Analysis of bleeding outcomes in patients with hypoproliferative thrombocytopenia in the A-TREAT clinical trial.

BACKGROUND: Despite prophylactic platelet transfusions, hypoproliferative thrombocytopenia is associated with bleeding; historical risk factors include hematocrit (HCT) ≤ $$ \le $$ 25%, activated partial thromboplastin time ≥ $$ \ge $$ 30 s, international normalized ratio ≥ $$ \ge $$ 1.2, and platelets ≤ $$ \le $$ 5000/µL. METHODS: We performed a post hoc analysis of bleeding outcomes and risk factors in participants with hematologic malignancy and hypoproliferative thrombocytopenia enrolled in the American Trial to Evaluate Tranexamic Acid Therapy in Thrombocytopenia (A-TREAT) and randomized to receive either tranexamic acid (TXA) or placebo. RESULTS: World Health Organization (WHO) grade 2+ bleeding occurred in 46% of 330 participants, with no difference between the TXA (44%) and placebo (47%) groups (p = 0.66). Overall, the most common sites of bleeding were oronasal (18%), skin (17%), gastrointestinal (11%), and genitourinary (11%). Among participants of childbearing potential, 28% experienced vaginal bleeding. Platelets ≤5000/µL and HCT < 21% (after adjusting for severe thrombocytopenia) were independently associated with increased bleeding risk (HR 3.78, 95% CI 2.16-6.61; HR 2.67, 95% CI 1.35-5.27, respectively). Allogeneic stem cell transplant was associated with nonsignificant increased risk of bleeding versus chemotherapy alone (HR 1.34, 95% CI 0.94-1.91). DISCUSSION: The overall rate of WHO grade 2+ bleeding was similar to previous reports, albeit with lower rates of gastrointestinal bleeding. Vaginal bleeding was common in participants of childbearing potential. Platelets ≤5000/µL remained a risk factor for bleeding. Regardless of platelet count, bleeding risk increased with HCT < 21%, suggesting a red blood cell transfusion threshold above 21% should be considered to mitigate bleeding. More investigation is needed on strategies to reduce bleeding in this population.

A novel approach to simultaneous genotyping of human platelet antigen systems and human leucocyte antigen class I loci using PacBio long-read sequencing.

BACKGROUND AND OBJECTIVES: Accurate human leucocyte antigen (HLA) and human platelet antigen (HPA) typing is essential for establishing a blood platelet donor bank to deal with refractoriness in patients undergoing multiple platelet transfusions. Current methods, such as Sanger and next-generation sequencing, encounter difficulties in haplotyping. Herein, the aim of this study was to establish a method for HLA and HPA typing based on the long read sequencing. STUDY DESIGN AND METHODS: The HPA and HLA class I genotypes of 268 platelet donors from the Taiyuan Blood Center, China were identified using long-read sequencing on the PacBio platform. Allele frequencies for HPA systems and HLA class I genes were calculated, and genetic variability within HPA system genes was analysed. RESULTS: Polymorphisms were identified in 8 of the 35 HPA systems (HPA-1 to HPA-6w, HPA-15 and HPA-21w), with the frequencies of the 'b' allele at 0.0187, 0.0709, 0.4086, 0.0075, 0.0149, 0.0317, 0.4310 and 0.0019, respectively. The alleles with the highest frequencies at the HLA-A, HLA-B and HLA-C loci are HLA-A02:01, B51:01, B46:01 and C06:02, respectively. Additionally, several genetic patterns in HPA systems were identified, including the c.166-1029C>T variant, which was found exclusively in samples carrying the HPA-1b allele. CONCLUSION: This study developed a targeted long-read sequencing method characterized by high throughput and simultaneity, capable of resolving allele ambiguities for effective HLA class I genotyping in establishing a platelet donor bank.

Construction and Validation of an Assistant Decision-Making Model for Platelet Transfusion Refractoriness in Patients with Acute Myeloid Leukemia.

