Extended use of dabigatran, warfarin, or placebo in venous thromboembolism

[Acute deep vein thrombosis-modern diagnostics and treatment]

Acute deep pelvic vein thrombosis (DVT) is usually a non-fatal disease that causes lifelong damage. In the case of clinical suspicion of DVT, D‑dimer determination and/or imaging must be performed. If a timely diagnosis is not possible, anticoagulation should be started. The focus of treatment is the safety of the patient. All studies on thrombus-eliminating procedures, such as thrombolysis, operative open thrombectomy and endovascular revascularization, did not show any advantages over pure anticoagulation and are associated with specific risks. The minimum duration of anticoagulation is 3 months. Thereafter, the decision of prolonged anticoagulation must be made individually for each patient. Compression therapy is an integral part of the treatment of acute TVT in Germany, even the evidence for its effectivenes with respect to the prevention of post-thrombotic syndrome is low.

Long term risk of symptomatic recurrent venous thromboembolism after discontinuation of anticoagulant treatment for first unprovoked venous thromboembolism event: systematic review and meta-analysis

OBJECTIVES

To determine the rate of a first recurrent venous thromboembolism (VTE) event after discontinuation of anticoagulant treatment in patients with a first episode of unprovoked VTE, and the cumulative incidence for recurrent VTE up to 10 years.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, and the Cochrane Central Register of Controlled Trials (from inception to 15 March 2019).

STUDY SELECTION

Randomised controlled trials and prospective cohort studies reporting symptomatic recurrent VTE after discontinuation of anticoagulant treatment in patients with a first unprovoked VTE event who had completed at least three months of treatment.

DATA EXTRACTION AND SYNTHESIS

Two investigators independently screened studies, extracted data, and appraised risk of bias. Data clarifications were sought from authors of eligible studies. Recurrent VTE events and person years of follow-up after discontinuation of anticoagulant treatment were used to calculate rates for individual studies, and data were pooled using random effects meta-analysis. Sex and site of initial VTE were investigated as potential sources of between study heterogeneity.

RESULTS

18 studies involving 7515 patients were included in the analysis. The pooled rate of recurrent VTE per 100 person years after discontinuation of anticoagulant treatment was 10.3 events (95% confidence interval 8.6 to 12.1) in the first year, 6.3 (5.1 to 7.7) in the second year, 3.8 events/year (95% confidence interval 3.2 to 4.5) in years 3-5, and 3.1 events/year (1.7 to 4.9) in years 6-10. The cumulative incidence for recurrent VTE was 16% (95% confidence interval 13% to 19%) at 2 years, 25% (21% to 29%) at 5 years, and 36% (28% to 45%) at 10 years. The pooled rate of recurrent VTE per 100 person years in the first year was 11.9 events (9.6 to 14.4) for men and 8.9 events (6.8 to 11.3) for women, with a cumulative incidence for recurrent VTE of 41% (28% to 56%) and 29% (20% to 38%), respectively, at 10 years. Compared to patients with isolated pulmonary embolism, the rate of recurrent VTE was higher in patients with proximal deep vein thrombosis (rate ratio 1.4, 95% confidence interval 1.1 to 1.7) and in patients with pulmonary embolism plus deep vein thrombosis (1.5, 1.1 to 1.9). In patients with distal deep vein thrombosis, the pooled rate of recurrent VTE per 100 person years was 1.9 events (95% confidence interval 0.5 to 4.3) in the first year after anticoagulation had stopped. The case fatality rate for recurrent VTE was 4% (95% confidence interval 2% to 6%).

CONCLUSIONS

In patients with a first episode of unprovoked VTE who completed at least three months of anticoagulant treatment, the risk of recurrent VTE was 10% in the first year after treatment, 16% at two years, 25% at five years, and 36% at 10 years, with 4% of recurrent VTE events resulting in death. These estimates should inform clinical practice guidelines, enhance confidence in counselling patients of their prognosis, and help guide decision making about long term management of unprovoked VTE.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017056309.

Influence of baseline anemia on long-term clinical outcomes in patients with venous thromboembolism: from the COMMAND VTE registry

The influence of anemia on the long-term clinical outcomes has not been fully evaluated in patients with venous thromboembolism (VTE). We evaluated the influence of anemia among 3012 patients in the COMMAND VTE Registry with a median follow-up period of 1219 days. The outcomes measures were ISTH major bleeding, recurrent VTE and all-cause death. There were 1012 patients (34%) with moderate/severe anemia (Hb ≤ 10.9 g/dl), 615 patients (20%) with mild anemia (Hb 11.0-12.9 g/dl for men, and 11.0-11.9 g/dl for women), and 1385 patients (46%) without anemia. The cumulative 5-year incidence of major bleeding was significantly higher in patients with anemia (moderate/severe anemia: 17.6%, mild anemia: 12.1%, and no anemia: 8.7%, P < 0.001). After adjusting the confounders, the excess risk of mild and moderate/severe anemia, respectively, relative to no anemia for major bleeding remained significant (mild: adjusted HR 1.41: [95% CI 1.00-1.98], P = 0.048; moderate/severe: adjusted HR 1.91: [95% CI 1.42-2.58], P < 0.001, respectively). The excess risk of moderate/severe anemia relative to no anemia was also significant for mortality (adjusted HR 2.89: 95% CI 2.45-3.42, P < 0.001), but the risk was neutral for recurrent VTE (adjusted HR 1.05: 95% CI 0.76-1.45, P = 0.77). In conclusions, VTE patients with mild and moderate/severe anemia had higher risk for major bleeding events without significant excess risk for recurrent VTE events, and the risk for major bleeding events increased according to the severity of anemia. We should pay more attention to the optimal intensity and duration of anticoagulation in VTE patients with anemia.

Acute pulmonary thromboembolism caused by factor V Leiden mutation in South Korea: A case report

RATIONALE

Although Factor V Leiden (FVL) mutation is a major cause of inherited thrombophilia in Western populations; the mutation is extremely rare in Asia.

PATIENT CONCERNS

Here we report a case of a 28-year old Korean woman admitted to our hospital with extensive pulmonary embolism.

DIAGNOSIS

She was heterozygous for FVL mutation up on evaluation, and screening for asymptomatic family members also revealed heterozygous FVL mutation for her mother.

INTERVENTIONS

Enoxaparin 1 mg/kg was initiated, followed by rivaroxaban 15 mg every 12 hours.

OUTCOMES

The patient showed improvement in both subjective dyspnea and right ventricular dysfunction and was successfully discharged after five hospital days.

LESSONS

FVL mutation screening may be considered in Asian patients with thrombophilia of uncertain etiology in the future.

Apixaban for Routine Management of Upper Extremity Deep Venous Thrombosis (ARM-DVT): Methods of a prospective single-arm management study

BACKGROUND

Upper extremity deep vein thrombosis (UEDVT) constitutes approximately 10% of all deep vein thromboses (DVTs). The incidence of UEDVT is increasing in association with use of peripherally inserted central venous catheters. Treatment for UEDVT is derived largely from evidence for treatment of lower extremity DVT. Limited evidence exists for the use of a direct oral anticoagulant for the treatment of UEDVT.

