How I treat pediatric venous thromboembolism

Selective iliofemoral stent placement for complex pediatric cases: a decade of institutional experience

BACKGROUND

Pediatric iliofemoral venous thromboembolism that is resistant to conventional treatments poses significant management challenges. Stent placement represents a potentially underutilized strategy in children when stenosis or thrombosis persists intraprocedurally or recurs postoperatively, despite treatments such as venoplasty, lysis, and thrombectomy.

OBJECTIVE

This study aims to report our institutional experience with iliofemoral stenting in 17 pediatric patients with recurrent iliofemoral venous thromboembolism or stenosis.

MATERIALS AND METHODS

We performed an IRB-approved retrospective review of pediatric patients (<18 years of age) who underwent iliofemoral venous stenting for recurrent stenosis or thrombosis between January 2012 and December 2022 at a single tertiary care institution. Patient demographics, risk factors for venous thromboembolism, presenting symptoms, and procedural characteristics were recorded. The primary outcome was stent patency rates at interval imaging follow-up.

RESULTS

Seventeen patients with mean age of 14.6 years (range 7-17) and mean BMI of 27.7 were stented during the study period. Sixteen of 17 patients presented with evidence of May-Thurner anatomy. 14/17 patients presented with acute iliofemoral venous thromboembolism, 2/17 with chronic venous thromboembolism, and 1/17 with left lower extremity swelling without thrombosis. Seventy-three total angiographic procedures were performed, which included angioplasty, lysis, and thrombectomy, and 23 stent placements. Patients underwent an average of 3 procedures (range 1-9) over a mean of 2.8 months (range 0-17 months) prior to undergoing stent placement. Stents were deployed successfully in all patients. The median follow-up was 18 months (range, 1-77 months). Primary and secondary patency rates were 13/17 (76%) and 14/14 (100%) at 12 months and 12/17 (71%) and 14/14 (100%) at 24 months, respectively.

CONCLUSION

In our experience of 17 patients, stent placement appears to be a durable option for children with iliofemoral venous thromboembolism following failure to establish vessel patency or development of recurrent thrombosis/stenosis postoperatively.

How I treat pediatric venous thromboembolism in the DOAC era

ABSTRACT

The direct oral anticoagulants (DOACs) rivaroxaban and dabigatran are newly licensed for the treatment and prevention of venous thromboembolism (VTE) in children and mark a renaissance in pediatric anticoagulation management. They provide a convenient option over standard-of-care anticoagulants (heparins, fondaparinux, and vitamin K antagonists) because of their oral route of administration, child-friendly formulations, and significant reduction in monitoring. However, limitations related to therapeutic monitoring when needed and the lack of approved reversal agents for DOACs in children raise some safety concerns. There is accumulating experience of safety and efficacy of DOACs in adults for a broad scope of indications; however, the cumulative experience of using DOACs in pediatrics, specifically for those with coexisting chronic illnesses, is sparse. Consequently, clinicians must often rely on their experience for treating VTE and extrapolate from data in adults while using DOACs in children. In this article, the authors share their experience of managing 4 scenarios that hematologists are likely to encounter in their day-to-day practice. Topics addressed include (1) appropriateness of indication; (2) use for special populations of children; (3) considerations for laboratory monitoring; (4) transition between anticoagulants; (5) major drug interactions; (6) perioperative management; and (7) anticoagulation reversal.

Venous thromboembolism characteristics, treatment and outcomes in young adults: findings from the Registro Informatizado de Enfermedad TromboEmbólica registry

BACKGROUND

Venous thromboembolism (VTE) is rare in patients aged <21 years. Young adults aged 18 to 21 years are frequently included in adult VTE studies, whereas pediatric VTE studies include patients aged up to either 18 or 21 years. The clinical characteristics of young adult patients with VTE have not been well defined.

OBJECTIVES

We aimed to highlight any unique characteristics or treatment considerations that may apply to young adult patients with VTE.

METHODS

Data from the prospective, international Registro Informatizado de Enfermedad TromboEmbólica registry were used. Patients were stratified into subcohorts according to age. The clinical characteristics, risk factors, management, and outcomes of young adult patients with VTE were compared with those of adolescents aged 12 to 18 years and adults aged >21 years.

RESULTS

Of 104 253 Registro Informatizado de Enfermedad TromboEmbólica patients enrolled until August 2022, 234 were adolescents and 884 were young adults. Less cases of pulmonary embolism were reported in adolescents (P < .001). Estrogen use was a common risk factor, more prevalent in adolescents and young adults (P < .001), whereas active cancer and immobilization were uncommon in both. Most patients were initially treated with low-molecular-weight heparin. VTE recurrence, major bleeding, and all-cause mortality rates were comparably low among adolescents and young adults. None of the patients aged <21 years died from VTE recurrence.

CONCLUSION

Young adults have some distinctive VTE risk factors. While VTE presentation may be similar among young adults and older patients, the outcomes of patients aged <21 years are more favorable.

