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BACKGROUND: Persons with hemophilia (PWH) are at risk for chronic hemophilic arthropathy (HA). Joint replacement surgery may be used to relieve intractable pain and/or restore joint function. OBJECTIVES: This multicenter, prospective, observational cohort study evaluated the rate of bleeding during the postoperative period after total hip (THA) or knee arthroplasty (TKA). PATIENTS/METHODS: We included PWH of any severity ≥18 years of age who were undergoing THA or TKA. Clinical decisions were made at the discretion of the treating physician according to local standards of care. Clinical data were prospectively recorded. Major bleeding was defined as bleeding in a critical site, bleeding that resulted in either a 2 g/dL or greater decrease in hemoglobin during any 24-hour period, or transfusion of two or more units of packed red blood cells. RESULTS: One hundred thirty-one procedures (98 TKA and 33 THA) were performed, 39 (29.8%) of which were complicated by major bleeding, including 46% of THA and 25% of TKA. The risk of major bleeding was increased in THA compared to TKA (OR 2.50, p=0.05), and by the presence of an inhibitor (OR 4.29, p=0.04), increased BMI (OR 4.49 and 6.09 for overweight and obese, respectively, compared to normal BMI, each p

Major options for second-line therapy in adults with chronic immune thrombocytopenia (ITP) include splenectomy, rituximab, and thrombopoietin receptor agonists (TRAs). The American Society of Hematology guidelines recommend rituximab over splenectomy, TRAs over rituximab, and splenectomy or TRAs while noting a lack of evidence on the cost-effectiveness of these therapies. Using prospective, observational, and meta-analytic data, we performed the first cost-effectiveness analysis of second-line therapies in chronic ITP, from the perspective of the U.S. health system. Over a 20-year time-horizon, our six-strategy Markov model shows that a strategy incorporating early splenectomy, an approach at odds with current guidelines and clinical practice, is the cost-effective strategy. All four strategies utilizing TRAs in the first or second position cost over $1 million per quality-adjusted life-year, as compared to strategies involving early use of splenectomy and rituximab. In a probabilistic sensitivity analysis, early use of splenectomy and rituximab in either order was favored in 100% of 10 000 iterations. The annual cost of TRAs would have to decrease over 80% to begin to become cost-effective in any early TRA strategy. Our data indicate that effectiveness of early TRA and late TRA strategies is similar with the cost significantly greater with early TRA strategies. Contrary to current practice trends and guidelines, early use of splenectomy and rituximab, rather than TRAs, constitutes cost-effective treatment in adults with chronic ITP.

Patients with immune thrombocytopenia (ITP) may respond to one thrombopoietin receptor agonist (TPO-RA) but not another. Limited data are available describing outcomes in patients who switched from romiplostim or eltrombopag to avatrombopag, a newer oral TPO-RA. We performed a retrospective observational study of adults with ITP who switched from eltrombopag or romiplostim to avatrombopag at four US tertiary ITP referral centres. Forty-four patients were included, with a mean ITP duration of 8.3 years and a median (range) of four prior ITP treatments. On avatrombopag, 41/44 patients (93%) achieved a platelet response (≥50 × 10

Clinicians generally counsel patients with a history of heparin-induced thrombocytopenia (HIT) to avoid heparin products lifelong. Although there are now many alternative (nonheparin) anticoagulants available, heparin avoidance remains challenging for cardiac surgery. Heparin is often preferred in the cardiac surgery setting based on the vast experience with the agent, ease of monitoring, and reversibility. To “clear” a patient with a history of HIT for cardiac surgery, hematologists must first confirm the diagnosis of HIT, which can be challenging due to the ubiquity of heparin exposure and frequency of thrombocytopenia in patients in the cardiac intensive care unit. Next, the “phase of HIT” (acute HIT, subacute HIT A/B, or remote HIT) should be established based on platelet count, immunoassay for antibodies to platelet factor 4/heparin complexes, and a functional assay (eg, serotonin release assay). As long as the HIT functional assay remains positive (acute HIT or subacute HIT A), cardiac surgery should be delayed if possible. If surgery cannot be delayed, an alternative anticoagulant (preferably bivalirudin) may be used. Alternatively, heparin may be used with either preoperative/intraoperative plasma exchange or together with a potent antiplatelet agent. The optimal strategy among these options is not known, and the choice depends on institutional experience and availability of alternative anticoagulants. In the later phases of HIT (subacute HIT B or remote HIT), brief intraoperative exposure to heparin followed by an alternative anticoagulant as needed in the postoperative setting is recommended.

Since 2013, the U.S. Food and Drug administration (FDA) has required that intravenous immune globulin (IGIV) products carry a boxed warning concerning the risk of thromboembolic events (TEEs). This study assessed the incidence of TEEs attributable to IGIV in a large population-based cohort. A self-controlled risk interval design was used to quantify the transient increase in TEE risk during the risk interval (days 0-2 and 0-13 following IGIV for arterial and venous TEEs, respectively) relative to a later control interval (days 14-27 following IGIV). Potential IGIV-exposed TEE cases from 2006 to 2012 were identified from the FDA-sponsored Sentinel Distributed Database and confirmed through medical record review. Inpatient IGIV exposures were not included in the venous TEE analysis due to concerns about time-varying confounding. 19,069 new users of IGIV who received 93,555 treatment episodes were included. Charts were retrieved for 62% and 70% of potential venous and arterial cases, respectively. There was a transient increase in the risk of arterial TEEs during days 0-2 following IGIV treatment (RR = 4.69; 95% CI 1.87, 11.90; absolute increase in risk = 8.86 events per 10,000 patients, 95% CI 3.25, 14.6), but no significant increase in venous TEE risk during days 0-13 following outpatient IGIV treatments (RR = 1.07, 95% CI 0.34, 3.48). Our results suggest there is a small increase in the absolute risk of arterial TEEs following IGIV. However, lower-than-expected chart retrieval rates and the possibility of time-varying confounding mean that our results should be interpreted cautiously. Continued pharmacovigilance efforts are warranted.

