An update on the impact of pre-transplant transfusions and allosensitization on time to renal transplant and on allograft survival

Post-transplant blood transfusions and pediatric renal allograft outcomes

The association of blood transfusions with GS after pediatric KTx is unclear. We retrospectively analyzed blood transfusions post-KTx and subsequent outcomes. Between 1984 and 2013, 482 children (<18 years of age) underwent KTx at our center. Recipient demographics, outcomes and transfusion data were collected. Cox regression with post-KTx blood transfusion as a time-dependent covariate was performed to model the impact of blood transfusion on outcomes. Of the 208 (44%) that were transfused, 39% had transfusion <1 month post-KTx; 48% >12 months. Transfused and non-transfused recipients were not significantly different. In univariate and multivariate analyses, there was no difference between transfused and non-transfused recipient patient survival, antibody-mediated and ACR, and DSA free survival. Transfusions <1 month post-KTx did not impact DCGS (P=NS). Patients transfused >12 months post-KTx had significantly lower 12 month eGFR (compared to non-transfused) and worse subsequent DCGS. Post-KTx blood transfusions have increased in pediatric KTx over time but have no negative association with rejection or DSA production. DCGS is unaffected by transfusion within first month. Transfusions after the first year occur in patients with more advanced chronic kidney disease and are associated with significantly worse DCGS.

Cryopreserved packed red blood cells in surgical patients: past, present, and future

Since the advent of anticoagulation and component storage of human blood products, allogeneic red blood cell transfusion has been one of the most common practices in modern medicine. Efforts to reduce the biochemical effects of storage, collectively known as the red blood cell storage lesion, and prolong the storage duration have led to numerous advancements in erythrocyte storage solutions. Cryopreservation and frozen storage of red blood cells in glycerol have been successfully utilised by many civilian and military institutions worldwide. Through progressive improvements in liquid storage of erythrocytes in novel storage solutions, the logistical need for cryopreserved red blood cells in the civilian setting has diminished. A growing body of current literature is focused on the clinical consequences of packed red blood cell age. Modern cryopreservation techniques show promise as a cost-effective method to ameliorate the negative effect of the red blood cell storage lesion, while meeting the technical and logistical needs of both civilian and military medicine. This review outlines the history of red blood cell cryopreservation, the clinical impact of red cell storage, and highlights the current literature on frozen blood and its impact on modern transfusion.

Effect of Moderate Hepatic Impairment on the Pharmacokinetics and Pharmacodynamics of Roxadustat, an Oral Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor

BACKGROUND AND OBJECTIVE

Roxadustat is a hypoxia-inducible factor prolyl hydroxylase inhibitor in phase III development for the treatment of anaemia associated with chronic kidney disease. This study evaluated the effects of moderate hepatic impairment on roxadustat pharmacokinetics, pharmacodynamics and tolerability.

METHODS

This was an open-label study in which eight subjects with moderate hepatic impairment (liver cirrhosis Child-Pugh score 7-9) and eight subjects with normal hepatic function (matched for body mass index, age and sex) received a single oral 100 mg roxadustat dose under fasted conditions. Blood samples were collected until 144 h post-dose in subjects with moderate hepatic impairment and until 96 h post-dose in subjects with normal hepatic function.

RESULTS

In subjects with moderate hepatic impairment, area under the concentration-time curve (AUC) from the time of drug administration to infinity (AUC∞) and observed maximum concentration (C max) were 23 % higher [geometric least-squares mean ratio (GMR) 123 %; 90 % CI 86.1-175] and 16 % lower (GMR 83.6 %; 90 % CI 67.5-104), respectively, than in subjects with normal hepatic function. Mean terminal half-life (t ½) appeared to be longer (17.7 vs. 12.8 h) in subjects with moderate hepatic impairment, however intersubject variability on apparent total systemic clearance after single oral dosing (CL/F), apparent volume of distribution at equilibrium after oral administration (V z/F) and t ½ was approximately twofold higher. Erythropoietin (EPO) baseline-corrected AUC from administration to the last measurable EPO concentration (AUCE,last) and maximum effect (E max) were 31 % (GMR 68.95 %; 90 % CI 29.29-162.29) and 48 % (GMR 52.29 %; 90 % CI 28.95-94.46) lower, respectively, than in subjects with normal hepatic function. The single oral roxadustat dose was generally well tolerated.

CONCLUSIONS

This study demonstrated the effect of moderate hepatic impairment on the pharmacokinetics and pharmacodynamics of roxadustat relative to subjects with normal hepatic function. These differences are not expected to be of clinical significance.

Retrospective analysis of perioperative transfusion requirements in living donor renal transplantation

BACKGROUND

Extensive bleeding in solid organ transplantation is a major challenge faced by transplant surgeons. Our aim was to audit the peri-operative transfusion requirements in our patients.

MATERIALS AND METHODS

A retrospective analysis of living donor renal transplant surgeries performed from 1st May 2014 to 31st December 2014 was done. The blood/blood component usage during the peri-operative period was obtained. Univariate analysis was performed and the significant factors identified were further analyzed through multivariate regression analysis.

