantation is a complex and highly regulated medical undertaking aimed at saving or significantly improving the lives of individuals suffering from end-stage organ disease. A critical phase in this process involves the meticulous assessment of a potential organ donor, the quality of the organs offered, and the suitability of these organs for specific recipients on the transplant waiting list. This systematic evaluation ensures the best possible outcomes for recipients while respecting the health and well-being of donors, particularly in live donation scenarios. This document outlines the key components of this assessment process.

1. Basic Assessment of Potential Organ Donors (Live or Deceased)

The initial assessment of any potential organ donor, whether living or deceased, follows a comprehensive protocol to determine overall health status, identify contraindications to donation, and gather crucial information relevant to potential organ quality and recipient matching.

• • 1.1 Medical History and Physical Examination:
    • A detailed medical history is compiled, reviewing past illnesses, surgeries, hospitalizations, medications, lifestyle factors (e.g., smoking, alcohol, substance use), and family history of significant diseases (particularly relevant for live donors).
    • Specific attention is paid to conditions that could compromise organ health or be transmissible, such as cancer (most absolute contraindication), uncontrolled or long-standing infections, severe systemic diseases (e.g., uncontrolled diabetes, severe hypertension, autoimmune disorders affecting organs), and conditions affecting the specific organ being considered (e.g., liver disease history for a potential liver donor).
    • A thorough physical examination is conducted to assess general health, signs of infection, organomegaly, neurological status (in deceased donors), and overall physical condition.
  • 1.2 Laboratory Assessments:
    • Blood Typing: ABO blood group compatibility is essential for solid organ transplantation (except for highly specific protocols like ABO-incompatible transplantation).
    • Tissue Typing (HLA Typing): Human Leukocyte Antigen (HLA) typing is performed to identify the donor’s specific HLA antigens. While less critical for immediate survival than ABO compatibility for most solid organs (except kidney), it is vital for matching recipients and predicting the likelihood of immune rejection.
    • Infectious Disease Screening: Extensive serological testing is conducted to detect transmissible diseases, including HIV, Hepatitis B, Hepatitis C, HTLV, Syphilis, CMV, EBV, and others depending on local protocols and donor risk factors. Nucleic Acid Testing (NAT) may also be used for more rapid and sensitive detection of some viruses. Active, uncontrolled systemic infection is typically a contraindication.
    • Organ Function Tests: Comprehensive blood tests assess the function of potential donor organs, including liver function tests (LFTs), kidney function tests (creatinine, BUN, GFR), cardiac enzymes, and pancreatic enzymes.
    • Hematology and Coagulation: Complete Blood Count (CBC) and coagulation profiles (PT, PTT, INR) assess overall blood health and clotting ability, important for surgical planning and assessing systemic health.
  • 1.3 Anatomic and Imaging Assessments:
    • Imaging studies such as CT scans, MRIs, or ultrasounds may be performed, particularly for potential live donors or deceased donors where there is suspicion of anatomical anomalies, masses, or structural damage to organs. For deceased donors, imaging related to the cause of death (e.g., head CT for brain death) is reviewed.
    • For live kidney donors, detailed angiography or CT angiography is necessary to map the renal vasculature. For live liver donors, volumetric studies and vascular imaging are critical.
    • Biopsies of specific organs (e.g., kidney, liver) may be performed, particularly in deceased donors over a certain age or with relevant medical history, to assess cellular health, fibrosis, and structural integrity.
  • 1.4 Specific Considerations for Deceased vs. Live Donors in Basic Screening:
    • For deceased donors, the assessment is often rapid and occurs in the context of critical illness and brain death or circulatory arrest. The focus is on identifying conditions acquired during the terminal event or critical care that might impact organ viability. Information gathering relies heavily on medical records, family interviews, and rapid diagnostic testing.
    • For live donors, the assessment is more comprehensive, prospective, and conducted over a longer period. The paramount principle is “do no harm” to the donor. The evaluation must ensure the donor is in excellent overall health and that donating will not significantly jeopardize their long-term well-being. This includes rigorous cardiac assessment, cancer screening appropriate for age, and evaluation of potential long-term risks associated with donating a specific organ (e.g., chronic kidney disease risk after nephrectomy).