Clinical Practice Points • Carfilzomib (CFZ) has rarely been associated with atypical hemolytic uremic syndrome (aHUS). • Patients with heterozygous complement factor H related protein 3 (CFHR)/CFHR1 deletions may be predisposed to CFZ-induced aHUS. • The benefit of eculizumab in the treatment of CFZ-induced aHUS that fails to improve with drug withdrawal and supportive care remains uncertain.

Abnormal bleeding in patients with liver disease may result from elevated portal pressure and varix formation, reduced hepatic synthesis of coagulation proteins, qualitative platelet dysfunction, and/or thrombocytopenia. Major mechanisms of thrombocytopenia in liver disease include splenic sequestration and impaired platelet production due to reduced thrombopoietin production. Alcohol and certain viruses may induce marrow suppression. Immune thrombocytopenia (ITP) may co-occur in patients with liver disease, particularly those with autoimmune liver disease or chronic hepatitis C. Drugs used for the treatment of liver disease or its complications, such as interferon, immunosuppressants, and antibiotics, may cause thrombocytopenia. Periprocedural management of thrombocytopenia of liver disease depends on both individual patient characteristics and the bleeding risk of the procedure. Patients with a platelet count higher than or equal to 50 000/µL and those requiring low-risk procedures rarely require platelet-directed therapy. For those with a platelet count below 50 000/µL who require a high-risk procedure, platelet-directed therapy should be considered, especially if the patient has other risk factors for bleeding, such as abnormal bleeding with past hemostatic challenges. We often target a platelet count higher than or equal to 50 000/µL in such patients. If the procedure is elective, we prefer treatment with a thrombopoietin receptor agonist; if it is urgent, we use platelet transfusion. In high-risk patients who have an inadequate response to or are otherwise unable to receive these therapies, other strategies may be considered, such as a trial of empiric ITP therapy, spleen-directed therapy, or transjugular intrahepatic portosystemic shunt placement.

Immune thrombocytopenia (ITP) may occur in isolation (primary) or in association with a predisposing condition (secondary ITP [sITP]). Eltrombopag is a well-studied treatment for primary ITP, but evidence is scarce for sITP. We evaluated real-world use of eltrombopag for sITP using electronic health records. Eligible patients had diagnoses of ITP and a qualifying predisposing condition, and eltrombopag treatment. We described patient characteristics, treatment patterns, platelet counts, and thrombotic and bleeding events. We identified 242 eligible patients; the most common predisposing conditions were hepatitis C and systemic lupus erythematosus. Average duration of eltrombopag treatment was 6.1 months. Most (81.4%) patients achieved a platelet count ≥ 30,000/µL at a mean of 0.70 months, 70.2% reached ≥ 50,000/µL at a mean of 0.95 months, and 47.1% achieved a complete response of > 100,000/µL at a mean of 1.43 months after eltrombopag initiation. At eltrombopag discontinuation, 105 patients (43%) experienced a treatment-free period for a mean 3.3 months. Bleeding events occurred with similar frequency before and during eltrombopag treatment whereas thrombotic events were less frequent during eltrombopag treatment. Our results suggest similar rates of platelet response with eltrombopag in patients with sITP as compared with primary ITP. In addition, a treatment-free period is possible for a substantial minority of patients. Supplementary Information The online version contains supplementary material available at 10.1007/s00277-021-04637-2.

Background Immune thrombocytopenia (ITP) is an autoimmune disease characterized by low platelet counts and increased risk of bleeding. In preparation for an upcoming guideline, the ITP Emergency Management Guideline Panel, including clinical experts in hematology, emergency medicine, research methodology, and patient representatives, identified the need for a standardized definition of a critical ITP bleed. The goal of the definition was to distinguish critical bleeds from bleeds that may not require urgent treatment, typically in the context of severe thrombocytopenia. Methods The panel met in person and virtually to achieve consensus on the criteria for critical bleeding events among patients with ITP. Existing ITP bleeding scores and published definitions of major bleeds in patients receiving anticoagulation informed the definition of a critical ITP bleed. The Platelet Immunology Scientific Standardization Committee (SSC) of the International Society on Thrombosis and Haemostasis endorsed the definition. Results A critical ITP bleed was defined as: (a) a bleed in a critical anatomical site including intracranial, intraspinal, intraocular, retroperitoneal, pericardial, or intramuscular with compartment syndrome; or (2) an ongoing bleed that results in hemodynamic instability or respiratory compromise. Conclusion The definition of a critical ITP bleed was developed by the ITP Emergency Management Guideline Panel and endorsed by the Platelet Immunology SSC. It incorporates both anatomic and physiologic risk and pertains to patients with confirmed or suspected ITP who typically have severe thrombocytopenia (platelet count below 20 × 109 /L).

Heparin-induced thrombocytopenia (HIT) is a prothrombotic condition resulting from pathogenic antibodies to complexes of heparin and platelet factor 4 (PF4). The diagnosis of HIT can be challenging due to the widespread use of heparin and the frequency of thrombocytopenia in hospitalized patients. Laboratory testing for HIT typically includes an immunoassay to detect antibodies to PF4-heparin and a functional assay. Current HIT diagnostic algorithms recommend using the 4Ts score to determine the need for HIT laboratory testing. Automated calculation of HIT clinical prediction scores in the electronic health record may improve the identification of patients who should undergo HIT testing. Another challenge in the management of patients with suspected HIT is the turnaround time of the laboratory testing needed to confirm the diagnosis. Due to the high daily thrombotic risk of HIT, clinicians must treat patients with intermediate to high pretest likelihood of HIT empirically while awaiting the test results. Treatment for HIT often involves alternative anticoagulants that lack reversal agents, which may increase bleeding risk, prolong hospital stays, and increase costs for patients suspected of having HIT. Rapid immunoassays hold promise to improve the speed of HIT diagnosis. These assays must retain a very high sensitivity for this "can't miss" diagnosis, yet have sufficient specificity to be of diagnostic value. A Bayesian approach has been proposed using two rapid immunoassays in succession, which decreased analytic turnaround time to 60 minutes. Such an approach has the potential to be a much-needed clinical advance in improving accuracy and speed in the diagnosis of HIT.

