RENAL TRANSPLANTATION 0039-6109/98 $8.00 + .OO

THE EVALUATION OF PROSPECTIVE RENAL

TRANSPLANT RECIPIENTS AND LIVING DONORS

Bertram L. Kasiske, MD

GENERAL APPROACH TO TRANSPLANT RECIPIENTS AND DONORS

For many patients, renal transplantation is the treatment of choice for end-stage renal disease (ESRD). As soon as it is evident that a patient will need therapy for ESRD, renal transplantation should be considered. Transplantation should be considered sooner, rather than later, because some patients may be able to undergo pre-emptive transplantation and avoid dialysis altogether. The evaluation of transplant candidates should be directed to ensuring that the risk of surgery and immunosuppression is acceptable to both patient and. physician. The evaluation should also attempt to determine the likelihood that the graft will function well enough and long enough to improve the quality of life of the recipient.

The shortage of organs for transplantation in the United States is growing. The median waiting time for a cadaveric kidney is more than 2 years. Therefore, increasing emphasis is being placed on using living donors for renal transplantation. In addition, kidneys from living-related donors tend to function longer than kidneys from cadaveric donors. The primary goal in the evaluation of a potential living donor is to ensure the donors safety. Both the short- and long-term risks of donation need to be carefully assessed. In addition, the living donor evaluation should

From the Division of Nephrology, Department of Medicine, University of Minnesota, College of Medicine, Hennepin County Medical Center, Minneapolis, Minnesota

SURGICAL CLINICS OF NORTH AMERICA

VOLUME 78 * NUMBER 1 . FEBRUARY 1998 27

28 KASISKE

consider whether the kidney to be transplanted will provide suitable long-term function for the recipient.

THE EVALUATION OF POTENTIAL RENAL TRANSPLANT RECIPIENTS

The Initial Evaluation

The recipient evaluation should be cost-effective. Often, a brief history and physical examination can determine that a patient is not a suitable candidate for transplantation before other, more expensive tests are carried out. Age and poor overall health may be reason enough not to proceed with additional evaluation (Table 1). Transplantation has no absolute age contraindication, but the risks of both surgery and immunosuppression increase with age. Age should be judged in the context of the patients overall health. The concept of physiologic age, although difficult to define, underscores the importance of considering both age and overall health status together.

Diabetes is now the most common cause of ESRD in the United States, and the incidence of ESRD from diabetes continues to grow at a faster rate than that due to other cause^.'^ Diabetes frequently influences the evaluation process from the outset. Compared with most other causes of ESRD, patients with diabetes experience increased morbidity and mortality. Thus, special consideration should be given to patients with diabetes to ensure that the risk of transplantation is minimized and their quality of life is enhanced as much as possible. With regard to risk, special consideration should be given to the cardiovascular evaluation because cardiovascular disease complications are particularly common among diabetics and may greatly increase the risk of transplant surgery. In addition, some diabetic patients may be candidates for simultaneous kidney-pancreas transplantation.

Screening for Cancer

Except for locally invasive basal cell or fully excised squamous cell carcinomas, patients with an active malignancy should not receive a

Table 1. POTENTIAL CONTRAINDICATIONS FOR RENAL TRANSPLANT RECIPIENTS

Advanced age and poor health Malignancy Infection Liver disease Previous allograft lost to recurrent focal segmental glomerulosclerosis Inoperable coronary artery disease Substance abuse Medical nonadherence

PROSPECTIVE RENAL TRANSPLANT RECIPIENTS AND LIVING DONORS 29

renal transplant. The pretransplant evaluation should screen for malig- nancies and should include a thorough physical examination, chest radiography, and stool Hemoccult testing. Flexible sigmoidoscopy should be considered for older individuals to rule out colorectal carci- noma, Women with a family history of breast carcinoma should undergo mammography, and all women over 40 should have had a recent mam- mogram. Women should also have a pelvic examination and Pap test.

