Abstract
Kidney transplantation is now the standard of care for properly selected patients with end-stage renal disease. Successful transplantation provides remarkable improvement in quality of life and decreases recipient mortality compared with maintenance dialysis. Evaluation and management of the kidney transplant recipient requires active collaboration between diverse professionals with specific skills, and each is critical to achieve optimal outcomes.
Keywords
delayed graft function, immunosuppression, kidney transplantation, live donor, lymphocele, nephrectomy, renal artery stenosis, renal transplantation, renal vein thrombosis, ureteral complication
Outline
Live Donor Kidney Transplantation, 582
Recipient Evaluation, 583
Deceased Donor Kidney Evaluation: Kidney Donor Profile Index, 584
Surgical Technique, 584
Immediate Postoperative Management, 585
Postoperative Complications, 586
Conclusions, 590
Before the success of hemodialysis and kidney transplantation, end-stage renal disease (ESRD) was a fatal diagnosis. Interestingly, critical advances in both technologies developed simultaneously in the 1950 to 1960s. Individual hemodialysis treatments for acute renal failure first became available in the 1950s based on the research and ingenuity of Willem Kolff. However, the ability to treat chronic renal failure awaited progress in the field of vascular access. The development of the external Teflon-based arteriovenous (AV) fistula by Belding Scribner at the University of Washington in 1960 and the subcutaneous AV fistula by James Cimino and Michael Brescia in 1966 heralded the successful treatment of ESRD with repeat intermittent hemodialysis. In 1972 Congress authorized Medicare approval of hemodialysis for the treatment of all patients with ESRD. The development of hemodialysis represented the culmination of countless decades of research by hundreds of physicians and scientists. Rapid progress in the field of transplantation was occurring simultaneously. In 1954 the first successful human kidney transplant was performed between identical twins at the Peter Bent Brigham Hospital in Boston. However, over the next 30 years, immunological constraints would prevent widespread adoption of the technique for nonhaploidentical individuals. Institution of calcineurin-based immunosuppressive regimens—first with cyclosporine and subsequently with FK506—revolutionized the field by producing dramatic improvement in both patient and graft survival, and comparisons started being made between ESRD patients treated with chronic dialysis and those treated with kidney transplantation. The conclusive demonstration of the increased life expectancy associated with successful kidney transplantation compared with chronic hemodialysis by Wolfe and colleagues in 1999 resulted in kidney transplantation becoming the standard of care for the treatment of ESRD in selected patients.
In 2016 there were 19,060 kidney transplants performed in the United States, with 13,431 from deceased donors and 3765 from living donors. Surgeons play an important role in the evaluation and care of the kidney transplant recipient and in the evaluation and management of kidney live donors. This chapter focuses on the surgical aspects of live kidney donation and the kidney transplant recipient.
Live Donor Kidney Transplantation
Since the first live donor kidney transplant performed between identical twins, the technology has provided recipients shorter wait times, less time on dialysis, and superior graft survival. Many studies have been performed in attempts to quantify the risks related with kidney donation. Early studies were retrospective and had limited follow-up, but for the most part demonstrated donors were not at increased risk for mortality or the development of ESRD. However, in 2014, Muzaale et al. studied 96,217 live kidney donors who donated a kidney between 1994 and 2011. The study found a small but statistically significant increased risk of <0.5% for the development of ESRD in kidney donors over 15 years. An important part of the live donor process is to thoroughly screen and evaluate potential live donors to minimize their risk related to kidney donation.
Live Donor Evaluation
The donor evaluation is composed of medical and psychosocial components. In the United States, the United Network for Organ Sharing (UNOS) mandates certain aspects of the donor evaluation, whereas other criteria and policies vary among transplant centers. In general, however, donor evaluation includes assessments of overall health, kidney structure and function, and the risk for development of kidney disease, the presence of blood disorders, malignancies and infections, histocompatibility with the intended recipient, and psychosocial evaluation. The team must feel the donor’s decision to donate is free of coercion and the donor understands the risks and benefits of donation. In addition, an independent donor advocate meets with potential donors to affirm informed consent. A multidisciplinary team approves live donor candidates.