Background: COVID-19–related acute illness is associated with an increased risk of venous thromboembolism (VTE). Objective: These evidence-based guidelines from the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in making decisions about the use of anticoagulation in patients with COVID-19. Methods: ASH formed a multidisciplinary guideline panel that included patient representatives and applied strategies to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process and performed systematic evidence reviews (through November 2021). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess evidence and make recommendations, which were subject to public comment. This is an update to guidelines published in February 2021 as part of the living phase of these guidelines. Results: The panel made one additional recommendation. The panel issued a conditional recommendation in favor of therapeutic-intensity over prophylactic-intensity anticoagulation in patients with COVID-19–related acute illness who do not have suspected or confirmed VTE. The panel emphasized the need for an individualized assessment of risk of thrombosis and bleeding. The panel also noted that heparin (unfractionated or low molecular weight) may be preferred because of a preponderance of evidence with this class of anticoagulants. Conclusion: This conditional recommendation was based on very low certainty in the evidence, underscoring the need for additional, high-quality, randomized controlled trials comparing different intensities of anticoagulation in patients with COVID-19–related acute illness.

Background: COVID-19–related critical illness is associated with an increased risk of venous thromboembolism (VTE). Objective: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in decisions about the use of anticoagulation for patients with COVID-19. Methods: ASH formed a multidisciplinary guideline panel, including 3 patient representatives, and applied strategies to minimize potential bias from conflicts of interest. The McMaster University Grading of Recommendations Assessment, Development and Evaluation (GRADE) Centre supported the guideline development process, including performing systematic evidence reviews (up to January 2022). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the GRADE approach to assess evidence and make recommendations, which were subject to public comment. This is an update to guidelines published in February 2021 and May 2021 as part of the living phase of these guidelines. Results: The panel made 1 additional recommendation: a conditional recommendation for the use of prophylactic-intensity over therapeutic-intensity anticoagulation for patients with COVID-19–related critical illness who do not have suspected or confirmed VTE. The panel emphasized the need for an individualized assessment of thrombotic and bleeding risk. Conclusions: This conditional recommendation was based on very low certainty in the evidence, underscoring the need for additional, high-quality, randomized controlled trials comparing different intensities of anticoagulation for patients with COVID-19–related critical illness.

Immune thrombotic thrombocytopenic purpura (iTTP) is an acquired, fatal microangiopathy if untreated. Randomized controlled trials (RCTs) demonstrated faster time to response with addition of caplacizumab to standard of care (SOC). However, concerns about RCT selection bias and the high cost of caplacizumab warrant examination of all evidence, including real-world observational studies. In this systematic review and meta-analysis, we searched for comparative studies evaluating SOC with or without caplacizumab for the treatment of iTTP. We assessed risk of bias using the Cochrane risk-of-bias-2 tool (RCTs) and the Newcastle-Ottawa Scale (observational studies). The primary efficacy and safety outcomes were all-cause mortality and treatment-emergent bleeding, respectively. Secondary outcomes included exacerbation and relapse, refractory iTTP, and time to response. We included 2 high-quality RCTs and 3 observational studies at high risk of bias comprising 632 total participants. Compared with SOC, caplacizumab was associated with a nonsignificant reduction in the relative risk [RR] of death in RCTs (RR, 0.21; 95% confidence interval [CI], 0.05-1.74) and observational studies (RR, 0.62; 95% CI, 0.07-4.41). Compared with SOC, caplacizumab was associated with an increased bleeding risk in RCTs (RR, 1.37; 95% CI, 1.06-1.77). In observational studies, bleeding risk was not significantly increased (RR, 7.10; 95% CI, 0.90-56.14). Addition of caplacizumab was associated with a significant reduction in refractory iTTP and exacerbation risks and shortened response time but increased relapse risk. Frontline addition of caplacizumab does not significantly reduce all-cause mortality compared with SOC alone, although it reduces refractory disease risk, shortens time to response, and improves exacerbation rates at the expense of increased relapse and bleeding risk.

Background Studies report hypercoagulability in coronavirus disease 2019 (COVID‐19), leading many institutions to escalate anticoagulation intensity for thrombosis prophylaxis. Objective To determine the bleeding risk with various intensities of anticoagulation in critically ill patients with COVID‐19 compared with other respiratory viral illnesses (ORVI). Patients/Methods This retrospective cohort study compared the incidence of major bleeding in patients admitted to an intensive care unit (ICU) within a single health system with COVID‐19 versus ORVI. In the COVID‐19 cohort, we assessed the effect of anticoagulation intensity received on ICU admission on bleeding risk. We performed a secondary analysis with anticoagulation intensity as a time‐varying covariate to reflect dose changes after ICU admission. Results Four hundred and forty‐three and 387 patients were included in the COVID‐19 and ORVI cohorts, respectively. The hazard ratio of major bleeding for the COVID‐19 cohort relative to the ORVI cohort was 1.26 (95% confidence interval [CI]: 0.86–1.86). In COVID‐19 patients, an inverse‐probability treatment weighted model found therapeutic‐intensity anticoagulation on ICU admission had an adjusted hazard ratio of bleeding of 1.55 (95% CI: 0.88–2.73) compared with standard prophylactic‐intensity anticoagulation. However, when anticoagulation was assessed as a time‐varying covariate and adjusted for other risk factors for bleeding, the adjusted hazard ratio for bleeding on therapeutic‐intensity anticoagulation compared with standard thromboprophylaxis was 2.59 (95% CI: 1.20–5.57). Conclusions Critically ill patients with COVID‐19 had a similar bleeding risk as ORVI patients. When accounting for changes in anticoagulation that occurred in COVID‐19 patients, therapeutic‐intensity anticoagulation was associated with a greater risk of major bleeding compared with standard thromboprophylaxis.

