Evaluation of the Kidney Transplant Candidate
Kidney transplantation improves patient survival and quality of life and reduces the total cost of medical care compared to dialysis.
Selection of the proper transplant candidate remains a challenge due to the presence of complex medical issues and ever-increasing disparity between donor organ supply and demand.
The transplant evaluation process includes a comprehensive assessment of patient’s motivation, perioperative risk, medical history including risk of kidney disease recurrence, cardiac disease, vascular disease, infection, cancer, liver disease, gastrointestinal disease, obesity, diabetes mellitus, coagulopathy, surgical history including urinary tract abnormalities, and psychosocial situation (Table 26-1).
In general, candidates should have a projected life expectancy exceeding 7 years.
The initial general evaluation begins with a thorough history and physical examination, a complete blood count, chemistry panel, and coagulation studies. Other tests including blood type, serologic testing for human immunodeficiency virus (HIV), cytomegalovirus (CMV), varicella zoster virus (VZV), herpes simplex virus (HSV), Epstein–Barr virus (EBV), hepatitis B and C, and rapid plasma regain (RPR) are all essential. Immunologic testing of human leukocyte antigens (HLA) and panel reactive antibodies (PRA) of the transplant recipients is important. Other recommended testing includes ECG, chest radiograph, imaging of the kidneys, and age-appropriate cancer screening (Table 26-2).1
Immunologic testing is done to assess sensitization or presence of preformed anti-HLA antibodies which can arise from prior transplantation, pregnancy, or blood transfusions.
For details regarding HLA, PRA, and cross-match, refer to Chapter 25, Overview of Kidney Transplantation.
Kidney transplantation should not be pursued in cases where limited life expectancy minimizes potential benefit of transplant if psychosocial barriers for posttransplant compliance exist.
Absolute contraindications to kidney transplant are listed in Table 26-3.
TABLE 26-1 COMPONENTS OF THE ASSESSMENT OF RENAL TRANSPLANT CANDIDATE EVALUATION
Assessment of motivation
Psychosocial situation and support
Patients with end-stage renal disease (ESRD) and other end-stage organ failure may be candidates for combined organ transplantation (e.g., kidney-liver if cirrhosis or primary
hyperoxaluria, kidney-pancreas if type 1 diabetes mellitus, kidney-heart if severe irreversible cardiomyopathy). Refer to Chapter 31, Combined Organ Transplantation.
TABLE 26-2 INITIAL TRANSPLANT CANDIDATE WORKUP
CBC with differential
Serologies: HIV, hepatitis B and C, CMV, EBV, HSV, RPR
Urinalysis, urine culture
Blood group and cross-matching
HLA typing and HLA antibodies
Colonoscopy if >50 yrs of age
Mammogram for women >40 yrs of age or with family history of breast cancer
PSA in men >50 yrs of age
Abdominal ultrasound to evaluate for gallstones in diabetes
Renal ultrasound to screen for acquired cystic disease or mass in native kidneys
CMP, complete metabolic panel; CBC, complete blood count; HIV, human immunodeficiency virus; CMV, cytomegalovirus; EBV, Epstein–Barr virus; HSV, herpes simplex virus; RPR, rapid plasma reagin; PT, prothrombin time; INR, international normalized ratio; aPTT, activated partial thromboplastin time; HLA, human leukocyte antigen; PSA, prostate-specific antigen.
Attention is given to the cause of ESRD and likelihood of recurrence, although no disease has a recurrence and graft failure rate that precludes initial kidney transplantation other than primary hyperoxaluria.
Advanced age is not a contraindication to transplantation on its own.
Retransplant must be carefully considered in cases of graft loss due to recurrent disease, nonadherence, or psychiatric issues.
Cardiovascular complications account for nearly 30% of deaths with a functioning allograft.2
TABLE 26-3 ABSOLUTE CONTRAINDICATIONS TO KIDNEY TRANSPLANTATION
Active ischemic heart disease or severe cardiomyopathy
Recent history of cancer other than non-melanoma skin cancer
Cirrhosis with portal hypertension
Active substance abuse or dependence
Incorrigible nonadherence to therapy
Peripheral vascular disease with amputation of lower extremities
All patients with advanced chronic kidney disease (CKD) are overall at high risk for cardiac disease.
Current screening strategies for identifying cardiovascular disease in asymptomatic pretransplant patients may include noninvasive cardiac stress testing with either stress echocardiography or nuclear myocardial perfusion.
Significant risk factors for coronary artery disease include diabetes, history of ischemic heart disease, older age (age ≥45 in men and ≥55 in women), hypertension, dyslipidemia, obesity, smoking, family history of premature coronary artery disease, left ventricular hypertrophy (LVH), atherosclerotic vascular disease (peripheral arterial disease [PAD], stroke), and abnormal baseline ECG (particularly in diabetics).2,5
If noninvasive cardiac testing is positive for ischemia, then the patient should undergo coronary angiography and potential revascularization procedures prior to transplantation.
We have a low threshold to perform coronary angiography in patients older than 45 years with diabetes, or adults with diabetes for more than 25 years, or long history of tobacco.
Most transplant centers perform noninvasive testing as the initial method of screening.
Significant valvular heart disease needs to be corrected before transplantation.
Left ventricular ejection fraction <35% is considered a major risk factor for complications after transplantation. In many cases, decreasing dry weight during dialysis may improve the cardiac function if patient has diastolic dysfunction or volume overload.
In many cases, mild to moderate cardiac dysfunction could improve after kidney transplantation.
Those with severe cardiac failure are not candidates for kidney transplant unless combined with a heart transplant.
Carotid imaging is routinely done in patients with a history of transient ischemic attack, cerebrovascular accident, or presence of carotid bruit in asymptomatic patients during physical examination.
Lower extremity Doppler ultrasound is indicated in patients with a history of claudication and/or signs of diminished peripheral arterial pulses on physical examination, particularly in diabetics.6
Screening for intracranial aneurysms with either CT or MRA should be done in patients with autosomal dominant polycystic kidney disease with history of headaches, stroke, or family history of intracranial aneurysm or cerebrovascular accident.
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