A critical aspect of the surgical evaluation is the renal anatomy. Most commonly, assessment of live donor anatomy uses multidetector computed tomography (MDCT) imaging with three-dimensional reconstruction. MDCT has an accuracy of 95% to 100% in the delineation of renal anatomy and vasculature. The importance of the MDCT cannot be overemphasized. Any nonstandard anatomy introduces technical challenges in both the donor and recipient. Only 70% to 75% of patients have single renal arteries bilaterally. Renal vein anatomy is more uniform, with the right renal veins having more variation than the left. Complete or partial ureteral duplication occurs in 1% of the population. Other considerations include the presence of a mass, stone, atherosclerosis, and the size of the kidneys. MDCT-based volumes have been shown to correlate with nuclear split renal function measurements, and can therefore be used as a reflection of renal function. Depending on the results, 4% to 16% of kidney donors will be excluded secondary to renal findings on imaging studies. Particular concerns are multiple small arteries or the presence of a small lower pole artery that supplies the ureter and therefore places the transplant at risk for ureteral necrosis.
In general, removal of the left kidney is preferred since the longer vascular pedicle makes the operation easier and safer. However, the overriding goal must be to minimize the donor operative risk and preserve long-term donor kidney function. If there is a size discrepancy in the kidneys, a functional study can be performed to ensure that both kidneys will be adequate over the long term.
Live Donor Nephrectomy
The traditional open flank incision for donor nephrectomy has been replaced by minimally invasive techniques. The first laparoscopic donor nephrectomy (LDN) was reported in 1995 by Ratner et al. The LDN provides smaller incisions with improved cosmetic outcome, decreased postoperative pain, decreased hospital length of stay, and earlier return to work. In addition, the advent of LDN has led to an increase in rate of live donation and has been adopted as the standard of care. Alternative techniques such as hand-assisted LDN, single-port LDN, mini-incision open nephrectomy, retroperitoneoscopic, and robotic donor nephrectomy have evolved and are supported by individual centers and surgeons. These approaches have been reported to result in similar donor and recipient outcomes.
LDN is performed with the patient in a lateral decubitus position. In the pure laparoscopic approach to left nephrectomy, trochars are placed in the left upper quadrant and subxiphoid midline. When the hand-assisted approach is used, the hand port is typically placed in the suprapubic midline or via a Pfannenstiel incision. After identification of the vessels and mobilization of the ureter and kidney, the vessels are ligated using a stapling device and the kidney is removed via the hand port site or a Pfannenstiel incision. When the right kidney is removed via a laparoscopic approach, the vein tends to be shorter and the recipient surgeon may need to alter the implantation technique.
LDN has a reported mortality rate of 0.03%, an overall complication rate of 5% to 8%, and a conversion to open rate of <1%.
Recipient Evaluation
Recipient evaluation is driven by whether the patient will benefit from renal transplant measured by both mortality and quality of life. For most patients, renal transplant trades a small upfront increased mortality and surgical discomfort for a potentially dramatic increase in life span and improvement in quality of life versus ongoing dialysis. There is a second ethical consideration in evaluating each patient: organ stewardship. With nearly 100,000 patients on the list, eliminating futile transplants that do not provide significant benefit to the recipient must be a priority.
Patients with a glomerular filtration rate of less than 20 to 30 m/min/m 2 should be considered for referral to a transplant center. Referral before initiation of dialysis is preferred. Complete evaluation of all options, including access placement and live donation, can take 6 months or longer.
In general, patients with ESRD as evidenced by measured creatinine clearance or calculated glomerular filtration rate (GFR) ≤20 mL/min/m 2 or who are on dialysis are candidates for renal transplant. Selected patients with a higher GFR can be considered for transplant depending on symptomatology.
Each patient should undergo a detailed history and physical examination. A comprehensive description of the workup is beyond the scope of this chapter, so we will focus on a few essential and unique elements. The high incidence of graft loss from cardiac disease after transplant mandates careful assessment of cardiac risk. Critical aspects of the history are onset and etiology of renal failure and symptomatology including level of activity, edema, shortness of breath, and fatigue. Evidence of coagulopathy should be sought. Other medical problems including diabetes, hypertension, heart disease, pulmonary disease, lupus, previous cancer, and renal calculi affect the decision to transplant as well as postoperative care. Surgical history including surgery on the kidneys, ureters or bladder, large and small bowel, and abdominal wall hernias affect surgical and postoperative planning.
