Association of balanced abdominal organ transplant center volumes with patient outcomes

BACKGROUND

The volume-outcome relationship for organ-specific transplantation is well-described; it is unknown if the relative balance of kidney compared with liver volumes within an institution relates to organ-specific outcomes. We assessed the association between relative balance within a transplant center and outcomes.

METHODS

National retrospective analysis of isolated kidney and liver transplants in United States 2005-2014 followed through 2019. Latent class analysis defined transplant center phenotypes. Multivariate Cox models estimated death-censored graft loss and mortality.

RESULTS

Latent class analysis identified four phenotypes: kidney only (n = 117), kidney dominant (n = 36), mixed/balanced (n = 90), and liver dominant (n = 13). Compared to mixed centers, the risk of kidney graft loss was higher at kidney-dominant (HR 1.07, p < .001) and liver-dominant (HR 1.10, p < .001) centers, while kidney-only (HR 1.06, p = .01) centers had higher mortality. Liver graft loss was not associated with phenotype, but risk of patient death was lower (HR 0.93, p = .02) at liver dominant and higher (HR 1.06, p = .02) at kidney-dominant centers.

CONCLUSIONS

A mixed phenotype was associated with improved kidney transplant outcomes, whereas liver transplant outcomes were best at liver-dominant centers. While these findings need to be verified with center-level resources, optimization of shared resources could improve patient and organ outcomes.

Noncirrhotic hyperammonemia after deceased donor kidney transplantation: A case report

A 72-year-old woman with end-stage kidney disease due to recurrent urinary tract infections and obstructive uropathy of a solitary kidney presented to our hospital for renal transplantation. She underwent successful transplantation of a deceased donor allograft, but developed acute mental status deterioration on the fifth postoperative day. Her serum ammonia was found to be markedly elevated to 447 μmol/L in the setting of normal hepatic function. She was treated with emergent dialysis and empiric antibiotics targeting urea-splitting organisms, and ultimately made a full neurologic recovery with stable renal allograft function. Noncirrhotic hyperammonemia (NCH) is an exceedingly rare clinical entity but seems to have a predilection for patients who have undergone solid organ transplantation. This report emphasizes the importance of rapid diagnosis and initiation of treatment for NCH, which is associated with a high rate of mortality and irreversible neurological morbidity. We outline the successful workup and management approach for this patient.

Hand-assisted laparoscopic retroperitoneal donor nephrectomy: A single-institution experience of over 500 cases-Operative technique and clinical outcomes

OBJECTIVE

Although there are several variations of laparoscopic living-donor nephrectomies, there is no consensus as to the best technique. Our objective was to describe our technique and assess the outcomes of our approach to hand-assisted laparoscopic retroperitoneal donor nephrectomies.

METHODS

From July 2001 to October 2015, 507 consecutive hand-assisted laparoscopic retroperitoneal donor nephrectomies were performed. Their clinical information was retrospectively reviewed including warm ischemia time, skin incision to kidney ready time, estimated blood loss, adverse intraoperative events, and postoperative complications.

RESULTS

Mean incision time to kidney removal was 135 minutes (55-260), mean warm ischemia time was 125 seconds (30-390), and mean blood loss was 83 mL (20-500). Average length of stay was 3 days (1-6). There were no significant differences between left and right kidney donors based on demographics, length of hospital stay, or warm ischemia time. There were no conversions to open surgery. Complications occurred in 4.9% of patients (25/507), including 4 cases of perioperative bleeding.

CONCLUSIONS

This is a single-center series describing the safety and efficacy of the hand-assisted laparoscopic retroperitoneal donor nephrectomy for both right and left sides. It does not require intraperitoneal manipulation and allows for safe extraction of either kidney with minimal warm ischemia time.