Background: Platelet transfusion refractoriness (PTR) is a complication of multiple transfusions in patients with hematological malignancies. PTR may induce a series of adverse events, such as delaying the treatment of the primary disease and life-threatening bleeding. Early prediction of PTR holds promise in facilitating prompt adjustments to treatment strategies by clinicians. Methods: We collected the clinical data of 250 patients with acute myeloid leukemia (AML). Subsequently, the patients were randomly divided into a training cohort and a validation cohort at a ratio of 7:3. The least absolute shrinkage and selection operator (LASSO) and multivariate logistic-regression methods were used to select characteristic variables. Assessment of the model was conducted through the receiver operating characteristic (ROC), calibration curve and decision curve analysis (DCA). Results: Out of 250 patients with AML, 95 individuals (38.0%) experienced PTR. Among those with positive platelet associated antibodies (PAAs), the incidence of PTR was 66.7% (30/45), while among patients positive for human leukocyte antigen(HLA)-I antibodies, the PTR incidence was 56.5% (48/85). The final predictive model incorporated risk factors such as KIT mutations, splenomegaly, the number of HLA-I antibodies, and positive PAAs. A prediction nomogram model was constructed based on these four risk factors. The LASSO-logistic regression model demonstrated excellent discrimination, calibration, and clinical decision value. Conclusion: The LASSO-logistic regression model in the study can better predict the risk of PTR. The study includes both PAAs and HLA antibodies, expanding the field of work that has not been involved in the previous prediction model of PTR.

Impact of platelet transfusion refractoriness in the first 30 days post-hematopoietic stem cell transplantation on outcomes of patients with myelodysplastic syndrome.

Introduction: Currently, no study has determined whether platelet transfusion refractoriness (PTR) post-hematopoietic stem cell transplantation (HSCT) before engraftment in patients with myelodysplastic syndrome (MDS) would impacts clinical outcomes. Methods: We performed a MDS-specific retrospective analysis to determine whether PTR in one-month post-HSCT in patients with MDS could influence outcomes. Results and discussion: Among the 315 patients enrolled, 110 (34.9 %) had PTR from stem cell infusion to one-month post-HSCT. Baseline characteristics of the PTR and non-PTR groups were similar. We found that patients with PTR had a slower and lower rate of platelet engraftment by day 28, as well as a slower recovery of neutrophils. The median days of neutrophil and platelet engraftment were 14 days (9-23) and 17 days (8-28) in the PTR groups versus 13 days (9-23) and 15 days (7-28) in the non-PTR group (P<0.001). By day 28, 84 of 110 patients (76.4%) with PTR achieved platelet engraftment compared with 181 of 205 patients (88.3%) without PTR achieving platelet engraftment (P=0.007). In addition, patients in the PTR group received significantly more red blood cell (median, 17 units vs. 10 units, P<0.001) and platelet transfusions (median, 13 units vs. 7 units, P<0.001). However, the overall survival was similar between the two groups. PTR in one-month post-HSCT, haploidentical donor, and ferritin level>1041ng/ml (median level) were independent adverse factors of platelet engraftment.

The Effect of High Intensity Interval Exercise on Platelet Engraftment in Autologous Bone Marrow Transplantation (BMT).

Background: Thrombocytopenia is a frequent complication after hematopoietic stem cell transplantation (HSCT). Although platelet transfusion is the most used treatment for severe thrombocytopenia, it is associated with well-established risks. High-intensity interval exercise (HIIE) results in thrombocytosis. Therefore, this study aimed to reduce thrombocytopenia by increasing platelet count through exercise. Materials and Methods: Twenty lymphoma and multiple myeloma patients were divided into HIIE and control groups. To determine the maximal exercise capacity, patients in the HIIE group performed a graded exercise test. All patients received granulocyte colony-stimulating factor for 5 days, followed by a HIIE trial. After 5 min warm up at 10 to 20% of peak power, patients in the HIIE group performed an HIIE protocol that included 12 intervals of one-minute work at 100% peak power interspersed by one-minute active rest at 20% of peak power. Patients in the control group were seated for the same duration without any physical activity. Two blood samples were taken before and immediately after the trials and were analyzed for measuring complete blood count. Results: Platelet count on the day of platelet engraftment in the HIIE group was significantly higher than in the control group (P=0.02). Single-donor platelet transfusion was significantly lower in the HIIE group than in the control group (P=0.05). Conclusion: Based on the findings of the present study, a short bout of HIIE had a positive effect on platelet engraftment through thrombocytosis and reduced platelet transfusion and its complications, which could be a useful strategy for HSCT patients.