POPULATION

Sequential patients identified within the Intermountain Healthcare System and University of Utah Healthcare system with symptomatic UEDVT defined as the formation of thrombus within the internal jugular, subclavian, axillary, brachial, ulnar, or radial veins of the arm.

INTERVENTION

Apixaban 10 mg PO twice daily for 7 days followed by apixaban 5 mg twice daily for 11 weeks.

COMPARISON

The historical literature review rate of venous thrombosis reported for recurrent clinically overt objective venous thromboembolism (VTE) and VTE-related death. If the confidence interval for the observed rate excludes the threshold event rate of 4%, we will conclude that treatment with apixaban is noninferior and therefore a clinically valid approach to treat UEDVT.

SAMPLE SIZE

We elected a sample size of 375 patients so that an exact 95% confidence interval would exclude an event rate of VTE in the observation cohort of 4%.

OUTCOME

Ninety-day rate of new or recurrent objectively confirmed symptomatic venous thrombosis and VTE-related death. The primary safety outcome is the composite of major and clinically relevant nonmajor bleeding.

Cessation of anticoagulation therapy following endovascular thrombus removal and stent placement for acute iliofemoral deep vein thrombosis

Summary. Background: The optimal duration of anticoagulation therapy (AT) following catheter-based therapy of acute iliofemoral deep vein thrombosis (IFDVT) with stent placement is unknown. Theoretically, resolving the underlying obstructive iliac vein lesion by a stent may eliminate the main trigger for recurrence, the post-thrombotic syndrome (PTS), and the need for extended-duration AT. Patients and methods: From 113 patients with acute IFDVT who underwent endovascular thrombus removal and stent placement, we compared patency rates and clinical outcomes between 58 patients on limited-duration AT (3–12 month) and 55 patients on extended-duration AT (> 12 months). Results: Mean follow-up duration was 26 ± 18 (range 3–77) months; it was 24 ± 18 (range 3–69) months after cessation of AT in the limited-duration AT group. In comparison to patients with extended-duration AT, patients with limited-duration AT were younger (38 versus 54 years; p < 0.001), more often female (74 % versus 49 %; p = 0.01), and had less often prior venous thromboembolism (VTE) (9 % versus 35 %; p = 0.001). May-Thurner syndrome was more frequent in the limited-duration AT group (66 % versus 38 %; p = 0.004). Overall, primary and secondary patency rates at 24 months were 80 % (95 % CI, 70–87 %) and 95 % (95 % CI, 88–98 %), respectively, with no difference between the groups. Overall, 17 (15 %) patients developed recurrent VTE, of which 14 (82 %) events were thrombotic stent occlusions, and 13 (76 %) events occurred during AT. In the limited-duration AT group, 98 % patients were free from the PTS at two years with a VTE recurrence rate of 3.5 per 100 patient years after cessation of AT. Conclusions: In selected patients with acute IFDVT and patent venous stent, particularly in younger and otherwise healthy patients with May-Thurner syndrome, it appears to be safe to discontinue AT 3–12 months after endovascular treatment. Clinical Trial Registration: The study is registered on the National Institutes of Health website (ClinicalTrials.gov; identifier NCT02433054).

Direct-Acting Oral Anticoagulants in Critically Ill Patients

The direct-acting oral anticoagulants (DOACs) have been increasingly used over vitamin K antagonists in recent years because they do not require monitoring and have an immediate anticoagulation effect. In general, DOACs have exhibited a better safety profile and noninferiority for prophylaxis and treatment of venous thromboembolism (VTE) and stroke prevention in patients with atrial fibrillation compared with vitamin K antagonists in the non-ICU population; whether this finding holds true in patients who are critically ill remains unknown. The current review addresses the role of DOACs in special ICU populations, use of these agents for VTE prophylaxis, perioperative management of DOACs, drug monitoring, and potential drug interactions of DOACs in critically ill patients. Adverse events and available reversal agents for DOACs are also discussed.

[Contemporary approaches to determine the duration of anticoagulant therapy for venous thromboembolism]

The review is devoted to the issue of optimal duration of anticoagulant therapy for venous thromboembolic complications (VTEC) using oral anticoagulants (OAC). These drugs are characterized by higher safety in comparison with vitamin K antagonists and make it possible to increase the duration of treatment for not only spontaneous thrombosis (with high risk of recurrence), but also thrombosis provoked by minor persistent and transient risk factors of VTEC. Efficacy and safety of prolonged treatment of VTEC using OAC was analyzed. Different classifications of primary thrombotic episode depending on risk of subsequent recurrence are presented. Moreover, scales for individual assessment of risk of recurrent thrombosis after anticoagulant therapy cancellation and risk of bleeding in case of continued treatment are given. Outcomes of long-term administration of rivaroxaban for VTEC are analyzed. It was concluded that OAC are safe for prolonged management of primary thrombotic episode. However, overall duration of treatment should be determined considering individual balance of benefits and risks.

The association of recurrence and bleeding events with mortality after venous thromboembolism: From the COMMAND VTE Registry

BACKGROUND

The duration of anticoagulation therapy after venous thromboembolism (VTE) should be based on the balance between risks of recurrent VTE and bleeding. However, there is uncertainty about the impact of these events on subsequent mortality.

METHODS

We evaluated the association of recurrent VTE and major bleeding events with mortality among 3026 patients in the COMMAND VTE Registry. We estimated the risks of the recurrent VTE events and the major bleeding events for subsequent mortality by the time-updated multivariable Cox proportional hazard model.

RESULTS

During the median follow-up period of 1218 days, 225 patients developed recurrent VTE events, 274 patients developed major bleeding events, and 763 patients died. The multivariable Cox proportional hazard model revealed that both the recurrent VTE and major bleeding events were strongly associated with subsequent mortality risk (recurrent VTE: HR 3.24, 95%CI 2.57-4.08, P < 0.001; major bleeding: HR 3.53, 95%CI 2.88-4.31, P < 0.001). Both the recurrent pulmonary embolism (PE) and recurrent deep vein thrombosis (DVT) events were associated with subsequent mortality risk (recurrent PE events: HR 4.42, 95%CI 3.28-5.95, P < 0.001; recurrent DVT events: HR 2.42, 95%CI 1.75-3.36, P < 0.001).

CONCLUSIONS

In the real-world patients with VTE, both the recurrent VTE events and the major bleeding events were strongly associated with subsequent mortality risk with the comparable effect size. The recurrent PE and recurrent DVT events were also associated with increased risks for mortality, although the magnitude of the effect on mortality was numerically greater with the recurrent PE events than with the recurrent DVT events.

