The History of Extracorporeal Membrane Oxygenation and the Development of Extracorporeal Membrane Oxygenation Anticoagulation.

Extracorporeal membrane oxygenation (ECMO) was first started for humans in early 1970s by Robert Bartlett. Since its inception, there have been numerous challenges with extracorporeal circulation, such as coagulation and platelet activation, followed by consumption of coagulation factors and platelets, and biocompatibility of tubing, pump, and oxygenator. Unfractionated heparin (heparin hereafter) has historically been the defacto anticoagulant until recently. Also, coagulation monitoring was mainly based on bedside activated clotting time and activated partial thromboplastin time. In the past 50 years, the technology of ECMO has advanced tremendously, and thus, the survival rate has improved significantly. The indication for ECMO has also expanded. Among these are clinical conditions such as postcardiopulmonary bypass, sepsis, ECMO cardiopulmonary resuscitation, and even severe coronavirus disease 2019 (COVID-19). Not surprisingly, the number of ECMO cases has increased according to the Extracorporeal Life Support Organization Registry and prolonged ECMO support has become more prevalent. It is not uncommon for patients with COVID-19 to be on ECMO support for more than 1 year until recovery or lung transplant. With that being said, complications of bleeding, thrombosis, clot formation in the circuit, and intravascular hemolysis still remain and continue to be major challenges. Here, several clinical ECMO experts, including the "Father of ECMO"-Dr. Robert Bartlett, describe the history and advances of ECMO.

Adolescents and young adults with newly diagnosed primary immune thrombocytopenia.

Current immune thrombocytopenia (ITP) guidelines target children and adults, leading to oversimplification. Adolescents and young adults (AYAS) comprise a separate group with distinct health and psychosocial issues. This study aimed to describe the clinical presentation and therapeutic strategies of ITP among AYAS. We analyzed data from two large ITP registries (PARC-ITP; CARMEN-France) and included newly diagnosed ITP patients (aged 12-25 years) with an initial platelet counts of <100×109/L. Patients with secondary ITP or non-immune thrombocytopenia (n=57) and pregnant women (n=10) were excluded. Of the 656 cases of AYAS with primary ITP registered from 2004 up to 2021, 12-month follow-up data were available for 72%. The initial median platelet count was 12×109/L. In 109 patients (17%), the diagnosis was incidental, without documented bleeding. Apart from gynecological bleeding, the clinical and therapeutical characteristics of females and males were similar. Platelet-enhancing drugs were reported in 66%, 45%, and 30% of patients at diagnosis, 1-6 months, and 6-12 months after diagnosis, respectively. Corticosteroids were the preferred treatment at all time points. At 12 months, 50% of all patients developed chronic ITP. In the subgroup of patients with initial severe thrombocytopenia (<20×109/L), those receiving frontline treatment had a higher remission rate at 1 year than those who followed an initial watch-and-wait strategy (53% and 32%; P<0.05). Our analysis indicates that the remission rate at 1 year may be associated with the initial treatment strategy. This hypothesis must be confirmed in prospective studies.

Eptacog beta efficacy and safety in the treatment and control of bleeding in paediatric subjects (<12 years) with haemophilia A or B with inhibitors.

INTRODUCTION: Eptacog beta is a new recombinant activated human factor VII bypassing agent approved in the United States for the treatment and control of bleeding in patients with haemophilia A or B with inhibitors 12 years of age or older. AIM: To prospectively assess in a phase 3 clinical trial (PERSEPT 2) eptacog beta efficacy and safety for treatment of bleeding in children <12 years of age with haemophilia A or B with inhibitors. METHODS: Using a randomised crossover design, subjects received initial doses of 75 or 225 µg/kg eptacog beta followed by 75 µg/kg dosing at predefined intervals (as determined by clinical response) to treat bleeding episodes (BEs). Treatment success criteria included a haemostasis evaluation of 'excellent' or 'good' without use of additional eptacog beta, alternative haemostatic agent or blood product, and no increase in pain following the first 'excellent' or 'good' assessment. RESULTS: Treatment success proportions in 25 subjects (1-11 years) who experienced 546 mild or moderate BEs were 65% in the 75 µg/kg initial dose regimen (IDR) and 60% in the 225 µg/kg IDR 12 h following initial eptacog beta infusion. By 24 h, the treatment success proportions were 97% for the 75 µg/kg IDR and 98% for the 225 µg/kg IDR. No thrombotic events, allergic reactions, neutralising antibodies or treatment-related adverse events were reported. CONCLUSION: Both 75 and 225 µg/kg eptacog beta IDRs provided safe and effective treatment and control of bleeding in children <12 years of age.

