Current state of anticoagulants to treat deep venous thrombosis

Self-reported adherence to direct oral anticoagulants versus warfarin therapy in a specialized thrombosis service-a cross-sectional study of patients in a Canadian Health Region

PURPOSE

Direct oral anticoagulants (DOACs) have a better safety and efficacy profile than warfarin and are currently recommended for stroke prevention in non-valvular atrial fibrillation (AF) and treatment of venous thromboembolism (VTE). Given that DOACs do not require regular laboratory monitoring compared to warfarin, patients' interactions with the health care system is reduced. Adequate adherence to DOACs is important and reported adherence to anticoagulation is unclear in clinical practice. This study aims to assess self-reported adherence to oral anticoagulants in a specialized Adult Outpatient Thrombosis Service (TS).  METHODS: This cross-sectional study included patients aged ≥ 18 years who were prescribed an oral anticoagulant and had attended at least one appointment with an Adult Outpatient Thrombosis Service (TS) between October 10, 2017, and May 31, 2019. Adherence to oral anticoagulant therapy was assessed using the 12-item validated Adherence to Refills and Medications Scale (ARMS) score. Logistic regression analyses were used to evaluate association between patient characteristics and medication adherence. Adherence rates in DOACs and warfarin were compared.

RESULTS

Three hundred and ninety-nine patients completed and returned the survey. Of the 399 who completed the survey, 74% were prescribed DOACs and 26% received warfarin. Most of the patients (89.3%) were ≥ 50 years of age and half (57.3%) were male. About two-thirds (67%) had at least post-secondary education. The duration of anticoagulation use differed between patients on DOAC and warfarin; a greater proportion of those who had used anticoagulants for less than 1 year was on DOACs compared to warfarin (20.9% vs 4.9%, p = 0.001). For patients who had been on anticoagulation for > 5 years, the proportion of warfarin patients was greater than DOAC (57.8% vs 20.5%, p = 0.001). Self-reported adherence to oral anticoagulant therapy using the 12-item ARMS scale for warfarin and DOACs were 87.3% and 90.9%, respectively. Among the warfarin users, patient satisfaction with TS was associated with medication adherence (OR = 0.22; 95% CI: 0.05-0.89).

CONCLUSIONS

Self-reported medication adherence was similar between warfarin and DOACs. Since suboptimal adherence is associated with poor clinical outcomes and increased costs, various stakeholders should emphasize the importance of medication adherence to oral anticoagulants at each patient encounter.

Adherence to Antithrombotic Therapy for Patients Attending a Multidisciplinary Thrombosis Service in Canada - A Cross-Sectional Survey

BACKGROUND

Poor medication adherence puts patients who require antithrombotic therapy at greater risk of complications. We started a multidisciplinary Adult Outpatient Thrombosis Service in 2017 in a Canadian health authority and were interested in the level of medication adherence in the population attending.

AIMS

The aim of this study is to assess adherence to antithrombotic medications for patients attending a multidisciplinary Thrombosis Service.

METHODS

We conducted a cross-sectional survey of outpatients seen at the Thrombosis Service between 2017 and 2019 using the 12-item validated Adherence to Refills and Medications Scale (ARMS) to assess adherence to antithrombotic (anticoagulants and antiplatelet) therapy. Linear regression analysis examined the factors associated with adherence to antithrombotic therapy.

RESULTS

Of 1058 eligible patients, 53.2% responded to the survey. Seventeen were excluded from the analysis for missing more than 6 responses to the 12 items on the ARMS. About 55% (n = 297) were on direct oral anticoagulants (DOACs), 19% (n = 102) on warfarin, 5.0% (n = 27) on low molecular weight heparin, 3.3% (n = 18) on antiplatelet therapy and 18% (n = 96) were no longer on antithrombotic therapy. Nearly half (47%, n = 253) had taken antithrombotic therapy for 1-5 years while 28% (n = 150) and 25% (n = 137) had taken antithrombotic treatments for <1 and >5 years, respectively. Most patients (87%, n = 475) were ≥50 years and half (51%, n = 277) were male. The mean adherence score was 13.9 (SD±2.2) and 88% (n = 481) of participants were adherent to antithrombotic treatment (ARMS = 12-16). Multivariable linear regression showed that patients with post-graduate education had 0.4% lower adherence to antithrombotic therapy as compared with elementary education (β = 0.0039, p = 0.048). Patients with prior antithrombotic agent use >5 years had 0.5% lower adherence to antithrombotic treatment compared to patients with <1 year (β = 0.0047, p = 0.0244).