Management of transplant candidates with a history of malignancy but no evidence of active tumor is particularly difficult. Although immu- nosuppression increases the risk of tumor recurrence in this setting, it is difficult to precisely determine that risk. For many patients, the risk may not be great enough to justify foregoing transplantation. Data from post- transplant tumor registries give some insight into the risk of recurrence, and that risk varies for different tumor types but generally declines over time. The overall risk of recurrence for a patient who has been free from all evidence of malignancy for 2 years is about 47% after renal transplantation, and the risk after 5 years is approximately 13%. How- ever, different tumors behave differently, and guidelines address how different tumors should be approached'

Screening for Infections

The presence of an active, potentially life-threatening infection is a contraindication to transplantation, and patients should be carefully screened for infections as part of the pretransplant evaluation. All pa- tients should be screened for human immunodeficiency virus (HIV), and transplantation should probably be avoided in those who are HIV p~si t ive.~ Chest radiography and a purified protein derivative (PPD) skin test should be used to screen for tuberculosis, especially in patients from high-risk populations. Patients who are PPD positive and have not already been adequately treated should probably receive prophylactic therapy prior to transplantation. Patients on peritoneal dialysis should not be transplanted if they have had peritonitis within the previous 3 to 4 weeks. Cytomegalovirus (CMV) infection is common after transplanta- tion. However, the best predictor of post-transplant CMV infection is an increased CMV antibody titer in the donor, especially if the recipient has a low titer. Screening for CMV antibodies in donor and recipient should not influence the decision to transplant but can be used to guide prophy- lactic therapy after tran~plantation.~

Liver Disease

All transplant candidates should be screened for the presence of viral hepatitis. It is generally accepted that patients who are hepatitis B surface antigen (HBsAg) positive are at increased risk of dying after transplantation. Nevertheless, HBsAg is not a contraindication to trans-

30 KASISKE

plantation per se. However, patients who are HBsAg positive and have serologic evidence of viral replication should probably not receive a transplant. Patients without evidence of active hepatitis B viral replica- tion, but with elevated enzymes, should be considered for biopsy. Even if enzymes are normal, a biopsy should be considered because liver enzymes are a poor marker of disease activity in ESRD patients. Patients with hepatitis B and moderate to severe chronic active hepatitis on biopsy are probably at high risk for disease progression after transplanta- tion. Such patients may best remain on dialysis. Patients without liver disease who are HBsAg negative should be vaccinated for hepatitis B.

The risk conferred by hepatitis C virus (HCV) is less well defined. Indeed, whether hepatitis C increases the risk of renal transplantation continues to be controversial. 'Nevertheless, patients who are HCV anti- body positive should be considered for liver biopsy if enzymes are elevated. Patients with evidence of viral replication and patients with chronic active hepatitis on biopsy are probably at increased risk for liver disease progression after transplantation. Such patients should be clearly informed of this risk, and careful consideration should be given to the advisability of transplantation.

Recurrent Renal Disease Risk

The possibility that the underlying renal disease will cause the allograft to fail is usually not great enough to preclude transplantation. An exception may be the occasional patient with idiopathic focal seg- mental glomerulosclerosis (FSGS) who has already lost at least one allograft to disease recurrence. For such a patient, the risk of losing a second or third allograft to recurrent FSGS may be quite The rate of graft loss due to recurrence of most other forms of glomerulone- phritis is too low to justify denying transplantation. Similarly, diabetes regularly recurs in the allograft, but the rate of progression is generally slow, and diabetes is still a relatively uncommon cause of graft failure. Primary oxalosis was once considered to be a contraindication to trans- plantation because recurrence in the allograft was rapid. Currently, pa- tients can be successfully treated with orthophosphate and pyridoxine, and pre-emptive renal transplantation with possible liver transplantation should be considered.

Cardiovascular Disease

The morbidity and mortality from ischemic heart disease (IHD) are high in both the early and late post-transplant periods. Therefore, pa- tients should be carefully screened for IHD as part of the pretransplant evaluation. Patients with symptomatic IHD should probably undergo coronary angiography prior to transplantation. Asymptomatic patients who are at increased risk for IHD should be considered for a noninvasive

PROSPECTIVE RENAL TRANSPLANT RECIPIENTS AND LIVING DONORS 31

cardiac stress test, and those with a positive stress test should undergo angiography. High-risk individuals include patients with a prior history of IHD, diabetics over the age of 40 to 45, and individuals with multiple risk factors, such as smoking, hypertension, hypercholesterolemia, and a positive family history of premature IHD.4 Patients who have critical coronary artery lesions on angiography should undergo revasculariza- tion prior to transplantation. Unfortunately, the rate of reocclusion after revascularization is high among patients with ESRD. Risk factor inter- vention should be aggressively pursued for all patients with IHD or increased risk for IHD. Many may be candidates for aspirin prophylaxis after transplantation.