Ferumoxytol-Enhanced Magnetic Resonance Imaging in Late-Stage CKD

Ferumoxytol is a superparamagnetic iron oxide particle encapsulated by a semisynthetic carbohydrate with properties that can be used by the nephrologist for diagnosis and therapy. Ferumoxytol is approved by the US Food and Drug Administration for treating iron deficiency anemia in the setting of chronic kidney disease, but not for clinical diagnostic imaging. It has gained appeal as a magnetic resonance imaging contrast agent in patients with estimated glomerular filtration rates < 30mL/min/1.73m(2) in whom gadolinium-based contrast magnetic resonance imaging agents are relatively contraindicated because of the association with gadolinium deposition and nephrogenic systemic fibrosis. Ferumoxytol metabolism is not dependent on kidney function, but rather is removed from the circulation by the reticuloendothelial system of the liver, spleen, and bone marrow. Additionally, the prolonged intravascular half-life (>14 hours) of ferumoxytol allows for longer image acquisition and repeat imaging, if necessary. In patients with contraindications for gadolinium contrast agents, ferumoxytol is an alternative agent for vascular assessment, including patency and course.

Induction treatment with rabbit antithymocyte globulin versus basiliximab in renal transplant recipients with planned early steroid withdrawal

STUDY OBJECTIVE

To compare the safety and efficacy of rabbit antithymocyte globulin (r-ATG) with basiliximab in renal transplant recipients for whom an early steroid withdrawal (ESW) regimen was planned.

DESIGN

Single-center, retrospective, cohort study.

SETTING

Tertiary care medical center, including inpatient hospital stays and outpatient nephrology clinics.

PATIENTS

Ninety-nine consecutive adult recipients of living- or deceased-donor renal transplants between January 1, 2004, and December 31, 2007, in whom ESW was planned and who received either r-ATG or basiliximab; patients receiving an extended-criteria kidney donation or a donation after cardiac death were excluded.

MEASUREMENTS AND MAIN RESULTS

All patients received mycophenolate mofetil and tacrolimus as maintenance therapy with planned ESW. Induction therapy was either r-ATG 1.5 mg/kg/day for 4 days (68 patients) or basiliximab 20 mg on postoperative days 0 and 4 (31 patients). The primary composite end point of biopsy-proven acute rejection (BPAR), graft loss, and death occurred in 6 patients (9%) and 9 patients (29%) in the r-ATG and basiliximab groups at 1 year after transplantation, respectively (p=0.01), with rates of 7% (5/68 patients) and 26% (8/31 patients) for BPAR (p=0.02), 0% and 3% (1/31 patients) for graft loss (p=0.31), and 2% (1/68 patients) and 0% for patient death (p>0.99). Average time to first BPAR was significantly longer in the r-ATG group (mean ± SD 151.4 ± 82.9 vs 53.6 ± 68.4 days, p<0.01). Kidney function at 12 months was similar between the two groups.

CONCLUSION

Rabbit-ATG was associated with a lower frequency and delayed onset of BPAR compared with basiliximab in renal transplant recipients who received an ESW regimen.

Racial and ethnic disparities in kidney transplantation

Success of renal transplantation, as a viable alternative to dialysis, has been tempered by long-standing racial disparities. Ethnic minorities have less access to transplantation, are less likely to be listed for transplantation, and experience a higher rate of graft failure. Reasons for the existing racial disparities at various stages of the transplantation process are complex and multi-factorial. They include a combination of behavioral, social, environmental, and occupational factors, as well as potential intended or unintended discrimination within the healthcare system. Immunologic factors such as human leukocyte antigen matching, composition of the organ donor pool, and patient immune response, all of which affect post-transplantation graft rejection rates and patient survival, also contribute to health disparities between ethnic groups.