Childhood B-Cell Acute Lymphoblastic Leukemia Following SARS CoV-2 Infection: A Potential Second "Hit" in Leukemogenesis.

The Coronavirus Disease 2019 (COVID-19) pandemic has become the worst pandemic in modern history. The lack of prior immunity to the virus has resulted in a high mortality rate, though children have fared better than adults, overall. We present a case of a child who developed B-cell acute lymphoblastic leukemia 1 week following a symptomatic COVID-19 infection. It is possible that this viral infection provided the "second hit" posited to occur in pediatric leukemogenesis as proposed by Dr Greaves, with his initial viral exposure occurring several weeks earlier.

Distinctive phenotypes in two children with novel germline RUNX1 mutations - one with myeloid malignancy and increased fetal hemoglobin.

RUNX1 associated familial platelet disorder (FPD) is a rare autosomal dominant hematologic disorder characterized by thrombocytopenia and/or altered platelet function. There is an increased propensity to develop myeloid malignancy (MM) - acute myeloid leukemia, myeloproliferative neoplasms or myelodysplastic syndrome often in association with secondary somatic variants in other genes. To date, 23 FPD-MM pediatric cases have been reported worldwide. Here, we present two new kindreds with novel RUNX1 pathogenic variants in which children are probands. The first family is a daughter/mother diad, sharing a heterozygous frameshift variant in RUNX1 gene (c.501delT p.Ser167Argfs*9). The daughter, age 13 years, presented with features resembling juvenile myelomonocytic leukemia - severe anemia, thrombocytopenia, high white cell count with blast cells, monocytosis, increased nucleated red cells and had somatic mutations with high allele burden in CUX1, PHF6, and SH2B3 genes. She also had increased fetal hemoglobin and increased LIN28B expression. The mother, who had a long history of hypoplastic anemia, had different somatic mutations- a non-coding mutation in CUX1 but none in PHF6 or SH2B3. Her fetal hemoglobin and LIN28B expression were normal. In the second kindred, the proband, now 4 years old with thrombocytopenia alone, was investigated at 3 months of age for persistent neonatal thrombocytopenia with large platelets. Molecular testing identified a heterozygous intragenic deletion in RUNX1 encompassing exon 5. His father is known to have increased bruising for several years but is unavailable for testing. These two cases illustrate the significance of secondary mutations in the development and progression of RUNX1-FPD to MM.

Laboratory misdiagnosis of von Willebrand disease in post-menarchal females: A multi-center study.

Increased awareness of von Willebrand Disease (VWD) has led to more frequent diagnostic laboratory testing, which insurers often dictate be performed at a facility with off-site laboratory processing, instead of a coagulation facility with onsite processing. Off-site processing is more prone to preanalytical variables causing falsely low levels of von Willebrand Factor (VWF) due to the additional transport required. Our aim was to determine the percentage of discordance between off-site and onsite specimen processing for VWD in this multicenter, retrospective study. We enrolled females aged 12 to 50 years who had off-site specimen processing for VWF assays, and repeat testing performed at a consulting institution with onsite coagulation phlebotomy and processing. A total of 263 females from 17 institutions were included in the analysis. There were 251 subjects with both off-site and onsite VWF antigen (VWF:Ag) processing with 96 (38%) being low off-site and 56 (22%) low onsite; 223 subjects had VWF ristocetin co-factor (VWF:RCo), 122 (55%) were low off-site and 71 (32%) were low onsite. Similarly, 229 subjects had a Factor VIII (FVIII) assay, and 67 (29%) were low off-site with less than half, 29 (13%) confirmed low with onsite processing. Higher proportions of patients demonstrated low VWF:Ag, VWF:RCo, and/or FVIII with off-site processing compared to onsite (McNemar's test P-value <.0005, for all assays). These results emphasize the need to decrease delays from sample procurement to processing for VWF assays. The VWF assays should ideally be collected and processed at the same site under the guidance of a hematologist.

Clinical utility of viscoelastic testing (TEG and ROTEM analyzers) in the management of old and new therapies for hemophilia.