Use of Eltrombopag to Improve Thrombocytopenia and Tranfusion Requirement in Anti-CD19 CAR-T Cell-Treated Patients.

Background/Objectives: Immune effector cell-associated hematotoxicity (ICAHT) is a frequent adverse event after chimeric antigen receptor (CAR)-T cell therapy. Grade ≥ 3 thrombocytopenia occurs in around one-third of patients, and many of them become platelet transfusion-dependent. Eltrombopag is a thrombopoietin receptor agonist (TPO-RA) able to accelerate megakaryopoiesis, which has been used successfully in patients with bone marrow failure and immune thrombocytopenia (ITP). Its role in managing thrombocytopenia and other cytopenias in CAR-T cell-treated patients has been scarcely addressed. Our aim was to report the safety and efficacy of this approach in patients included in the Spanish Group for Hematopoietic Transplantation and Cellular Therapy (GETH-TC) registry. Methods: This is a retrospective, multicenter, observational study. Patients who developed platelet transfusion dependence subsequently to CAR-T cells and received eltrombopag to improve platelet counts were recruited in 10 Spanish hospitals. Results: Thirty-eight patients were enrolled and followed up for a median (interquartile range [IQR]) of 175 (99, 489) days since CAR-T cell infusion. At the moment eltrombopag was indicated, 18 patients had thrombocytopenia and another severe cytopenia, while 8 patients had severe pancytopenia. After 32 (14, 38) days on eltrombopag, 29 (76.3%) patients recovered platelet transfusion independence. The number of platelet units transfused correlated with the time needed to restore platelet counts higher than 20 × 109/L (Rho = 0.639, p < 0.001). Non-responders to eltrombopag required more platelet units (58 [29, 69] vs. 12 [6, 26] in responders, p = 0.002). Nineteen out of twenty-three (82.6%) patients recovered from severe neutropenia after 22 (11, 31) days on eltrombopag. Twenty-nine out of thirty-five (82.9%) patients recovered red blood cell (RBC) transfusion independence after 29 (17, 44) days. Seven patients recovered all cell lineages while on treatment. No thromboembolic events were reported. Only two transient toxicities (cholestasis, hyperbilirubinemia) were reported during eltrombopag treatment, none of which compelled permanent drug withdrawal. Conclusions: Eltrombopag could be safely used to manage thrombocytopenia and accelerate transfusion independence in CAR-T cell-treated patients.

[Current Status of Application and Quality Evaluation of Commercial Platelet Pathogen Reduction Technology --Review].

With the development of transfusion medicine, platelet pathogen contamination is of increasing concern to the industry. Currently, pathogen reduction technology (PRT) has been successfully applied to platelets and achieved good results. This paper provides an overview of the research progress of commercial platelet PRT, a comprehensive analysis of the current application status of platelet PRT, preclinical mechanism studies, clinical cohort studies and alternative or complementary strategies, and makes recommendations to provide a scientific basis for safeguarding blood safety in China and developing platelet PRT products applicable to our national conditions.

Lowering platelet-count threshold for transfusion in preterm neonates decreases the number of transfusions without increasing severe hemorrhage events.