Evaluation of fluoroquinolones for the prevention of BK viremia after renal transplantation

BACKGROUND AND OBJECTIVES

Nearly 30% of renal transplant recipients develops BK viremia, a prerequisite for BK nephropathy. Case reports have evaluated treatment options for BK virus, but no controlled studies have assessed prophylactic therapies. Fluoroquinolone antibiotics were studied for prevention of BK viremia after renal transplantation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective analysis evaluated adult renal transplant recipients with at least one BK viral load (blood) between 90 and 400 days after transplantation. Six to 12 months of co-trimoxazole was used for Pneumocystis prophylaxis. In sulfa-allergic/-intolerant patients, 6 to 12 months of atovaquone with 1 month of a fluoroquinolone was used. Fluoroquinolones can inhibit BK DNA topoisomerase. The two groups studied were those that received 30 days of levofloxacin or ciprofloxacin after transplantation and those that did not. The primary endpoint was BK viremia rates at 1 year. Of note, of the 160 patients not receiving fluoroquinolone prophylaxis, 40 received a fluoroquinolone for treatment of a bacterial infection within 3 months after transplantation. Subgroup analysis evaluating these 40 patients against the 120 who had no exposure to fluoroquinolones was completed.

RESULTS

A 1-month fluoroquinolone course after transplantation was associated with significantly lower rates of BK viremia at 1 year compared with those with no fluoroquinolone. In the subgroup analysis, exposure to fluoroquinolone for treatment of bacterial infections within 3 months after transplantation was associated with significantly lower 1-year rates of BK viremia.

CONCLUSIONS

This analysis demonstrates that fluoroquinolones are effective at preventing BK viremia after renal transplantation.

C4d positivity is often associated with acute cellular rejection in renal transplant biopsies following Campath-1H (Alemtuzumab) induction

Peritubular capillary C4d positivity, a marker for antibody-mediated rejection, is observed in approximately 20-50% of indicated renal transplant biopsies and in just 2% of unremarkable protocol biopsies. However, C4d staining has not been evaluated in protocol renal biopsies from patients with Campath-1H induction treatment, and the association between various types of inflammatory cells and acute antibody-mediated rejection is unclear. This study investigated the rates of C4d positivity in unremarkable protocol renal biopsies, biopsies with acute tubular necrosis (ATN), and biopsies with acute cellular rejection (ACR), all following Campath-1H treatment and post-operative immunosuppression. There was low positivity of C4d staining in both the protocol and ATN groups, but the ACR group had a 47.2% rate of positivity (combining focal and diffuse positive cases). Since Campath-1H treatment caused significant depletion of circulating lymphocytes but not circulating monocytes in renal recipients, this study also investigated the role of monocytes in humoral rejection. In ACR cases, CD68 positive monocytes were composed of 59.4 +/- 4.69% inflammatory cells, which was significantly higher than CD3 positive lymphocytes (38.9 +/- 4.4%). Co-localization of positive C4d staining in endothelium and marginating CD68 positive monocytes was illustrated by double staining. Our data indicate that acute antibody-mediated rejection occurs much more frequently in renal transplants with ACR. Moreover, the high percentage of monocytes observed in ACR cases (due to monocytes being less sensitive to Campath-1H depletion) suggests that monocytes are involved in antibody-mediated rejection.

Campath-1H Induction and the Incidence of Infectious Complications in Adult Renal Transplantation

BACKGROUND

The purpose of this study was to evaluate adult renal transplantation patients who received a alemtuzumab (Campath-1H)-based induction protocol for the incidence of infectious complications.

METHODS

We began using 30 mg Campath-1H intravenously for induction therapy in May 2003. The patients were treated with a maintenance regimen of tacrolimus or mycophenolate mofetil (MMF), and rapidly tapered prednisone; valganciclovir was used for CMV prophylaxis. Forty-nine adult patients who received renal transplants between May 1, 2003 and June 7, 2004 were included. The mean follow-up time was 13.7 months with a range of 10-24 months. Data were collected via a retrospective chart review.

RESULTS

The infectious complications noted in the Campath-1H group were compared with a historical group of 56 patients receiving conventional immunosuppression. There was one case of cytomegalovirus (CMV) viremia and two cases of CMV disease (one pneumonitis and one enteritis). There were four cases of urinary tract infection and one extremity cellulitis. One patient developed Cryptococcal meningitis. Eight of the 49 (16%) patients in the Campath group had an infectious complication, compared to 18 out of 56 (32%) in the historical group.