Hemophilia A and B are rare inherited bleeding disorders resulting from deficiency of coagulation factors VIII and IX respectively. In the past few decades, the field of hemophilia has witnessed pivotal management challenges and therapeutic advances. Routine coagulation and factor assays, while useful in the classification of severity and treatment monitoring in hemophilia patients, have been shown to be of limited use in managing clinical presentations and outcomes. This prompted the investigation of viscoelastic studies in hemophilia care, which have established their utility in various bleeding and thrombotic states. In this review, we will discuss and critically assess the current literature highlighting the use of viscoelastic studies in various aspects of hemophilia including the determination of clinical phenotype, management of patients with inhibitors, perioperative management, and monitoring of novel agents.

Utility of thromboelastography for the diagnosis of von Willebrand disease.

Von Willebrand disease (VWD) is an inherited bleeding disorder that is caused by a quantitative or qualitative deficiency of von Willebrand factor (VWF). The National Heart, Lung, and Blood Institute (NHLBI) guidelines for the diagnosis of VWD state that a VWF activity (VWF:RCo) of <30 IU/dL or <50 IU/dL with symptoms of clinical bleeding are consistent with the diagnosis of VWD. However, current gold-standard diagnostic testing takes days to have complete results. Thromboelastography (TEG) is a testing method that provides a graphical trace that represents the viscoelastic changes seen with fibrin polymerization in whole blood, therefore providing information on all phases of the coagulation process. This study describes the TEG characteristics in 160 patients who presented for workup of a bleeding disorder and a subset of those were subsequently diagnosed with VWD. The TEG parameters, K-time (representing the dynamics of clot formation) and the maximal rate of thrombus generation (MRTG), were found to be sensitive in detecting patients with VWF:RCo <30 IU/dL. The TEG, unlike VWF:RCo, can be done in real time, and results are available to the clinician within an hour. This will definitely be beneficial in acute situations such as evaluation of and management of acute bleeding in patients with acquired deficiencies of VWF and may play an important role in the surgical management of patients with VWD.

A comparative prospective observational study of children and adults with immune thrombocytopenia: 2-year follow-up.

Comparative clinical studies of children and adults with immune thrombocytopenia (ITP) are poorly covered in the literature. However, the accepted classification of ITP-childhood ITP and adult ITP-results in considerable differences in treatment protocols and practice guidelines. The analysis of the Pediatric and Adult Registry on Chronic ITP (PARC-ITP) of patients at first presentation demonstrated fewer differences in clinical and laboratory findings at initial diagnosis between children and adults than expected. The present report of 2-year follow-up data supports the hypothesis that there are common aspects of childhood and adult ITP. Data of 3360 children and 420 adults were collected during the time of 2004 until 2015 at initial diagnosis. Follow-up information was available for 51% and 33% of children and 66% and 49% of adults at 12- and 24-months, respectively. Similarities were found in unexpected areas of ITP, such as the rate of late remission at 12 and 24 months, reported bleeding sites, platelet count in bleeders, and the frequency of treated patients with persistent or chronic ITP. Differences were confirmed for the overall rate of remission and treatment modalities. Unexpected differences were found in the percentage of nonbleeders, with more adults in the nonbleeder group. More studies are needed to investigate different age groups with the aim to optimize their management.

Independent adjudicator assessments of platelet refractoriness and rFVIIa efficacy in bleeding episodes and surgeries from the multinational Glanzmann's thrombasthenia registry.

Glanzmann's thrombasthenia (GT) is a rare congenital bleeding disorder associated with decreased platelet aggregation due to qualitative/quantitative deficiencies of the fibrinogen receptor. Severe bleeding episodes and perioperative bleeding are typically managed with platelet transfusions, although patients can develop anti-platelet antibodies or experience clinical refractoriness. The GT Registry (GTR) was established to collect efficacy/safety data on hemostatic treatments for GT, including recombinant factor VIIa (rFVIIa). At the request of the United States Food and Drug Administration, three hematology experts evaluated platelet refractoriness, antibody status, and rFVIIa efficacy data on a case-by-case basis to support a potential indication for rFVIIa in GT. Adjudication included 195 patients with 810 events (619 severe bleeding episodes, 192 surgeries), and a consensus algorithm was developed to describe adjudicators' coding of refractoriness and antibody status based on treatment patterns over time. Most rFVIIa-treated events were in patients without refractoriness or antibodies. Adjudicators rated most rFVIIa-treated bleeding episodes as successful (251/266, 94.4%; rFVIIa only, 101/109, 92.7%; rFVIIa ± platelets ± other agents, 150/157, 95.5%); efficacy was consistent in patients with platelet refractoriness ± antibodies (75/79, 94.9%), antibodies only (10/10, 100.0%), and neither/unknown (166/177, 93.8%). Adjudicators also rated most rFVIIa-treated surgeries as successful (159/160, 99.4%; rFVIIa only, 65/66, 98.5%; rFVIIa ± platelets ± other agents, 94/94, 100.0%); efficacy was consistent in patients with platelet refractoriness ± antibodies (69/70, 98.6%), antibodies only (24/24, 100.0%), and neither/unknown (66/66, 100.0%). Unblinding the adjudicators to investigator efficacy ratings changed few assessments. Doses of rFVIIa were narrowly distributed, regardless of other hemostatic agents used.

