Kidney disease is becoming a common term in daily medical care, and nowhere more obviously than in those with heart, liver, and lung disease. Kidney failure caused by hemodynamic perturbations, viral infection, drug toxicity, diabetes, and coagulation abnormalities is increasingly identified in patients with heart, lung, and liver failure, and in nonrenal transplant recipients. Heart, lung, and liver recipients have a rate of chronic kidney disease (CKD) in up to 30% of cases and of end-stage renal disease in up to 10% of cases. On the road to posttransplant CKD comes the management of acute and indolent kidney disease, difficult dialysis, and the realization that any pretransplant kidney disease is a risk for posttransplant mortality. Mortality is frequently attributable to infection and the failure to thrive. Consequently, kidney disease becomes one of the most important and terrifying management issues in the pre- and posttransplant period.
The recognition of renal failure in heart, liver, and, lung disease may be masked by the poor nutritional condition of patients, impairment in creatinine production, or errors in creatinine measurement in the face of hyperbilirubinemia. More recently, the effect on the serum creatinine imposed by hypervolemic dilution has been recognized. Importantly, 1 deleterious effect of severe extracellular fluid volume expansion is a “lag” time in the recognition of acute kidney injury. Thus, nephrologists must be on the lookout for renal disease, using lower conventional thresholds of serum creatinine values, and volume management is paramount for ventilation, oxygenation, nutrition, and ambulation in these tenuous patients.
On the other hand, overdiuresis results not only in underperfusion of the renal parenchyma but also of other organs and may enhance the risks for gastrointestinal bleeding, myocardial infarction, falls, neurologic injury, and fracture. Acid-base balance, hyper- and hypokalemia, and hyponatremia are not uncommon accompaniments of the development of liver and heart failure. These biochemical abnormalities portend a poor prognosis. Yet, all of these abnormalities are within the domain of the nephrologist's expertise, and their successful management is key to improved outcomes and, therefore, access to liver or heart transplantation.
Modification of dialysis modalities is often required in those with heart, lung, and liver failure. Deliberately reduced efficiency of osmotic clearance is critical for the acute liver failure patient to avoid cerebral edema and herniation. Even very slow volume removal may not be tolerated by the heart- and liver-failure patient and not at all by a post-heart transplant recipient with right-heart dysfunction. Unfortunately, the condition of lung transplant recipients may not improve with volume removal because fluid may be sequestered in compartments uninfluenced by vascular changes, a consequence of substantial postoperative injury, rejection, or infection.
Long-term, all nonrenal allograft recipients receive nephrotoxic medications, and currently, one of the most popular immunosuppressive regimens for hepatic transplant recipients is tacrolimus monotherapy. As a result, renal parenchymal injury that is initiated in the pretransplant interval in those suffering with heart, lung, and liver disease from either organ underperfusion, diabetes, or vascular disease may be exacerbated by infection, bleeding, vasopressor use, and maintenance immunosuppression by a calcineurin inhibitor. In this edition of Advances in Chronic Kidney Disease, Dr Hani discusses the management of kidney failure in the liver transplant candidate and Dr Pham informs us on optimal dialytic therapy of post-heart, -liver, and -lung allograft recipients.
The fact that kidney failure limits posttransplant survival has led to the practice of dual-organ transplantation, so-called “kidney plus.” The kidney, because it follows the “vital” organ transplant, has until just the last few years been given minimal consideration. Recently, however, recommendations have been published regarding reasonable approaches for the selection of candidates for dual-organ transplantation. Some of these recommendations include kidney biopsy, and, classically, physicians including nephrologists have avoided kidney biopsy in these patients for fear of the increased risk of bleeding. However, in certain settings, biopsy may be safe and helpful. Appropriately, in this issue, Dr Bloom reviews the practice of simultaneous liver-kidney transplantation and the value of kidney biopsy in these patients. In this vein, the contribution of the kidney biopsy to heart transplant candidates is discussed by Dr Cohen, who additionally appraises the selection criteria for heart kidney candidates and their outcomes. Another dual transplant, kidney-pancreas, whose popularity has declined in the past few years, is critically reviewed by Dr Wiseman.
For successful transplantation, the immunosuppressive regimen must provide adequate containment of the immune response against the allograft while mitigating the risk of infection and malignancy. In the last few years, several original treatment protocols have become available. Furthermore, individualized immunosuppressive treatment is developing into a reality. To this end, Dr Yabu discusses current and future approaches to kidney transplantation immunosuppression.
Notably, organ donors, without whom much transplantation would not be feasible, are receiving increasing attention. From the policy stage, they are receiving recognition for their contribution to society. By contrast, from the medical perspective, organ donors are under increasing scrutiny for transmission of infection and other diseases. The epidemiology of donor-transmitted infection, along with the testing techniques used to identify donor infections before donation, are reviewed by Dr Ison. Finally, with the emphasis on living donation because of long waiting lists and the natural desire for optimal recipient outcomes, a change in some of the demographic characteristics of living donors has taken place. These changes, along with recent updates of the short- and long-term outcomes of living kidney donors, are presented by this author.
In summary, transplantation has increasingly become the destination therapy for many people with end-organ disease. Those with heart, lung, or liver failure will frequently require specialized kidney care while awaiting transplantation. Moreover, recipients will increasingly require advanced immunosuppressive therapy to limit infections, malignancy, and kidney failure. Living donors do and will, for the foreseeable future, continue to offer the kidney transplant recipient their best outcomes. However, even with excellent long-term living donor outcomes, research is imperative to detect risk factors that could predict death, renal failure, and other morbid outcomes.
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