Thrombocytopenia is common in preterm neonates and can be associated with hemorrhage. Most platelet transfusions are prophylactic. Previously, higher platelet-count thresholds were recommended for neonates, but this recommendation has been questioned in recent studies. In the PlaNeT2 trial, mortality and serious bleeding were more frequent in neonates with the highest platelet-count threshold than in others. Following this trial, we changed our platelet transfusion practice by lowering the platelet-count threshold for prophylactic transfusion from 50,000 to 25,000/mm3. We conducted a before-after retrospective cohort study to quantify the frequency of platelet transfusions and assess the new protocol by analyzing death and serious hemorrhage events. This retrospective monocentric study included neonates born before 37 weeks of gestation with platelet count < 150,000/mm3 during the 2 years preceding the new platelet transfusion protocol (high prophylactic transfusion threshold, 50,000/mm3) and during the 2 years after the new platelet transfusion protocol (low prophylactic transfusion threshold, 25,000/mm3). The primary outcome was the proportion of neonates receiving at least one platelet transfusion in both groups. We also compared the proportion of deaths and severe hemorrhage events. A total of 707 neonates with thrombocytopenia were identified. In the high-threshold group, 99/360 (27.5%) received at least one platelet transfusion as compared with 56/347 (16.1%) in the low-threshold group (p < 0.001). The groups did not differ in proportion of deaths or severe hemorrhage events. CONCLUSIONS: A reduced platelet-count threshold for transfusion allowed for a significant reduction in the number of platelet transfusions without increasing severe hemorrhage events. WHAT IS KNOWN: • A recent randomized trial suggested that restrictive platelet-count thresholds for platelet transfusion could be beneficial for preterm neonates. WHAT IS NEW: • On lowering the platelet-count threshold for transfusion from 50,000 to 25,000/mm3, the number of transfusions significantly decreased without increasing severe hemorrhage events in a neonatal intensive care unit.

A Contemporary Review of Blood Transfusion in Critically Ill Patients.

Blood transfusion is a common therapeutic intervention in hospitalized patients. There are numerous indications for transfusion, including anemia and coagulopathy with deficiency of single or multiple coagulation components such as platelets or coagulation factors. Nevertheless, the practice of transfusion in critically ill patients has been controversial mainly due to a lack of evidence and the need to consider the appropriate clinical context for transfusion. Further, transfusion carries many risk factors that must be balanced with benefits. Therefore, transfusion practice in ICU patients has constantly evolved, and we endeavor to present a contemporary review of transfusion practices in this population guided by clinical trials and expert guidelines.

Inpatient outcomes of NSTEMI among patients with immune thrombocytopenia: a propensity matched national study.

Patients with immune thrombocytopenia (ITP) admitted for non-ST elevation myocardial infarction (NSTEMI) present a unique therapeutic challenge due to the increased risk of bleeding with antiplatelet and anticoagulation therapies. There is limited evidence studying hospital mortality and complications in this population. The study included a patient cohort from the 2018-2021 National Inpatient Sample database. Propensity score matched NSTEMI patients with and without ITP using a 1:1 matching ratio. Outcomes analyzed were in-hospital mortality, rates of diagnostic angiogram, percutaneous coronary intervention (PCI), acute kidney injury (AKI), congestive heart failure (CHF), cardiogenic shock, cardiac arrest, mechanical ventilation, tracheal intubation, ventricular tachycardia (VT), ventricular fibrillation (VF), major bleeding, need for blood and platelet transfusion, length of stay (LOS), and total hospitalization charges. A total of 1,699,020 patients met inclusion criteria (660,490 females [39%], predominantly Caucasian 1,198,415 (70.5%); mean [SD] age 67, [3.1], including 2,615 (0.1%) patients with ITP. Following the propensity matching, 1,020 NSTEMI patients with and without ITP were matched. ITP patients had higher rates of inpatient mortality (aOR 1.98, 95% CI 1.11-3.50, p 0.02), cardiogenic shock, AKI, mechanical ventilation, tracheal intubation, red blood cells and platelet transfusions, longer LOS, and higher total hospitalization charges. The rates of diagnostic angiogram, PCI, CHF, VT, VF, and major bleeding were not different between the two groups. Patients with ITP demonstrated higher odds of in-hospital mortality for NSTEMI and need for platelet transfusion with no difference in rates of diagnostic angiogram or PCI.