Background: The effectiveness and safety of non-heparin anticoagulants for the treatment of heparin-induced thrombocytopenia (HIT) are not fully established, and the optimal treatment strategy is unknown. In a systematic review and meta-analysis, we aimed to determine precise rates of platelet recovery, new or progressive thromboembolism (TE), major bleeding, and death for all non-heparin anticoagulants and to study potential sources of variability. Methods: Following a detailed protocol (PROSPERO: CRD42020219027), EMBASE and Medline were searched for all studies reporting clinical outcomes of patients treated with non-heparin anticoagulants (argatroban, danaparoid, fondaparinux, direct oral anticoagulants [DOAC], bivalirudin, and other hirudins) for acute HIT. Proportions of patients with the outcomes of interest were pooled using a random-effects model for each drug. The influence of the patient population, the diagnostic test used, the study design, and the type of article was assessed. Findings: Out of 3’194 articles screened, 92 studies with 119 treatment groups describing 4’698 patients were included. The pooled rates of platelet recovery ranged from 74% (bivalirudin) to 99% (fondaparinux), TE from 1% (fondaparinux) to 7% (danaparoid), major bleeding from 1% (DOAC) to 14% (bivalirudin), and death from 7% (fondaparinux) to 19% (bivalirudin). Confidence intervals were mostly overlapping, and results were not influenced by patient population, diagnostic test used, study design, or type of article. Interpretation: Effectiveness and safety outcomes were similar among various anticoagulants, and significant factors affecting these outcomes were not identified. These findings support fondaparinux and DOACs as viable alternatives to conventional anticoagulants for treatment of acute HIT in clinical practice. Registration Information: PROSPERO: CRD42020219027. Funding Information: This study was supported by a research grant of the Swiss National Science Foundation (#179334). Declaration of Interests: Conflict-of-interest disclosure: M.N. received research grants from Bayer Healthcare. A.C. has served as a consultant for synergy and his institution has received research support on his behalf from alexion, Bayer, Novartis, novo Nordisk, Pfizer, Sanofi, spark, and Takeda. All other authors declare that no conflict of interest exists.

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal thrombotic microangiopathy caused by autoantibody-mediated severe deficiency of ADAMTS13. Standardized definitions of response, exacerbation, remission, and relapse were initially proposed in 2003 and modified by the International Working Group for TTP in 2017. These definitions, which have been widely used in clinical practice and research, are based primarily on the platelet count and are benchmarked against the timing of discontinuation of therapeutic plasma exchange (TPE). They do not incorporate ADAMTS13 activity or the temporizing effects on the platelet count of caplacizumab, a novel anti–von Willebrand factor (VWF) nanobody. In light of these limitations, the IWG aimed to develop revised consensus outcome definitions that incorporate ADAMTS13 activity and the effects of anti-VWF therapy, by using an estimate-talk-estimate approach. The updated definitions distinguish clinical remission and clinical relapse (defined primarily by platelet count) from ADAMTS13 remission and ADAMTS13 relapse (defined by ADAMTS13 activity). The revised definitions of exacerbation and remission are benchmarked against not only the timing of discontinuation of TPE but also that of anti-VWF therapy. Retrospective validation of the revised definitions is described, although they have yet to be prospectively validated. Clinical implications of the updated outcome definitions are also discussed and an example of their application to clinical practice is provided to highlight their clinical relevance.

Background Thrombopoietin receptor agonists (TPO-RAs) are used to treat primary immune thrombocytopenia (ITP). Some patients have discontinued treatment while maintaining a hemostatic platelet count. Objectives To develop expert consensus on when it is appropriate to consider tapering TPO-RAs in ITP, how to taper patients off therapy, how to monitor patients after discontinuation, and how to restart therapy. Methods We used a RAND/UCLA modified Delphi panel method. Ratings were completed independently by each expert before and after a meeting. Second-round ratings were used to develop the panel's guidance. The panel was double-blinded: The sponsor and nonchair experts did not know each other's identities. Results Guidance on when it is appropriate to taper TPO-RAs in children and adults was developed based on patient platelet count, history of bleeding, intensification of treatment, trauma risk, and use of anticoagulants/platelet inhibitors. For example, it is appropriate to taper TPO-RAs in patients who have normal/above-normal platelet counts, have no history of major bleeding, and have not required an intensification of treatment in the past 6 months; it is inappropriate to taper TPO-RAs in patients with low platelet counts. Duration of ITP, months on TPO-RA, or timing of platelet response to TPO-RA did not have an impact on the panel's guidance on appropriateness to taper. Guidance on how to taper patients off therapy, how to monitor patients after discontinuation, and how to restart therapy is also provided. Conclusion This guidance could support clinical decision making and the development of clinical trials that prospectively test the safety of tapering TPO-RAs.

Contains fulltext : 232751.pdf (Publisher’s version ) (Closed access) Clinical research in venous thromboembolism (VTE) is hindered by variability in the collection and reporting of data and outcomes. A consistent data language facilitates efficiencies, leads to higher quality data, and permits between-study comparisons and evidence synthesis. The International Society on Thrombosis and Haemostasis (ISTH) launched an international task force of more than 50 researchers to develop common data elements for clinical research in venous thromboembolism. The project was organized in seven working groups, each focusing on a topic area: General Core Data Elements; Anticoagulation and Other Therapies; Chronic VTE and Functional Outcomes; Diagnosis of VTE; Malignancy; Perioperative; and Predictors of VTE. The groups met via teleconference to collaboratively identify key data elements and develop definitions and data standards that were structured in a project-specific taxonomy. A Steering Committee met by teleconference and in-person to determine the overall scope of the project and resolve questions arising from the working groups. ISTH held an open public comment period to enable broader stakeholder involvement and feedback. The common data elements were then refined by the working groups to create a set of 512 unique data elements that are publicly available at http://isth.breakthrough.healthcare. The ISTH VTE Common Data Elements are intended to be a living project with ongoing curation, future expansion, and adaptation to meet the needs of the thrombosis and hemostasis research community.