RESULTS

A total of 510 patients (398 males: 78%, and 112 females: 22%) ranging from 18 to 77 years in age were included in the study. Of these, 269 (52.7%) patients were not transfused, while 241 (47.3%) patients received a total of 845 units of blood/blood components. The mean pre-operative hemoglobin in the transfused group was 8.7g/dl while in the non-transfused group it was 10.3g/dl. Leukoreduced packed red blood cell (PRBC) was the major blood component transfused during the peri-operative period. Multivariate regression analysis revealed that pre-operative hemoglobin was a major predictor of intra-operative PRBC transfusion (p = <0.001). Average post-operative length of stay (PLOS) was 10 ± 6 days. There was no significant difference in the PLOS between the transfused and non-transfused groups of patients; however, a statistical significant increase in utilization for both PRBC (p = 0.044) and fresh frozen plasma (p = 0.002) was observed with increased PLOS.

CONCLUSION

Nearly 47.3% of patients undergoing living donor renal transplant received transfusion. PRBC was the most common product transfused and pre-operative hemoglobin was identified as strong predictor of blood consumption.

Alloantibody Generation and Effector Function Following Sensitization to Human Leukocyte Antigen

Allorecognition is the activation of the adaptive immune system to foreign human leukocyte antigen (HLA) resulting in the generation of alloantibodies. Due to a high polymorphism, foreign HLA is recognized by the immune system following transplant, transfusion, or pregnancy resulting in the formation of the germinal center and the generation of long-lived alloantibody-producing memory B cells. Alloantibodies recognize antigenic epitopes displayed by the HLA molecule on the transplanted allograft and contribute to graft damage through multiple mechanisms, including (1) activation of the complement cascade resulting in the formation of the MAC complex and inflammatory anaphylatoxins, (2) transduction of intracellular signals leading to cytoskeletal rearrangement, growth, and proliferation of graft vasculature, and (3) immune cell infiltration into the allograft via FcγR interactions with the FC portion of the antibody. This review focuses on the generation of HLA alloantibody, routes of sensitization, alloantibody specificity, and mechanisms of antibody-mediated graft damage.

The impact of blood transfusions in deceased organ donors on the outcomes of 1,884 renal grafts from United Network for Organ Sharing Region 5

BACKGROUND

Historically, strategies to reduce acute rejection and improve graft survival in kidney transplant recipients included blood transfusions (BTs) before transplantation. While advents in recipient immunosuppression strategies have replaced this practice, the impact of BTs in the organ donor on recipient graft outcomes has not been evaluated. We hypothesize that BTs in organ donors after neurologic determination of death (DNDDs) translate into improved recipient renal graft outcomes, as measured by a decrease in delayed graft function (DGF).

METHODS

Donor demographics, critical care end points, the use of BTs, and graft outcome data were prospectively collected on DNDDs from March 2012 to October 2013 in the United Network for Organ Sharing Region 5 Donor Management Database. Propensity analysis determined each DNDD's probability of receiving packed red blood cells based on demographic and critical care data as well as provider bias. The primary outcome measure was the rate of DGF (dialysis in the first week after transplantation) in different donor BT groups as follows: no BT, any BT, 1 to 5, 6 to 10, or greater than 10 packed red blood cell units. Regression models determined the relationship between donor BTs and recipient DGF after accounting for known predictors of DGF as well as the propensity to receive a BT.

RESULTS

Data were complete for 1,884 renal grafts from 1,006 DNDDs; 52% received any BT, 32% received 1 to 5 U, 11% received 6 to 10, and 9% received greater than 10 U of blood. Grafts from transfused donors had a lower rate of DGF compared with those of the nontransfused donors (26% vs. 34%, p < 0.001). After adjusting for known confounders, grafts from donors with any BT had a lower odds of DGF (odds ratio, 0.76; p = 0.030), and this effect was greatest in those with greater than 10 U transfused.

CONCLUSION

Any BT in a DNDD was associated with a 23% decrease in the odds of recipients developing DGF, and this effect was more pronounced as the number of BTs increased.

LEVEL OF EVIDENCE

Therapeutic study, level III; epidemiologic/prognostic study, level II.

Renal replacement therapy: implications for the surgeon

Renal replacement therapy comprises peritoneal dialysis, haemodialysis and renal transplantation. Patients undergoing renal replacement therapy often require surgery for a number of different reasons. This review summarizes likely surgical procedures for these patients and some of the common complications.

Using red blood cell genomics in transfusion medicine

Blood types (blood group antigens) are heritable polymorphic antigenic molecules on the surface of blood cells. These were amongst the first human Mendelian traits identified, and the genetic basis of nearly all of the hundreds of blood types is known. Clinical laboratory methods have proven useful to identify selected blood group gene variants, and use of genetic blood type information is becoming widespread. However, the breadth and complexity of clinically relevant blood group genetic variation poses challenges. With recent advances in next-generation sequencing technologies, a more comprehensive DNA sequence-based genetic blood typing approach is now feasible. This chapter introduces the practitioner to high-resolution genetic blood typing beginning with an overview of the genetics of blood group antigens, the clinical problem of allosensitization, current blood type testing methods, and then discussion of next-generation sequencing and its application to the problem of genetic blood typing.

