Faculty Bibliography

Patients with chronic renal failure (CRF) due to various mechanisms are prone to significant pulmonary comorbidities. With the improvements in renal replacement therapy (RRT), patients with CRF are now expected to live longer, and thus may develop complications in the lung from these processes. The preferred treatment of CRF is kidney transplantation and patients who are selected to undergo transplant must have a thorough preoperative pulmonary evaluation to assess pulmonary status and to determine risk of postoperative pulmonary complications. A MEDLINE((R))/PubMed((R)) search was performed to identify all articles outlining the course of pre-surgical pulmonary evaluation with an emphasis on patients with CRF who have been selected for renal transplant. Literature review concluded that in addition to generic pre-surgical evaluation, renal transplant patients must also undergo a full cardiopulmonary and sleep evaluation to investigate possible existing pulmonary pathologies. Presence of any risk factor should then be aggressively managed or treated prior to surgery.

INTRODUCTION: Previously, increasing age has been a part of the exclusion criteria used when determining eligibility for a pancreas transplant. However, the analysis of pancreas transplantation outcomes based on age groupings has largely been based on single-center reports. METHODS: A UNOS database review of all adult pancreas and kidney-pancreas transplants between 1996 and 2012 was performed. Patients were divided into groups based on age categories: 18-29 (n = 1823), 30-39 (n = 7624), 40-49 (n = 7967), 50-59 (n = 3160), and >/=60 (n = 280). We compared survival outcomes and demographic variables between each age grouping. RESULTS: Of the 20 854 pancreas transplants, 3440 of the recipients were 50 yr of age or above. Graft survival was consistently the greatest in adults 40-49 yr of age. Graft survival was least in adults age 18-29 at one-, three-, and five-yr intervals. At 10- and 15-yr intervals, graft survival was the poorest in adults >60 yr old. Patient survival and age were found to be inversely proportional; as the patient population's age increased, survival decreased. CONCLUSION: Pancreas transplants performed in patients of increasing age demonstrate decreased patient and graft survival when compared to pancreas transplants in patients <50 yr of age.

OBJECTIVE: There is reluctance to use donation after cardiac death (DCD) organs for fear of worse outcomes due to increased warm ischemia time. Extensive evidence to confirm the quality of DCD pancreas transplants is not manifest. METHODS: A united network for organ sharing database review of pancreas transplants performed between 1996 and 2012 was conducted. We compared outcomes and all demographic variables between donors after cardiac death and donors after brain death in pancreas transplantation. RESULTS: There were 320 DCD pancreas transplants and 20,448 donation after brain death pancreas transplants performed in the United States between 1996 and 2012. There was no statistically significant difference in graft survival or patient survival in pancreas transplantation in DCD versus donation after brain death donors measured at 1-year, 3-year, 5-year, 10-year, and 15-year intervals. There was no significant difference between donor and recipient age, race, sex, and body mass index (BMI) between the groups. There was no significant difference between the recipient ethnicity or time on wait list between the groups. CONCLUSIONS: Pancreata procured by DCD have comparable outcomes to those procured after brain death. Donation after cardiac death pancreas transplant is a viable method of increasing the donor pool, decreasing wait list mortality, and improving the quality of life for type 1 diabetic patients.

This study sought to examine various factors that may prevent transplant candidates from completing their transplant workup prior to listing. We reviewed the records of 170 subjects (cases = 100, controls 70) who were either on dialysis or had less than 20 mL/min creatinine clearance and were therefore candidates for preemptive transplantation. Approximately, 56% of preemptive patients completed their workup, while only 36% of patients on dialysis completed their workup. Our data revealed that factors contributing toward completion of workup included intrinsic motivation (four times more likely), lack of specific medical comorbidities (three times more likely), and preemptive status (two times more likely). Among patients on dialysis, intrinsic motivation (five times more likely) and absence of cardiovascular complications (four times more likely) were associated with completion. When comparing patients on dialysis to patients not on dialysis, there were significant differences between the two groups in distance from home to the transplant center, level of education, and presence of medical comorbidities. We believe that targeted interventions such as timely referral, providing appropriate educational resources, and development of adequate support systems, have the potential to improve workup compliance of patients with advanced chronic kidney disease, including those on dialysis.

Desmopressin acetate (DDAVP), a medication used in the treatment of bleeding and polyuric disorders, has the potential to cause hyponatremia when free water is not appropriately restricted with its use. This free water retention is reversible when DDAVP is discontinued. We report a case of symptomatic DDAVP-induced hyponatremia in which discontinuation of DDAVP led to a rapid increase of serum sodium. In order to prevent rapid free water excretion, DDAVP and hypertonic saline were used concurrently. With close monitoring, this can be an effective treatment strategy in patients with DDAVP-induced hyponatremia.