2. Assessment of Organ Quality

Beyond the donor’s overall health, the specific quality of the organ itself must be assessed to predict its function post-transplantation. Organ quality exists on a spectrum, and assessment involves multiple factors.

• • 2.1 Factors Influencing Organ Quality:
    • Donor Age: Older donor age is a significant factor, often associated with reduced cellular reserve and increased risk of delayed graft function or potentially shorter graft survival, though many organs from older donors function well.
    • Cause of Donor Death/Injury: The nature of the terminal event (e.g., trauma, stroke, anoxia) and its impact on organ perfusion and oxygenation are critical.
    • Donor Hemodynamic Status: Prolonged periods of hypotension or shock preceding organ retrieval can cause ischemic damage.
    • Duration of Ischemia:
      • Warm Ischemia Time: The time an organ is without blood supply before cold preservation begins. This is maximally critical in DCD donors and during the retrieval process.
      • Cold Ischemia Time: The time an organ is stored on ice or machine perfusion after retrieval until reperfusion in the recipient. Each organ has different tolerances (e.g., heart/lungs < kidneys/liver).
    • Specific Organ Findings: Gross appearance (color, texture, turgor), presence of macroscopic lesions, and findings from biopsies (e.g., extent of glomerulosclerosis in kidney, fibrosis/steatosis in liver).
  • 2.2 Assessment Methods:
    • Visual and Palpatory Assessment: The retrieval surgeon carefully examines the organ in situ and after removal, noting its size, appearance, texture, and any visible abnormalities.
    • Biopsies: As mentioned, biopsies provide histological assessment of cellular health, damage, or disease.
    • Functional Testing: For kidneys, assessing urine output during critical care can be informative. For livers, synthetic function markers may be relevant.
    • Machine Perfusion: For kidneys and increasingly livers, machine perfusion allows for objective assessment of flow rates, resistance, and potentially metabolic parameters (like lactate clearance) during preservation, providing insights into organ viability.

3. Determining Suitability for a Given Recipient

The final step involves matching the assessed donor organ with the most suitable recipient on the waiting list. This is not simply about finding any recipient, but finding one where the risk-benefit analysis is optimized.

• • 3.1 Recipient Factors:
    • Medical Urgency: Recipients are prioritized based on the severity of their illness and the likelihood of death without transplantation (e.g., MELD score for liver, LAS score for lung, status for heart).
    • ABO Compatibility: As noted, direct compatibility is usually required.
    • Size Matching: The donor organ must be appropriately sized for the recipient’s body cavity to prevent surgical complications or functional issues.
    • HLA Matching: While not always necessary for immediate survival (less so for liver, heart), better HLA matching significantly reduces the risk of chronic rejection for kidneys and improves long-term outcomes.
    • Crossmatch Testing: A final immunological test comparing donor lymphocytes (or cells) with recipient serum is performed immediately before transplantation. A positive crossmatch indicates pre-existing recipient antibodies against donor tissue, predicting hyperacute or accelerated rejection, and is generally a contraindication (unless specific desensitization protocols are used).
    • Recipient Medical Status: The recipient must be medically stable enough to undergo major surgery and subsequent immunosuppression. Active infections, severe comorbidities (e.g., advanced heart disease for non-cardiac transplant), or uncontrolled psychiatric illness can be contraindications.
    • Psychosocial Evaluation (Recipient): Assessing the recipient’s understanding of the procedure, adherence potential to medication regimens, support system, and overall psychological readiness is crucial for long-term success.
  • 3.2 Balancing Donor Quality and Recipient Need:
    • The goal is to match the “best” organs to recipients who are likely to achieve the longest graft survival. However, in a time-sensitive situation with a critically ill recipient, a less-than-ideal organ might be considered if the alternative is death on the waiting list. This involves a shared decision-making process with the recipient (or their surrogate) and the transplant team, weighing the risks of using a marginal organ against the risks of remaining on the waitlist.