Family history of renal disease can point out congenital etiologies. In some cases, for example, in patients with polycystic renal disease, this may lead to suggesting other family members undergo testing. Family cardiac history also is critical to assess recipient risk.
Physical examination focuses on cardiac and pulmonary risk and should include assessment of congestive heart failure by pulmonary and cardiac auscultation, palpation, percussion, and assessment of jugular venous pressure and the presence of generalized and peripheral edema. Careful examination of the abdomen for renal size and intraabdominal pathology is essential.
A unique feature of the transplant evaluation involves assessment of the ability of the patient to care for the graft postsurgery and reflects the central imperative regarding organ stewardship. Assessment of medical compliance and social support provide the basis for this decision. A critical component of the recipient evaluation includes evaluation by licensed social work professionals.
Relative contraindications to transplant are advanced age and severe obesity. Cutoffs vary by center but few centers are routinely performing transplants in patients over 80 years of age or with a body mass index higher than 50 kg/m 2 . This relates to the well-documented increased complication rates and lower life expectancy in these groups. Each patient should be considered on a case-by-case basis.
It is important to establish a plan for urinary drainage. Inadequate bladder capacity or lack of urinary conduit precludes operation. A general guideline would be a bladder size of at least 75 cc. In patients with a smaller capacity, bladder stretching procedures, augmentations, or urinary conduits can be considered. Urological consultation is highly recommended in these situations.
Previous malignancy requires a variable waiting period before transplant due to risk for recurrence and concerns that immunosuppression may inhibit host immunological control of certain cancers. The Israel Penn registry contains information about cancer recurrence in transplant patients and can be a helpful resource to determine appropriate waiting times.
Description of successful transplantation in patients infected with HIV occurred in the early 2000s, and selected patients with low viral load and adequate CD4 counts (typically >200/mL) may benefit from transplantation.
Absolute contraindications for renal transplant include active systemic infection, active substance abuse, significant psychiatric illness likely to interfere with compliance, severe cardiac disease, severe peripheral vascular disease, cirrhotic liver disease (grade 3 or 4 fibrosis), noncompliance with current medical regimen, significant pulmonary disease or oxygen dependence, oxalosis (usually requires liver/kidney transplant), and inadequate family or social support.
As discussed, cardiovascular morbidity and mortality frequently leads to graft loss, and testing to determine risk enhances decision making. A low threshold for nuclear stress testing to determine cardiac ischemia with progression to cardiac catheterization for equivocal results provides invaluable input for risk adjustment. Although data are limited, in general, patients with significant areas of cardiac ischemia should not be offered renal transplantation without some type of coronary revascularization.
Other recommended testing includes pulmonary function tests, cancer screening at appropriate intervals and serological testing for hepatitis, cytomegalovirus, and Epstein-Barr virus. Other preoperative testing is dependent on the underlying cause of renal disease and comorbidities. Abdominal imaging is useful to assess vascular calcifications, size of kidneys in patients with polycystic renal disease, and anatomy in patients with prior surgery or congential anomalies. Carotid Doppler in patients with vascular disease and cerebral imaging in patients with polycystic renal disease to look for intracerebral aneurysms should be considered.
Given the typical comorbidities and risk for disease progression in patients on dialysis combined with extended waiting periods, following patients on the waiting list is essential. Patients should be seen at regular intervals and after significant medical events for reevaluation.
A multidisciplinary team reviews all data and determines suitability for renal transplantation. The selection committee should comprise representatives from transplant surgery, nephrology, social work, human leukocyte antigen (HLA) laboratory, pre- and posttransplant nursing, pharmacy, dietary, psychological services, and finance. Input from all these professional groups ensures the most consistent and evidence-based decision making.
