Due to organ shortage and difficulties for availability of cadaveric donors, living donor transplantation is an important choice for having allograft. Live donor surgery is elective and easier to organize prior to starting dialysis thereby permitting preemptive transplantation as compared to cadaveric transplantation. Because of superior results with living kidney transplantation, efforts including the usage of “Medically complex living donors” are made to increase the availability of organs for donation. The term “Complex living donor” is probably preferred for all suboptimal donors where decision-making is a problem due to lack of sound medical data or consensus guidelines. Donors with advanced age, obesity, asymptomatic microhematuria, proteinuria, hypertension, renal stone disease, history of malignancy and with chronic viral infections consist of this complex living donors. This medical complex living donors requires careful evaluation for future renal risk. In this review we would like to present the major issues in the evaluation process of medically complex living kidney donor.
Advances in immunosuppressive therapy, refinement in surgical techniques and in public awareness, altruism, and goodwill have allowed an increase in the number of living donor kidney transplantation; whereby, virtually all biological related, unrelated and medically and psychosocially suitable individuals can be considered as donors [
Risk factors associated with complex living donor.
Type of risk factor | Example |
---|---|
Evidence of current renal disease | Hematuria, proteinuria, nephrolithiasis |
Direct risk for CKD | Hypertension, obesity |
Reduced nephron mass | Age ≥ 65 years |
Genetic risk factor | Family history of ESRD in 1st relative |
Risk factors for a CKD | Diabetes in first degree relative, impaired fasting glucode |
Cardiovascular risk factors | Smoking, hyperlipidemia, hypertension |
Other | Black race, sickle trait |
Combination of previous factors | Hypertensive black patient |
CKD: chronic kidney disease and ESRD: end stage renal disease.
First of all, to avoid conflict of interests, the proposed donor should be carefully evaluated by a physician not involved in the care of the proposed recipient. The physician must confirm that the patient’s wish to donate is voluntary. Informed consent is a core value in living kidney donation. Prior to donor nephrectomy, the potential donor must be informed of [ The nature of the evaluation process. The results and consequences/morbidity of testing, including the possibility that the conditions that may be discovered can impact future healthcare, insurability, and social status of the potential donor. The risks of operative donor nephrectomy, as assessed after the complete evaluation. These should include, but not be limited to the risk of death, surgical morbidities, changes in health and renal function, impact upon insurability/employability, and unintended effects upon family and social life. The responsibility of the individual and the social system in the management of discovered conditions (e.g., if the donor is discovered to have tuberculosis, the donor should undergo treatment, the community has a responsibility to help the donor secure proper care with referral to an appropriate physician). The expected transplant outcomes (favorable and unfavorable) for the recipient and any specific recipient conditions which may impact upon the decision to donate the kidney. Disclosure of recipient specific information which must have the assent of the recipient. Alternative renal replacement therapies available to the potential recipient.
Additionally, the potential donor should be capable of understanding the information presented in the consent process.
Previously, older kidney donors, such as those over 50 years of age, were not considered as suitable. However, the kidneys from such donors are now commonly used if these individuals are in good physical and mental condition and have adequate kidney function. A survey of kidney transplant centers in the United States in 2007 showed that almost 60 percent of centers had no upper-age limit for kidney donors [
Obesity (BMI > 30 kg/m2) in proposed living donors is associated with increased risk for surgical complications as well as future medical problems including diabetes, hypertension, nephrolithiasis, glomerular disease with associated albuminuria or overt proteinuria, and ESRD [ Patients with a BMI > 35 kg/m2 should be discouraged from donating, especially when other comorbid conditions are present. Obese patients should be encouraged to lose weight prior to kidney donation and should be advised not to donate if they have other associated comorbid conditions. Obese patients should be informed of both acute and long-term risks, especially when other comorbid conditions are present. Healthy lifestyle education should be available to all living donors.
According to our transplantation protocol we also advise lifestyle modifications including diet and exercise to our obese donor candidates.
Urine dipstick testing in the absence of fever, trauma, menstruation, or intensive exercise should be repeated twice to confirm the presence of microscopic hematuria. Isolated microscopic hematuria (defined as >3–5 urinary sediment red blood cells (RBCs)/HPF) may not be a contraindication to donation. RBCs with glomerular origin have a dysmorphic appearance observed by phase-contrast microscopy and automated RBC analysis. Patients with persistent microscopic hematuria should not be considered for kidney donation unless urine cytology and a complete urologic work up are performed [
Proteinuria greater than 250 mg is a marker of glomerular pathology and renal disease. Proteinuria should be assessed as a standard part of the donor evaluation process. The collection should be repeated and its accuracy checked when the result is abnormal. An overestimate of proteinuria should be suspected if total urine creatinine-to-body-weight ratios are greater than 25 mg/kg (>20
Hypertension has been considered to be a contraindication in potential renal transplant donors. However, the precise risk to donors who have borderline elevation in BP and those with a family history of hypertension has not been conclusively determined. In general, screening for hypertension in a potential donor includes BP measurement on three separate occasions [ Patients with a BP > 140/90 mmHg by ABPM are generally not acceptable as donors. BP should preferably be measured by ABPM, particularly among older donors (≥50 years) and/or those with high office BP readings. Some patients with easily controlled hypertension who meet other defined criteria (e.g., >50 years of age, GFR ≥ 80 mL/min, and urinary albumin excretion < 30 mg/day) may represent a low-risk group for development of kidney disease after donation and may be acceptable as kidney donors. Donors with hypertension should be regularly followed by a physician.
