Efficacy and safety of pathogen-reduced platelet concentrates in children with cancer: a retrospective cohort study

Multinational Analysis of Children Transfused With Pathogen Inactivated Platelets

BACKGROUND

Pathogen inactivated (PI) platelets are a technological advancement in blood safety; however, the pediatric experience is not well characterized. We studied pediatric patients who received transfusions of PI platelets across several centers and countries to determine if transfusion reaction rates differed when compared with conventional platelets.

METHODS

This is a retrospective multisite study conducted during 2 time periods. The study period started at the time each site began using PI platelets on a widespread basis, and the control period was a similar timespan before PI introduction. Suspected acute transfusion reactions were compared.

RESULTS

The study included 3839 pediatric patients who were 0 to 18 years of age who received >7930 platelet transfusions, in total, across 4 centers in 3 countries between 2013 and 2019. The age distribution of patients in the study and control period was not significantly different (P = .190). There was not a difference in the percentage of patients who had any type of transfusion reaction between the time periods (1.0% and 1.1%, P = .803). There were fewer patients with mild allergic reactions in the study period compared with the control period (0.2% and 0.7% of patients with reactions, respectively, P = .018).

CONCLUSIONS

Pediatric patients have the same rate of acutely suspected transfusion reactions when receiving PI or conventional platelet transfusions. Subgroup analysis found fewer mild allergic reactions in the study period, which was contemporaneous to the addition of using platelet additive solution more broadly. Future studies of PI platelets should include children to better assess transfusion efficacy and hemostatic outcomes.

Hemostatic efficacy of pathogen-reduced platelets in children undergoing cardiopulmonary bypass

BACKGROUND

Pediatric patients undergoing cardiopulmonary bypass (CPB) often require blood component transfusions. Pathogen-reduction (PR) of platelets reduces the risk of microbial contamination; however, its effect on hemostatic efficacy in this population is unclear. This study sought to characterize the hemostatic efficacy of PR platelets in children undergoing CPB.

STUDY DESIGN AND METHODS

We performed a retrospective chart review of patients admitted to a pediatric intensive care unit following CPB surgery from 2015 to 2019. Demographic data, validated scoring of repair complexity, products received, and outcomes were compared. The primary outcome was postoperative chest tube bleeding.

RESULTS

A total of 140 patients were enrolled. The majority of surgeries (124/140) were Risk Adjustment for Congenital Heart Surgery (RACHS) 1-3 repairs. Seventy-four percent of patients (104/140) received only standard platelets whereas 26% (36/140) received PR platelets. There were no differences between the groups in the age (p = .90), sex (p = .20) or RACHS score (p = .06). Postoperatively, there was no difference in the median chest tube output for 1 h (p = .27), 2 h (p = .26), 4 h (p = .09), 8 h (p = .16), or for the first 24 h following surgery (p = .23) in patients who received standard versus PR platelets. There was also no difference in receipt of platelets (p = .18), cell saver (p = .79), or cryoprecipitate (p = .28).

CONCLUSION

Patients receiving PR platelets did not have more blood loss or require more transfusions than those who received standard platelets. This suggests that PR platelets may provide acceptable hemostasis with the additional benefits of reduced risk of microbial contamination in pediatric patients undergoing CPB.

What Laboratory Tests and Physiologic Triggers Should Guide the Decision to Administer a Platelet or Plasma Transfusion in Critically Ill Children and What Product Attributes Are Optimal to Guide Specific Product Selection? From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding

OBJECTIVES

To present consensus statements and supporting literature for plasma and platelet product variables and related laboratory testing for transfusions in general critically ill children from the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding.

DESIGN

Systematic review and consensus conference of international, multidisciplinary experts in platelet and plasma transfusion management of critically ill children.

SETTING

Not applicable.