Heparin-induced thrombocytopenia (HIT) is a prothrombotic adverse drug reaction occurring in

Background Second‐line treatment for immune thrombocytopenia (ITP) is not well reported for patients treated in real‐world clinical settings. Objective The purpose of this study was to compare outcomes of four second‐line treatments for ITP. Patients/methods Included adult patients had at least two medical records containing ITP diagnoses and second‐line eltrombopag, romiplostim, rituximab, or splenectomy. Date of treatment initiation or splenectomy was set as index date, between July 1, 2008, and March 31, 2017. Patients had first‐line corticosteroid or intravenous immune globulin treatment and continuous database activity from 6 months before to 12 months after index. Patient characteristics, treatment patterns, platelet counts, bleeding‐related episodes (BREs), and thrombotic events (TEs) were compared by second‐line treatment cohort. Results The sample included 3332 patients (mean age, 60.5 years; 52.3% female): eltrombopag (5.8%), romiplostim (9.9%), rituximab (73.3%), and splenectomy (11.0%). Patients having splenectomy were younger, more likely female and commercially insured, and less likely to require a third line of treatment than medical regimen cohorts. Proportions of patients having treatment‐free (≥180 days with no second‐line index or rescue agent) periods varied significantly (P = .01) by regimen: 33% for eltrombopag, 23% for romiplostim, 26% for rituximab, and 17% for splenectomy. All regimens significantly improved platelet counts, while TE and BRE rates differed significantly (P = .03 and P = .01, respectively) when all treatment groups were compared. Conclusions Over an average 7‐year follow‐up, all second‐line regimens improved platelet counts, but eltrombopag yielded the highest proportion of patients with completely treatment‐free periods of at least 180 days.

We have shown that patients with suspected heparin-induced thrombocytopenia (HIT) have a high incidence of major bleeding. Recent studies have implicated elevated soluble glycoprotein VI (sGPVI) levels as a potential risk factor for bleeding. We sought to determine if elevated sGPVI plasma levels are associated with major bleeding events in patients with suspected HIT. We used a cohort of 310 hospitalized adult patients with suspected HIT who had a blood sample collected at the time HIT was suspected. Plasma sGPVI levels were measured by using enzyme-linked immunosorbent assay. Patients were excluded who had received a platelet transfusion within 1 day of sample collection because of the high levels of sGPVI in platelet concentrates. We assessed the association of sGPVI (high vs low) with International Society on Thrombosis and Haemostasis major bleeding events by multivariable logistic regression, adjusting for other known risk factors for bleeding. Fifty-four patients were excluded due to recent platelet transfusion, leaving 256 patients for analysis. Eighty-nine (34.8%) patients had a major bleeding event. Median sGPVI levels were significantly elevated in patients with major bleeding events compared with those without major bleeding events (49.09 vs 31.93 ng/mL; P < .001). An sGPVI level >43 ng/mL was independently associated with major bleeding after adjustment for critical illness, sepsis, cardiopulmonary bypass surgery, and degree of thrombocytopenia (adjusted odds ratio, 2.81; 95% confidence interval, 1.51-5.23). Our findings suggest that sGPVI is associated with major bleeding in hospitalized patients with suspected HIT. sGPVI may be a novel biomarker to predict bleeding risk in patients with suspected HIT.

Clarity and guidance is required with regard to the use of direct oral anticoagulants in antiphospholipid syndrome (APS) patients, within the confines of the recent European Medicines Agency recommendations, discrepant recommendations in other international guidelines and the limited evidence base. To address this, the Lupus Anticoagulant/Antiphospholipid Antibodies Scientific and Standardization Committee (SSC) chair and co-chairs together with SSC Control of Anticoagulation members propose guidance for healthcare professionals to help them manage APS patients. Uncertainty in this field will be addressed. This guidance will also serve as a call and focus for research.

Background Most patients with suspected heparin-induced thrombocytopenia (HIT) and an intermediate probability 4Ts score do not have HIT. We aimed to develop a metric based on the rate of platelet count fall to aid in discriminating HIT status among patients with an intermediate 4Ts score. Methods We derived a measure of the maximum 24-hour percentage decrease in platelet count (Fallmax ) in a cohort of patients with suspected HIT and an intermediate 4Ts score at the University of Pennsylvania. We validated this metric in a prospectively collected cohort of patients with suspected HIT and an intermediate 4Ts score from four hospitals in Hamilton, Ontario. Results One hundred fifty-eight and 139 patients were included in the analysis from the derivation and validation cohorts, respectively. Fallmax was significantly higher in HIT-positive patients in the derivation cohort (49.6% versus 38.6%, P = .009) and validation cohort (43.5% versus 29.3%, P = .027). The area under the receiver operating characteristic curve was 0.68 (95% confidence interval [CI] 0.57-0.78) and 0.71 (0.59-0.83) in the two cohorts, respectively. At Fallmax ≥ 30%, sensitivity and specificity were 95.5% and 29.4% in the derivation cohort and 80.0% and 52.7% in the validation cohort. Conclusions Among patients with suspected HIT and an intermediate 4Ts score, Fallmax aided in discriminating HIT-negative from HIT-positive patients. Using a measure that accounts for the rate of platelet count fall may help to avoid unnecessary suspension of heparin and treatment with an alternative anticoagulant in HIT-negative patients with an intermediate probability 4Ts score, though further evaluation is warranted.

Since November 2018, Blood Advances has published American Society of Hematology (ASH) clinical practice guidelines on venous thromboembolism, immune thrombocytopenia, and sickle cell disease. More ASH guidelines on these and other topics are forthcoming. These guidelines have been developed using consistent processes, methods, terminology, and presentation formats. In this article, we describe how patients, clinicians, policymakers, researchers, and others may use ASH guidelines and the many related derivates by describing how to interpret information and how to apply it to clinical decision-making. Also, by exploring how these documents are developed, we aim to clarify their limitations and possible inappropriate usage.

