Impact of gender on safety and efficacy of Rivaroxaban in adolescents & young adults with venous thromboembolism

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.

Do women with venous thromboembolism bleed more than men during anticoagulation? Data from the real-life, prospective START-Register

Background:

Venous thromboembolism (VTE) is a frequent and serious disease that requires immediate and long-term anticoagulant treatment, which is inevitably associated with a risk of bleeding complications. Some studies, though not all, reported a higher risk of bleeding in female patients treated with either old anticoagulants [vitamin k antagonists (VKAs)] or recent anticoagulants [direct oral anticoagulants (DOACs)]. Furthermore, analyses of clinical trials reported an abnormal vaginal bleeding in women of reproductive age treated with DOACs. This study aimed at comparing the risk of bleeding in an inception cohort of VTE women and men included in a prospective observational registry.

Methods:

Baseline characteristics and bleeding events occurring during anticoagulation in patients of both sexes, included in the START-Register after a first VTE, were analyzed.

Results:

In all, 1298 women were compared with 1290 men. Women were older and more often had renal diseases; their index events were often provoked (often by hormonal contraception and pregnancy), and more frequently presented as isolated pulmonary embolism (PE). The rate of bleeding was similar in women (2.9% patient-years) and men (2.1% patient-years), though it was higher when uterine bleeds were included (3.5% patient-years, p = 0.0141). More bleeds occurred in VKA- than DOAC-treated patients (6.4% versus 2.6%, respectively; p = 0.0013). At multivariate analysis, age ⩾ 75 years was associated with higher prevalence of bleeds.

Conclusion:

The occurrence of bleeding was not different between women and men during anticoagulation after VTE. Only after inclusion of vaginal/uterine bleeds, the rate of bleeding was higher in women. The incidence of bleeding was higher in women treated with VKAs.

Plain Language Summary

Community-Onset Venous Thromboembolism in Children: Pediatric Emergency Medicine Perspectives

Pediatric venous thromboembolism (VTE) is a condition increasingly encountered by emergency medicine physicians. Unfortunately, despite increased incidence, the diagnosis of pediatric VTE relies on a high index of suspicion from clinicians. Delays in diagnosis and initiation of treatment can lead to poor outcomes in children, including an increased risk of mortality from pulmonary embolism, increased risk of VTE recurrence, and the development of the post-thrombotic syndrome. The majority of pediatric VTE events are associated with the presence of at least one underlying prothrombotic risk. Timely recognition of these risk factors in the emergency department (ED) setting is paramount for a prompt diagnosis and treatment initiation. Compared with children with hospital-acquired VTE, children presenting to the ED with new onset VTE tend to be older (>11 years of age), have a lower incidence of co-morbidities, and present more frequently with a deep venous thrombosis of the lower extremity. Currently, there are no validated pediatric-specific VTE clinical pretest probability tools that reliably assist with the accurate and timely diagnosis of pediatric VTE. Compression ultrasound with Doppler is the most common imaging modality used for VTE diagnosis, and low molecular weight heparins are the most common anticoagulants initiated in children presenting with VTE in the ED. Special consideration should be given to patients who present to the ED already on anticoagulation therapy who may require acute management for clinically-significant bleeding or change in antithrombotic therapy approach for progression/recurrence of VTE.

Heavy menstrual bleeding in women on anticoagulant treatment for venous thromboembolism: Comparison of high- and low-dose rivaroxaban with aspirin

BACKGROUND

Rivaroxaban may induce heavy menstrual bleeding. It is unknown if this effect is dose related or if rivaroxaban is associated with more menstrual bleeding than aspirin.

OBJECTIVES

To demonstrate and compare menstrual patterns and actions taken among women receiving aspirin and two doses of rivaroxaban.

METHODS

The EINSTEIN-CHOICE trial compared once-daily rivaroxaban 20 mg, rivaroxaban 10 mg, and aspirin 100 mg for extended treatment of venous thromboembolism in patients who had completed 6 to 12 months of anticoagulant therapy. In 362 women with menstrual cycles, menstrual flow duration and intensity assessed at days 30, 90, 180, and 360 were compared with those before starting anticoagulant therapy.