Utility of thromboelastography with platelet mapping for monitoring platelet transfusion in qualitative platelet disorders.

BACKGROUND: Patients with pathogenic variants in RASGRP2 (inherited platelet disorder (IPD)-18) exhibit normal platelet counts but impaired platelet aggregation and αIIbß3 activation. Moderate-to-severe bleeding episodes require patients to be transfused with platelets and/or pro-hemostatic agents. We recently demonstrated that hemostatic efficacy of transfused platelets is limited by dysfunctional endogenous platelets in a mouse model of IPD-18 (Rasgrp2-/- mice), as dysfunctional platelets were recruited to the forming hemostatic plug but did not participate in clot contraction. Thus, higher amounts of transfused platelets were required to outcompete these dysfunctional cells and to reverse bleeding. OBJECTIVE: We here studied the usefulness of thromboelastography with platelet mapping (TEG-PM) for ex vivo monitoring of the hemostatic potential in Rasgrp2-/- mice transfused with various amounts of wild-type (WT) platelets. METHODS: Whole blood (WB) samples from WT and Rasgrp2-/- mice were tested in TEG-PM and parameters for clot formation and contraction (K time, α-angle, maximum amplitude [MA]) were measured. RESULTS: Rasgrp2-/- WB samples did not contract in TEG-PM, consistent with a critical role of this protein in αIIbß3 activation. Addition of WT platelets improved TEG parameters in a ratio-dependent manner, consistent with our recent in vivo studies showing impaired hemostasis at a 5:1, but not at a 2:1 ratio of mutant to WT platelets. K and α values were identified as better predictors of transfusion efficacy than MA, the most platelet-dependent TEG parameter. CONCLUSION: This proof-of-concept study supports the use of TEG-PM to monitor platelet transfusion ratios and hemostatic potential in IPD-18 and potentially other platelet disorders.

Corticosteroids for improving patient-relevant outcomes in HELLP syndrome: a systematic review and meta-analysis.

BACKGROUND: We conducted this updated systematic review to assess the effects of corticosteroids vs. placebo or no treatment for improving patient-relevant outcomes in hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome. METHODS: CENTRAL, MEDLINE/PubMed, Web of Science, and Scopus, from the date of inception of the databases to February 3, 2024 were searched. Reference lists of included studies and systematic reviews were thoroughly searched. We included RCTs that enrolled women with HELLP syndrome, whether antepartum or postpartum, to receive any corticosteroid versus placebo or no treatment. No language or publication date restrictions were made. We used a dual independent approach for screening titles and abstracts, full text screening, and data extraction. Risk of bias was assessed in the included studies using Cochrane's RoB 2 tool. Pairwise meta-analyses were conducted, where two or more studies met methodological criteria for inclusion. GRADE approach was used to assess certainty of evidence for the pre-specified outcomes. RESULTS: Fifteen trials (821 women) compared corticosteroids with placebo or no treatment. The effect of corticosteroids is uncertain for the primary outcome i.e., maternal death (risk ratio [RR] 0.77, 95% confidence interval [CI] 0.25 to 2.38, very low certainty evidence). Out of 6 studies reporting maternal death, 5 were judged overall to have "low risk" of bias. The effect of corticosteroids is also uncertain for other important outcomes including pulmonary edema (RR 0.70, 95% CI 0.23 to 2.09), dialysis (RR 3, 95% CI 0.13 to 70.78), liver morbidity (hematoma, rupture, and failure; RR 0.22, 95% CI 0.03 to 1.83), or perinatal death (0.64, 95% CI 0.21 to 1.97) because of very low certainty evidence. Low certainty evidence suggests that corticosteroids have little or no effect on the need for platelet transfusion (RR 0.98, 95% CI 0.60 to 1.60) and may result in a slight reduction in acute renal failure (RR 0.67, 95% CI 0.40 to 1.12). Subgroup and sensitivity analyses showed results that were similar to the primary synthesis. CONCLUSIONS: In women with HELLP syndrome, the effect of corticosteroids vs. placebo or no treatment is uncertain for patient-relevant outcomes including maternal death, maternal morbidity, and perinatal death. These uncertainties regarding this critical question should be addressed by adequately powered rigorous trials. SYSTEMATIC REVIEW REGISTRATION: Center for Open Science, osf.io/yzku5.