Anticoagulant treatment for pediatric splanchnic vein thrombosis: a systematic review and meta-analysis

BACKGROUND

The clinical characteristics of splanchnic vein thrombosis (SVT) in pediatric patients and its optimal treatment strategies are unknown.

OBJECTIVES

This study aimed to assess the effectiveness and safety of anticoagulant therapy for pediatric SVT.

METHODS

MEDLINE and EMBASE databases were searched up to December 2021. We included observational and interventional studies that enrolled pediatric patients with SVT and reported anticoagulant treatment and outcomes, including rates of vessel recanalization, SVT extension, venous thromboembolism (VTE) recurrence, major bleeding, and mortality. Pooled proportions of vessel recanalization were calculated with their 95% CI.

RESULTS

A total of 506 pediatric patients (aged 0-18 years) across 17 observational studies were included. The majority of patients had portal vein thrombosis (n = 308, 60.8%) or Budd-Chiari syndrome (n = 175, 34.6%). Most events were triggered by transient provoking factors. Anticoagulation (heparins and vitamin K antagonists) was prescribed in 217 (42.9%) patients, and 148 (29.2%) patients underwent vascular interventions. The overall pooled proportions of vessel recanalization were 55.3% (95% CI, 34.1%-74.7%; I2 = 74.0%) among anticoagulated patients and 29.4% (95% CI, 2.6%-86.6%; I2 = 49.0%) among non-anticoagulated patients. SVT extension, major bleeding, VTE recurrence, and mortality rates were 8.9%, 3.8%, 3.5%, and 10.0%, respectively, in anticoagulated patients and 2.8%, 1.4%, 0%, and 50.3%, respectively, in non-anticoagulated patients.

CONCLUSION

In pediatric SVT, anticoagulation appears to be associated with moderate recanalization rates and a low risk of major bleeding. VTE recurrence is low and comparable to that reported in pediatric patients with other types of provoked VTE.

50 Years of Pediatric Hemostasis: Knowledge, Diagnosis, and Treatment

Studies from the past 50 years have contributed to the expanding knowledge regarding developmental hemostasis. This is a dynamic process that begins in the fetal phase and is characterized by physiological variations in platelet counts and function, and concentrations of most coagulation factors and the native coagulation inhibitors in early life, as compared with adulthood. The developmental hemostasis studies since the 1980 to 1990s established the laboratory reference values for coagulation factors. It was only a decade or two later, that thromboelastography (TEG) or (rotational thromboelastometry [ROTEM]) as well as thrombin generation studies, provided special pediatric reference values along with the ability to evaluate clot formation and lysis. In addition, global whole blood-based clotting assays provided point of care guidance for proper transfusion support to children hospitalized in intensive care units or undergoing surgery. Although uncommon, thrombosis in children and neonates is gaining increasing recognition, typically as a secondary complication in sick children. Bleeding in children, and particularly intracerebral hemorrhage in newborns, still represent a therapeutic challenge. Notably, our review will outline the advancements in understanding developmental hemostasis and its manifestations, with respect to the pathophysiology of thrombosis and bleeding complications in young children. The changes of transfusion policy and approach to thrombophilia testing during the last decade will be mentioned. Subsequently, a brief summary of the data on anticoagulant treatments in pediatric patients will be presented. Finally, we will point out the 10 most cited articles in the field of pediatric and neonatal hemostasis.

Paediatric otogenic sinus venous thrombosis: the role of Fusobacterium necrophorum

Objectives

Sinus venous thrombosis (SVT) is a rare complication of acute otitis media (AOM) with acute mastoiditis (AM), which during recent years has been associated with Fusobacterium necrophorum (Fn) infection. Our objective was to review clinical, microbiologic, and hematologic features of paediatric otogenic SVT, with a specific focus on the role of Fn.

Methods

A retrospective database review in a tertiary paediatric hospital between 2000-2019.

Results

Fifty children aged 6-155 months were treated for AM with SVT. Forty-seven (94%) underwent cortical mastoidectomy. Forty-six children received low-molecular-weight heparin (LMWH). Follow-up imaging revealed recanalisation in 92% of cases. No long-term neurologic or haematologic complications were observed. Since 2014, when anaerobic cultures and PCR were routinely used in our institute, Fn was isolated from 15/21 children with SVT. Their time to recanalisation was longer, and the rate of lupus anticoagulant antibodies (LAC) was higher than in the 6 non-Fn patients. Children positive for LAC also had a longer time to recanalisation.

Conclusions

Fn is a common pathogen in AM with SVT; its thrombogenic role was demonstrated by a higher prevalence of LAC and a longer time to recanalisation.

Presentation, Management and Outcomes of Pediatric Pulmonary Embolus: A Retrospective Review

OBJECTIVES

To review the presentation, management, and outcomes of pediatric pulmonary embolism (PE) patients treated at a single institution over 10 years to determine whether laboratory findings and clinical presentation predict disease severity.