The risk for strokes after renal transplantation is also increased. Patients with a history of cerebral vascular disease should be carefully evaluated prior to transplantation and should be free of symptoms for at least 6 months prior to transplantation. For asymptomatic patients with a carotid bruit, carotid ultrasonography should be considered. However, in the general population, controlled clinical trials have shown that the success of prophylactic carotid endarterectomy is center-depen- dent. The decision to treat asymptomatic patients with prophylactic carotid endarterectomy should probably be individualized. Certainly, prophylactic aspirin and risk-factor intervention should be considered in patients with atherosclerotic cerebral vascular disease.

Psychosocial Evaluation

Nonadherence to immunosuppression is a major cause of renal allograft failure. An attempt should be made prior to transplantation to identify individuals who are likely to be nonadherent. However, it is often difficult to reliably predict who will fail to adhere to therapy, and care should be taken to avoid unjustifiably denying transplantation to patients who may have changed their behavior. Most believe that pa- tients with a history of substance abuse should undergo treatment and demonstrate a period of abstinence before transplantation.'O Finally, can- didates with major cognitive or psychiatric disorders are usually discov- ered during the early phases of the evaluation, and they can be referred to appropriate specialists.

Urologic Evaluation

Patients with chronic urinary infection and/or incomplete bladder emptying can usually be identified during the history and physical examination. Therefore, a voiding cystourethrogram is probably not necessary for all patients. For patients with a urinary diversion, every attempt should be made to establish bladder drainage before trans- plantation. If necessary, intermittent self-catheterization can be used following transplantation. Consideration should also be given to ne-

32 KASISKE

phrectomy prior to transplantation. Selected patients with ureteral reflux and chronic infection, polycystic kidneys that are too large or have infected cysts, severe nephrotic syndrome, nephrolithiasis with infection, renal carcinoma, or hypertension that is difficult to control may be candidates for unilateral or bilateral nephrectomy. A laparoscopic ap- proach can sometimes be used to reduce the morbidity and cost of nephrectomy.

Gastrointestinal Evaluation

Cholecystectomy should be considered for patients who have had recent cholecystitis. Otherwise, routine screening for asymptomatic cho- lelithiasis may not be necessary. Patients with symptomatic diverticulitis should be considered for partial colectomy. However, screening for asymptomatic disease may not be cost-effective. Similarly, pretransplant radiographic or endoscopic evaluation for peptic ulcer disease can prob- ably be restricted to patients with signs and symptoms of peptic ulcer disease.

Blood and Tissue Typing

The three major immunologic barriers to transplantation should be assessed as part of the pretransplant evaluation: (1) ABO blood group compatibility, (2) A, B, and DR major histocompatibility complexes (MHC), and (3) the presence of preformed antibodies. In general, trans- plants should not be performed across incompatible ABO blood groups. Although some consider the degree of MHC matching to be an optional consideration for living donor and cadaveric transplantation, the United Network for Organ Sharing (UNOS) mandates the sharing of zero- antigen mismatched kidneys and awards points (as part of its cadaveric organ allocation system) in inverse proportion to the degree of MHC mismatching. As a final screen, the recipients serum is tested against donor tissue for the presence of preformed antibodies that can cause hyperacute rejection. The presence of preformed antibodies is generally considered to be a contraindication to transplantation with that donor.