It's time for head-to-head trials with direct oral anticoagulants

Direct oral anticoagulants (DOACs) have become the recommended first choice anticoagulant agent for treatment of acute venous thromboembolism (VTE) in non-cancer patients and are increasingly prescribed worldwide. They have not only intrinsic advantages, such as rapid onset of action and wide therapeutic windows, but also a lower risk of major, intracranial and fatal bleeding in VTE patients compared to vitamin K antagonists. Even though DOACs are often referred to as uniform drug class, there is growing evidence that each DOAC has a specific risk profile. Indirect comparisons and retrospective cohort studies suggest that apixaban may be associated with a lower risk of major bleeding than other DOACs, but there are no head-to-head trials with DOACs. Therefore, current guidelines do not recommend one DOAC over another and the choice of a specific DOAC is mainly based on physician and patient preferences, reimbursement and availability. Retrospective cohort studies and VTE registries are important to identify potential differences in efficacy and safety between DOACs; but they are methodologically too limited to inform the optimal choice of oral anticoagulant agent. Randomized controlled trials are crucial to inform sound treatment recommendations, because proper randomization is the key to unprejudiced treatment allocation and minimization of unmeasured and unknown confounding. Given increasing evidence of differences in safety profiles of DOACs from indirect comparisons and observational studies, it's time for head-to-head trials with DOACs.

Efficacy and Safety of Direct Oral Anticoagulants for Risk of Cancer-Associated Venous Thromboembolism

Efficacy and safety of direct oral anticoagulants (DOACs) for preventing primary and recurrent venous thromboembolism (VTE) in patients with cancer remain unclear. In this study, we conducted a systematic review to summarize the most up-to-date evidence from randomized controlled trials (RCTs). Our primary outcomes included the benefit outcome (VTE) and safety outcome (major bleeding). A random-effects model was used to pool the relative risks (RRs) for data syntheses. The Grading of Recommendations Assessment, Development and Evaluation tool was used to evaluate the quality of the entire body of evidence across studies. We included 11 RCTs with a total of 3741 patients with cancer for analyses. The DOACs were significantly related with a reduced risk of VTE when compared with non-DOACs: RR = 0.77, 95% confidence interval [CI]: 0.61-0.99, P = .04. Nonsignificant trend towards a higher risk of major bleeding was found in DOACs: RR = 1.28 95% CI: 0.81-2.02, P = .29. The quality of the entire body of evidence was graded as moderate for risk of VTE, and low for risk of major bleeding. To summarize, DOACs were found to have a favorable effect on risk of VTE but a nonsignificant higher risk of major bleeding compared with non-DOACs in patients with cancer. The safety effect of DOACs in patients with cancer requires further evaluation in adequately powered and designed studies.

Oral anticoagulation therapy and subsequent risk of venous thromboembolism in atrial fibrillation patients

OBJECTIVE

Oral anticoagulation (OAC) prescribed to AF patients for the prevention of cardioembolic complications likely has the added benefit of preventing venous thromboembolism (VTE). This study evaluated, among AF patients who are anticoagulated, whether type of OAC was associated with subsequent VTE risk.

METHODS

Non-valvular AF patients prescribed OACs between 2010 and September 2015 were identified via the MarketScan administrative claims databases. OACs included warfarin and direct OACs (DOACs: dabigatran, rivaroxaban, and apixaban). Incident VTE was defined by ICD-9-CM codes. Patients were matched on age, sex, CHA₂DS₂-VASc, and high-dimensional propensity scores. The final analysis included 117,912 AF patients.

RESULTS

In total, 1357 VTE events accrued over a mean follow-up of 484 days. In multivariable-adjusted, propensity score-matched Cox models, relative to new users of warfarin, risk of incident VTE was lower among new users of dabigatran [hazard ratio (95% confidence interval) = 0.55 (0.47-0.66)] and apixaban [0.51 (0.39-0.68)], but similar among new users of rivaroxaban [1.01 (0.87-1.19)]. In head-to-head DOAC comparisons, VTE risk was lower among users of dabigatran [0.48 (0.36-0.64)] and apixaban [0.61 (0.47-0.78)] vs rivaroxaban. Findings were mostly similar across patient sub-groups.

CONCLUSIONS

In this large practice-based population of AF patients prescribed OACs for primary prevention of stroke and systemic embolization, subsequent risk of VTE was lowest among those prescribed apixaban and dabigatran, while risk was similar with prescriptions for warfarin and rivaroxaban. Among AF patients prescribed OACs, lowering the risk of VTE may be an additional benefit of apixaban and dabigatran, beyond the reduced bleeding risk observed in randomized clinical trials.

Direct oral anticoagulants for extended treatment of venous thromboembolism: insights from the EINSTEIN CHOICE study

The risk of recurrence of venous thromboembolism (VTE) persists after interruption of the initial anticoagulation therapy. New evidence shows that direct oral anticoagulants are effective for extended treatment of VTE and may reduce the risk of all-cause mortality. The optimal duration of anticoagulation after VTE is, however, controversial and complicated by the need for individualised assessment and balance between thrombosis and bleeding risks. Three direct oral anticoagulants (rivaroxaban, apixaban and dabigatran) have been studied for extended treatment of VTE. Dabigatran was shown to be safer than vitamin K antagonists and similarly effective for the prevention of recurrent VTE. Dabigatran, apixaban and rivaroxaban resulted in significant decreases in the rate of recurrent symptomatic VTE when compared to placebo, without a statistically significant difference in the risk of major bleeding. The latest guidelines of the American College of Chest Physicians suggest the use of low-dose aspirin to prevent VTE recurrence in patients who want to stop anticoagulation. In the randomised, double-blind, phase 3 EINSTEIN CHOICE trial, once-daily rivaroxaban at doses of 20 mg or 10 mg and 100 mg of aspirin were compared in VTE patients for whom there was clinical equipoise for extended anticoagulation. Either a treatment dose (20 mg) or a prophylactic dose (10 mg) of rivaroxaban significantly reduced the risk of VTE recurrence without a significant increase in bleeding risk compared with aspirin. The EINSTEIN CHOICE trial included patients with provoked or unprovoked VTE. Patients with VTE provoked by minor persistent or minor transient risk factors enrolled in this trial had not-negligible VTE recurrence rates. These new findings on extended therapy suggest the possibility of anticoagulation regimens at intensities tailored to the patients' risk profiles and VTE characteristics, with a shift of the risk-benefit balance in favour of extended treatment.

Preventive Effects of Different Drugs on Asymptomatic Lower Extremities Deep Venous Thrombosis After Artificial Joint Replacement: A Mixed Treatment Comparison

This network meta-analysis aims to compare the preventive effects of 8 drugs (edoxaban, dabigatran, apixaban, rivaroxaban, warfarin, bemiparin, ximelagatran, and enoxaparin) on asymptomatic deep venous thrombosis (DVT) of lower extremities after artificial joint replacement. PubMed, Cochrane Library, and Embase were searched from their inception through October 2015 for randomized controlled trials comparing 8 drugs for the prevention of asymptomatic DVT of lower extremities after artificial joint replacement. Network meta-analysis combined the direct and indirect evidence to evaluate odd ratios (ORs) and surface under the cumulative ranking curves values. A total of 15 randomized controlled trials satisfying the inclusion criteria were enrolled. Edoxaban, apixaban, and rivaroxaban had poorer preventive effects on asymptomatic DVT of lower extremities after undergoing artificial joint replacement when compared with warfarin [OR = 0.16, 95% confidence interval (CI), 0.04-0.60; OR = 0.22, 95% CI, 0.07-0.64; OR = 0.16, 95% CI, 0.05-0.49, respectively]. When compared with enoxaparin, the preventive effects of edoxaban and rivaroxaban were poorer (OR = 0.37, 95% CI, 0.15-0.85; OR = 0.37, 95% CI, 0.21-0.59, respectively). The preventive effects of edoxaban and rivaroxaban were poorer than dabigatran (OR = 0.38, 95% CI, 0.14-0.99; OR = 0.38, 95% CI, 0.18-0.73, respectively). The surface under the cumulative ranking curves values showed that warfarin had better preventive effects on asymptomatic DVT of lower extremities after undergoing artificial joint replacement. Among the 8 drugs (edoxaban, dabigatran, apixaban, rivaroxaban, warfarin, bemiparin, ximelagatran, and enoxaparin), warfarin had better preventive effects on asymptomatic DVT of lower extremities after undergoing artificial joint replacement.