METHODS

We performed a retrospective chart review of patients treated for PE in a 14-bed pediatric intensive care unit from January 1, 2008, to December 31, 2018. Associations between clot burden and disease severity, clinical risk factors (body mass index, recent hospitalization, estrogen use), clinical presentation (heart rate, oxygen saturation), and laboratory values (white blood cell count, D-Dimer, troponin, proBNP) were performed using Student t test, χ2 tests, and 1-way analysis of variance. Patients were risk stratified by American Heart Association guidelines.

RESULTS

Eighteen (72%) patients (girls) were treated for PE. Common risk factors included recent hospitalization (67%) and oral contraceptives (62%). Risk factors, clinical presentation (including hypoxemia and tachypnea), and laboratory studies did not correlate with disease severity or clot burden. Electrocardiogram and radiographic findings were non-specific. Computer tomography pulmonary angiography (CTPA) was required to diagnose 94%. Sixteen received unfractionated heparin, and 5 required additional intervention. Risk factors, clinical features, and laboratory studies did not predict who required intervention.

CONCLUSIONS

Of 18 pediatric patients treated for PE at a single institution over 10 years, vital signs and laboratory data did not predict disease severity or clot burden, and CTPA was required for diagnosis in all but 1. Emergency room providers must have a high index of suspicion for diagnosis and cannot be reassured by normal electrocardiogram or plain film findings. At a time when pediatric providers are under pressure to minimize unnecessary radiation exposure, this lack of correlation of clinical presentation and laboratory findings highlights the importance of considering CTPA when PE is suspected.

[Thrombosis of the inferior vena cava and right atrium in a neonate with thrombophilia: diagnosis, treatment, result]

Hereditary thrombophilia is rare pathology giving rise to a ninefold increase in the risk for the development of thromboembolism in infants. The problem is multifactorial and characterized by high mortality, especially in neonates. Infants who develop thrombosis, particularly those with no family history, are often subjected to testing for hereditary thrombophilia. However, genetic testing for thrombophilia does not change the plan of treatment but makes it possible to perform prevention of thrombosis within the risk periods for the patient. Poor awareness of paediatricians, the complexity of carrying out genetic testing, the absence of approaches supported by evidence-based medicine due to shortage of high-quality clinical trials and no guidelines on prevention of thromboembolism in infants, as well as the frequent occurrence of diversified causes and diseases in different age groups make the problem significant for modern medicine. Further studies are needed to address many unanswered as yet questions.

Updated recommendations for the treatment of venous thromboembolism

Venous thromboembolism (VTE), which includes pulmonary embolism and deep vein thrombosis, is a condition characterized by abnormal blood clot formation in the pulmonary arteries and the deep venous vasculature. It is often serious and sometimes even fatal if not promptly and appropriately treated. Moreover, the later consequences of VTE may result in reduced quality of life. The treatment of VTE depends on various factors, including the type, cause, and patient comorbidities. Furthermore, bleeding may occur as a side effect of VTE treatment. Thus, it is necessary to carefully weigh the benefits versus the risks of VTE treatment and to actively monitor patients undergoing treatment. Asian populations are known to have lower VTE incidences than Western populations, but recent studies have shown an increase in the incidence of VTE in Asia. A variety of treatment options are currently available owing to the introduction of direct oral anticoagulants. The current VTE treatment recommendation is based on evidence from previous studies, but it should be applied with careful consideration of the racial, genetic, and social characteristics in the Korean population.

Management and Clinical Outcome of Posterior Reversible Encephalopathy Syndrome in Pediatric Oncologic/Hematologic Diseases: A PRES Subgroup Analysis With a Large Sample Size

This study investigated the management and clinical outcomes along with associated factors of posterior reversible encephalopathy syndrome (PRES) in childhood hematologic/oncologic diseases. We present data from children with hematologic/oncologic diseases who developed PRES after treatment of the primary disease with chemotherapy and hematopoietic stem cell transplantation (HSCT) at 3 medical centers in Changsha, China from 2015 to 2020, and review all previously reported cases with the aim of determining whether this neurologic manifestation affects the disease prognosis. In the clinical cohort of 58 PRES patients, hypertension [pooled odds ratio (OR) = 4.941, 95% confidence interval (CI): 1.390, 17.570; P = 0.001] and blood transfusion (OR = 14.259, 95% CI: 3.273, 62.131; P = 0.001) were significantly associated with PRES. Elevated platelet (OR = 0.988, 95% CI: 0.982, 0.995; P < 0.001), hemoglobin (OR = 0.924, 95% CI: 0.890, 0.995; P < 0.001), and blood sodium (OR = 0.905, 95% CI: 0.860, 0.953; P < 0.001), potassium (OR = 0.599, 95% CI: 0.360, 0.995; P = 0.048), and magnesium (OR = 0.093, 95% CI: 0.016, 0.539; P = 0.008) were protective factors against PRES. Data for 440 pediatric PRES patients with hematologic/oncologic diseases in 21 articles retrieved from PubMed, Web of Science, and Embase databases and the 20 PRES patients from our study were analyzed. The median age at presentation was 7.9 years. The most common primary diagnosis was leukemia (62.3%), followed by solid tumor (7.7%) and lymphoma (7.5%). Most patients (65.0%) received chemotherapy, including non-induction (55.2%) and induction (44.8%) regimens; and 86.5% used corticosteroids before the onset of PRES. Although 21.0% of patients died during follow-up, in most cases (93.2%) this was not attributable to PRES but to severe infection (27.3%), underlying disease (26.1%), graft-vs.-host disease (14.8%), multiple organ dysfunction syndrome (8.0%), and respiratory failure (3.4%). PRES was more common with HSCT compared to chemotherapy and had a nearly 2 times higher mortality rate in patients with oncologic/hematologic diseases than in those with other types of disease. Monitoring neurologic signs and symptoms in the former group is therefore critical for ensuring good clinical outcomes following treatment of the primary malignancy.