Neonatal Hemostatic Disorders: Issues and Challenges.

Neonates form a unique cohort with distinct features associated with the hemostatic system compared with older children and adults. The development of the human hemostatic system begins around 10 weeks in utero and continues to evolve during childhood. This dynamic period termed developmental hemostasis should be taken into consideration when diagnosing a neonate with disorders of bleeding or thrombosis.

Hypercoagulability in adolescent girls on oral contraceptives-global coagulation profile and estrogen receptor polymorphisms.

Oral contraceptive (OCP) induced changes on coagulation are complex with high inter-individual variability. The precise reason for differences in this variability is unknown. We hypothesized that global coagulation assays better delineate these changes and variability in hypercoagulability may be the result of differences in estrogen metabolism and thrombophilia. Fifty-two adolescents initiating OCPs were prospectively enrolled; 33 subjects completed the study. Samples were analyzed prior to and after OCPs for procoagulant and anticoagulant factor activities and thrombin generation (TG) +/-thrombomodulin. Participants were genotyped for common thrombophilia and estrogen receptor-α (ESR-α) single nucleotide polymorphisms (SNPs). SNP genotypes were compared to coagulation parameters; TG parameters and differences pre and post OCPs were examined. At baseline, a striking finding was elevated FVIII levels. FVL was absent in all and F2 G20210A was present in one participant. The ESR-α polymorphism was present in heterozygous state in 59% and homozygous state in 21% participants. There were no differences in VWF levels and FVIII: C after being on OCPs. Protein S levels decreased with OCPs. Sixty percent of participants showed evidence of hypercoagulability on TG testing on OCPs. Higher thrombin peak and endogenous thrombin potential (ETP) were seen on TG after OCPs. With thrombomodulin, ETP and thrombin peak did not decrease after OCPs, signifying 'thrombomodulin resistance'. We demonstrated that OCPs induce a state of "variable" hypercoagulability in adolescents, predominantly through the protein S pathway. Genetic and nongenetic factors may account for the variable increase in hypercoagulability. Further research is needed to understand this.

Myelofibrosis, hepatic extramedullary hematopoiesis and ascites associated with vitamin D deficiency in early infancy.

Primary myelofibrosis is rare in children. Many causes have been described for secondary myelofibrosis including vitamin D deficiency. Here, we describe a patient with myelofibrosis secondary to vitamin D deficiency, as diagnosed by laboratory evidence. The patient also developed resultant extramedullary hematopoiesis with secondary development of ascites as a result of myelofibrosis. These are findings rarely reported in association with vitamin D deficiency. Potential mechanisms are also discussed.

Association of laboratory test results with the bleeding history in patients with inherited platelet function disorders (the Bleeding Assesment Tool - LABoratory tests substudy): communication from the Platelet Physiology ISTH-SSC.

Background: In hemophilia and von Willebrand disease, the degree of alteration of laboratory assays correlates with bleeding manifestations. Few studies have assessed the predictive value for bleeding of laboratory assays in patients with inherited platelet function disorders (IPFDs). Objectives: To assess whether there is an association between platelet function assay results and bleeding history, as evaluated by the International Society on Thrombosis and Haemostasis (ISTH) bleeding assessment tool (BAT). Methods: Centers participating in the international ISTH-BAT validation study were asked to provide results of the diagnostic assays employed for the patients they enrolled, and the association with the individual patients' bleeding score (BS) was assessed. Results: Sixty-eight patients with 14 different IPFDs were included. Maximal amplitude of platelet aggregation was significantly lower in patients with a pathologic BS and correlated inversely with the BS, a finding largely driven by the subgroup of patients with Glanzmann thrombasthenia and CalDAG-GEFI deficiency; after their exclusion, TRAP-induced aggregation remained significantly lower in patients with a pathologic BS. Bleeding time was significantly more prolonged in patients with a high BS than in those with a normal BS (27.1 ± 6.2 minutes vs 15.1 ± 10.6 minutes; P < .01). Reduced α-granule content was significantly more common among patients with a pathologic BS than among those with a normal BS (80% vs 20%; P < .05). Receiver operating characteristic curve analysis revealed a significant discriminative ability of all the aforementioned tests for pathologic BS (P < .001), also after exclusion of patients with Glanzmann thrombasthenia and CalDAG-GEFI deficiency. Conclusion: This study shows that altered platelet laboratory assay results are associated with an abnormal ISTH-BAT BS in IPFD.