Use of modified intention-to-treat analysis in studies of direct oral anticoagulants and risk of selection bias: a systematic review

BACKGROUND

Following their evaluation in randomised controlled trials (RCTs), direct oral anticoagulants (DOACs) have replaced warfarin for stroke prevention in atrial fibrillation (AF), and treatment and prevention of venous thromboembolism (VTE). To avoid selection bias, it is recommended that RCTs use an intention-to-treat (ITT) analysis strategy.

OBJECTIVE

The objective of this study was to systematically review and compare reported analytical strategies, the proportion of randomised patients included in analyses and the reasons for participant exclusions.

STUDY SELECTION

A systematic search of PubMed, EMBASE and the Cochrane library for phase III trials of DOACs was conducted. Titles and abstracts were screened for relevance by two independent reviewers. Patient population, intervention studied, number of patients included in randomisation and analysis, reasons for exclusions from analysis and trial conclusions were extracted from each article.

FINDINGS

Twenty-nine studies were included, five were about stroke prevention in AF, 10 about VTE treatment and 14 about thromboprophylaxis. Trials of AF and VTE treatment had low proportions of postrandomisation exclusions (around 1%). In contrast, surgical and medical thromboprophylaxis trials excluded almost 30% of participants postrandomisation. This was in spite of authors' claims of using an ITT or modified ITT approach. Higher exclusion proportions in these trials were associated with non-clinically defined primary outcomes and incomplete outcome assessments.

CONCLUSIONS

Clinicians should be aware that the level of evidence in favour of DOAC use for thromboprophylaxis is weak due to high rates of postrandomisation exclusions and risks of selection bias.

Extended anticoagulation for the secondary prevention of venous thromboembolic events: An updated network meta-analysis

BACKGROUND

Extended treatment is preconized in a significant proportion of patients with unprovoked venous thromboembolism (VTE). However, limited direct/indirect comparisons are available to appropriately weight the benefit/risk ratio of the diverse treatments available. We aimed to compare the rate of symptomatic recurrent VTE and major bleeding (MB), the net clinical benefit (VTE+MB) and death on vitamin-K antagonist (VKA), direct oral anticoagulants (DOAC) and antiplatelet drugs for extended anticoagulation.

METHODS

A systematic literature search through September 2018 identified randomized trials studying these pharmacologic therapies for extended anticoagulation following VTE. Treatment effects were calculated using network meta-analysis with frequentist fixed-effects model.

RESULTS

18 trials (18,221 patients) were included in the analysis. All treatments reduced the risk of recurrence compared to placebo/observation. Nonetheless, VKA (RR 0.22; 95%CI 0.13-0.39) and DOAC (RRs ranging from 0.25-0.32; 95%CI ranging from 0.13-0.52) were more effective than aspirin, whereas low-dose VKA was less effective than standard-dose VKA (RR 2.47; 95%CI 1.34-4.55). The efficacy of DOAC was globally comparable to standard-adjusted dose VKA. Low- (RR 3.13; 95%CI 1.37-7.16) and standard-dose (RR 3.23; 95%CI 1.16-8.99) VKA also increased the risk of MB, which was not the case for any DOAC. Low-dose VKA and low-dose DOAC had similar effects on MB compared to standard-doses. Although there was a trend for reduced MB and enhanced net clinical benefit for DOAC compared to VKA, this was not statistically significant. The specific anticoagulant therapies had no significant effects on deaths.

CONCLUSION

Standard-dose VKA and low/standard-dose DOAC share similar effects on VTE recurrence and MB, whereas aspirin and low-dose VKA were associated with lower benefit/risk ratio.

Direct oral anticoagulants in patients with venous thromboembolism and thrombophilia: a systematic review and meta-analysis

Essentials We investigated direct oral anticoagulant (DOAC) use in venous thromboembolism and thrombophilia. A comprehensive search identified 10 studies, 8 of which were included in a meta-analysis. DOACs were overall safe and effective in patients with venous thromboembolism and thrombophilia. Efficacy/safety of DOACs was maintained in low-risk antiphospholipid syndrome patient subgroup. SUMMARY: Background Direct oral anticoagulants (DOACs) are increasingly used in acute and long-term treatment of venous thromboembolism (VTE). However, their role in management of thrombophilia-associated VTE is controversial. Methods Through a comprehensive search on MEDLINE, Cochrane Library, and Clinicaltrials.gov, we identified 10 eligible studies, 8 of which reporting data on 1994 thrombophilia patients were included in a random-effects meta-analysis. Eligible studies were phase 2 to 3 randomized controlled trials comparing DOACs to vitamin K antagonists (VKAs) in patients with VTE, including those with thrombophilia. Results Of eight studies included in meta-analysis, four evaluated rivaroxaban, three dabigatran, and one edoxaban. No results could be obtained on apixaban use. The rates of VTE recurrence (RR, 0.70; 95% CI, 0.34-1.44; I2  = 0%) and major/clinically relevant non-major bleeding events (RR, 0.92; 95% CI, 0.62-1.36; I2  = 23%) were similar between thrombophilia patients treated with DOACs compared to VKAs. Results were comparable to findings in patients without known thrombophilia: RR, 1.02; 95% CI, 0.80-1.30; I2  = 46% for VTE recurrence and RR, 0.72; 95% CI, 0.57-0.90; I2  = 84% for major/clinically relevant non-major bleeding events. Conclusions Rates of VTE recurrence and bleeding events were both low and comparable in patients with various thrombophilias receiving either treatment, suggesting that DOACs are an appropriate treatment option in this population. Due to limited data, it is unclear whether these findings apply to specific subgroups such as high-risk antiphospholipid syndrome, uncommon thrombophilias, or the use of apixaban.

Rivaroxaban and the EINSTEIN clinical trial programme

: Rivaroxaban, a direct oral anticoagulant, is widely used for the treatment of venous thromboembolism (VTE) in adult patients. The approval of rivaroxaban for the treatment of deep vein thrombosis and pulmonary embolism and the extended secondary prevention of recurrent VTE is based on the results of the EINSTEIN DVT and EINSTEIN PE trials, and the EINSTEIN EXT and EINSTEIN CHOICE trials, respectively. This review provides an updated overview of these completed EINSTEIN studies in adult patients, including results of subanalyses in patients at high risk of recurrent VTE, and discusses the emerging data from the EINSTEIN Junior programme, which is evaluating the use of rivaroxaban for the treatment of paediatric VTE. In the EINSTEIN DVT and EINSTEIN PE trials, rivaroxaban (15 mg twice daily for 21 days, followed by 20 mg once daily thereafter) was shown to be an effective and safe alternative to standard anticoagulation for the treatment of deep vein thrombosis and pulmonary embolism in a broad range of adult patients. These results are supported by increasing amounts of real-world data from patients treated with rivaroxaban in routine clinical practice worldwide. In the EINSTEIN EXT and EINSTEIN CHOICE trials, rivaroxaban was superior to placebo and acetylsalicylic acid, respectively, for the extended treatment of VTE - physicians can now choose between two doses of rivaroxaban (20 mg once daily or 10 mg once daily) for the extended prevention of recurrent VTE, based on a patient's risk of recurrence, bleeding and personal preferences.