CONCLUSION

Campath-1H induction for renal transplantation appears to have a low incidence of associated infectious complications when compared to historical regimens.

Chronic active thrombotic microangiopathy in native and transplanted kidneys

We report 2 complicated cases of thrombotic microangiopathy with chronic features and active components. The first case was a 36-yr-old woman with positive anti-DNA antibody and possible lupus cerebritis, who developed thrombotic microangiopathy secondary to a series of syndromes, including preeclampsia and anti-phospholipid antibody syndrome. Renal biopsy revealed no evidence of lupus nephritis and her renal function returned to normal 1 week after the biopsy. The second case was a 46-yr-old man who developed thrombotic microangiopathy of unknown etiology, which led to end-stage renal disease within 6 mo. The patient received a living related-donor transplant, but thrombotic microangiopathy recurred in the donor kidney only 40 days after the renal transplantation.

Percutaneous Ultrasound-Guided Pancreas Allograft Biopsy: A Single-Center Experience

Percutaneous ultrasound-guided pancreas allograft biopsy is the preferred technique for evaluating pancreas allograft rejection. Experience from large centers has shown it to be safe and effective. We report our experience with 120 percutaneous allograft biopsies performed at a single center. Biopsy tissue was obtained in 54 patients. Thirty-three patients received simultaneous pancreas and kidney transplants, 14 received isolated pancreas transplants, and 7 received a pancreas transplant after kidney transplantation. Biopsies were performed by pancreas transplantation surgeons with the assistance of radiologists under ultrasound guidance using an Acuson XP 128/10 ultrasound machine. One hundred twenty allograft biopsies were performed in 54 patients. Twenty-seven (50%) patients underwent multiple biopsies. In 102 (85%) biopsies the specimens were adequate for examination. Eighteen (15%) biopsy samples had no pancreatic tissue and showed surrounding fat and small bowel. 1 (1.8%) patient bleeding developed that required transfusion of 3 units of packed red blood cells, but no surgical intervention was necessary. One (1.8%) patient had a pancreatic fistula, which healed with nonoperative management. Biochemical evidence of pancreatitis was noted in 5 (9.2%) patients, but none of these patients had clinical signs of pancreatitis. Percutaneous ultrasound-guided pancreas allograft biopsy is a safe procedure with a low complication rate and a high tissue yield for histopathologic examination.

Transplantation and 6-month follow-up of renal transplantation from a donor with systemic lupus erythematosus and lupus nephritis

Transplantation of kidneys with pre-existing glomerulonephritis (GN) has rarely been reported. Little is known of the subsequent evolution of donor pathology in the recipient. We report a transplant using a donor with systemic lupus erythematosus (SLE) and a history of remote acute renal failure but normal renal function at death. Although the screening harvest biopsy was unremarkable, time zero post-implantation renal biopsy showed evidence of lupus nephritis (LN). Sequential protocol biopsies demonstrated gradual resolution of the donor pathology, and renal function was stable despite severe cardiac disease in the recipient. Studies examining the role of functional and biopsy data on outcomes in expanded criteria renal transplantation are reviewed, and the limits of guidance from use of this data are discussed. Pre-existing mild GN may not be an absolute donor exclusion for candidates willing to accept expanded criteria donors. Use of expanded pool kidneys should be guided by functional, biopsy and demographic information, as no single factor alone predicts outcome.

Acute cellular rejection predominated by monocytes is a severe form of rejection in human renal recipients with or without Campath-1H (alemtuzumab) induction therapy

Campath-1H has been used successfully for induction and has resulted in a low rate of acute cellular rejection (ACR) in renal transplantation in combination with various postoperative immunosuppression regimens. This study was undertaken to investigate the extent of monocyte involvement in ACR, with or without Campath-1H induction. We found that monocytes represented the majority of inflammatory cells in grades Ib or higher ACR, but not with Ia type of ACR, regardless of the status of Campath-1H induction. Cases of ACR, following Campath-1H induction, appear to demonstrate a 'pure form' of monocytic ACR, whereas monocytes were mixed with many other types of inflammatory cells in the cases of ACR in the absence of Campath-1H induction. In addition with Campath-1H induction, the cases of monocyte-predominant ACR were found to uniformly exhibit a good response to corticosteroid treatment. We conclude that monocyte-predominate ACR may represent a severe form of rejection, with or without Campath-1H treatment.