Model of Short- and Long-Term Outcomes of Emicizumab Prophylaxis Treatment for Persons with Hemophilia A

BACKGROUND

Hemophilia A (HA) can result in bleeding events because of low or absent clotting factor VIII (FVIII). Prophylactic treatment for severe HA includes replacement FVIII infusions and emicizumab, a bispecific factor IXa- and factor X-directed antibody.

OBJECTIVE

To develop an economic model to predict the short- and long-term clinical and economic outcomes of prophylaxis with emicizumab versus short-acting recombinant FVIII among persons with HA in the United States.

METHODS

A Markov model was developed to compare clinical outcomes and costs of emicizumab versus FVIII prophylaxis among persons with severe HA from U.S. payer and societal perspectives. Patients started prophylaxis at age 1 year in the base case. Mutually exclusive health states considered were "no arthropathy," "arthropathy," "surgery," and "death." Serious adverse events, breakthrough bleeds, and inhibitor development were simulated throughout the modeled time horizon. In addition to the prophylaxis drug costs, patients could incur other direct costs related to breakthrough bleeds treatment, serious adverse events, development of inhibitors, arthropathy, and orthopedic surgery. Indirect costs associated with productivity loss (i.e., missed work or disabilities) were applied for adults. Model inputs were obtained from the HAVEN 3 trial, published literature, and expert opinion. The model used a lifetime horizon, and results for 1 year and 5 years were also reported. Deterministic sensitivity analyses and scenario analyses were conducted to assess robustness of the model.

RESULTS

Over a lifetime horizon, the cumulative number of all treated bleeds and joint bleeds avoided on emicizumab versus FVIII prophylaxis were 278.2 and 151.7, respectively. Correspondingly, arthropathy (mean age at onset: 12.9 vs. 5.4 years) and FVIII inhibitor development (mean age at development: 13.9 vs. 1.1 years) were delayed. Total direct and indirect costs were lower for emicizumab versus FVIII prophylaxis for all modeled time horizons ($97,159 vs. $331,610 at 1 year; $603,146 vs. $1,459,496 at 5 years; and $15,238,072 vs. $22,820,281 over a lifetime horizon). The sensitivity analyses indicated that clinical outcomes were sensitive to efficacy inputs, while economic outcomes were driven by the discount rate, dosing schedules, and treatments after inhibitor development. Results for moderate to severe patients were consistent with findings in the severe HA population.

CONCLUSIONS

The model suggests that emicizumab prophylaxis confers additional clinical benefits, resulting in a lower number of bleeding events and delayed onset of arthropathy and inhibitor development across all time assessment horizons. Compared with short-acting recombinant FVIII, emicizumab prophylaxis leads to superior patient outcomes and cost savings from U.S. payer and societal perspectives.

DISCLOSURES

Funding for this study was provided by Genentech. Raimundo and Patel are employees of Genentech and own stock or stock options. Zhou, Han, Ji, Fang, Zhong, and Betts are employees of Analysis Group, which received consultancy fees from Genentech for conducting this study. Mahajerin received consultancy fees from Genentech for work on this study. Portions of this research were presented as a poster at the 2018 American Society of Hematology Conference; December 1-4, 2018; San Diego, CA.

FondaKIDS III: A long-term retrospective cohort study of fondaparinux for treatment of venous thromboembolism in children

BACKGROUND

The incidence of venous thromboembolism (VTE) and use of anticoagulation are rising in children, but treatment options remain limited. As a newer anticoagulant, fondaparinux may be a safe and effective alternative with the benefit of once-daily dosing, but there is relatively little data supporting its use.

PROCEDURE

This retrospective cohort study describes the long-term dosing, efficacy, and safety of fondaparinux for treatment of VTE in children at a single institution. The study included children <18 years old treated with fondaparinux for VTE between 2008 and 2018. Descriptive statistics were used to present the findings.