Use of Mortality as an Endpoint in Noninferiority Trials May Lead to Ethically Problematic Conclusions

BACKGROUND

Noninferiority trials are becoming more common. Their design often requires investigators to "trade" a secondary benefit for efficacy. Use of mortality as an outcome of interest leads to important ethical conflicts whereby researchers must establish a minimal clinically important difference for mortality, a process which has the potential to result in problematic conclusions.

OBJECTIVE

We sought to investigate the frequency of the use of mortality as an outcome in noninferiority trials, as well as to determine the average pre-specified noninferiority ("delta") values.

DESIGN

We searched MEDLINE for reports of parallel-group randomized controlled noninferiority trials published in five high-impact general medical journals.

MAIN OUTCOME MEASURES

Data abstracted from articles including trial design parameters, results, and interpretation of results based on CONSORT recommendations.

RESULTS

One hundred seventy-three manuscripts reporting 196 noninferiority comparisons were included in our analysis. Of these, over a third (67 trials) used mortality either as their sole endpoint (11 trials) or as part of a composite endpoint (56 trials). Nine trials were consort A, 21 trials consort B, 19 trials consort C, 12 were consort F, 4 consort G, and 2 were consort H. Four analyses showed statistically significant more deaths in the new treatment arm, while meeting consort criteria as "inconclusive" (consort G), (Behringer et al. in Lancet. 385(9976):1418-1427, 2015; Kaul et al. in N Engl J Med. 373(18):1709-1719, 2015; Bwakura-Dangarembizi et al. in N Engl J Med. 370(1):41-53, 2014) and thirteen trials utilizing mortality as an endpoint and had an absolute increase of > 3%, and six had an absolute increase of > 5%.

CONCLUSIONS

The use of mortality as an outcome in noninferiority trials is not rare and scenarios where the new treatment is statistically worse, but a conclusion of noninferiority or inconclusive do occur. We highlight these issues and propose simple steps to reduce the risk of ethically dubious conclusions.

New versus Old Oral Anticoagulants: How Can We Set the Scale Needle? Considerations on a Case Report

Ischemic stroke is a complex multifactorial disorder. Anticoagulation is a growing research area, with the main goal of preventing systemic embolization and stroke. We report the case of a 41-year-old woman with antiphospholipid syndrome who was unsuccessfully treated with Dabigatran, a new oral anticoagulant, as she developed a major stroke involving the right carotid artery, due to deep venous thrombosis with pulmonary embolism. We therefore suggest a closer monitoring of the safety and efficacy of dabigatran. Moreover, in the presence of multifactorial causes of pro-coagulation, we believe that warfarin should remain the mainstay of oral anticoagulation.

Vascular protease-activated receptor 4 upregulation, increased platelet aggregation, and coronary lipid deposits induced by long-term dabigatran administration - results from a diabetes animal model

Essentials The impact of long-term thrombin inhibition outside the coagulation cascade is far from clear. We aimed to assess the impact of dabigatran etexilate (DE) in diabetic and control rats. In diabetic rats, DE increased platelet aggregation and lead to coronary lipid deposits. Long-term thrombin inhibition may increase atherosclerotic and atherothrombotic risk. SUMMARY: Background Besides its role in the coagulation cascade, thrombin contributes to platelet aggregation and to a plethora of non-hemostatic functions. Objectives To assess the impact of long-term thrombin inhibition with dabigatran etexilate (DE) on platelet aggregation and on extrahemostatic thrombin-related functions in diabetic and control rats. Methods Markers of inflammation, endothelial dysfunction, oxidative stress, angiogenesis and cell adhesion molecules were quantified in control rats (Control; n = 6), DE-treated control rats (Control-Dabi; n = 8), diabetic rats (Diabetes; n = 5), and DE-treated diabetic rats (Diabetes-Dabi; n = 8). Agonist-induced platelet aggregation, aortic and coronary lipid deposits and aortic protease-activated receptor 4 (PAR4) expression were also assessed. Results Control-Dabi rats showed significantly higher high-sensitivity C-reactive protein, von Willebrand factor (VWF), vascular endothelial growth factor (VEGF) and fibronectin levels, and significantly lower PAR4 agonist-induced aggregation, than Control rats. Control-Dabi rats also showed mild aortic lipid deposits, whereas no such changes were observed in Control rats. Diabetes-Dabi rats showed significantly higher VWF, VEGF and fibronectin levels than Diabetes rats, and similar PAR4 agonist-induced aggregation as Diabetes rats, and significantly higher ADP-induced aggregation than Diabetes rats. Coronary lipid deposits were observed in 75% of Diabetes-Dabi rats and in none of the Diabetes rats. PAR4 expression was 20.4% higher in Control-Dabi rats and 27.4% higher in Diabetes-Dabi rats than in their non-treated peers. Conclusions This study indicates that long-term thrombin inhibition increases vascular PAR4 expression, promotes atherosclerosis-related mechanisms, and, in diabetic rats, increases platelet aggregation and favors the occurrence of coronary lipid deposits. These experimental data suggest that long-term thrombin inhibition may increase atherosclerotic and atherothrombotic risk, particularly in the presence of diabetes.

Direct Oral Anticoagulant Drugs: On the Treatment of Cancer-Related Venous Thromboembolism and their Potential Anti-Neoplastic Effect

Cancer patients develop a hypercoagulable state with a four- to seven-fold higher thromboembolic risk compared to non-cancer patients. Thromboembolic events can precede the diagnosis of cancer, but they more often occur at diagnosis or during treatment. After malignancy itself, they represent the second cause of death. Low molecular weight heparins are the backbone of the treatment of cancer-associated thromboembolism. This treatment paradigm is possibly changing, as direct oral anticoagulants (DOACs) may prove to be an alternative therapeutic option. The currently available DOACs were approved during the first and second decades of the 21st century for various clinical indications. Three molecules (apixaban, edoxaban and rivaroxaban) are targeting the activated factor X and one (dabigatran) is directed against the activated factor II, thrombin. The major trials analyzed the effect of these agents in the general population, with only a small proportion of cancer patients. Two published and several ongoing studies are specifically investigating the use of DOACs in cancer-associated thromboembolism. This article will review the current available literature on the use of DOACs in cancer patients. Furthermore, we will discuss published data suggesting potential anti-cancer actions exerted by non-anticoagulant effects of DOACs. As soon as more prospective data becomes available, DOACs are likely to be considered as a potential new therapeutic option in the armamentarium for patients suffering of cancer-associated thromboembolism.