EVALUATION OF POTENTIAL LIVING DONORS

The Donor Initial Evaluation

The primary goal of the living donor evaluation is to ensure the safety and well-being of the donor (Table 2). Both the potential donor and his or her physician must ultimately agree that the risk of donation is acceptable. An initial evaluation should attempt to quickly and effi- ciently identify individuals who cannot donate because they are immu-

PROSPECTIVE RENAL TRANSPLANT RECIPIENTS AND LIVING DONORS 33

Table 2. POTENTIAL CONTRAINDICATIONS FOR LIVING KIDNEY DONORS

ABO incompatibility Diabetes Positive crossmatch Age less than 18 or over 65 years Malignancy Nephrolithiasis Infection Hypertension (>140/90 mm Hg)

Proteinuria (>150 mg/24 h) Renal disease or reduced renal function

Increased medical risk for surgery Inability to give informed consent

nologically incompatible. This saves time, money, and unnecessary anxi- ety expended by family members who are ultimately found to be immunologically incompatible. Blood typing is relatively inexpensive, and if the blood type is not compatible with that of the recipient, the evaluation of that potential donor need not proceed further. Some cen- ters also perform an initial crossmatch to eliminate the need for addi- tional, expensive work-up if the crossmatch is positive. A preliminary medical evaluation can then be carried out if the blood type is compati- ble and the preliminary crossmatch is negative. This preliminary exami- nation can then be followed by a more detailed evaluation that usually culminates in a renal angiogram.

Ideally, the donor evaluation should be carried out by individuals who are not members of the transplant team. This eliminates any possi- ble conflict of interest among transplant team members, who must balance their wishes to offer transplantation to the recipient with their obligation to protect the donor. Unfortunately, cost and other logistical barriers may not permit completely separate teams to evaluate potential donors and recipients. However, every donor can and should have a personal physician who is not a member of the transplant team. The donors physician can be an effective advocate who can help the patient make an informed decision on donation.

Choosing of the Best Living Donor

The best donor is usually a blood relative. If more than one blood relative wishes to donate, the choice should be based on both medical and nonmedical criteria. In addition to choosing the best MHC match, donor age, geographic location, occupational risk, and parental responsi- bilities may play a role in the decision. The best MHC match is an identical twin. The next best match is an MHC-identical (two-haplotype) sibling, followed by a one-haplotype matched sibling or parent. It is essential that the donation be truly voluntary and that the potential donor be given every opportunity to choose not to donate. Health care workers should protect individuals who decide not to donate by offering to tell the family that the donor is not suitable.

If a suitable blood relative is not found, consideration can be given to using an emotionally related donor.8 The survival of kidneys donated

34 KASISKE

from spouses exceeds that from cadaveric donors.14 A relative by mar- riage or adoption or even a very close personal friend may be a suitable donor. However, great care should be taken to ensure that the donation is truly voluntary.

The Economic Risk of Donation

In the United States, Medicare covers all expenses related to organ donation. Nevertheless, potential donors should understand that there may still be some financial risk. Expenses that may not be covered by Medicare include time off from work (vacation or sick leave) and travel to and from the transplant center. The cost of health insurance should not increase as a result of donation; however, there is always a remote possibility that a medical condition will be discovered during the evalua- tion, such as proteinuria, that could jeopardize future insurability.

Psychological Assessment

A psychological evaluation of the donor should be carried out by a trained psychologist, psychiatrist, and/or social worker. This evaluation should ensure that the potential donor is informed about the psychologi- cal risks of donation, including the depression that may occur if the outcome is not favorable. The evaluation should also attempt to uncover any psychological pressures influencing the voluntary nature of the potential donor's decision to donate. Finally, during this phase of the evaluation, provision should be made for psychological support for the donor after transplantation.

Surgical Risk of Donation

Mortality associated with nephrectomy is estimated to be 0.03% to 0.05%.3, Major postoperative complications have been estimated to occur in approximately 4% of cases. These include incidental splenec- tomy, deep vein thrombosis, pulmonary embolus, intra-abdominal ab- scess, wound hematoma or infection, pneumonia, and atelectasis. Malnu- trition, cardiovascular disease, poorly controlled blood pressure, and diabetes each increase the risk of postoperative complications. Thus, evidence for any of these conditions should generally preclude organ donation.

