Figure 36-1. The growth in the number of patients awaiting transplant (A) has exceeded the relatively stagnant rate of deceased-donor kidney transplants leading to progressively increasing waiting times over the last decade. Living donors had a slight increase early in the last decade, which may be in part due to the introduction of the laparoscopic donation procedure, but rates of living donation are currently flat (B). (Adapted from: SRTR and OPTN Annual Data Report, 2012, available at: srtr.transplant.hrsa.gov/annual_reports/2012/Default.aspx. Accessed July 15, 2015)
Further Strategies for Increasing the Number of Donor Kidneys
Many of the unique approaches for increasing the number of potential donors have come from Japan, where cultural beliefs have limited the number of available deceased-donor transplants. Several groups have reported successful kidney transplantation across ABO blood group barriers, using aggressive pretransplant immunosuppression, plasmapheresis to decrease anti-ABO titers, and in some cases splenectomy.1,2 This strategy has been implemented with increasing frequency in the United States as a result of the marked increases in the waiting times for blood group O and B recipients.12 While this strategy may be effective for living-donor pairs that are ABO incompatible in the United States, it is more common to place these ABO-incompatible pairs into one of the kidney exchange programs.
For donor recipient pairs that are incompatible due to a positive crossmatch, an important strategy currently being implemented in the United States, as well as internationally, involves the use of desensitization protocols to facilitate transplantation across a known positive anti-HLA crossmatch. These protocols may involve pretransplant infusion of gamma globulin in the recipient to bind circulating antibody, plasmapheresis of the recipient to remove circulating antibody, and/or the use of agents, such as rituximab, to decrease antibody production. These protocols could potentially impact the increasing number of sensitized patients on waiting lists who have little hope of finding a compatible donor.13 Lastly, a hybrid approach for the highly sensitized recipient with a crossmatch-incompatible donor could involve finding a kidney that is “less incompatible” through an exchange program, and then converting the positive crossmatch to a compatible crossmatch with desensitization techniques. Further strategies have recently been implemented to expand the number of kidneys procured from deceased donors. In addition to the use of kidneys from DCD donors described earlier, transplant centers have considered using kidneys from donors that are less than optimal, previously designated as expanded criteria donors (ECD). In the previous allocation scheme, these donors were between age 50 and 59, and had two out of three other clinical feature: history of hypertension, died of a cerebrovascular injury, or had a terminal creatinine of greater than 1.5 mg/dL. Additionally, any donor over age 60 was considered an ECD. These kidneys clearly had a shorter survival compared to younger, healthier donors and therefore potential recipients were required to give consent to receive these kidneys before transplant. The advantage to certain patient groups who were predicted to do poorly on dialysis (i.e., older patients or patients with diabetes) was an increased overall patient survival if they received a timely transplant with an ECD kidney, rather than wait a prolonged time on the list. In the newer allocation scheme, ECD kidneys are now defined as KDPI >85%. In the new allocation system, kidneys with KDPI >85% will be allocated to an expanded list (regional versus local) in order to increase organ utilization and minimize the chance of discard. The increased use of “kidney pumping” may help to determine the quality of these ECD kidneys by observing flow rates on the pump, and may also decrease the rates of posttransplant delayed graft function.14
THE TRANSPLANT PROCEDURE
Recipient Preoperative Assessment
Table 36-1 Etiology of Renal Disease as Indications for Renal Transplantation, Ranked in Order of Prevalence
Although the evaluation of potential recipients is focused on the assessment of cardiovascular status, further studies must exclude malignancies and infections that would contraindicate transplantation and immunosuppression. Potential kidney recipients who are infected with hepatitis C should be evaluated by a hepatologist to determine the risks of immunosuppression causing progression to end-stage liver disease. Potential kidney recipients with evidence of advanced liver disease should be evaluated for a combined liver and kidney transplant. For patients with less advanced liver disease, consideration could be given to treatment with newer antiviral drugs before proceeding with kidney transplantation to provide the opportunity for viral clearance.16 Kidney transplantation was previously contraindicated in people with HIV infection secondary to concerns of exacerbating an already immunologically compromised state. Recent advances in antiretroviral therapy and the ability to provide effective prophylaxis against opportunistic infections has prompted several centers to perform transplantation in people with end-stage renal disease and HIV infection. Early results suggest that progression of HIV to AIDS has not been seen following transplantation and immunosuppression, with early allograft success rates comparable to those in non–HIV-positive recipients.17 Potential patients with a previous history of tuberculosis or conversion to purified protein derivative positivity should be evaluated for active disease.
Colonoscopy, mammography, and Pap smear should be performed as dictated by age-specific standard guidelines. For most malignancies, a disease-free interval of 5 years is recommended before kidney transplantation. Controversy exists about pretransplant waiting times for certain malignancies, such as early stage breast cancer or prostate cancer, and some centers will not require any pretransplant waiting. Similarly, pretransplant wait times are probably not necessary for nonmelanoma skin cancers and early stage renal cancers. For patients with congenital abnormalities as the cause of renal failure, a complete workup of the genitourinary systems is necessary, including urodynamics and voiding cystourethrograms. These studies are particularly important in children with end-stage disease resulting from posterior urethral valves, to ensure that the bladder will serve as an adequate conduit for the kidney transplant. For patients with severe reflux disease and chronic pyelonephritis, native nephroureterectomy may be required to prevent posttransplant infection secondary to chronic reflux into the native ureters. For patients with inadequate bladder capacity and function, pretransplant reconstructive procedures such as ileal augmentation or ileal conduits may be required.