RESULTS

A total of 277 patients were identified and analyzed in this study. Seventy-six percent of patients reached therapeutic levels with 0 or 1 dose adjustments over a median treatment duration of 93 days. Of the patients included in the efficacy analysis, 91% of patients had improvement in their clot status, including 69% (160/233) with complete resolution and 22% (53/233) with partial resolution. Twenty-six patients (11%) had VTE recurrence, but only seven (3%) of the new thrombi developed while on fondaparinux. Major bleeding occurred in seven patients (2.5%), primarily in patients with underlying medical conditions with increased bleeding risk. Minor bleeding occurred in 53 patients (19%).

CONCLUSIONS

This study demonstrates the stable long-term pediatric dosing of fondaparinux with similar efficacy and safety when compared to other anticoagulants. Given its advantages, fondaparinux can be considered a reasonable alternative for treatment of VTE in children.

Knowledge and Awareness of Venous Thromboembolism in Intensive Care Units in Zhejiang Province, China: A Cross-Sectional Survey

Background

The 2009 China Intensive Care Units (ICU) prevention guidelines lack venous thromboembolism (VTE) risk assessment. This survey was conducted to assess the risk of VTE, develop and establish a diagnosis, and provide prevention and treatment guidelines for ICU VTE.

Material/Methods

A cross-sectional questionnaire survey of ICU doctors ICUs was conducted online in the tertiary and secondary hospitals of Zhejiang province in China. The questionnaire included VTE-related hospital hardware information, VTE awareness, knowledge, and monitoring system.

Results

The risk assessment rates at the time of admission and changed disease condition were 67.7% and 60.4%, respectively. D-dimer and ultrasound were commonly used for VTE screening. Heparin is preferred for short-term intravenous anticoagulant therapy, and warfarin is preferred for long-term therapy. We found that 23.53% of the ICUs have bedside ultrasound and staff for ultrasound examination, and 59.4% of the hospitals are equipped with VTE monitoring information systems. The VTE early identification specification is the key to whether the VTE assessment is performed after the patient enters the ICU.

Conclusions

The survey assessed the VTE risk and key VTE management elements. However, high heterogeneities were detected in the assessment. The ICU doctors have relatively limited awareness of VTE. Thus, there is an urgent need to update and standardize the ICU VTE guidelines for the prevention and treatment of VTE in China.

Catheter-directed thrombolysis for submassive pulmonary embolism in children: A case series

Incidence of venous thromboembolism, including pulmonary embolism (PE), continues to rise in children. Optimum management of submassive PE is unclear. The principal objective of this retrospective study was to investigate the radiological and clinical outcomes in children with submassive PE treated with catheter-directed thrombolysis (CDT). Five patients underwent six episodes of CDT. No patient developed major/clinically relevant non-major bleeding. Most patients had complete radiological thrombus resolution and no patient had evidence of chronic thromboembolic pulmonary hypertension. There is an urgent need for larger prospective cohort studies/randomized controlled trials to investigate the role of CDT in pediatric PE.

Hemophilia - Impact of Recent Advances on Management

There have been numerous advances in the field of hemophilia management in the past decade, including long acting factor products, non-factor products, and potentially curative interventions such as gene therapy. Each of these interventions introduces exciting treatment modalities to patients with both hemophilia A and B, however they also pose a daunting array of possible management options. Adverse reactions to novel agents are being reported as more patients are treated and long-term sustainability of interventions such as gene therapy is yet to be determined. The practicing hematologist should be aware of the intricacies involved in customizing care for their individual patients and be aware of the monitoring strategies for each interventional strategy to avoid adverse events. Upfront cost vs. long term benefit should be considered as choices of treatment strategies are made, especially in resource poor countries. The goal of the newer agents is to decrease annualized bleed rates and avoid debilitating arthropathy. This article looks at current treatment models for prophylaxis and management of inhibitors, reviews the recent advances in the field (with bioengineered factor products, non-factor products and gene therapy) and summarizes the incorporation of these new interventions in the treatment plan for patients with hemophilia.

Economic impact model of delayed inhibitor development in patients with hemophilia a receiving emicizumab for the prevention of bleeding events

Aims: Cumulative exogenous factor VIII (FVIII) exposure is an important predictor of developing neutralizing antibodies (inhibitors) to FVIII in patients with persons with hemophilia A (PwHA). The aim of this study was to model the costs of emicizumab versus FVIII prophylaxis and total treatment costs for patients with severe HA.Materials and Methods: An Excel-based decision model was developed to calculate cumulative costs in PwHA over a 20-year time horizon from the US payer perspective. The model considered persons with severe HA beginning at age 12 months with no prior FVIII exposure and initiating prophylaxis with emicizumab or FVIII. PwHA could develop inhibitors on accumulation of 20 FVIII exposure days. PwHA with inhibitors replaced FVIII with bypassing agents until inhibitors resolved spontaneously, following immune tolerance induction (ITI), or at the end of the time horizon. The primary model outcome was the difference in emicizumab versus FVIII treatment costs in 2019 USD. Sensitivity analyses were performed to test the robustness of results.Results: Total incremental cost over 20 years was -$1,945,480 (emicizumab arm, $4,919,058; FVIII arm, $6,864,538). Prophylaxis costs (emicizumab arm, $4,096,105; FVIII arm, $6,290,919) comprised the majority of costs in both groups, followed by breakthrough bleed treatment for the FVIII arm ($342,652) and ITI costs for the emicizumab arm ($733,671). Higher costs in the FVIII group reflected earlier inhibitor development (FVIII, 4 months; emicizumab, 162 months) and switch to bypassing agents.Limitations: The model design reflects a simplified treatment pathway for patients with severe HA who initiate FVIII or emicizumab prophylaxis. In the absence of clinical data, a key conservative assumption of the model is that patients receiving emicizumab and FVIII prophylaxis have the same risk of developing inhibitors.Conclusions: This study suggests that prophylaxis with emicizumab results in cost savings compared to FVIII prophylaxis in HA.