Long-Term Risk of Donation

The long-term risk of donating a kidney appears to be very small if the donor does not have underlying renal disease. We conducted a meta-

PROSPECTIVE RENAL TRANSPLANT RECIPIENTS AND LIVING DONORS 35

analysis of epidemiologic studies that examined the long-term effects of reduced renal mass.6 There were 48 studies in which 3124 patients with reduced renal mass were compared with 1703 two-kidney controls. Organ donors made up 61% of the patients with reduced renal mass. No progressive decline in renal function occurred during the follow-up period. Proteinuria was more common after a 50% reduction in renal mass, but there were no progressive increases in protein excretion over time. A small increment in systolic blood pressure was noted in patients with reduced renal mass, but this increase was insufficient to result in an increased prevalence of hypertension. Thus, from these results, the long-term risk of donating a kidney appears to be very small. However, the exact risk of donating is unknown, and a registry of living donors is needed that would allow the accurate collection of these data.

It is at least theoretically possible that donating a kidney could accelerate diabetic nephropathy, so the donor should be screened for diabetes. However, the theoretical risk of accelerating diabetic nephropa- thy should be weighed against the risk of false-positive screening tests for diabetes. A fasting plasma glucose level, a glucose tolerance test, and a glycosylated hemoglobin are all reasonable tests to screen for diabetes. About 4% to 10% of normal individuals may have a false-positive glucose tolerance test.

Autosomal recessive polycystic kidney disease is uncommon and should be evident in any patient old enough to donate a kidney. Autoso- ma1 dominant polycystic kidney disease (ADPKD) is much more com- mon. Specific criteria based on age and the number of cysts present have been developed to aid in the diagnosis of ADPKD (Table 3)." The specificity of ultrasound diagnosis using these criteria is nearly 100% by age 30, so that ultrasonography should be sufficient if the potential donor is over 30. If the potential donor is 25 to 30 years old, CT should be obtained to enhance the diagnostic sensitivity. If the potential donor is less than 25, testing for the ADPKD 1 and ADPKD 2 genes should be considered.

Hereditary nephritis, or Alport's syndrome, is generally familial, although up to 15% of cases may occur in the absence of a family history. When family history of hereditary nephritis is documented, it is usually inherited in an X-linked pattern. Males with the gene usually develop hematuria by age 5, long before they would be considered candidates for

Table 3. CRITERIA FOR DIAGNOSING AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE

Age (years) Criteria

Less than 30 30-59 At least 60

At least two renal cysts (unilateral or bilateral) At least two cysts in each kidney At least four cysts in each kidney

Data from Ravine D, Gibson RN, Walker RG, et al: Evaluation of ultrasonographic diagnostic criteria for autosomal dominant polycystic kidney disease 1. Lancet 343B24-827, 1994.

36 KASISKE

donation. Asymptomatic males do not carry the gene, and heterozygous females with hematuria rarely progress to ESRD. Potential donors for recipients with hereditary nephritis should be carefully screened and offered genetic counseling. Patients should be examined for microhema- turia, renal dysfunction, hearing impairment, and eye abnormalities. Male relatives without hematuria or other abnormalities are suitable donors. Female relatives without hematuria may be suitable donors; however, a young women should consider the possibility that she may have a child with the disease who may someday need renal transplanta- tion. Genetic testing can be used to determine whether the woman is a carrier. Female relatives with hematuria or other abnormalities should probably not donate. Finally, both donors and recipients should be informed that recipients with hereditary nephritis may develop anti- glomerular basement membrane disease that could result in graft failure.

The standard dipstick test for hematuria is very sensitive, but a positive result must be confirmed by microscopic e~amination.~ Patients with isolated microscopic hematuria should probably undergo a urologic evaluation to rule out malignancy. If this evaluation is negative, biopsy may be considered. A high proportion of such patients are found to have an abnormality on biopsy, that is, IgA nephropathy or thin glomerular basement membranes, and these patients should probably not be donors. However, if the biopsy is normal, the long-term prognosis is probably excellent, and donation may still be considered.

Proteinuria is usually defined by greater than 150 mg/24 h total protein excretion, or greater than 30 mg/24 h albumin excretion, and proteinuria is usually a contraindication to d~nat ion .~ However, occa- sional patients with isolated postural proteinuria may be suitable candi- dates. Pyuria should also be considered to be a contraindication unless it can be unequivocally shown that there is a reversible cause, such as cystitis.