PATIENTS

Critically ill pediatric patients at risk of bleeding and receiving plasma and/or platelet transfusions.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A panel of 10 experts developed evidence-based and, when evidence was insufficient, expert-based statements for laboratory testing and blood product attributes for platelet and plasma transfusions. These statements were reviewed and ratified by the 29 Transfusion and Anemia EXpertise Initiative - Control/Avoidance of Bleeding experts. A systematic review was conducted using MEDLINE, EMBASE, and Cochrane Library databases, from inception to December 2020. Consensus was obtained using the Research and Development/University of California, Los Angeles Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method. We developed five expert consensus statements and two recommendations in answer to two questions: what laboratory tests and physiologic triggers should guide the decision to administer a platelet or plasma transfusion in critically ill children; and what product attributes are optimal to guide specific product selection?

CONCLUSIONS

The Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding program provides some guidance and expert consensus for the laboratory and blood product attributes used for decision-making for plasma and platelet transfusions in critically ill pediatric patients.

Preventing adverse reactions in pediatric transfusions using washed platelet concentrate

Blood transfusion is an important form of supportive care in children; however, transfusion-associated adverse reactions (TARs) are a problem. As with adults, allergic transfusion reactions (ATRs) and febrile non-hemolytic transfusion reactions (FNHTRs) are major TARs, and the frequency of ATRs caused by platelet concentrate (PC) tends to be particularly high. The plasma component of the blood product is thought to be a major factor in the onset of TARs such as ATR and FNHTR. By contrast, in children, age, underlying disease, and number of blood transfusions may be relevant patient-related factors. Although acetaminophen or diphenhydramine may be used prophylactically to prevent TARs, there is no clear evidence of their effectiveness. Volume-reduced PC is used to prevent TARs; however, it may be difficult to maintain the quality of platelets. Plasma-replaced PC stored with platelet additive solution raises the concern that TARs cannot be completely prevented by residual plasma. Washed PC removes most of the plasma, so it can effectively prevent ATR and FNHTR. The recent development of platelet additive solution [M-sol, bicarbonate Ringer's solution supplemented with acid-citrate-dextrose formula A (BRS-A)] in Japan has enabled the maintenance of the quality of platelets for long periods. The clinical use of washed PC in Japan has therefore progressed. Washed PC with M-sol or BRS-A for pediatric patients can effectively prevent TARs without diminishing the transfusion effect. The supply of washed PC has begun from the Japanese Red Cross Society, and it has become possible to use washed PC at all medical institutions in Japan.

Novel Blood Component Therapies in the Pediatric Setting

There have been recent advances in safer blood component preparation and use of adjuvant blood derivatives, which have limited safety and efficacy data on use in children. This article reviews the literature on use of whole blood, solvent/detergent-treated plasma, pathogen-reduced platelets, and fibrinogen concentrate in pediatric patients. Many countries have adopted pathogen-reduced blood product technology, and hospitals in the United States are slowly adopting these products. The pediatric transfusion medicine community needs to appraise the evidence for their use and continue to advocate the inclusion of children in the most robust randomized clinical trials for novel blood components.

Platelets treated with pathogen reduction technology: current status and future direction

Allogeneic platelets collected for transfusion treated with pathogen reduction technology (PRT), which has been available in some countries for more than a decade, are now increasingly available in the United States (US). The implementation of PRT-treated platelets, also known as pathogen-reduced platelets (PRPs), has been spurred by the need to further decrease the risk of sepsis associated with bacterial contamination coupled with the potential of this technology to reduce the risk of infections due to already recognized, new, and emerging infectious agents. This article will review available PRP products, examine their benefits, highlight unresolved questions surrounding this technology, and summarize pivotal research studies that have compared transfusion outcomes (largely in adult patients) for PRPs with non-PRT-treated conventional platelets (CPs). In addition, studies describing the use of PRPs in pediatric patients and work done on the association between PRPs and HLA alloimmunization are discussed. As new data emerge, it is critical to re-evaluate the risks and benefits of existing PRPs and newer technologies and reassess the financial implications of adopting PRPs to guide our decision-making process for the implementation of transfusing PRPs.