A case study of a patient with platelet transfusion refractoriness (PTR) combined with human leucocyte antigen (HLA) antibody positivity during hepatic arterial infusion chemotherapy in conjunction with the 'atezolizumab plus bevacizumab' regimen.

Hepatic arterial infusion chemotherapy in conjunction with the combination therapy of atezolizumab (T) and bevacizumab (A) is widely used in hepatocellular carcinoma. Some adverse events such as hypertension, weakness and elevated transaminase levels occurred during treatment, while there is currently no reported case about thrombocytopenia with concomitant HLA antibody-positive PTR. We summarize the critical care nursing experience of a patient with PTR because of HLA antibody positivity during hepatic arterial infusion chemotherapy in conjunction with atezolizumab plus bevacizumab (T + A) regimen. This paper explains the nursing measures for patients with severe thrombocytopenia and proposes nursing measures for situations where conventional treatments are ineffective. Key nursing points include the administration of intravenous immunoglobulin (IVIG) and HLA-compatible platelets, prevention of complications, psychological care, oral care, and skin management. Through systematic treatment and targeted nursing care, the patient's platelet count rebounded after 9 days, leading to a successful recovery and discharge. Subsequent follow-up assessments revealed the patient's sustained well-being. Thrombocytopenia is a potential adverse reaction during the treatment of liver cancer. When platelet transfusion is ineffective, vigilance is necessary for the possibility of HLA positivity, and prompt symptomatic management is warranted.

Targeting tissue factor pathway inhibitor with concizumab to improve hemostasis in patients with Glanzmann thrombasthenia: an in vitro study.

BACKGROUND: Glanzmann thrombasthenia (GT) is caused by an inherited defect of platelet αIIbß3 integrin. Concizumab, a monoclonal antibody specific for tissue factor pathway inhibitor, abolishes its anticoagulant effect. OBJECTIVES: To evaluate the in vitro ability of concizumab to improve hemostasis in GT. METHODS: The effects of concizumab were evaluated in whole blood or platelet-rich plasma from GT patients (n = 5-9) using a thrombin generation assay, rotational thromboelastometry (ROTEM), a global fibrinolytic capacity assay, and a flow chamber assay (Total Thrombus formation Analysis System). Washed platelets (WPs) and 20 nM recombinant activated factor VII (rFVIIa) were included for comparison. RESULTS: The lag time in the thrombin generation assay was significantly longer (+85%; P < .0001) in GT patients than in controls. WPs, rFVIIa, and concizumab each significantly improved thrombin generation profiles. The ROTEM clotting time (CT) was significantly longer in GT patients than in controls (677 seconds vs 523 seconds; P = .03). However, CT improved after adding WPs, rFVIIa, or concizumab. Under flow, occlusive thrombi were present in all healthy controls after 10 minutes, whereas platelet-fibrin depositions were not seen in GT patients. Subocclusive or occlusive thrombi formed when GT blood was mixed with WPs, rFVIIa, or concizumab. Clots in GT platelet-rich plasma were more susceptible to fibrinolysis and were improved by WPs, rFVIIa, or concizumab. CONCLUSION: Concizumab enhanced thrombin generation, decreased the ROTEM CT, improved thrombus formation under flow, and reduced clot lysis. Our results demonstrate the potential of concizumab for subcutaneous prophylaxis in GT patients.

Platelet transfusions in adult ICU patients with thrombocytopenia: A sub-study of the PLOT-ICU inception cohort study.