Hypertension (blood pressure greater than 140/90 mm Hg) is at least a relative contraindication to donation. Nephrectomy appears to cause a small increase in blood pressure in normal individuals.6 Thus, it is likely that nephrectomy may exacerbate blood pressure control in individuals with hypertension. In addition, hypertension is a common cause of ESRD, and it is possible that organ donation could accelerate renal damage due to hypertension. In patients with borderline blood pressure elevation, echocardiographic evidence of left ventricular hyper- trophy may help in the diagnosis of hypertension.

Nephrolithiasis tends to be recurrent and can lead to obstruction, infection, and ESRD. Therefore, nephrolithiasis is at least a relative contraindication to kidney donation. However, a potential donor who has passed only one stone, has been free of stone disease for at least 10 years, and has a negative pyelogram could be considered for donation if a metabolic evaluation shows that the risk for future stone formation is low.8

Many centers perform donor-specific blood transfusions to reduce the risk of rejection after transplantation. If an angiogram is part of

PROSPECTIVE RENAL TRANSPLANT RECIPIENTS AND LIVING DONORS 37

the evaluation, donor-specific transfusions should be done prior to the angiogram because some patients develop cytotoxic antibodies after transfusion that may preclude donation. Traditionally, an angiogram of both kidneys has been used to define the vascular anatomy and help in selecting the better kidney for transplantation. Recently, spiral CT using intravenous radiocontrast has proven equally effective, and the spiral CT is associated with less morbidity and risk to the donor.,2 If both kidneys have a single renal artery, the left kidney is usually selected because it has a longer renal vein. However, if one kidney has two renal arteries, the kidney with only one artery may be preferable. Occasionally, asymptomatic, unilateral fibromuscular dysplasia may be encountered, and it is tempting to transplant the involved kidney after surgically removing the arterial lesion. Because the natural history of fibromuscular dysplasia discovered incidentally is unknown, the risk of donating is also unclear. However, at least some patients may develop fibromuscular dysplasia in the contralateral kidney, so the decision to accept a donor with incidentally discovered fibromuscular dysplasia is difficult.

Risk to the Recipient

Recipients and donors should be aware that kidneys from older donors, especially over 60 years of age, may function less well than kidneys from younger donors. The donors renal function, adjusted for age and body size, should generally be normal. Although donor age and renal function should be taken into account, it is difficult to specify precise levels of age or renal function that should preclude donation.

The potential donor should be screened for infections that could be transmitted to the recipient. In particular, the donor should be screened for HIV, viral hepatitis, and active tuberculosis. Antibody titers of CMV should be obtained to help assess the risk of transmitting CMV to the recipient and the need for possible prophylactic therapy. An active malignancy is an absolute contraindication to tran~plantation.~ However, it is difficult to precisely define the time interval that a potential donor with a history of a cured malignancy should wait before donating.*

EVALUATION OF POTENTIAL CADAVERIC DONORS

The Initial Evaluation

If no suitable living donor is available, transplant candidates must rely on cadaveric kidneys. Most cadaveric kidneys are from donors who have been declared brain dead. When a potential brain-dead donor is available, hospital personnel should immediately contact the organ procurement organization for help in assessing the appropriateness of the potential donor and in approaching the family. Cadaveric donation is most often successful if carried out as a cooperative effort between the

38 KASISKE

patients caregivers and professionals experienced in organ procurement. However, the declaration of brain death should be made by physicians who are not part of the transplant team, in order to avoid any potential conflict of interest. Most states have laws goveming the definition of brain death.

Some centers use kidneys from donors who are not brain dead but who have been declared dead because their heart has stopped beating. These non-heart beating donors may be used in controlled and uncontrolled circumstances. Controlled, non-heart beating donors are patients in whom efforts to prolong life have become futile, and life support is discontinued in an intensive care unit setting. Uncontrolled donation occurs when patients present to the emergency department, often with severe brain trauma that falls short of a strict definition of brain death. Kidneys from controlled, non-heart beating donors gener- ally function better than those from uncontrolled donors. Great care must be taken to guard against conflicts of interest between the potential donors physicians and the organ procurement team. Strict moral, ethi- cal, and legal criteria must be applied, and communication between caregivers and the donors family is essential.