4. Specific Issues: Organ from a Deceased Donor (Brain Death – DBD)

Deceased donors who meet neurological criteria for brain death (DBD) represent the traditional and still most common source of solid organs for transplantation. Their assessment involves unique considerations within the intensive care unit setting.

• • 4.1 Medical Issues:
    • Establishing Brain Death: Rigorous neurological testing according to established criteria is paramount before donation can proceed.
    • Maintaining Hemodynamic Stability: Brain death can cause significant hormonal and autonomic dysfunction, leading to hypotension, arrhythmias, and diabetes insipidus. Intensive management is required to maintain blood pressure and perfusion to vital organs using fluids, vasopressors, and hormonal support (e.g., vasopressin, thyroid hormone, corticosteroids).
    • Managing Fluid and Electrolyte Balance: Careful monitoring and correction of severe electrolyte imbalances are necessary to preserve organ function.
    • Infection Management: Identifying and managing potential infections that may have contributed to or developed during the terminal illness is critical to avoid transmission.
  • 4.2 Surgical Issues:
    • Coordination and Timing: The retrieval surgery must be meticulously coordinated with multiple surgical teams working simultaneously to recover different organs from the same donor within strict time limits.
    • Minimizing Warm Ischemia: Once circulation is stopped, timely cross-clamping of vessels and initiation of cold perfusion are essential to minimize warm ischemia time for all organs.
    • In-Situ Cooling and Preservation: Cold preservation solutions are flushed through the organs in situ to cool them rapidly before removal.
    • Ex Situ Preparation and Packaging: Retrieved organs are carefully inspected, flushed with cold preservation solution on the back table, and packaged sterilely on ice for transport.
  • 4.3 Suitability Considerations:
    • The physiological insults experienced by a brain-dead donor in the ICU (inflammation, hormonal changes, hemodynamic instability) can potentially impact organ viability and function. The duration and severity of critical illness are factors considered when assessing the suitability of organs from DBD donors for a given recipient.

5. Specific Issues: Organ from a Live Donor

Live donation is an altruistic act, and the assessment process is fundamentally different as the donor’s health is the primary concern. Live donation is currently possible for kidneys, partial liver, partial lung (rare), and intestinal segments (very rare).

• • 5.1 Psychosocial Issues:
    • A thorough psychosocial evaluation is mandatory to ensure the donor is acting voluntarily, without coercion, understands the risks involved (short-term and long-term), has adequate social support, and is psychologically prepared for the surgery and recovery.
    • The relationship between the donor and recipient is explored, and potential for future relationship strain is considered. Independent donor advocacy is crucial.
    • Assessment includes screening for psychiatric conditions that could impair decision-making or recovery.
  • 5.2 Medical Issues:
    • The medical evaluation is exhaustive, focusing on excluding any condition that would make the surgery unsafe for the donor or compromise their long-term health after donation.
    • This includes comprehensive screening for cardiovascular disease, diabetes, hypertension (if not well-controlled), obesity, cancer, and any disease affecting the capacity of the remaining organ/segment to maintain adequate function (e.g., assessing GFR for potential kidney donors, liver function reserve for liver donors).
    • Identifying latent or subclinical conditions is crucial.
    • Long-term risks specific to donating an organ are discussed (e.g., slight increased risk of hypertension or proteinuria after nephrectomy, risk of biliary complications after partial hepatectomy).
  • 5.3 Surgical Issues:
    • Donor surgery is planned to be as safe as possible. Minimally invasive or laparoscopic techniques are often used for kidney retrieval to reduce pain and recovery time.
    • The surgical team must have extensive experience with the specific donor procedure to minimize complications.
    • Ensuring adequate remnant organ function is a primary surgical consideration (e.g., ensuring sufficient liver volume remains).
  • 5.4 Suitability Considerations:
    • The procured organ must be of sufficient quality, and the donor must be left with adequate remaining function to live a healthy life.
    • Live donor organs often have shorter cold ischemia times and come from healthier individuals than deceased donors, potentially leading to better immediate and long-term outcomes for the recipient.
    • Compatibility requirements (ABO, crossmatch) are the same as for deceased donation, though living donation allows for paired exchange programs or desensitization protocols for incompatible pairs.