We previously identified gender disparities in academic success during evaluation of the American Society of Hematology (ASH) Clinical Research Training Institute (CRTI) and hypothesized that it may be related to caregiving. The objective was to evaluate the impact of gender and caregiving responsibilities on academic success. A cross-sectional survey that included a question about caregiving responsibilities was distributed to alumni who participated in CRTI from 2003 to 2016 and asked about academic productivity in the previous 3 years. Publications and grants were abstracted from submitted curriculum vitae. Academic success was defined as number of first- or senior-author publications, total publications, grants, and percent effort in research. Of 280 potential respondents, 258 responded (92% response rate), 169 (66%) had caregiving responsibilities, and 110 (43%) were men. Respondents with caregiving responsibilities had fewer first- or senior-author publications (median, 3 vs 5; P = .003) and less percent effort in research (median, 40% vs 50%; P = .006). Men had more first- or senior-author publications (median, 4 vs 3; P = .002) and more total publications (median, 12 vs 6.5; P = .0002) than women. When stratified by those without (P = .0001) or with (P = .042) caregiving responsibilities, men had more publications than women. Among men, caregiving responsibilities significantly reduced all outcomes. However, among women, caregiving did not have an impact. In conclusion, men had more publications than women whether or not they had caregiving responsibilities. However, among men, caregiving reduced academic productivity whereas among women, caregiving did not have impact. The scientific community will need to continue to identify the reasons for disparities and implement changes to address them.

Background Microfluidic clotting assays permit drug action studies for hemophilia therapeutics under flow. However, limited availability of patient samples and Inter‐donor variability limit the application of such assays, especially with many patients on prophylaxis. Objective To develop approaches to phenocopy hemophilia using modified healthy blood in microfluidic assays. Methods Corn trypsin inhibitor (4 µg/mL)‐treated healthy blood was dosed with either anti–factor VIII (FVIII; hemophilia A model) or a recombinant factor IX (FIX) missense variant (FIX‐V181T; hemophilia B model). Treated blood was perfused at 100 s−1 wall shear rate over collagen/tissue factor (TF) or collagen/factor XIa (FXIa). Results Anti‐FVIII partially blocked fibrin production on collagen/TF, but completely blocked fibrin production on collagen/FXIa, a phenotype reversed with 1 µmol/L bispecific antibody (emicizumab), which binds FIXa and factor X. As expected, emicizumab had no significant effect on healthy blood (no anti‐FVIII present) perfused over collagen/FXIa. The efficacy of emicizumab in anti‐FVIII‐treated healthy blood phenocopied the action of emicizumab in the blood of a patient with hemophilia A perfused over collagen/FXIa. Interestingly, a patient‐derived FVIII‐neutralizing antibody reduced fibrin production when added to healthy blood perfused over collagen/FXIa. For low TF surfaces, reFIX‐V181T (50 µg/mL) fully blocked platelet and fibrin deposition, a phenotype fully reversed with anti‐TFPI. Conclusion Two new microfluidic hemophilia A and B models demonstrate the potency of anti‐TF pathway inhibitor, emicizumab, and a patient‐derived inhibitory antibody. Using collagen/FXIa‐coated surfaces resulted in reliable and highly sensitive hemophilia models.

BACKGROUND: The optimal dosing strategy of four-factor prothrombin complex concentrate (4F-PCC) to treat oral factor Xa (FXa) inhibitor-associated bleeding has not been established. OBJECTIVES: To evaluate the effectiveness and safety of fixed versus variable 4F-PCC dosing for the management of FXa inhibitor-associated bleeding. METHODS: A systematic literature search and meta-analysis of clinical studies was performed using PubMed, Embase, and Cochrane databases from inception to January 2022. The primary outcomes included hemostatic effectiveness, mortality, and thromboembolic events. Secondary outcomes included 4F-PCC usage, total length of stay in hospital and in intensive care units, and time to 4F-PCC administration. The pooled incidence or mean was calculated using a random-effects model and compared between the 2 dosing strategies. RESULTS: Twenty-five studies were included and data from 1,760 patients (fixed dosing, n = 228; variable dosing, n = 1,532) were analyzed. There were no significant differences in hemostatic effectiveness, thromboembolic events, or mortality rates between the dosing strategies. Hospital length of stay was significantly longer in the fixed-dosing group, with a mean stay of 7.4 days (95% CI: 3.6-11.1) compared to 5.9 days (95% CI: 5.5-6.3) in the variable-dosing group (P < 0.001). The mean initial 4F-PCC dose was significantly higher with variable dosing than fixed dosing (38 IU/kg; 95% CI: 32-44 vs. 27 IU/kg; 95% CI: 26-28, P < 0.001). CONCLUSIONS: A fixed-dosing strategy appears to be a safe and effective alternative to variable weight-based dosing and was associated with lower 4F-PCC usage. However, direct comparative studies are needed to confirm these results.

The inaugural McMaster Immune Thrombocytopenia (ITP) Summit was held virually in 2021. The objectives of the Summit were to recognize the difficulties in establishing the diagnosis of ITP and to understand gaps in current knowledge of ITP mechanisms that might lead to better diagnostic approaches and treatments. The half-day program consisted of virtual educational sessions targeting clinicians and basic scientists. The planning committee chose 8 topics to review that would cover current knowledge and inform future research priorities. In this report, we summarized the presentations delivered at the 2021 McMaster ITP Summit and the discussions. Based on the information presented at the Summit, the following research priorities were identified: 1) investigation of platelet production as a target for ITP treatments; 2) characterization of antigen processing and antigen presentation on platelets; 3) interaction between megakaryocytes and the immune system; 4) the role for ITP gene panels; 5) the need for better methods for platelet antibody testing; 6) the role of prediction models for diagnosis and prognosis; 7) new treatment strategies, including intensification of initial therapy; and 8) personalized treatment algorithms.