Six months versus two years of oral anticoagulation after a first episode of unprovoked deep-vein thrombosis. The PADIS-DVT randomized clinical trial

The optimal duration of anticoagulation after a first episode of unprovoked deep-vein thrombosis is uncertain. We aimed to assess the benefits and risks of an additional 18 months of treatment with warfarin versus placebo, after an initial 6 months of anticoagulation for a first unprovoked proximal deep-vein thrombosis. We conducted a multicenter, randomized, double-blind, controlled trial comparing an additional 18 months of warfarin with placebo in patients with a unprovoked proximal deep-vein thrombosis initially treated for 6 months (treatment period: 18 months; follow up after treatment period: 24 months). The primary outcome was the composite of recurrent venous thromboembolism or major bleeding at 18 months. Secondary outcomes were the composite at 42 months, as well as each component of the composite, and death unrelated to pulmonary embolism or major bleeding, at 18 and 42 months. All outcomes were centrally adjudicated. A total of 104 patients, enrolled between July 2007 and October 2013 were analyzed on an intention-to-treat basis; no patient was lost to follow-up. During the 18-month treatment period, the primary outcome occurred in none of the 50 patients in the warfarin group and in 16 out of 54 patients (cumulative risk, 29.6%) in the placebo group (hazard ratio, 0.03; 95% confidence interval: 0.01 to 0.09; P<0.001). During the entire 42-month study period, the composite outcome occurred in 14 patients (cumulative risk, 36.8%) in the warfarin group and 17 patients (cumulative risk, 31.5%) in the placebo group (hazard ratio, 0.72; 95% confidence interval: 0.35-1.46). In conclusion, after a first unprovoked proximal deep-vein thrombosis initially treated for 6 months, an additional 18 months of warfarin therapy reduced the composite of recurrent venous thrombosis and major bleeding compared to placebo. However, this benefit was not maintained after stopping anticoagulation. Clinical registration: this trial was registered at www.clinicaltrials.gov as #NCT00740493.

Update on extended treatment for venous thromboembolism

The importance of assessing the probability of venous thromboembolism recurrence, a condition that includes deep vein thrombosis and pulmonary embolism, lies in the fact that it is the most important factor in deciding the duration of anticoagulant treatment. Risk of recurrence depends mostly on the presence of a risk factor for developing venous thromboembolism, with patients with unprovoked events being at the higher risk of recurrence. The risk of recurrence needs to be balanced with the risk of bleeding and the potential severity of these thrombotic and hemorrhagic events. In patients with an unprovoked venous thromboembolism who complete treatment for the acute (first 10 days) and post-acute phase of the disease (from day 10 to 3-6 months), the decision has to be made regarding prolonged antithrombotic therapy to prevent recurrences. The main goal of extended treatment is preventing recurrences with a safety profile in terms of bleeding risk. Many therapeutic options are now available for these patients, including antiplatelet therapy with aspirin or direct oral anticoagulants. Moreover, apixaban and rivaroxaban at prophylactic doses have demonstrated efficacy in preventing recurrences with a low risk of bleeding. Key messages Extending treatment (longer than 3-6 months) is challenging in patients with venous thromboembolism (VTE) and depend on the risk of venous thromboembolism recurrence, the bleeding risk and patient and physician preferences. Anticoagulation treatment should be stopped in patients with provoked VTE and in those with unprovoked VTE and a high bleeding risk after an initial period of 3-6 months. There are some therapeutic alternatives (including Aspirin and low dose of some NOACs) to reduce venous thromboembolism recurrence risk in patients with unprovoked VTE and a low bleeding risk for extended treatment of VTE (after an initial period of 3-6 months).

Who should get long-term anticoagulant therapy for venous thromboembolism and with what?

After an initial 3 to 6 months of anticoagulation for venous thromboembolism (VTE), clinicians and patients face an important question: "Do we stop anticoagulants or continue them indefinitely?" The decision is easy in some scenarios (eg, stop in VTE provoked by major surgery). In most scenarios, which are faced on a day-to-day basis in routine practice, it is a challenging decision because of uncertainty in estimates in the long-term risks (principally major bleeding) and benefits (reducing recurrent VTE) and the tight trade-offs between them. Once the decision is made to continue, the next question to tackle is "Which anticoagulant?" Here again, it is a difficult decision because of the uncertainty with regard to estimates of efficacy and the safety of anticoagulant options and the tight trade-offs between choices. We conclude with the approach that we take in our clinical practice.

Breadth of complications of long-term oral anticoagulant care

The majority of patients with venous thromboembolism (VTE) have a considerable long-term risk of recurrence and may require extended duration of anticoagulant treatment after the initial 3 to 6 months. The decision to extend treatment is based not only on the individual risk of recurrence, but should also consider the potential complications associated with anticoagulation, taking into account that anticoagulant drugs are among the drugs most frequently associated with hospital admission due to adverse drug reactions. The most feared complication of oral anticoagulants is bleeding, which in some cases may be fatal or may affect critical organs. Case-fatality rates of bleeding have been reported to be ∼3 times higher than case-fatality rates of recurrent VTE. Even when nonserious, bleeding may require medical intervention and/or may impact on patient quality of life or working activity. Factors associated with bleeding during anticoagulant treatment include, among others, advanced age, cancer, renal or liver insufficiency, or concomitant antithrombotic drugs, but no bleeding risk score is sufficiently accurate for use in clinical practice. Not uncommonly, bleeding occurs as a complication of trauma or medically invasive procedures. Nonbleeding complications associated with oral anticoagulants are unusual, and their relevance is extremely uncertain, and include vascular calcification, anticoagulation-related nephropathy, and osteoporosis. Finally, because VTE not uncommonly affects young individuals and the mean age of the population is ∼60 years, the costs associated with extended anticoagulation should not be forgotten. The costs of the drugs need to be balanced against health outcome costs associated with both recurrent VTE and bleeding.

Fatal recurrent VTE after anticoagulant treatment for unprovoked VTE: a systematic review

Current guidelines recommend long-term anticoagulant therapy in patients with unprovoked venous thromboembolism (VTE). The risk of fatal recurrent VTE after treatment discontinuation (versus that of fatal bleeding during anticoagulation) is of particular relevance in the decision to continue or stop anticoagulation after the first 3 months. Our primary aim was to provide a point-estimate of the yearly rate of fatal recurrent VTE and VTE case-fatality rate in patients with unprovoked VTE after anticoagulation cessation. Data were extracted from both randomised controlled trials and observational studies published before May 1, 2017. The pooled fatality rates were calculated using a random-effects model. 18 studies with low-to-moderate bias were included in the primary analysis, totalling 6758 patients with a median (range) follow-up duration of 2.2 (1–5) years. After anticoagulation cessation, the weighted pooled rate of VTE recurrence was 6.3 (95% CI 5.4–7.3) per 100 patient-years and the weighted pooled rate of fatal recurrent VTE was 0.17 (95% CI 0.047–0.33) per 100 patient-years, for a case-fatality rate of 2.6% (95% CI 0.86–5.0). These numbers are a solid benchmark for comparison to the risks associated with long-term anticoagulation treatment for the decision on the optimal duration of treatment of patients with unprovoked VTE.