Perinatal Stroke

Perinatal strokes are a diverse but specific group of focal cerebrovascular injuries that occur early in brain development and affect an estimated 5 million people worldwide. The objective of this review is to describe the epidemiology, clinical presentations, pathophysiology, outcomes, and management for the 6 subtypes of perinatal stroke. Some perinatal strokes are symptomatic in the first days of life, typically with seizures, including neonatal arterial ischemic stroke, neonatal hemorrhagic stroke, and cerebral sinovenous thrombosis. The remaining subtypes present in the first year of life or later, usually with motor asymmetry and include arterial presumed perinatal ischemic stroke, presumed perinatal hemorrhagic stroke, and in utero periventricular venous infarction. The consequences of these injuries include cerebral palsy, epilepsy, and cognitive and behavioral challenges, in addition to the psychosocial impact on families. While there have been significant advances in understanding mechanisms of both injury and recovery, there is still a great deal to learn regarding causation and the optimization of outcomes.

Recurrent intestinal ischemia following surgery for gastric and duodenal perforations: a case report

Background

Extremely low birth weight (ELBW) is a risk factor for various gastrointestinal complications. In the recent decades, advances in medicine have increased the survival of ELBW infants with necrotizing enterocolitis (NEC). To our knowledge, there have been no reports of neonates or infants developing simultaneous gastric and duodenal perforations and later developing NEC. We report a case of an extremely low birth weight infant (ELBWI) who developed both gastric and duodenal perforations at the same time and developed NEC after operation for gastric and duodenal perforations.

Case presentation

The patient was a female infant with ELBW who developed both gastric and duodenal perforations at the same time and developed NEC after operation for gastric and duodenal perforations. After birth, endotracheal intubation was performed. However, barotrauma occurred during positive pressure ventilation, resulting in a large area of emphysema in the left lower lung field, leading to collapse of the left lung. This giant bulla may have compressed the pulmonary vein, possibly resulting in pulmonary venous thrombosis (PVT). This episode could have triggered simultaneous gastric and duodenal perforations. In addition, we hypothesized that PVT caused acute arterial ischemia, leading to the development of NEC. The infant was started on heparin for anticoagulation. Later, the infant developed non-immunoglobulin E (IgE)-mediated gastrointestinal food allergies (non-IgE-GI-FAs). The giant bulla associated with barotrauma might have caused PVT, resulting in arterial emboli and multiple simultaneous gastrointestinal perforations.

Conclusions

Anticoagulation therapy with heparin for acute arterial thrombosis is effective for preventing the development of short bowel syndrome. Duodenal and intestinal surgery probably acted as risk factors for the subsequent development of non-IgE-GI-FAs. The infant had been stabilized at the time of writing this report.

Management of perioperative hemostasis in a severe hemophilia A patient with inhibitors on emicizumab using global hemostasis assays

Background:

Patients with severe hemophilia A and inhibitors are at risk of bleeding during invasive procedures. The standard of care for preventing perioperative bleeding has been replacement therapy with FVIII concentrates or for patients with high-titer inhibitors, bypassing agents. However, there is no consensus on the appropriate management of surgery in patients receiving the novel agent emicizumab. The aim of this study was to demonstrate a case of a patient on emicizumab undergoing major surgery with bypassing agents with preoperative use of the thrombin generation assay (TGA) and thromboelastography (TEG).

Methods:

We report a patient with hemophilia A with inhibitors who had undergone a total knee replacement while on emicizumab combined with a bypassing agent. We utilized TEG and TGA to determine which bypassing agent to choose as well as to inform about the ideal dose.

Results:

We elected to use recombinant FVIIa as a bypassing agent for the surgery based upon the TGA results.

Conclusion:

The TGA can be utilized to support decision-making in patients on emicizumab undergoing major surgery to both predict efficacy and potentially minimize the risk of thrombotic events.

Current and emerging biologics for the treatment of hemophilia

INTRODUCTION

The development of new biologic agents able to restore thrombin generation has become the focus of innovation in hemophilia management. There is growing interest in the proposal of novel, non-replacement therapy with alternative mechanisms of action and route of administration, hoping to solve still unmet needs in treatment of hemophilic patients with or without inhibitors.