Type 2 diabetes mellitus is an increasingly common cause of ESRD. When the recipient has diabetes mellitus, the risk of related donors developing diabetes later in life is a major concern. All potential living donors should have a fasting plasma glucose estimation to exclude undiagnosed diabetes or glucose intolerance. Most transplantation centers regard established diabetes mellitus as a contraindication to living donation, and many centers exclude individuals deemed as high risk. Although little is known as to whether single-kidney status would accelerate the progression of diabetic nephropathy, there were experimental studies suggesting the increased risk of developing diabetic nephropathy after nephrectomy [
A history of urinary tract stones is at least a relative contraindication to donation because urinary system stones tend to recur and may cause obstruction of a solitary kidney. However, renal transplantations performed from donors with kidney stones were reported previously [ No hypercalciuria, hyperuricemia, or metabolic acidosis. No cystinuria or hyperoxaluria. No urinary tract infection. Multiple stones or nephrocalcinosis are not evident on computed tomography (CT) scan.
Contraindications to donation in individuals with urinary stones are (1) nephrocalcinosis on X-ray or bilateral stone disease; and (2) stone types that have high recurrence rates and are difficult to prevent, such as the following. Cystine stones that have a high rate of recurrence and a need for urologic procedures in the donor. Struvite stones or infection stones that are difficult to eradicate, and thus it is not feasible to transplant a kidney with them into an immunosuppressed patient. Stones associated with inherited or other systemic disorders, such as primary or enteric hyperoxaluria, distal renal tubular acidosis, and sarcoid because of the probability of a high rate of recurrence and the risk of renal insufficiency. Stones in the setting of inflammatory bowel disease with an increased risk of stones particularly after bowel resection, also increased risk of renal insufficiency. Recurrence while on appropriate treatment (i.e., failed therapy).
Asymptomatic potential donor with current single stone may be suitable if [ the donor meets the criteria shown previously for single stone formers and current stone is ≤1.5 cm in size or potentially removable during transplant. An asymptomatic potential donor with no history of calciluria or colic event is found to have a single stone on evaluation may be suitable for kidney donation if [ no metabolic abnormality or urinary infection exists and if multiple stones or nephrocalcinosis are not evident on CT.
Incidental renal stone detected by magnetic resonance or computerized tomography renal angiography is relatively common (7.4%) in the report from the single center by Kim et al. [
Kidney donor candidates should be screened for both personal and family history of malignancy. They should undergo standard age- and gender-appropriate screening tests as recommended by national organizations. A prior history of the following malignancies usually excludes live kidney donation [ Melanoma, testicular cancer, renal cell carcinoma, choriocarcinoma, hematological malignancy, bronchial cancer, breast cancer, and monoclonal gammopathy [
A prior history of malignancy usually excludes live kidney donation but may be acceptable if [ The specific cancer is curable and the potential transmission of the cancer can reasonably be excluded. Examples include colon cancer (Dukes A, >5 years ago), nonmelanoma skin cancer, or carcinoma in situ of the cervix.
An oncology consultation is also advised to donor candidates with a history of malignancy during the donor evaluation process.
HIV positive status is a contraindication for donation. Donor with a positive hepatitis C Virus (HCV) serology may be only considered for donation to a HCV positive recipient, if the donor PCR is negative, certain genotypes (genotype 4) are treated and eradicated from the donor, and there is no evidence of chronic hepatitis or cirrhosis on liver biopsy. There is no data on live kidney transplantation from HCV positive donors; however, cadaveric renal transplantations from HCV positive donors to HCV positive recipients were reported [
Although the detection of hepatitis B surface antigen (HBsAg) in a potential kidney donor generally excludes the individual from live kidney donation [
Tuberculosis is a common infection of renal transplant recipients in developing countries. The peak incidence is after the first year of transplantation and mortality is considerable [
Urinary tuberculosis is a contraindication for donation. Additionally, in Amsterdam forum it was suggested that donors previously treated for urinary tuberculosis might have dormant tuberculosis within the kidney and thus remain unsuitable for donation [
Because of superior results with living kidney transplantations, efforts including the use of “medically complex living donors” are made to increase the availability of organs for donation. However, in the evaluation process of these proposed donors we should not forget the following four issues: (1) the risk to the donor must be low, (2) the donor must be fully informed, (3) the decision to donate must be independent and voluntary, and (4) there must be good chance of a successful recipient outcome [