BACKGROUND: Platelet transfusions are frequently used in the intensive care unit (ICU), but current practices including used product types, volumes, doses and effects are unknown. STUDY DESIGN AND METHODS: Sub-study of the inception cohort study 'Thrombocytopenia and Platelet Transfusions in the ICU (PLOT-ICU)', including acutely admitted, adult ICU patients with thrombocytopenia (platelet count <150 × 109/L). The primary outcome was the number of patients receiving platelet transfusion in ICU by product type. Secondary outcomes included platelet transfusion details, platelet increments, bleeding, other transfusions and mortality. RESULTS: Amongst 504 patients with thrombocytopenia from 43 hospitals in 10 countries in Europe and the United States, 20.8% received 565 platelet transfusions; 61.0% received pooled products, 21.9% received apheresis products and 17.1% received both with a median of 2 (interquartile range 1-4) days from admission to first transfusion. The median volume per transfusion was 253 mL (180-308 mL) and pooled products accounted for 59.1% of transfusions, however, this varied across countries. Most centres (73.8%) used fixed dosing (medians ranging from 2.0 to 3.5 × 1011 platelets/transfusion) whilst some (mainly in France) used weight-based dosing (ranging from 0.5 to 0.7 × 1011 platelets per 10 kg body weight). The median platelet count increment for a single prophylactic platelet transfusion was 2 (-1 to 8) × 109/L. Outcomes of patients with thrombocytopenia who did and did not receive platelet transfusions varied. CONCLUSIONS: Among acutely admitted, adult ICU patients with thrombocytopenia, 20.8% received platelet transfusions in ICU of whom most received pooled products, but considerable variation was observed in product type, volumes and doses across countries. Prophylactic platelet transfusions were associated with limited increases in platelet counts.

Comparison of red blood cell transfusions and hemostatic transfusions and their relation to thromboses in pediatric patients receiving extracorporeal membrane oxygenation therapy.

OBJECTIVE: To evaluate the association of RBC transfusions with thrombosis in pediatric patients on extracorporeal membrane oxygenation (ECMO) and compare this with the transfusion of other blood products and their association with thrombosis. METHODS: This was a secondary analysis of the Bleeding and Thrombosis during ECMO (BATE) study, which was a multicenter prospective observational study involving patients less than 19 years of age treated with ECMO. RESULTS: 514 patients were analyzed, of which 282 (55%) were neonates (≤31 days) and 302 (58.7%) were male. When analyzing the entire cohort independently of other blood products, each 10 mL/kg of packed red blood cells (PRBCs) was associated with a 1.0% increase in the average number of thromboses (1.010; 1.008,1.013; p < .001). In neonates, each 10 mL/kg of PRBC was associated with a 0.9% increase in the average number of thromboses (1.009; 1.003,1.013; p < .001). In pediatric patients, each 10 mL/kg of PRBC was associated with a 1.2% increase in the average number of thromboses (1.012; 1.008,1.012; p < .001). The percent increase in the average number of thromboses was similar between PRBCs, platelets, and FFP, but increased significantly with cryoprecipitate. CONCLUSIONS: RBC transfusions and hemostatic transfusions are likely associated with thromboses in pediatric patients on ECMO.

Prophylactic versus restrictive platelet transfusion strategy in patients with haematological malignancies in the ICU setting, a propensity-score analysis.

PURPOSE: Prophylactic platelet transfusions (PT) aim to reduce bleeding. We assessed whether restrictive PT compared to prophylactic strategy could apply in ICU. MATERIAL AND METHODS: We conducted a retrospective monocentric study including patients >18 yo with haematological malignancy admitted to the ICU with thrombocytopenia <20 G/L between 2018 and 2021. Patients were classified in 2 groups according transfusion strategy applied during the first 3 days: prophylactic or restrictive transfusion. RESULTS: 180 patients were included, 87 and 93 in the restrictive and prophylactic groups respectively. After propensity-score analysis, 2 groups of 54 matched patients were analyzed. Restrictive strategy led to a significant reduction in PT with incidence rate for 100-ICU-patients-days of 34.9 and 49.9, incidence rate ratio = 0.699 [0.5-0.9], p = 0.006, representing a 31% decrease. Decreased PT persisted until day 28 with platelet concentrates transfusions-free days at day 28 of 21 [13-25] and 16.5 [10.2-21] in the 2 groups (p = 0.04). Restrictive strategy did not result in higher grade ≥ 2 bleeding. Transfusion efficiency was low with similar number of days with platelet <10 or < 20 G/L regardless of strategy. Platelet transfusion strategy was not associated with 28-day mortality. Platelet nadir <5G/L was associated with day-28 mortality with HR = 1.882 [1.011-3.055], p = 0.046. CONCLUSION: A restrictive PT strategy appears feasible in the ICU.