Long-term outcome of pediatric renal transplantation: a single center study in Japan

Little is known about the risk factors for long-term poor outcome in pediatric renal transplantation. Between 1973 and 2010, 111 renal transplants (92 living donations) were performed in 104 children (56 males, mean age, 12.5 yr) at the Social Insurance Chukyo Hospital, and followed-up for a mean period of 13.6 yr. The patient survival at 1, 5, 10, 15, 20 (living- and deceased-donor transplants), and 30 yr (living-donor transplants only) was 98.1%, 92.8%, 87.8%, 84.9%, 82.6%, and 79.3%. The graft survival at 1, 5, 10, 15, 20, and 30 yr was 92.0%, 77.3%, 58.4%, 50.8%, 38.5%, and 33.3%. The most common cause of graft loss was CAI, AR, death with functioning, recurrent primary disease, ATN, and malignancy. Donor gender, ATN, malignancy/cardiovascular events, and eras affected patient survival. AR and CAI were the risk factors for graft loss. The evolved immunosuppression protocols improved the outcome by reducing AR episodes and ATN but not CAI, suggesting CAI as the major risk factor for graft loss. CAI was correlated with AR episodes, CMV infection, and post-transplant hypertension. Strategies for preventing the risk factors for malignancy/cardiovascular events and CAI, including hypertension/infection, are crucial for better outcomes.

Hemorrhage requiring surgical intervention among children on pulsatile ventricular assist device support

Bleeding complications are a source of morbidity after Berlin EXCOR VAD implantation yet remain poorly characterized. We evaluated our experience to describe the bleeding complications among pediatric VAD recipients. We hypothesized that those with bleeding requiring exploration had abnormal coagulation profile compared with those without bleeding. The retrospective study included 43 consecutive patients with end-stage heart failure supported on pediatric mechanical cardiac support as a bridge to transplantation. Day-/event-based analysis on factors below associated with (i) bleeding and (ii) bleeding in next 48 h. Cases with bleeding were compared with day-matched patients without bleeding complications. Among 43 subjects bleeding occurred in 47% of cases, which necessitated exploration or chest tube placement. Twenty of 34 interventions for bleeding occurred in the first seven post-operative days. No differences in coagulation parameters or use of antiplatelet agents were noted among those who had bleeding vs. those who did not. Our results indicate that (i) re-bleeding requiring re-exploration was common, (ii) most of the bleeding occurred early post-implantation, (iii) there were no differences in coagulation parameters or the use of antiplatelet agents within 48 h of bleeding compared with those who did not bleed on each successive post-operative day.

Anemia management trends in hospital-based dialysis centers (HBDCs), 2010 to 2013

BACKGROUND

Few data have been reported on anemia management practices in hospital-based dialysis centers (HBDCs), which are uniquely different from other freestanding dialysis centers. Examining data from HBDCs would help determine if HBDCs and the general US dialysis population have similar trends related to how anemia is managed in dialysis patients.

OBJECTIVE

Given recent changes in the prescribing information of erythropoiesis-stimulating agents (ESAs) and in end-stage renal disease-related health policy and reimbursement, this study describes trends in anemia management practices in HBDCs from January 2010 through March 2013.

METHODS

Electronic medical records of 5404 adult hemodialysis patients in 50 US-based HBDCs were analyzed retrospectively. Patients included in the study cohort were aged ≥18 years and had at least 1 hemoglobin (Hb) measurement and 1 dose of an ESA between January 2010 and March 2013. End points included Hb concentration, darbepoetin alfa dosing, epoetin alfa dosing, and iron biomarkers (transferrin saturation and ferritin) and dosing.

RESULTS

From 2010 to 2013, mean monthly Hb levels declined from 11.4 to 10.7 g/dL; the percentage of patients with mean monthly Hb levels <10 g/dL increased from 11.3% to 24.4%; and the percentage of patients with mean monthly Hb levels >12 g/dL declined from 30.1% to 11.2%. The median darbepoetin alfa cumulative 4-week dose also declined 38.8%, and the weekly epoetin alfa dose declined 24%. From January 2010 to March 2013, the percentage of patients with transferrin saturation >30% increased from 35.8% to 43.6%, the percentage of patients with ferritin levels >500 ng/mL increased from 62.0% to 77.9%, the percentage of patients with ferritin levels ≥800 ng/mL increased from 28.9% to 47.3%, and the median cumulative 4-week intravenous iron dose increased 50%.

CONCLUSIONS

These study results support growing evidence that meaningful changes have occurred over the last 3 years in how anemia is clinically managed in US hemodialysis patients. Study limitations include that changes in patient clinical/demographic characteristics over time were not controlled for and that study findings may not be applicable to HBDCs that have different patient populations and/or do not use an electronic medical record system. Continuing to evaluate anemia management practices in HBDCs would provide additional information on the risks and benefits of anemia care. Consistent with national data, the findings from this study indicate that from 2010 to 2013, HBDCs modified anemia management practices for dialysis patients, as evidenced by reductions in mean monthly Hb levels and ESA dosing and by increases in iron biomarkers and dosing.