Adverse transfusion reactions in transfused children

Transfusion in paediatrics requires specific guidelines, because child physiology and pathology differ significantly as compared to adults. Adverse transfusion reactions in transfused children also vary in type and frequency, but there is a better understanding of these reactions in adults than in children. However, for the most frequent adverse transfusion reactions, the overall prevalence is higher in children than in adults, with the exception of post-transfusion red blood cell alloimmunisation, which is lower, excluding patients with haemoglobinopathies. In several studies, allergic reactions were the most frequently reported adverse transfusion reaction in paediatrics, and the platelet concentrate the most frequently implicated blood product. Early diagnosis of certain adverse transfusion reactions such as haemosiderosis, is essential in order to initiate the best therapy and obtain a good clinical outcome. The prevention of adverse transfusion reactions in children is required, but needs further clinical studies in paediatrics. Lastly, changes in technology, policy and clinical practices will improve transfusion safety in children.

New Approaches and Trials in Pediatric Transfusion Medicine

Blood transfusions are frequently lifesaving, but there is growing awareness of their associated infectious and noninfectious adverse events. Patient blood management advocates for judicious use of transfusions and considerations of alternatives to correct anemia or achieve hemostasis. Several transfusion practices, either already implemented or under investigation, aim to further improve the safety of transfusions. An enduring challenge in pediatric and neonatal transfusion practice is that studies typically focus on adults, and findings are extrapolated to younger patients. This article aims to summarize some of the newer developments in transfusion medicine with a focus on the neonatal and pediatric population.

Refrigeration, cryopreservation and pathogen inactivation: an updated perspective on platelet storage conditions

Conventional storage of platelet concentrates limits their shelf life to between 5 and 7 days due to the risk of bacterial proliferation and the development of the platelet storage lesion. Cold storage and cryopreservation of platelets may facilitate extension of the shelf life to weeks and years, and may also provide the benefit of being more haemostatically effective than conventionally stored platelets. Further, treatment of platelet concentrates with pathogen inactivation systems reduces bacterial contamination and provides a safeguard against the risk of emerging and re-emerging pathogens. While each of these alternative storage techniques is gaining traction individually, little work has been done to examine the effect of combining treatments in an effort to further improve product safety and minimize wastage. This review aims to discuss the benefits of alternative storage techniques and how they may be combined to alleviate the problems associated with conventional platelet storage.

Pathogen reduction and blood transfusion safety in Africa: strengths, limitations and challenges of implementation in low-resource settings

Transfusion-transmitted infection risk remains an enduring challenge to blood safety in Africa. A high background incidence and prevalence of the major transfusion-transmitted infections (TTIs), dependence on high-risk donors to meet demand, suboptimal testing and quality assurance collectively contribute to the increased risk. With few exceptions, donor testing is confined to serological evaluation of human immunodeficiency virus (HIV), hepatitis B and C (HBV and HCV) and syphilis. Barriers to implementation of broader molecular methods include cost, limited infrastructure and lack of technical expertise. Pathogen reduction (PR), a term used to describe a variety of methods (e.g. solvent detergent treatment or photochemical activation) that may be applied to blood following collection, offers the means to diminish the infectious potential of multiple pathogens simultaneously. This is effective against different classes of pathogen, including the major TTIs where laboratory screening is already implemented (e.g. HIV, HBV and HCV) as well pathogens that are widely endemic yet remain unaddressed (e.g. malaria, bacterial contamination). We sought to review the available and emerging PR techniques and their potential application to resource-constrained parts of Africa, focusing on the advantages and disadvantages of such technologies. PR has been slow to be adopted even in high-income countries, primarily given the high costs of use. Logistical considerations, particularly in low-resourced parts of Africa, also raise concerns about practicality. Nonetheless, PR offers a rational, innovative strategy to contend with TTIs; technologies in development may well present a viable complement or even alternative to targeted screening in the future.

Current Status of Platelet Transfusion in Pediatric Patients

Outside the neonatal period, most platelets that are transfused to pediatric patients are given to those who are thrombocytopenic secondary to malignancy and associated therapy and/or hematopoietic progenitor cell transplant, or to those with significant bleeding associated with surgery, especially cardiac surgery. Indications for platelet transfusion, doses, and other practices for children largely mimic adult platelet transfusion protocols because there are few pediatric-specific studies in this area. Pediatric platelet transfusion practices would benefit from focused pediatric research. The appropriate indications and doses for platelet transfusions in oncology, hematopoietic progenitor cell transplant, and cardiac surgery patients need to be determined.