Direct Oral Anticoagulants and Travel-related Venous Thromboembolism

Travel- related thromboembolism reflects the relationship between venous thromboembolism (VTE) and long-haul flights. Although this condition is rare, it may cause significant morbidity and mortality. Therefore, travelers should be evaluated for the risks for thrombosis. Travel physicians should employ a clinical risk score and select in vestigations, prophylaxis, and treatment that are appropriate for each individual. This review summarizes current VTE clinical risk scores and patient management from various reliable guidelines. We summarized 16 reliable publications for reviewing data. Direct oral anticoagulants (DOACs) are currently the standard treatment for VTE and a prophylactic measure for VTE in orthopedic surgery. Compared with a vitamin K antagonist (VKA), DOACs show better safety and similar efficacy without the need for monitoring, and have fewer food/drug interactions. Inferred from the data on general VTE, DOACs may be used to treat travel-related VTE. Although the data are lacking, DOACs may be used off-label as VTE prophylax is. Before using DOACs, physicians must know the pharmacology of the drugs well and should realize that the availability of antidotes for bleeding complications is limited.

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.

Venous Thromboembolism: Advances in Diagnosis and Treatment

IMPORTANCE

Venous thromboembolism (VTE), comprising deep vein thrombosis (DVT) and pulmonary embolism (PE), is a common and potentially fatal disease.

OBJECTIVE

To summarize the advances in diagnosis and treatment of VTE of the past 5 years.

EVIDENCE REVIEW

A systematic search was conducted in EMBASE Classic, EMBASE, Ovid MEDLINE, and other nonindexed citations using broad terms for diagnosis and treatment of VTE to find systematic reviews and meta-analyses, randomized trials, and prospective cohort studies published between January 1, 2013, and July 31, 2018. The 10th edition of the American College of Chest Physicians Antithrombotic Therapy Guidelines was screened to identify additional studies. Screening of titles, abstracts, and, subsequently, full-text articles was performed in duplicate, as well as data extraction and risk-of-bias assessment of the included articles.

FINDINGS

Thirty-two articles were included in this review. The application of an age-adjusted D-dimer threshold in patients with suspected PE has increased the number of patients in whom imaging can be withheld. The Pulmonary Embolism Rule-Out Criteria safely exclude PE when the pretest probability is low. The introduction of direct oral anticoagulants has allowed for a simplified treatment of VTE with a lower risk of bleeding regardless of etiology or extent of the VTE (except for massive PE) and has made extended secondary prevention more acceptable. Thrombolysis is best reserved for patients with massive PE or those with DVT and threatened limb loss. Insertion of inferior vena cava filters should be avoided unless anticoagulation is absolutely contraindicated in patients with recent acute VTE. Graduated compression stockings are no longer recommended to treat DVT but may be used when acute or chronic symptoms are present. Anticoagulation may no longer be indicated for patients with isolated distal DVT at low risk of recurrence.

CONCLUSIONS AND RELEVANCE

Over the past 5 years, substantial progress has been made in VTE management, allowing for diagnostic and therapeutic strategies tailored to individual patient characteristics, preferences, and values.

Extended treatment of venous thromboembolism: a systematic review and network meta-analysis

OBJECTIVE

To evaluate efficacy and safety of oral anticoagulant regimens and aspirin for extended venous thromboembolism (VTE) treatment.

METHODS

We searched MEDLINE, Embase, CENTRAL and conference proceedings for randomised controlled trials studying vitamin K antagonists (VKAs), direct oral anticoagulants (DOACs) or aspirin for secondary prevention of VTE beyond 3 months. ORs (95% credible intervals) between treatments were estimated using random-effects Bayesian network meta-analysis.

RESULTS

Sixteen studies, totaling more than 22 000 patients, were included. Compared with placebo or observation and with aspirin, respectively, the risk of recurrent VTE was lower with standard-intensity VKAs (0.15 (0.08 to 0.24) and 0.23 (0.09 to 0.54)), low-dose factor Xa inhibitors (0.16 (0.06 to 0.38) and 0.25 (0.09 to 0.66)), standard-dose factor Xa inhibitors (0.17 (0.08 to 0.33) and 0.27 (0.11 to 0.65)) and the direct thrombin inhibitor (0.15 (0.04 to 0.37) and 0.23 (0.06 to 0.74)) although the risk of major bleeding was higher with standard-intensity VKAs (4.42 (1.99 to 12.24) and 4.14 (1.17 to 18.86)). Effect estimates were consistent in male patients and those with index pulmonary embolism or with unprovoked VTE and in sensitivity analyses. In addition, compared with placebo or observation, the risk of all-cause mortality was reduced with standard-intensity VKAs (0.44 (0.20 to 0.87)) and low-dose factor Xa inhibitors (0.38 (0.12 to 0.995)).

CONCLUSIONS

Standard-intensity VKAs and DOACs are more efficacious than aspirin for extended VTE treatment. Despite a higher risk of major bleeding, standard-intensity VKAs was associated with a lower risk of all-cause mortality. Since overall efficacy and safety of standard-intensity VKAs and DOACs are in equipoise, patient factors, costs and patient preferences should be considered when recommending extending anticoagulation treatment.

The American College of Chest Physician score to assess the risk of bleeding during anticoagulation in patients with venous thromboembolism

Essentials The risk of bleeding influences the duration of anticoagulation (AC) after venous thromboembolism. We assessed the ACCP bleeding risk score in an inception-cohort of patients receiving AC. 53% were categorized at high-risk, but their bleeding rate was low during long-term AC. ACCP score had low predictive value for bleeding.

SUMMARY

Background The American College of Chest Physicians (ACCP) guideline proposes a score to decide on extended anticoagulation after an unprovoked venous thromboembolism (VTE). Methods We investigated the ACCP score to predict bleeding risk in an inception cohort of 2263 patients on long-term anticoagulation (1522 treated with vitamin K antagonists [VKAs] and the remaining with direct oral anticoagulants [DOACs]) belonging to the Italian START2 Register. Results More than half the patients were categorized as high risk; nevertheless, a higher proportion received anticoagulation for > 1 year compared with those in the low-risk category. For 3130 years (median 12 [interquartile range 6, 24] months), 48 bleeding outcomes occurred (1.53%/year) in the cohort (1.7%/year and 0.95%/year in high- and low-risk categories, respectively). The c-statistic of the ACCP score was 0.55 (0.48-0.63), 0.50 (0.42-0.58) and 0.56 (0.48-0.64) in low-, moderate- and high-risk categories, respectively. The bleeding incidence was higher during the first 90 days of treatment (3.0%/year) than afterwards (1.2%/year; relative risk (RR), 2.5 [1.3-4.7]), and similar among the three categories. The bleeding rate was not different during the initial 3 months of treatment in patients receiving VKAs or DOACs; it was, however, lower in the latter patients in the subsequent period (0.5%/year vs. 1.4%/year, respectively). Conclusion The bleeding rate during extended treatment was rather low in our patients. ACCP score had insufficiently predictive value for bleeding and cannot be used to guide decisions on extended treatment. New prediction tools for bleeding risk during anticoagulant treatments (including DOACs) are required.