For patients with suspected clotting disorders based on a previous history of thromboembolic events (frequent clotting problems with dialysis access) or diseases associated with an increased frequency of clotting disorders (i.e., lupus), a hematologic workup is necessary to determine the necessity for anticoagulation at the time of the transplant. The length of time for anticoagulation is dependent on the severity of the clotting disorder and a history of a previous thrombotic event. This workup should include a determination of serum levels of protein C, protein S, anticardiolipin antibody, factor V Leiden, antithrombin III levels, and the G20210 A prothrombin gene mutation.
Living-Donor Nephrectomy: Open and Laparoscopic
A living kidney donor operation is a unique surgical procedure for two reasons. First, the donor has no medical reason to be in the operating room, and the process is driven only by his or her willingness to help another person with the gift of donation. Second, the removed tissue must be in perfect condition because it will be reimplanted into the recipient. These two features, therefore, necessitate that the donor operation is done safely and done well. The original donor operation was done through a generous flank incision, allowing for good exposure and careful dissection of the renal vessels. Unfortunately, this flank approach generally left a large incision, with its accompanying morbidity, pain, and sometimes adverse cosmetic result. The development of the laparoscopic procedure to remove kidneys has revolutionized the field, although its initial introduction was met with trepidation because of concerns over donor safety. With the explosive growth and dissemination of this procedure, it has now become the standard for donor nephrectomy.
The procedure is most commonly done through a transperitoneal approach, although some surgeons prefer to remain retroperitoneal. Once the operative space is expanded with carbon dioxide gas and the scope is inserted, two to three additional ports are placed to allow for the passage of instruments to dissect the kidney (Fig. 36-2). Some centers also favor the use of a gastight “hand-port,” which allows placement of the surgeon’s hand in the operative space to assist in exposure and to have available if sudden bleeding is encountered. Once the kidney vessels are transected and the vessel stumps are controlled by laparoscopic staples, the kidney can be removed through a 2- to 3-in incision, which can be placed in a position that leaves minimal scarring and avoids cutting muscle tissue. Most commonly this is via a Pfannenstiel incision, and recently the use of natural orifice approaches has been described. Additionally, some centers have adopted the use of a robotic assisted technique, to facilitate the dissection of important vascular structures. Donors who undergo the laparoscopic procedure typically have reduced pain medicine requirements, have a slightly shorter hospital stay, and are able to return to their usual activities sooner.6,7
The safety of this relatively new procedure has been established, in addition to the demonstration that kidneys recovered through a laparoscopic approach function as well as kidneys removed in an open operation. There has been an increased interest in live donation, coincident with the introduction of the laparoscopic procedure, suggesting that this procedure has removed some of the disincentives of the donation process.
Recipient Operative Procedure
The kidney transplant is heterotopically placed in the extraperitoneal iliac fossa. Although this is a less technically demanding procedure than either liver or pancreas transplants, attention to detail is imperative to optimize immediate graft function and avoid technical complications resulting in loss of the kidney transplant.
The living- or deceased-donor kidney is inspected for the presence of multiple vessels, duplication of the urinary collecting system, and parenchymal abnormalities. The artery and vein are dissected from surrounding structures to provide the necessary length for transplantation. In the case of multiple arteries, a decision must be made as to whether to perform ex vivo reconstruction to achieve a single implantable conduit versus implanting the vessels separately. This decision is in part dependent on the quality of the recipient vessels and an assessment as to whether the anastomosis of multiple vessels directly into the recipient would require an unacceptable period of warm ischemia to the kidney. In general, in an adult the anastomosis of the renal artery and vein are performed in an end-to-side fashion to the external iliac vessels, although occasionally the presence of atherosclerotic disease requires transplantation to the common iliac vessels. In children who weigh less than 20 kg, or for third transplants in adults, an intraperitoneal approach is used and the vascular anastomoses are frequently performed to the aorta and inferior vena cava. For kidneys from deceased donors, a Carrel patch of aorta is used to prevent stenosis and to provide a common patch for multiple arteries. Warm ischemia time should be minimized to prevent delayed graft function. Ensuring adequate intravascular volume and stable hemodynamics at the time of reperfusion is extremely important to achieve optimal function of the transplant.
Figure 36-2. A: The laparoscopic donor procedure is performed with the donor in a lateral position, typically using three to four ports, with extraction of the kidney through a 6- to 8-cm incision. B: Preoperative computed tomography angiogram revealing the arterial and venous anatomy. C: Intraoperative photograph of laparoscopic view of right kidney just prior to transection of the renal vein. The artery has already been divided.