Evidence for the transmission of parvovirus B19 in patients with bleeding disorders treated with plasma-derived factor concentrates in the era of nucleic acid test screening.

BACKGROUND: Parvovirus B19 (B19V) is a small, nonenveloped virus that typically causes a benign flu-like illness that occurs most frequently in childhood. The virus is resistant to current viral inactivation steps used in the manufacture of antihemophilic factor concentrates and B19V transmission through these products has been documented. Since 2000, B19V nucleic acid test (NAT) screening of plasma pools has been implemented to further decrease the viral burden in these products, but no study has examined populations using these products to assess the impact of the screening on B19V transmission. STUDY DESIGN AND METHODS: Blood specimens obtained from participants of a surveillance system established in federally supported specialized bleeding disorders clinics were used in a B19V seroprevalence study. RESULTS: A total of 1643 specimens from 1043 participants age 2 to 7 years born after B19V NAT screening was implemented were tested. Age-specific prevalence rates were generally higher for subjects exposed to either plasma-derived products alone or in combination with other products compared to subjects with no exposure to antihemophilic products. Overall, compared to participants unexposed to blood or blood products, those exposed to plasma-derived products alone were 1.7 times more likely to have antibodies to B19V (p = 0.002). CONCLUSION: These results are consistent with continued B19V transmission through plasma-derived factor concentrates. Effective viral inactivation and detection processes are needed to protect users of these products from infection with B19V or other new or emerging viruses.

Emergency department visits in children with hemophilia.

BACKGROUND: The pediatric emergency department (ED) management of bleeding and other complications of hemophilia constitutes an increasingly important component of hemophilia therapy. This retrospective study examined the overall ED use by children with hemophilia in a single center, with a particular aim to investigate visits related to injury or bleeding, and those related to blood stream infection in patients with a central venous catheter (CVC). METHODS: Electronic medical records of patients with hemophilia presenting to Children's Hospital of Michigan ED were reviewed. Different categories of ED visits over a 5-year period (January 2006-December 2010) were examined. RESULTS: There were 536 ED visits from 84 male patients (median age 4 years, range 0-21) with hemophilia over the 5-year period. The reasons for ED visits were: injury or bleeding (61.2%); suspected CVC-related infection (11.8%); causes unrelated to hemophilia (19.2%); and routine clotting factor infusion (7.8%). Eighteen visits from six patients were secondary to injury or bleeding in a patient not yet diagnosed with hemophilia. An intracranial hemorrhage was detected in five visits. Overall, 5.4% of all visits represented distinct episodes of bloodstream infection. CONCLUSION: The pediatric ED is an indispensable component of the overall hemophilia care, because: (1) patients with potentially lethal problems such as ICH or CVC-related infection may present to the ED for their initial management; (2) previously undiagnosed patients with hemophilia may also present to the ED for their first bleeding episodes, initiating the diagnostic investigations; (3) the ED provides after-hours treatment service for many episodes of injury or bleeding, and also for clotting factor infusion.

Global Emerging HEmophilia Panel (GEHEP): A Multinational Collaboration for Advancing Hemophilia Research and Treatment.

GEHEP, established in 2009, is an independent, multi-institutional, international consortium of early career hematology specialists in the field of hemophilia and other inherited bleeding disorders. The main objective of the group, whose members practice at institutions in North America, Europe, and South Africa, is to advance hemophilia care by providing a forum for mentored collaborative research, developing programs for improving clinical care, and promoting academic career development of junior faculty. GEHEP members collect and document anonymized data on intra- and interinstitutional differences in patient populations, diagnosis, and treatment in the field of hemophilia and other bleeding disorders. To facilitate sharing of aggregated data among GEHEP members, a global protocol was developed and approved by most members' local institutional review board. Current GEHEP research initiatives are varied, encompassing work in pediatric and adult patients. GEHEP members have presented research at international meetings on the initiation of prophylaxis in children, use of immune tolerance induction in adults, and prevalence of acute coronary syndromes in older patients with hemophilia. The main goal of the continuing work of GEHEP is to advance the care of patients with hemophilia worldwide.