Monocyte-mediated acute renal rejection after combined treatment with preoperative Campath-1H (alemtuzumab) and postoperative immunosuppression

Campath-1H (alemtuzumab), a humanized monoclonal antibody against CD52, can cause more profound depletion of lymphocytes than monocytes. The resultant imbalance of lymphocytes and monocytes after Campath-1H treatment of a renal-transplant recipient may lead to an acute rejection dominated by monocytes. We report such a case of acute transplant rejection in a 49-yr-old man who received a living non-related kidney transplant and was treated with preoperative Campath-1H and postoperative immunosuppression. An initial post-transplant renal biopsy showed diffuse mild acute rejection with 95% CD68-positive monocytes, but only 5% CD3-positive T lymphocytes. Inflammatory cells in the renal biopsy were negative for CD34 and CD1a stains, suggesting non-involvement of CD34-derived dendritic cells in the acute rejection. After steroid treatment for 2 wk, the patient's serum creatinine concentration diminished to 1.5 mg/dl. The histopathological features of acute rejection were absent in a second biopsy of the transplanted kidney. In summary, this case is an instance of monocyte-mediated acute rejection of a transplanted kidney.

Proteolysis of synaptobrevin, syntaxin, and SNAP-25 in alveolar epithelial type II cells

Synaptobrevin-2, syntaxin-1, and SNAP-25 were identified in rat alveolar epithelial type II cells by Western blot analysis. Synaptobrevin-2 was localized in the lamellar bodies, and syntaxin-1 and SNAP-25 were found in 0.4% Nonidet P40-soluble and -insoluble fractions, respectively, of the type II cells. When the isolated type II cells were stimulated for secretion with calcium ionophore A23187 or with phorbol 12-myristate 13-acetate, these proteins were found to have been proteolyzed. Preincubation of cells with calpain inhibitor II (N-acetylleucylleucylmethionine), however, prevented the proteolysis. Treatment of the cell lysate with exogenous calpain resulted in a time-dependent decrease of these proteins. The data suggest that synaptobrevin, syntaxin, and SNAP-25 are subject to proteolytic modification by activated calpain in intact type II cells stimulated for secretion.

Resuscitation with lactated Ringer's solution after hemorrhage: lack of cardiac toxicity

The toxicity of D-lactate has been recognized for almost 30 years. This compound is found in the racemic mixture of lactated Ringer's solutions routinely used for peritoneal dialysis and the resuscitation of trauma victims. The current study was designed to investigate whether toxicity occurred at the D-lactate concentrations achieved during hemorrhage resuscitation with racemic lactated Ringer's solution. Conscious unrestrained male Sprague-Dawley rats (n = 24) were monitored for electrocardiographic abnormalities while undergoing hemorrhage and subsequent resuscitation with either L-lactated, D-lactated, or racemic lactated Ringer's solution. The rats infused with D-lactate showed significant toxicity as evidenced by bradycardia, premature ventricular contractions, and ventricular fibrillation. No such alterations were observed in the animals resuscitated with L-lactate or racemic solutions. Resuscitation with the racemic lactate mixture increased the D-lactate concentrations in the blood, but was not associated with overt changes in cardiac rhythm. The infusion of the different resuscitation fluids produced few significant differences in acid-base status of hemorrhaged rats. These findings indicate that although toxicity may be achieved with a Ringer's solution containing only D-lactate, resuscitation using the racemic mixture does not achieve D-lactate concentrations high enough to be detrimental to the animal.