6. Specific Issues: Donor After Cardiac Death (DCD) and Extended Criteria Donor (ECD)

These categories represent expanded pools of potential donors and involve specific assessment challenges related to organ quality and suitability.

• • 6.1 Donor After Cardiac Death (DCD): Medical and Surgical Issues
    • DCD involves retrieving organs after the irreversible cessation of circulatory and respiratory function. This introduces a period of warm ischemia from the withdrawal of support until cold perfusion can be initiated.
    • Controlled DCD: Occurs in a hospital setting after the family decides to withdraw life support. Once circulation stops and death is declared after a mandated waiting period (e.g., 2-5 minutes), rapid organ recovery and in-situ cooling using preservation solutions are initiated.
    • Uncontrolled DCD: Occurs after unexpected cardiac arrest (e.g., out-of-hospital). The warm ischemia time is unknown and potentially much longer, severely limiting organ viability (primarily kidneys, sometimes liver).
    • Assessment focuses on estimating or minimizing warm ischemia time and using aggressive preservation techniques, particularly machine perfusion, to assess viability and reduce injury. Organs susceptible to warm ischemia (heart, lungs) are generally not retrieved from DCD donors, though this is changing with normothermic regional perfusion techniques.
  • 6.2 Extended Criteria Donor (ECD): Definition and Criteria
    • ECD criteria vary by organ and organization (e.g., defined for kidneys by previous consortia as >60 years old, or 50-59 with two of hypertension, creatinine >1.5 mg/dL, or death from stroke; similar concepts exist for other organs).
    • ECD organs may have characteristics associated with a higher risk of delayed graft function, primary non-function, or potentially reduced long-term graft survival compared to ‘standard’ donors. These characteristics often relate to donor age, comorbidities (hypertension, diabetes), cause of death, or organ-specific findings (e.g., steatosis in liver, significant atherosclerosis).
  • 6.3 ECD: Medical and Surgical Issues
    • Assessment involves a more critical evaluation of organ function and structure. Biopsies are more frequently utilized (e.g., mandatory kidney biopsy for ECD kidneys) to quantify damage (e.g., glomerulosclerosis).
    • Machine perfusion is particularly valuable for ECD kidneys and livers, providing better assessment of viability and potentially improving outcomes compared to cold storage alone.
    • Surgical teams may need to adapt techniques based on organ characteristics (e.g., managing calcified vessels).
  • 6.4 Suitability Considerations for DCD/ECD:
    • These organs are often offered to recipients who are sicker (higher urgency) or have been on the waiting list for a significant time, accepting the potential risks in exchange for receiving a transplant sooner.
    • Thorough informed consent is paramount, ensuring the recipient understands the specific risks associated with a DCD or ECD organ compared to a standard donor organ.
    • Matching involves considering the recipient’s underlying condition, likelihood of handling potential post-transplant complications (like delayed graft function), and life expectancy.

Conclusion

The assessment of a potential organ donor, evaluation of organ quality, and determination of suitability for a given recipient is a multi-faceted process requiring expertise across medical, surgical, laboratory, and psychosocial disciplines. It involves a rigorous risk-benefit analysis for both the donor (in live donation) and the recipient. Utilizing standardized protocols, advanced diagnostic techniques, and careful consideration of individual donor and recipient characteristics ensures that the gift of organ donation can most effectively lead to successful transplantation and improved patient outcomes. The criteria and processes are continually refined based on ongoing research and clinical experience to maximize the utilization of available organs while maintaining safety and efficacy.