Thrombotic thrombocytopenic purpura (TTP) is a rare, potentially fatal thrombotic microangiopathy caused by severe ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin motif 13) deficiency. Prompt treatment improves survival; however, reference standard enzyme-linked immunosorbent assay and FRETS-VWF73 ADAMTS13 activity assays have long turnaround times (TATs) that necessitate empiric treatment of many patients who ultimately are found not to have TTP. Rapid assays with analytical TATs <1 hour have recently become available. We conducted a systematic review and meta-analysis of the performance characteristics of rapid assays relative to reference standard assays for ADAMTS13 activity for patients with suspected or confirmed TTP. Nineteen studies representing 3 rapid ADAMTS13 assays and 4207 patient samples were included. The HemosIL AcuStar chemiluminescence immunoassay (CLIA) demonstrated high sensitivity (0.98; 95% confidence interval [CI], 0.94-1.00), specificity (0.99; 95% CI, 0.97-1.00), and positive (PPV) (0.96; 95% CI, 0.90-0.98) and negative predictive values (NPV) (0.99; 95% CI, 0.99-1.00). The Technofluor fluorescence resonance energy transfer (FRET) and Technoscreen assays had sensitivity of 0.93 (95% CI, 0.86-0.96) and 0.98 (95% CI, 0.42-1.00), specificity of 0.98 (95% CI, 0.95-0.99) and 0.87 (95% CI, 0.76-0.94), PPV of 0.97 (95% CI, 0.85-1.00) and 0.71 (95% CI, 0.59-0.80), and NPV of 0.96 (95% CI, 0.93-0.98) and 0.99 (95% CI, 0.72-1.00), respectively. The proportion of discrepant results (relative to reference standard assays) was 0.04 (95% CI, 0.03-0.05) for HemosIL AcuStar, 0.04 (95% CI, 0.02-0.06) for Technofluor FRET, and 0.11 (95% CI, 0.07-0.16) for the Technoscreen assay. With rapid TAT and high sensitivity, the HemosIL AcuStar CLIA seems able to reliably avert empiric plasma exchange, corticosteroids, and caplacizumab in patients without TTP.

Globally, an estimated 300 million individuals have sickle cell trait (SCT), the carrier state for sickle cell disease (SCD). Although SCD is associated with increased morbidity and shortened life span, SCT has a life span comparable with that of the general population. However, "sickle cell crisis" has been used as a cause of death for decedents with SCT in reports of exertion-related death in athletes, military personnel, and individuals in police custody. To appraise this practice, the American Society of Hematology convened an expert panel of hematologists and forensic pathologists to conduct a systematic review of the literature relating to the occurrence of sickle cell pain crises and exertion-related mortality in people with SCT. Multiple bibliographic databases were searched with controlled vocabulary and keywords related to "sickle cell trait," "vaso-occlusive pain," and "death," yielding 18 of 1474 citations. Independent pairs of reviewers selected studies and extracted data. We found no studies comparing uncomplicated acute pain crises in individuals with SCT and SCD. Additionally, no study was identified to support the occurrence of acute vaso-occlusive pain crises in individuals with SCT. Furthermore, this systematic review did not identify any evidence to support an association between SCT and sudden unexplained death in the absence of exertion-related rhabdomyolysis. We conclude that there are no data to support the diagnosis of acute vaso-occlusive sickle cell crisis as a cause of death in SCT, nor does the available evidence support the use of SCT as a cause of exertion-related death without rhabdomyolysis.

Desmopressin (1-desamino-8-d-arginine vasopressin [DDAVP]) can be used to prevent or stop bleeding. However, large interindividual variability is observed in DDAVP response and determinants are largely unknown. In this systematic review and meta-analysis, we aimed to identify the response to DDAVP and the factors that determine DDAVP response in patients. We included studies with patients with any bleeding disorder receiving DDAVP. First and second screening round and risk of bias assessment were performed by independent reviewers. The main outcome was proportion of patients with complete (factor level >50 U/dL) or partial (30-50 U/dL) response to DDAVP. Determinants of response including disease type, age, sex, von Willebrand factor (VWF) and factor VIII (FVIII) mutations, and baseline factor levels were investigated. In total, 591 articles were found and 103 were included. Of these, 71 articles (1772 patients) were suitable for the study's definition of response. Meta-analysis showed a pooled response proportion of 0.71 (0.64; 0.78) and a significant difference in response between disease subtypes. For hemophilia A, baseline FVIII activity (FVIII:C) was a borderline significant determinant of response. In patients with von Willebrand disease (VWD) type 1, VWF antigen (VWF:Ag), VWF activity, and FVIII:C were significant determinants. A large variation in response was observed for specific mutations in VWF and FVIII. Response to DDAVP varied between disease subtypes and was largely determined by the baseline levels of FVIII:C for hemophilia A and VWF:Ag for VWD. Our findings highlight the significant differences in response and emphasize the need for a standardized response definition and further research into response mechanisms.