BACKGROUND: Reset osmostat (RO) occurs in 36% of patients with syndrome of inappropriate antidiuretic hormone secretion (SIADH) and is not often considered when evaluating hyponatremic patients. Patients with RO are not usually treated, but recent awareness that symptoms are associated with mild hyponatremia creates a therapeutic dilemma. We encountered patients with hyponatremia, hypouricemia and high urine sodium concentration (UNa), who had normal fractional excretion (FE) of urate and excreted dilute urines that were consistent with RO. We decided to test whether a normal FEurate in nonedematous hyponatremia irrespective of UNa or serum urate would identify patients with RO. METHODS: We determined FEurate in nonedematous hyponatremic patients. A diagnosis of RO was made if urine osmolality (Uosm) was <200 mOsm/kg in a random urine. We performed a modified water-loading test in patients with a normal FEurate whose random Uosm was >200 mOsm/kg. RESULTS: All nonedematous hyponatremic patients with FEurate of 4%-11% had RO, as determined by Uosm <200 mOsm/kg on a random urine collection in 8 patients, or after a modified water-loading test in 6 patients. Plasma antidiuretic hormone (ADH) in 4 patients was undetectable at <1 pg/mL during water-loading. Nine patients had baseline concentrated urine, 12 had UNa >20 mmol/L, 9 were hypouricemic, yet all had a normal FEurate. Comorbidities were similar to those reported in RO. CONCLUSIONS: RO, a benign form of SIADH, occurs commonly. A normal FEurate in a nonedematous hyponatremic patient is highly suggestive of RO. Determining FEurate is superior to serum urate. The therapeutic dilemma for RO must be resolved.

Although RNA interference (RNAi) has emerged as an important tool for studying the effects of gene knockdown, it is still difficult to predict the success of RNAi effectors in human systems. By examining the basic thermodynamic equations for RNA interactions in RNAi, we demonstrate how the free energies of RNA folding and phosphoester bond hydrolysis can drive RNAi without ATP. Our calculations of RNAi efficiency are close to actual values obtained from in vitro experimental data from 2 previous studies, for both silencing complex formation (2.50 vs. 2.40 for relative efficiency of RISC formation) and mRNA cleavage (0.50 vs. 0.56 for proportion cleaved). Our calculations are also in agreement with previous observations that duplex unwinding and target site folding are major energy barriers to RNAi.

Cerebral salt-wasting (CSW), or renal salt-wasting (RSW), has evolved from a misrepresentation of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) to acceptance as a distinct entity. Challenges still confront us as we attempt to differentiate RSW from SIADH, ascertain the prevalence of RSW, and address reports of RSW occurring without cerebral disease. RSW is redefined as 'extracellular volume depletion due to a renal sodium transport abnormality with or without high urinary sodium concentration, presence of hyponatremia or cerebral disease with normal adrenal and thyroid function.' Our inability to differentiate RSW from SIADH lies in the clinical and laboratory similarities between the two syndromes and the difficulty of accurate assessment of extracellular volume. Radioisotopic determinations of extracellular volume in neurosurgical patients reveal renal that RSW is more common than SIADH. We review the persistence of hypouricemia and increased fractional excretion of urate in RSW as compared to correction of both in SIADH, the appropriateness of ADH secretion in RSW, and the importance of differentiating renal RSW from SIADH because of disparate treatment goals: fluid repletion in RSW and fluid restriction in SIADH. Patients with RSW are being incorrectly treated by fluid restriction, with clinical consequences. We conclude that RSW is common and occurs without cerebral disease, and propose changing CSW to RSW.

BACKGROUND: Vitamin D has key roles in regulating systems that could be important in the pathobiological state of proteinuria. Because of this, it could be helpful in treating patients with proteinuric renal diseases. The objective is to determine the effect of oral paricalcitol on protein excretion in patients with proteinuric chronic kidney disease. STUDY DESIGN: Double-blind randomized study. SETTING & PARTICIPANTS: 61 patients with estimated glomerular filtration rate of 15 to 90 mL/min/1.73 m(2) and protein excretion greater than 400 mg/24 h. INTERVENTION: Randomization to 6 months of treatment with paricalcitol, 1 mug/d, or placebo. OUTCOMES & MEASUREMENTS: The predefined primary end point was to compare change in mean spot urinary protein-creatinine ratio between the baseline measurement and the last study evaluation (6 months in study completers) between the 2 groups. Every 4 weeks, there was measurement of serum intact parathyroid hormone, serum calcium, serum phosphorus, serum creatinine, and urine spot protein and creatinine. RESULTS: At baseline, mean urinary protein-creatinine ratios were 2.6 and 2.8 g/g in the placebo and paricalcitol groups, respectively. At final evaluation, mean ratios were 2.7 and 2.3, respectively. Changes in protein excretion from baseline to last evaluation were +2.9% for controls and -17.6% for the paricalcitol group (P = 0.04). A 10% decrease in proteinuria occurred in controls (7 of 27; 25.9%) and the paricalcitol group (16 of 28; 57.1%; P = 0.03). LIMITATIONS: The relatively small sample size limits the extent to which results should be generalized. CONCLUSIONS: Paricalcitol resulted in a significant reduction in protein excretion in patients with proteinuric renal disease.