AREAS COVERED

The review describes the new molecules, in particular the bi-specific antibody mimicking the coagulation function of FVIII and/or those which work by inhibiting the natural anticoagulants, their mechanism of action and the results of ongoing clinical trials.

EXPERT OPINION

Exciting results in enhancing the protection against bleeding and improving quality of life are emerging from clinical trials. However, these molecules with their mechanisms of action also open new problems. Treatment of bleeding and management of surgery in subjects with a rebalanced hemostasis may be difficult, especially for the lack of laboratory tests perfectly reflecting the in vivo coagulation status. A careful surveillance is required to evaluate the risk of thrombotic complication in patients with rebalanced hemostasis, in addition to understand whether these new products offer the same protection on joints as regular prophylaxis with the missing clotting factors.

In vitro assessment of edoxaban anticoagulant effect in pediatric plasma

INTRODUCTION

Anticoagulant therapy in pediatric patients remains an issue and safer therapies, such as direct oral anticoagulants could overcome the limitations of conventional anticoagulant treatments in this population. Edoxaban, a factor Xa inhibitor, is used for the prevention and treatment of venous thromboembolism. Due to its pharmacokinetic characteristics, edoxaban is a promising candidate molecule for children. This study compared edoxaban in vitro effect in children and adults.

MATERIALS AND METHODS

Blood samples were prospectively collected from 87 adults and 97 children (n = 12: <2 year-old; n = 8: 2-4 year-old; n = 9: 5-7 year-old; n = 14: 8-9 year-old; n = 10: 10-13 year-old; n = 15: 14-15 year-old; and n = 29: 16-18 year-old). Plasma samples were supplemented in vitro with edoxaban to a final concentration of 50, 150 or 300 ng/mL, and then edoxaban effect on prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen (Clauss assay), specific anti-factor Xa activity and thrombin generation assay (TGA) (with 5pM tissue factor and 4 nM phospholipids) was evaluated.

RESULTS

PT, aPTT, and specific anti-Xa activity exhibited similar dose-dependent responses to edoxaban in the different age groups. The reduction of thrombin peak, the most edoxaban-sensitive TGA parameter, was similar in adults and children, but for the youngest group (<2 year-old) where the peak value reduction (median [Q1-Q3]) was higher than in adults (51% [44-59] versus 40% [32-46], p < 0.01; 74% [63-80] versus 65% [58-70], p < 0.05; and 84% [73-88] versus 76% [70-80], p < 0.05 for 50, 150 and 300 ng/mL edoxaban, respectively).

CONCLUSIONS

Edoxaban in vitro effect are comparable in children and adults except in the <2-year-old group.

Landmark trials in thrombotic vascular disease: a critical appraisal of potential practice-changing trials in 2016-2017

Recent years have witnessed an onslaught of large, multicenter, randomized controlled trials evaluating the prevention and management of thrombotic vascular diseases. While these trials have applied rigorous methodology to pragmatic and clinically relevant questions, several important gaps in knowledge remain. In this review, we critically appraise landmark studies in thrombosis published between 2016 and 2017 that address several ongoing areas of clinical uncertainty. Specifically, we review the role of endovascular therapy in the prevention of post-thrombotic syndrome following acute lower limb deep vein thrombosis (DVT) (ATTRACT trial), the efficacy of edoxaban as the first direct oral anticoagulant used for the treatment of cancer-associated thrombosis (HOKUSAI VTE-Cancer study), whether aspirin can be considered for thromboprophylaxis post-major orthopedic surgery (EPCAT-2 trial), and the need for anticoagulant therapy for treatment of isolated distal DVT (CACTUS trial). Using illustrative cases, we highlight the applicability of these trials to current practice and emphasize the unanswered questions that remain.

Deep venous thrombosis of lower limbs in adolescents: a study in a tertiary hospital

BACKGROUND

Venous thromboembolism (VTE) - which includes deep venous thrombosis (DVT) and pulmonary embolism (PE) - has been increasingly recognized in the pediatric population. The estimated incidence is 0.07-0.14 cases per 10,000 children. Most cases are associated with two or more risk factors. Medium and long-term complications include recurrence and post-thrombotic syndrome (PTS).

OBJECTIVE

To characterize the adolescent population with the diagnosis of DVT of lower limbs in a tertiary hospital, regarding its clinical presentation, associated risk factors, treatment and outcome.

METHODS

Retrospective analysis of adolescents with the diagnosis of DVT of lower limbs in our hospital for a period of 7 years.

RESULTS

Eight patients were identified; seven were females; median age was 15 years. The main symptoms were local pain and edema. Left lower limb was affected in six patients. PE occurred in two cases. Positive family history of venous thromboembolism was found in five patients. Seven patients had at least two identifiable risk factors. Combined oral contraceptive pill use was the most common (seven patients). Factor V Leiden mutation was found in three patients and protein C deficiency in one. Iliac vein compression syndrome was diagnosed in one patient. The median time for discharge was 8 days. Election treatment was enoxaparin followed by warfarin, for a median period of 10.9 months. Three patients developed PTS.