Deceased Donor Kidney Evaluation: Kidney Donor Profile Index
Multiple factors determine the suitability of a particular deceased donor kidney to an individual. The ability of a particular allograft to meet a recipient’s demands is a function of the maximal glomerular filtration the kidney can provide with respect to the recipient’s body surface area, metabolic demand, and lean muscle mass. The maximal glomerular filtration a kidney can provide depends on both the absolute number of glomeruli and their ability to increase their filtration capacity through hyperperfusion and hypertrophy. Age, height, sex, obesity, and hypertension all significantly affect glomerular mass. Specifically, there is a progressive decline in absolute glomerular mass with increasing age. Several scoring systems have been developed to assess the quality of a deceased donor allograft and assist in clinical decision making. The scoring system currently used in the allocation of deceased donor kidneys in the United States is the Kidney Donor Risk Index (KDRI). The KDRI uses donor factors to calculate a score that estimates the relative risk for posttransplant graft failure ( Table 37.1 ). The Kidney Donor Profile Index (KDPI) allows for a continuous assessment of allograft quality compared with the prior designation of standard criteria donor (SCD) or extended criteria donor (ECD) system. For example, a KDPI 1% deceased donor kidney has an 83.3% 5-year predicted graft survival compared with a 46.9% graft survival for a KDPI 99% deceased donor kidney based on data from 2004 to 2011 and scaled to a reference population of all deceased donor kidneys allocated by UNOS in 2013. Unfortunately, no systems account for recipient factors in combination with donor factors.
| KDRI Donor Factors | Applies to |
|---|---|
| Age (integer years) | All donors |
| Height (cm) | All donors |
| Weight (kg) | All donors <80 kg |
| Ethnicity | African American donors |
| History of hypertension | Hypertensive donors |
| Cause of death | CVA |
| Serum creatinine | All donors |
| HCV status | HCV-positive donors |
| DCD status | DCD donors |
Surgical Technique
The technical aspects of kidney transplantation are well described and have not significantly changed in the past several decades. Laterality does not significantly affect the approach. A curvilinear incision (hockey stick) is typically made from the level of the anterior superior iliac spine to immediately cephalad to the lateral aspect of the pubic tubercle, while staying lateral to the rectus abdominis and linea semilunaris muscles. Care is taken to protect the spermatic cord in men. In women, the round ligament is routinely ligated. There are a variety of ways to enter the retroperitoneal space, which is then widely exposed. The inferior epigastric artery and vein are typically encountered caudally and divided to allow better exposure to the bladder. This exposure allows visualization of the external iliac artery and vein. The perivascular lymphoconnective tissue is typically ligated and divided to minimize the risk for lymphocele formation. The external iliac artery and vein are exposed and clamps placed. Typically, the venous anastomosis is performed first, followed by the arterial anastomosis. Both anastomoses are done in an end-to-side fashion. For deceased donors, the donor artery uses a Carrel patch of aorta to minimize the risk for stenosis, and for live donors, an arterial punch may be used to increase the diameter of the arteriotomy in the recipient for the same reason. Immunosuppression is typically administered before reperfusion. A well-perfused kidney should immediately become pink with a palpable arterial pulsation and thrill ( Fig. 37.1 ). Furosemide and mannitol may be administered at this time per surgeon preference. After ensuring adequate hemostasis, the bladder is filled with irrigant to help identification. Typical anastomotic technique is the Lich-Greigor, which is a mucosal-to-mucosal anastomosis. A drain may be placed per surgeon preference.
Immediate Postoperative Management
Postoperative graft function is dependent on numerous factors related to both the donor and the recipient. Recipients can most broadly be categorized into two groups based on the presence or absence of delayed graft function (DGF) defined as the need for dialysis within the first week posttransplant. However, heterogeneity exists within these groups and the rate of decline of a recipient’s serum creatinine may be a more accurate reflection of postoperative allograft function ( Fig. 37.2 ). In general, acute kidney injury (AKI) present in the donor will be exacerbated by the procurement and transplant events, and recipients of these organs should be anticipated to have DGF. Additional donor factors influencing graft function include the quality of the organ with the DGF rate increasing from 16.3% in KDPI 0% to 20% kidneys to 39.2% in KDPI 86% to 100% kidneys. A progressive increase is seen in DGF rates when comparing living donor, brain dead donor, and donation after cardiac death (DCD) organs. Recipient factors influencing postoperative graft function include diabetes and duration of time on dialysis as well as the degree of immunological compatibility. Finally, both the cold and warm ischemia times (CIT and WIT, respectively) affect immediate allograft function due to increased ischemia/reperfusion insults ( Box 37.1 ). Specifically, the rate of DGR increases with increasing CIT and appears to compound the effect of increasing donor age or DCD donation. Interestingly, however, overall kidney quality as determined by prognostic scores such as KDPI and the overall functional glomerular mass are much more important determinants of long-term outcome than the presence of DGF. It is important to assess risk factors for DGF to anticipate expected kidney allograft function after transplantation.