Isohemagglutinin titration in pooled and apheresis platelets.

BACKGROUND: Platelet inventory constraints necessitate ABO-incompatible platelet transfusion. Many minimize the hemolytic impact by confirming low titre (LT) donor isohemagglutinins. This process is costly. Pathogen-reduced platelets (PRP) in platelet additive solutions (PAS) will dilute plasma and decrease high-titre isohemagglutinins (HT). We determined the proportion of HT platelets and incompatible transfusions for units suspended in plasma to reassess the need for titres following introduction of PRP/PAS. STUDY DESIGN AND METHODS: Our titre method is manual tube (1:50) dilution of platelet supernatant from apheresis or whole blood derived buffy coat pools suspended in plasma, tested with A1/B red cells. Testing included 49,058 pooled and 11,738 apheresis platelets over 4 years. The HT proportion, rate of out-of-group transfusions, and hemolytic reactions were determined. The impact of PAS dilution was estimated. RESULTS: Totally 60,796 platelet units were tested. Group O pooled and group B apheresis platelets had HT in 6.6% and 5.7%, respectively. Group A pooled and apheresis platelets included 2% with HT. Approximately 25% of platelets transfused were ABO-incompatible and no hemolytic reactions were reported. Based on the proportions of PAS-E and plasma for PRP platelets, plasma from each donor comprises 11 mL (6% of total volume) vs 20-257 mL in untreated pools. PAS-E will replace and dilute residual plasma by at least 50%. DISCUSSION: Rare platelet pools may demonstrate HT. PRP platelets with PAS will reduce titres and may abrogate the need for titration. A strategy of group specific transfusion or transfusion of group A PRP platelet transfusions may be a safe alternative.

Impact of restrictive platelet transfusion strategies on transfusion rates: A cohort study in very preterm infants.

BACKGROUND: Evidence supports a restrictive platelet transfusion threshold in preterm neonates. We aimed to describe the effect of implementing this threshold on transfusion rates. STUDY DESIGN AND METHODS: This retrospective observational cohort study included all very preterm infants (born <32 weeks' gestation) admitted to a neonatal intensive care unit between 2004 and 2022, divided into three epochs. Platelet transfusion thresholds changed from 30 × 109/L for stable neonates and 50 × 109/L for unstable neonates (January 2004 to December 2009) to 20 × 109/L for stable neonates and 50 × 109/L for unstable neonates (January 2010 to June 2019) to 25 × 109/L for non-bleeding neonates and 50 × 109/L for neonates with major bleeding (July 2019 to July 2022). The primary outcome was the percentage of transfused neonates in each epoch. Secondary outcomes included the median number of transfusions per neonate, the percentage of transfusions given above 25 or 50 × 109/L, and major bleeding and mortality rates. RESULTS: The percentage of neonates transfused was 12.2% (115/939), 5.8% (96/1660), and 4.8% (25/525) in Epoch I, II, and III, respectively (p < .001), a relative reduction of 61%. The median number of transfusions per transfused neonate was 2.0 (interquartile range [IQR]: 1.0-3.0) in Epoch I, and 1.0 (IQR: 1.0-2.0) in subsequent Epochs (p = .04). The percentage of infants receiving at least one transfusion above 50 × 109/L in Epoch I, II, and III was 51.3% (59/115), 17.7% (17/96), and 20.0% (5/25; p < .001). Mortality and bleeding rates did not significantly differ between epochs. DISCUSSION: Implementation of restrictive platelet guidelines led to reduction of the rate and number of platelet transfusions.