Administrative claims provide a rich data source for retrospective studies of real-world clinical practice, yet some important data may be inconsistent or unavailable. This study explored factors influencing discontinuation of thrombopoietin receptor agonists (TPO-RAs) among patients with immune thrombocytopenia (ITP), by adding medical chart abstraction for additional details. Adult (≥ 18 years) patients with continuous commercial or Medicare Advantage with Part D health insurance coverage were included. Inclusion criteria were ≥ 1 claim for eltrombopag or romiplostim and ≥ 2 diagnoses of ITP between December 31, 2017, and January 1, 2020. Providers were asked to provide access to medical charts for abstraction. The analyses included only patients who discontinued TPO-RA and described patient characteristics, treatment patterns, platelet values, and reasons for discontinuation. Among 207 ITP patients treated with a TPO-RA, 137 (66%) discontinued treatment during the observation period. The mean TPO-RA treatment duration was 185 days. Mean platelet count at the time of discontinuation was 197 × 10

BackgroundCOVID-19–related acute illness is associated with an increased risk of venous thromboembolism (VTE).ObjectiveThese evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in decisions about the use of anticoagulation for thromboprophylaxis in patients with COVID-19 who do not have confirmed or suspected VTE.MethodsASH formed a multidisciplinary guideline panel, including 3 patient representatives, and applied strategies to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including performing systematic evidence reviews (up to March 2021). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the grading of recommendations assessment, development, and evaluation (GRADE) approach to assess evidence and make recommendations, which were subject to public comment.ResultsThe panel agreed on 1 additional recommendation. The panel issued a conditional recommendation against the use of outpatient anticoagulant prophylaxis in patients with COVID-19 who are discharged from the hospital and who do not have suspected or confirmed VTE or another indication for anticoagulation.ConclusionsThis recommendation was based on very low certainty in the evidence, underscoring the need for high-quality randomized controlled trials assessing the role of postdischarge thromboprophylaxis. Other key research priorities include better evidence on assessing risk of thrombosis and bleeding outcomes in patients with COVID-19 after hospital discharge.

Background: Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), occurs in ∼1 to 2 individuals per 1000 each year, corresponding to ∼300 000 to 600 000 events in the United States annually. Objective: These evidence-based guidelines from the American Society of Hematology (ASH) intend to support patients, clinicians, and others in decisions about treatment of VTE. Methods: ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and adult patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment. Results: The panel agreed on 28 recommendations for the initial management of VTE, primary treatment, secondary prevention, and treatment of recurrent VTE events. Conclusions: Strong recommendations include the use of thrombolytic therapy for patients with PE and hemodynamic compromise, use of an international normalized ratio (INR) range of 2.0 to 3.0 over a lower INR range for patients with VTE who use a vitamin K antagonist (VKA) for secondary prevention, and use of indefinite anticoagulation for patients with recurrent unprovoked VTE. Conditional recommendations include the preference for home treatment over hospital-based treatment for uncomplicated DVT and PE at low risk for complications and a preference for direct oral anticoagulants over VKA for primary treatment of VTE.

Background: COVID-19–related critical illness is associated with an increased risk of venous thromboembolism (VTE). Objective: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in making decisions about the use of anticoagulation for thromboprophylaxis in patients with COVID-19–related critical illness who do not have confirmed or suspected VTE. Methods: ASH formed a multidisciplinary guideline panel that included 3 patient representatives and applied strategies to minimize potential bias from conflicts of interest. The McMaster University Grading of Recommendations Assessment, Development and Evaluation (GRADE) Centre supported the guideline development process by performing systematic evidence reviews (up to 5 March 2021). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the GRADE approach to assess evidence and make recommendations, which were subject to public comment. This is an update on guidelines published in February 2021. Results: The panel agreed on 1 additional recommendation. The panel issued a conditional recommendation in favor of prophylactic-intensity over intermediate-intensity anticoagulation in patients with COVID-19–related critical illness who do not have confirmed or suspected VTE. Conclusions: This recommendation was based on low certainty in the evidence, which underscores the need for additional high-quality, randomized, controlled trials comparing different intensities of anticoagulation in critically ill patients. Other key research priorities include better evidence regarding predictors of thrombosis and bleeding risk in critically ill patients with COVID-19 and the impact of nonanticoagulant therapies (eg, antiviral agents, corticosteroids) on thrombotic risk.

The optimal prophylactic preprocedural management of patients with coagulopathy due to liver disease is not known.Our objective was to compare the efficacy and safety of fresh frozen plasma (FFP) with prothrombin complex concentrate (PCC) in the preprocedural management of patients with coagulopathy of liver disease.We conducted a systematic review to examine published evidence regarding treatment with FFP or PCC in adults with coagulopathy of liver disease undergoing an invasive procedure. Direct comparisons and single-arm studies were eligible. Efficacy outcomes included major bleeding, mortality, and correction of prothrombin time (PT) and/or international normalized ratio (INR). Safety outcomes included thrombosis and transfusion-related complications.A total of 95 articles were identified for full-text review. Nine studies were eligible and included in the review. No randomized trials comparing FFP versus PCC were identified. Only two studies directly compared FFP versus PCC. In these studies, PCC appeared to result in higher rates of correction of PT/INR, but bleeding outcomes were not different. In the single-arm studies, bleeding events appeared low overall. Volume overload was the most common recorded adverse event in patients receiving FFP. Thromboembolic events occurred rarely, but exclusively in the PCC group. Due to heterogeneity in study definitions and bias, meta-analysis was not possible. Our study found no evidence to favor a specific product over another.Insufficient data exist on the effects of FFP versus PCC administration before invasive procedures in patients with coagulopathy of liver disease to make conclusions with respect to relative efficacy or safety.