Bleeding in patients receiving non-vitamin K oral anticoagulants: clinical trial evidence

In optimizing anticoagulation therapy, it is essential to balance treatment efficacy with the major adverse effect of anticoagulant treatment, bleeding risk. This narrative review examines the efficacy and safety of the non-vitamin K antagonist oral anticoagulants (NOACs) dabigatran, rivaroxaban, apixaban, and edoxaban compared with standard anticoagulation or placebo. NOAC therapies provide equivalent to superior protection versus standard therapy, with similar or superior safety, and potential benefits in convenience. We will review the phase III evidence for each of the available NOACs in different antithrombotic indications, including atrial fibrillation (in the absence of significant mitral stenosis or mechanical heart valves); prophylaxis of venous thromboembolism (VTE) in patients undergoing orthopedic surgery; and acute and long-term treatment of VTE. Further, we will illustrate scenarios in which the evidence is stronger for a particular agent in the context of the overall positive safety and efficacy profile of NOACs in general. Limitations of the factor Xa inhibitors include the lack of a specific antidote in case of a bleeding emergency (an approved agent is available for reversing the effect of the direct thrombin inhibitor). We discuss the options for mitigating bleeding and describe the ongoing developments towards specific reversal agents. In conclusion, the available data for efficacy and safety, together with reliable pharmacokinetics obviating the need for regular monitoring, indicate that NOACs may offer substantial benefits for patients with nonvalvular atrial fibrillation or VTE.

The prevention of venous thromboembolism recurrence in the elderly: a still open issue

INTRODUCTION

Venous thromboembolism (VTE) is frequent in the elderly, with an unclear recurrence risk. After the initial and early maintenance anticoagulant treatment, the decision about its extension versus recurrences is difficult because of the high risk of bleeding in this population. Areas covered: This paper analyzes recent literature on VTE recurrence and risk of bleeding associated with extended anticoagulation in elderly patients with VTE, focusing on available data regarding efficacy and safety of old anticoagulant or recent direct oral anticoagulant (DOACs). Expert commentary: The following are clinically important and still unmet needs in elderly patients with VTE: the current real risks for recurrence or for bleeding are still uncertain; the available clinical predictive rules for recurrence are of less use; in general, the phase III trials on DOACs proved less satisfactory in the elderly than in the general population; low dose DOACs use for extended treatment seems promising and data on long periods of therapy are needed; low dose aspirin does not seem an appropriate therapeutic alternative to anticoagulants due to the high rate of bleeding in the elderly; antithrombotic drugs, with low risk of bleeding should be assessed as alternative therapeutic options for extended treatment in the elderly.

Pulmonary Embolism: Contemporary Medical Management and Future Perspectives

Pulmonary embolism (PE) contributes substantially to the global disease burden. A key determinant of early adverse outcomes is the presence (and severity) of right ventricular dysfunction. Consequently, risk-adapted management strategies continue to evolve, tailoring acute treatment to the patients' clinical presentation, hemodynamic status, imaging and biochemical markers, and comorbidity. For subjects with hemodynamic instability or 'high-risk' PE, immediate systemic reperfusion treatment with intravenous thrombolysis is indicated; emerging approaches such as catheter-directed pharmacomechanical reperfusion might help to minimize the bleeding risk. Currently, direct, non-vitamin K-dependent oral anticoagulants are the mainstay of treatment for acute PE. They have been shown to simplify initial and extended anticoagulation regimens while reducing the bleeding risk compared to vitamin K antagonists. (This is a review article based on the invited lecture of the 37th Annual Meeting of Japanese Society of Phlebology.).

Less abnormal uterine bleeding with dabigatran than warfarin in women treated for acute venous thromboembolism

Essentials Factor Xa inhibitors cause more abnormal menstrual bleeding (AUB) than vitamin-K antagonists (VKA). We analyzed data of AUB in women, evaluating dabigatran versus VKA. We observed a 41% lower risk of AUB in women on dabigatran compared to those on VKA. Our findings of lower AUB risk on dabigatran should be corroborated in future studies.

SUMMARY

Introduction Although direct oral anticoagulants (DOACs) are associated with a better safety profile than warfarin in patients with acute venous thromboembolism (VTE), direct factor Xa inhibitors involve a higher risk of abnormal uterine bleeding (AUB). We aimed to determine the risk of AUB during anticoagulation with dabigatran compared with warfarin. Methods Post-hoc analysis of the pooled RE-COVER studies and the RE-MEDY trial. Incidences of AUB, based on a defined preferred terms search for adverse events, in female patients aged 18-50 years treated with dabigatran, were compared with those in women treated with warfarin. Results Of the 2964 women included in the above-mentioned trials, 1280 women were in the relevant age category (18-50 years) and included in the current analysis. A total of 643 patients were randomized to treatment with dabigatran and 637 to treatment with warfarin. The overall rate of AUB was 8.1%, 5.9% for the women treated with dabigatran and 9.6% in those treated with warfarin, for an odds ratio for dabigatran-treated patients of 0.59 (95% confidence interval [CI], 0.39-0.90; P = 0.015). In the dabigatran-treated patients, three (0.5%) suffered major bleeding (MB) vs. five (0.8%) in the warfarin-treated patients (HR, 0.65; 95% CI, 0.15-2.72). MB or non-major relevant bleeding occurred in 30 (4.7%) patients randomized to receive dabigatran and 57 (8.9%) randomized to receive warfarin (HR, 0.53; 95% CI, 0.34-0.83). None of the bleeding events was fatal. Conclusion Dabigatran treatment was associated with a significantly (41%) lower risk of AUB than warfarin. Future studies in daily practice are needed to corroborate these findings.

Anticoagulant Effects of Dabigatran in Paediatric Patients Compared with Adults: Combined Data from Three Paediatric Clinical Trials

BACKGROUND

 Physiological age-related changes in the haemostatic and coagulation systems result in differing anticoagulant assay responses to standard anticoagulants. Therefore, we investigated the response of anticoagulant assays to dabigatran etexilate (DE) in children compared with adults.

OBJECTIVE

 This article assesses the relationship between plasma dabigatran concentration and coagulation assay results across age groups in children and adults.

PATIENTS AND METHODS

 Data from three clinical trials in which children received DE following standard of care for venous thromboembolism were compared with data from adult clinical trials. The effects of dabigatran concentration on diluted thrombin time (dTT), ecarin clotting time (ECT) and activated partial thromboplastin time (aPTT) were analysed graphically and with modelling.

RESULTS

 The concentration-dTT relationships were consistent in children across all ages and adults in the graphical analysis. For ECT and aPTT, relationships based on ratios over baseline were similar across all ages; absolute clotting times showed that the same exposure resulted in longer clotting times in some of the children aged < 1 year versus adults. Modelling showed concentration-clotting time relationships for all three assays were largely comparable between adults and children, except in those aged < 2 months, in whom there was a slight upward shift in ECT and aPTT relative to adults.

CONCLUSION

 Results suggest that developmental haemostatic changes will have little impact on response to DE. However, further paediatric clinical trials assessing the relationship between coagulation assay responses and clinical outcomes will be needed to confirm this finding.