CONCLUSIONS

Although uncommon, VTE is an emerging reality in adolescents, particularly in females using oral contraceptive pills. Appropriated prevention strategies and treatment are required as most orientations are extrapolated from adults.

Venous Thromboembolism: A Survey of Oral Anticoagulant Preferences in the Treatment of Challenging Patient Populations

Venous thromboembolism (VTE) is a highly morbid condition with several available oral anticoagulant treatment options. Numerous studies have been published comparing warfarin to direct oral anticoagulants; however, several populations remain underrepresented in these reports. We surveyed members of The Venous ThromboEmbolism Network U.S. working group regarding their oral anticoagulant preferences for the treatment of VTE in different and challenging populations. In individuals with VTE and no other medical comorbidities, respondents preferred either rivaroxaban (48.7%) or apixaban (48.7%). Apixaban (53.3%) was preferred in elderly individuals with an increased risk of bleeding. Warfarin was preferred in individuals with liver or kidney dysfunction (42% and 47%), altered metabolism (>55%), and antiphospholipid antibody syndrome (84.2%). Low-molecular-weight heparin was preferred in individuals with malignancy (56.6%), followed by edoxaban (23.7%). These findings may help guide clinicians when choosing an anticoagulant in these challenging situations and demonstrate the urgent need for additional study in these groups.

Direct oral anticoagulants for the treatment of venous thromboembolism in patients with active malignancy: a systematic review and meta-analysis

Low molecular weight heparins (LMWHs) are considered the standard of care for the treatment of venous thromboembolism (VTE) associated with cancer. We conducted a meta-analysis to evaluate the safety and efficacy of direct oral anticoagulants (DOACs) in patients with cancer. We systematically searched Medline for potential randomized-control clinical trials (RCTs) and post-hoc analyses. For each study, data on recurrent VTE, major or clinically relevant non-major bleeding (CRNMB), and major bleeding (MB) were extracted. Initially, a total of 1395 citations were identified. Eight studies met our eligibility criteria. The utilization of DOACs in patients with cancer showed a statistically significant reduction in the risk of VTE recurrence compared to LMWH or warfarin (RR = 0.64; 95% CI 0.46-0.88). Similar rates of major or CRNMB were observed between DOACs and LMWH or warfarin (RR = 1.00; 95% CI 0.75-1.33). There was no significant difference in the rate of MB between DOACs and LMWH or warfarin (RR = 1.31; 95% CI 0.71-2.44). Our results suggest that DOACs might reduce the incidence of VTE recurrence in patients with cancer without putting them at high risk for MB/CRNMB or MB. Our findings were mainly driven by the results of the Hokusai VTE Cancer trial. Given the level of investigated evidence, our findings should be interpreted with caution since the majority of the data were originated from sub-group analyses of large (RCTs). Future studies that are adequately powered are warranted to assess efficacy and safety data of DOACs for the treatment of VTE in patients with different types of cancer.

Emicizumab for hemophilia A with factor VIII inhibitors

INTRODUCTION

Hemophilia is a serious bleeding disorder characterized by repeated bleeding episodes into joints and muscles which can lead to permanent disabilities. Treatment with factor replacement therapy has proven to be effective at preventing these complications; however, it can lead to formation of neutralizing antibodies termed inhibitors which significantly complicate the management of the disorder. These inhibitor patients suffer from increased morbidity and mortality and there has been a major unmet need for novel therapeutic approaches. Recently, one such therapy, emicizumab, has been licensed in the United States. Areas covered: This manuscript contains a detailed discussion of the mechanism of action, the clinical trial development program as well as a review of the benefits and risks of this novel agent. In addition, practical considerations for the use of the agent are also described. Expert commentary: Emicizumab represents a new class of medication for the treatment of hemophilia A which in the past has relied on factor replacement therapy and bypassing agent (alternative factor) therapy. Emicizumab fulfills two major unmet needs in patients with hemophilia who have FVIII inhibitors. First, it provides for a much more effective therapy for the prevention of bleeding and second it substantially reduces the treatment burden.

The role of emicizumab, a bispecific factor IXa- and factor X-directed antibody, for the prevention of bleeding episodes in patients with hemophilia A

Hemophilia A, characterized by impaired or absent expression of factor VIII, has long been managed via direct factor replacement. Functionally, factor VIII acts as a cofactor for factor IXa and allows activation of factor X, which, in combination with factor V, generates thrombin. Bispecific antibodies such as emicizumab are recombinant, monoclonal antibodies capable of recognizing and binding to two distinct antigenic targets simultaneously; emicizumab binds factors IXa and X, resulting in spatial approximation and activation of factor X, thereby mimicking the actions of factor VIII. Critically, the presence of antifactor VIII antibodies, for example, inhibitors, impacts neither the mechanism nor the efficacy by which emicizumab functions. The results and interim analyses of the emicizumab clinical trials, HAVEN 1, 2, 3, and 4, are additionally reviewed and discussed.