Cases of de novo immune thrombocytopenia (ITP), including a fatality, following SARS-CoV-2 vaccination in previously healthy recipients led to studying its impact in preexisting ITP. In this study, 4 data sources were analyzed: the Vaccine Adverse Events Reporting System (VAERS) for cases of de novo ITP; a 10-center retrospective study of adults with preexisting ITP receiving SARS-CoV-2 vaccination; and surveys distributed by the Platelet Disorder Support Association (PDSA) and the United Kingdom (UK) ITP Support Association. Seventy-seven de novo ITP cases were identified in VAERS, presenting with median platelet count of 3 [1-9] ×109/L approximately 1 week postvaccination. Of 28 patients with available data, 26 responded to treatment with corticosteroids and/or intravenous immunoglobulin (IVIG), and/or platelet transfusions. Among 117 patients with preexisting ITP who received a SARS-CoV-2 vaccine, 19 experienced an ITP exacerbation (any of: ≥50% decline in platelet count, nadir platelet count 20% decrease from baseline, and/or use of rescue therapy) following the first dose and 14 of 70 after a second dose. Splenectomized persons and those who received 5 or more prior lines of therapy were at highest risk of ITP exacerbation. Fifteen patients received and responded to rescue treatment. In surveys of both 57 PDSA and 43 UK patients with ITP, prior splenectomy was associated with worsened thrombocytopenia. ITP may worsen in preexisting ITP or be identified de novo post–SARS-CoV2 vaccination; both situations responded well to treatment. Proactive monitoring of patients with known ITP, especially those postsplenectomy and with more refractory disease, is indicated.

Background and Objectives The determinants of guideline panels’ recommendations remain uncertain. The objective of this study was to investigate factors considered by members of 8 panels convened by the American Society of Hematology (ASH) to develop guidelines using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Study Design and Setting Web-based survey of the participants in the ASH guidelines panels. Analysis: two-level hierarchical, random-effect, multivariable regression analysis to explore the relation between GRADE and non-GRADE factors and strength of recommendations (SOR). Results In the primary analysis, certainty in evidence [OR = 1.83; (95CI% 1.45–2.31)], balance of benefits and harms [OR = 1.49 (95CI% 1.30–1.69)] and variability in patients’ values and preferences [OR = 1.47 (95CI% 1.15–1.88)] proved the strongest predictors of SOR. In a secondary analysis, certainty of evidence was associated with a strong recommendation [OR = 3.60 (95% CI 2.16–6.00)] when panel members recommended “for” interventions but not when they made recommendations “against” interventions [OR = 0.98 (95%CI: 0.57–1.8)] consistent with “yes” bias. Agreement between individual members and the group in rating SOR varied (kappa ranged from −0.01 to 0.64). Conclusion GRADE's conceptual framework proved, in general, to be highly associated with SOR. Failure of certainty of evidence to be associated with SOR against an intervention, suggest the need for improvements in the process.

Two specific reversal agents for direct oral anticoagulants (DOACs) have been approved in the United States: idarucizumab for dabigatran reversal and andexanet alfa for apixaban and rivaroxaban reversal. Non-specific prohemostatic agents such as prothrombin complex concentrate (PCC) and activated PCC have also been used for DOAC reversal. The goal of this document is to provide comprehensive guidance from the Anticoagulation Forum, a North American organization of anticoagulation providers, regarding use of DOAC reversal agents. We discuss indications for reversal, provide guidance on how the individual reversal agents should be administered, and offer suggestions for stewardship at the health system level.

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy characterized by severe congenital or immune‐mediated deficiency in ADAMTS13, the enzyme that cleaves von Willebrand factor multimers. This rare condition leads invariably and rapidly to a fatal outcome in the absence of treatment, and therefore raises multiple diagnostic and therapeutic challenges. The novel concepts and mechanisms identified in the laboratory for this disease have been rapidly and successfully translated into the clinic for the benefit of patients, making TTP an archetypal disease that has benefited from targeted therapies. After decades of empirical treatment with plasma exchange, identification of ADAMTS13 as the key enzyme involved in TTP pathophysiology provided an explanation for the remarkable efficacy of plasma administration, in which the missing enzyme is replenished, and paved the way for development of a recombinant form of the enzyme. Similarly, the demonstration of a major role of anti‐ADAMTS13 antibodies through models of passive transfer of autoimmunity spurred development of immunomodulatory strategies based on B‐cell depletion. More recently, an inhibitor of the platelet‐von Willebrand factor interaction demonstrated efficacy in large clinical trials through prevention of formation of further microthrombi and protection of organs from ischemia. These translational breakthroughs in TTP are described in our review.

Key Points The proposed guideline manuscript template is the first detailed template for transparent and complete reporting of guidelines.Consistent application of the template may simplify preparing an evidence-based guideline manuscript and facilitate its use., Visual Abstract, Trustworthy health guidelines should provide recommendations, document the development process, and highlight implementation information. Our objective was to develop a guideline manuscript template to help authors write a complete and useful report. The McMaster Grading of Recommendations Assessment, Development and Evaluation Centre collaborated with the American Society of Hematology (ASH) to develop guidelines for the management of venous thromboembolism. A template for reporting the guidelines was developed based on prior approaches and refined using input from other key stakeholders. The proposed guideline manuscript template includes: (1) title for guideline identification, (2) abstract, including a summary of key recommendations, (3) overview of all recommendations (executive summary), and (4) the main text, providing sufficient detail about the entire process, including objectives, background, and methodological decisions from panel selection and conflict-of-interest management to criteria for updating, as well as supporting information, such as links to online (interactive) tables. The template further allows for tailoring to the specific topic, using examples. Initial experience with the ASH guideline manuscript template was positive, and challenges included drafting descriptions of recommendations involving multiple management pathways, tailoring the template for a specific guideline, and choosing key recommendations to highlight. Feedback from a larger group of guideline authors and users will be needed to evaluate its usefulness and refine. The proposed guideline manuscript template is the first detailed template for transparent and complete reporting of guidelines. Consistent application of the template may simplify the preparation of an evidence-based guideline manuscript and facilitate its use.