RESULTS

Menstrual flow duration increased in 12%-18% of the 134 women given 20-mg rivaroxaban, in 6% to 12% of 120 women given 10-mg rivaroxaban, and in 9% to 12% of 108 women given aspirin. Corresponding increases in flow intensity were 19% to 24%, 14% to 21%, and 13% to 20%. The odds ratios (ORs) for increased menstrual flow duration were 1.36 (95% confidence interval [CI], 0.62-2.96) for rivaroxaban 20 mg versus aspirin, 0.77 (95% CI, 0.33-1.81) for rivaroxaban 10 mg versus aspirin, and 0.57 (95% CI, 0.26-1.25) for rivaroxaban 10 mg versus 20 mg. The ORs for increased menstrual flow intensity were 1.41 (95% CI, 0.67-2.99), 1.07 (95% CI, 0.49-2.34), and 0.76 (95% CI, 0.37- 1.57), respectively.

CONCLUSIONS

There were no statistically significant differences in menstrual hemorrhage patterns between women treated with 10 or 20 mg of rivaroxaban and aspirin. Compared with 10-mg rivaroxaban or aspirin, 20-mg rivaroxaban showed numerically more often increased menstrual flow duration and intensity.

Treatment of venous thromboembolism in pediatric patients

Venous thromboembolism (VTE) is rare in healthy children, but is an increasing problem in children with underlying medical conditions. Pediatric VTE encompasses a highly heterogenous population, with variation in age, thrombosis location, and underlying medical comorbidities. Evidence from pediatric clinical trials to guide treatment of VTE is lacking so treatment is often extrapolated from adult trials and expert consensus opinion. Aspects unique to children include developmental hemostasis and the major role of central venous access devices. There is an absence of information regarding the optimal target levels of anticoagulation for neonates and infants and lack of suitable drug formulations. Anticoagulants, primarily low-molecular-weight heparin and warfarin, are used to treat children with symptomatic VTE. These drugs have significant limitations, including the need for subcutaneous injections and frequent monitoring. Randomized clinical trials of direct oral anticoagulants in pediatric VTE are ongoing, with results anticipated soon. These trials will provide new evidence and options for therapy that have the potential to improve care. International collaborative registries offer the ability to study outcomes of rare subgroups of pediatric VTE (eg, renal vein thrombosis), and will be important to ultimately guide therapy in a more disease-specific manner.

Definitions, adjudication, and reporting of pulmonary embolism-related death in clinical studies: A systematic review

BACKGROUND

Pulmonary embolism (PE)-related death is a component of the primary outcome in many venous thromboembolism (VTE) studies. The absence of a standardized definition for PE-related death hampers study outcome evaluation and between-study comparisons.

OBJECTIVES

To summarize definitions for PE-related death used in recent VTE studies and to assess the PE-related death rate.

PATIENTS/METHODS

A systematic literature search was conducted on 26 April 2018 from 1 January 2014 up to the search date in MEDLINE, Embase, and CENTRAL. Cohort studies and randomized trials in which PE-related death was included in the primary outcome were eligible. Screening of titles, abstracts, and full-text articles, and data extraction were independently performed in duplicate by two authors. Study outcomes included the definition for PE-related death, VTE case-fatality rate, and death due to PE rate. Descriptive statistics were used to analyze the data.

RESULTS

Of the 6807 identified citations, 83 studies were included of which 27% were randomized trials, 31% were prospective, and 42% retrospective cohort studies. Thirty-five studies (42%) had a central adjudication committee. Thirty-eight (46%) reported a definition for PE-related death of which the most frequently used components were "autopsy-confirmed PE" (50%), "objectively confirmed PE before death" (55%), and "unexplained death" (58%). Median VTE case-fatality rate was 1.8% (interquartile range, 0.0-13).

CONCLUSIONS

Only half of the included studies reported definitions for PE-related death, which were very heterogeneous. Case-fatality rate of VTE events varied widely across studies. Standardization of the definition and guidance on adjudication and reporting of PE-related death is needed.

How I treat heavy menstrual bleeding associated with anticoagulants

Anticoagulant-associated heavy menstrual bleeding (HMB) is an underrecognized but not uncommon problem in clinical practice. Premenopausal women should be advised of the potential effect of anticoagulant therapy on menstrual bleeding at the time of treatment initiation. Consequences of HMB should be assessed and treated on an ongoing basis. In the acute setting, the decision to withhold anticoagulants is based on an individual patient's risk of thrombosis and the severity of the bleeding. For women who require long-term anticoagulation, a levonorgestrel intrauterine system, tranexamic acid (during menstrual flow), high-dose progestin-only therapy, or combined hormonal contraceptives are effective for controlling HMB. The risk of thrombosis during anticoagulant therapy with these treatments is not well studied but is likely to be low. Selection of type of hormonal therapy is based on patient preference, other indications for and contraindications to therapy, adverse effect profile, and ongoing thrombotic risk factors. Women who do not respond to medical treatment or who do not wish to retain their fertility should be considered for surgical management.