Minimizing the Risk to the Recipient of a Cadaveric Kidney

Infection and cancer are contraindications to donation. The potential cadaveric donor should be carefully screened for infections that may be transmitted to the recipient. Patients with bacterial sepsis or other tissue- invasive infections should generally be excluded. Patients with HIV are also excluded from donation, as are hepatitis B antigen-positive patients. More controversial is whether to exclude all potential donors who are HCV antibody positive. Because HCV can be transmitted with trans- plantation, most centers exclude HCV-positive donors. Generally, pa- tients with any evidence of cancer cannot be donors. The exception is the occasional patient with a (histologically confirmed) primary, nonme- tastasizing brain tumor.

With the current shortage of cadaveric kidneys, the criteria for accepting kidneys have expanded. Most centers avoid kidneys older than 60 or younger than 6 years of age. However, a few centers are using very old or very young kidneys and transplanting two kidneys rather than one kidney into a single recipient. Some use older kidneys but only in older recipients. It is important that the marginal nature of such a kidney be carefully explained to the potential recipient and that informed consent be obtained. Similarly, kidneys from donors with slightly elevated serum creatinine or evidence of glomerulsclerosis on biopsy are being used more often. However, care should be taken to ensure that the recipient is aware that results with these marginal kid- neys may not be as good as those with undamaged kidneys.

PROSPECTIVE RENAL TRANSPLANT RECIPIENTS AND LIVING DONORS 39

References

1. Alfrey EJ, Rubin GD, Kuo PC, et al: The use of spiral computed tomography in the evaluation of living donors for kidney transplantation. Transplantation 59:643-645, 1995

2. Artero M, Biava C, Amend W, et al: Recurrent focal glomerulosclerosis: Natural history and response to therapy. Am J Med 92375-383, 1992

3. Bia MJ, Ramos EL, Danovitch GM, et al: Evaluation of living renal donors. The current practice of US transplant centers. Transplantation 60:322-327, 1995

4. Expert Panel on Detection Evaluation and Treatment of High Blood Cholesterol in Adults: Summary of the Second Report of the National Cholesterol Education Program (NCEP) (Adult Treatment Panel 11). JAMA 269:3015-3023, 1993

5. Kasiske BL, Keane WF Laboratory assessment of renal disease: Clearance, urinalysis, and renal biopsy. In Brenner BM, Rector FC Jr (eds): The Kidney. Philadelphia, WB Saunders, 1995, pp 1137-1174

6. Kasiske BL, Ma JZ, Louis TA, Swan SK Long-term effects of reduced renal mass in humans. Kidney Int 48:814-819, 1995

7. Kasiske BL, Ramos EL, Gaston RS, et a1 The evaluation of renal transplant candidates: Clinical practice guidelines. J Am SOC Nephrol 6:l-34, 1995

8. Kasiske BL, Ravenscraft M, Ramos EL, et a1 The evaluation of living renal transplant donors: Clinical practice guidelines. J Am SOC Nephrol 72288-2313, 1996

9. Penn I: Donor transmitted disease. Transplant Proc 23:2629-2631, 1991 10. Ramos EL, Kasiske BL, Alexander SR, et al: The evaluation of candidates for renal

transplantation: The current practice of US. transplant centers. Transplantation 57490- 497, 1994

11. Ravine D, Gibson RN, Walker RG, et a1 Evaluation of ultrasonographic diagnostic criteria for autosomal dominant polycystic kidney disease 1. Lancet 343:824-827, 1994

12. Rubin GD, Alfrey EJ, Dake MD, et al: Assessment of living renal donors with spiral CT. Radiology 195:457462, 1995

13. Stephanian E, Matas AJ, Mauer M, et al: Recurrence of disease in patients retrans- planted for focal segmental glomerulosclerosis. Transplantation 53:755-757, 1992

14. Terasaki PI, Ceckd JM, Gjertson DW, Takemoto S: High survival rates of kidney transplants from spousal and living unrelated donors. N Engl J Med 333:333-336,1995

15. United States Renal Data System: USRDS 1996 Annual Data Report. Bethesda, The National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 1996

Address reprint requests to Bertram L. Kasiske, MD

Division of Nephrology, Department of Medicine Hennepin County Medical Center

701 Park Avenue Minneapolis, MN 55415