The benefit associated with the incorporation of vincristine-corticosteroid pulses in maintenance therapy for pediatric acute lymphoblastic leukemia (ALL) is unclear, particularly in the context of modern intensive therapy. This systematic review and meta-analysis examined the impact of reducing the frequency of vincristine-steroid pulses during maintenance for pediatric patients newly diagnosed with B-cell ALL. Two authors reviewed all eligible studies identified through a comprehensive search, extracted data from 25 publications (12 513 patients), and assessed the risk of bias. We created historical and contemporary subgroups; the latter included trials providing both a version of Protocol III from the early Berlin-Frankfurt-Munster trials and eliminating routine prophylactic cranial radiation. Meta-analysis of event-free survival data suggested no benefit between more frequent or less frequent pulses in contemporary trials (hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.85-1.09), which differed significantly from historical trials (HR, 0.79; 95% CI, 0.68-0.91; P = .04). We found no significant impact of reduced pulse frequency on overall survival or relapse risk. There was however increased odds of grade 3+ nonhepatic toxicity in the high-pulse frequency group (odds ratio, 1.31; 95% CI, 1.12-1.52). This systematic review suggests that the previous benefit conferred by frequent pulses of vincristine-steroids in maintenance therapy for pediatric B-cell ALL in historical trials no longer applies in contemporary trials but is associated with toxicity. These results will help guide the development of the next phase of clinical trials in the field of pediatric ALL and question the continued use of pulses in maintenance among patients not in clinical trials, particularly those experiencing toxicity.

Intracranial hemorrhage (ICH) is a severe complication that is relatively common among patients with hemophilia. This systematic review aimed to obtain more precise estimates of ICH incidence and mortality in hemophilia, which may be important for patients, caregivers, researchers, and health policy makers. PubMed and EMBASE were systematically searched using terms related to "hemophilia" and "intracranial hemorrhage" or "mortality." Studies that allowed calculation of ICH incidence or mortality rates in a hemophilia population ≥50 patients were included. We summarized evidence on ICH incidence and calculated pooled ICH incidence and mortality in 3 age groups: persons of all ages with hemophilia, children and young adults younger than age 25 years with hemophilia, and neonates with hemophilia. Incidence and mortality were pooled with a Poisson-Normal model or a Binomial-Normal model. We included 45 studies that represented 54 470 patients, 809 151 person-years, and 5326 live births of patients with hemophilia. In persons of all ages, the pooled ICH incidence and mortality rates were 2.3 (95% confidence interval [CI], 1.2-4.8) and 0.8 (95% CI 0.5-1.2) per 1000 person-years, respectively. In children and young adults, the pooled ICH incidence and mortality rates were 7.4 (95% CI, 4.9-11.1) and 0.5 (95% CI, 0.3-0.9) per 1000 person-years, respectively. In neonates, the pooled cumulative ICH incidence was 2.1% (95% CI, 1.5-2.8) per 100 live births. ICH was classified as spontaneous in 35% to 58% of cases. Our findings suggest that ICH is an important problem in hemophilia that occurs among all ages, requiring adequate preventive strategies.

Treatment of splanchnic vein thrombosis (SVT) is challenging, and evidence to guide therapeutic decisions remains scarce. The objective of this systematic review and meta-analysis was to determine the efficacy and safety of anticoagulant therapy for SVT. MEDLINE, EMBASE, and clinicaltrials.gov were searched from inception through December 2019, without language restrictions, to include observational studies and randomized controlled trials reporting radiological or clinical outcomes in patients with SVT. Pooled proportions and risk ratios (RRs) with 95% confidence intervals (CIs) were calculated in a random-effects model. Of 4312 records identified by the search, 97 studies including 7969 patients were analyzed. In patients receiving anticoagulation, the rates of SVT recanalization, SVT progression, recurrent venous thromboembolism (VTE), major bleeding, and overall mortality were 58% (95% CI, 51-64), 5% (95% CI, 3-7), 11% (95% CI, 8-15), 9% (95% CI, 7-12), and 11% (95% CI, 9-14), respectively. The corresponding values in patients without anticoagulation were 22% (95% CI, 15-31), 15% (95% CI, 8-27), 14% (95% CI, 9-21), 16% (95% CI, 13-20), and 25% (95% CI, 20-31). Compared with no treatment, anticoagulant therapy obtained higher recanalization (RR, 2.39; 95% CI, 1.66-3.44) and lower thrombosis progression (RR, 0.24; 95% CI, 0.13-0.42), major bleeding (RR, 0.73; 95% CI, 0.58-0.92), and overall mortality (RR, 0.45; 95% CI, 0.33-0.60). These results demonstrate that anticoagulant therapy improves SVT recanalization and reduces the risk of thrombosis progression without increasing major bleeding. The incidence of recurrent VTE remained substantial in patients receiving anticoagulation, as well. Effects were consistent across the different subgroups of patients. This trial was registered on the PROPERO database at (https://www.crd.york.ac.uk/prospero//display_record.php?ID=CRD42019127870) as #CRD42019127870.