CONCLUSION

Self-reported adherence to antithrombotic therapy was high (88%) within a multidisciplinary Thrombosis Service. Patients with advanced education and prolong duration of antithrombotic therapy were more likely to have lower self-reported adherence to antithrombotic treatment.

Comparison of Treatment Result Between Anticoagulation Alone and Catheter-Directed Thrombolysis Plus Anticoagulation in Acute Lower Extremity Deep Vein Thrombosis

Purpose

Deep vein thrombosis (DVT) is the third most common cause of cardiovascular morbidity and mortality. Anticoagulation has been the primary treatment modality for acute DVT. However, catheter-directed thrombolysis (CDT) has recently become widely accepted as an additional therapy to anticoagulation. We assessed comparative outcomes in patients with acute DVT who underwent anticoagulation therapy alone (ACA) group and those treated with CDT group.

Materials and Methods

We retrospectively reviewed medical records of 149 patients with DVT from January 2011 to December 2015. We compared patients who received ACA group (n=120) and those who received CDT plus anticoagulation (CDT group, n=29). We analyzed the prevalence of lesions, thrombus removal rate in each lesion, and recurrence-free rate between the two groups.

Results

We found thrombus involvement in a total of 281 lesions in the ACA group and 85 lesions in the CDT group. For the distribution of lesions in each group, those in the femoral vein accounted for 34.2% of all lesions and those in the popliteal vein accounted for 31.7%. During follow-up, the overall thrombus removal rate was 91.1% in the ACA group and 87.0% in the CDT group (P=0.273). The recurrence-free rate was higher in the CDT group in a log-rank test; however, there was no statistically significant difference between the two groups (P=0.594).

Conclusion

According to our results, there was no significant difference in thrombus removal and recurrence-free rates between the CDT and ACA groups. ACA still has an important role in the treatment of DVT.

Edoxaban: A Review in Deep Vein Thrombosis and Pulmonary Embolism

Edoxaban (Lixiana, Savaysa) is an oral, direct factor Xa inhibitor which has recently been approved for use in the treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE) [collectively, venous thromboembolism (VTE)] and for the prevention of recurrent VTE. This article reviews the pharmacological properties of edoxaban as well as its tolerability and therapeutic efficacy in the treatment and prevention of recurrent VTE events. As demonstrated in the pivotal Hokusai-VTE phase III trial, once-daily edoxaban after initial treatment with heparin was non-inferior to standard therapy with heparin/warfarin in preventing recurrent VTE events and was associated with a significantly lower risk of clinically relevant bleeding than the traditional therapy. Edoxaban shares the advantages of other direct oral anticoagulants (DOACs) over traditional therapies, including the lack of requirement for routine coagulation monitoring, a rapid onset and offset of action, and few drug-drug interactions. It offers the convenience of once-daily dosing, can be taken without regard to food and allows for a dose reduction in patients with certain clinical features, such as moderate renal impairment or low body weight. In conclusion, edoxaban represents an effective and potentially safer alternative to traditional vitamin K antagonist therapy for the treatment and prevention of recurrent VTE. Its recent approval expands the range of DOAC agents for recurrent VTE, further facilitating treatment individualization.

Deep Vein Thrombus Occurring Immediately After Blunt Abdominal Trauma

CASE

A 13-year-old adolescent girl with blunt abdominal injury was transferred to our hospital. Enhanced computed tomography (CT) showed not only retroperitoneal hematoma around the inferior vena cava and left common iliac vein but also thrombus extending from the left common iliac vein to the femoral vein.

OUTCOME

Enhanced CT performed on the second day revealed no increase in retroperitoneal hematoma and a new small thrombus in the popliteal vein. Anticoagulant therapy was therefore started with administration of unfractionated heparin. Administration of warfarin was started on the 12th day and heparin administration was stopped on the 14th day. The patient was discharged on the 19th day with continuation of warfarin administration. Enhanced CT performed 10 months after injury showed no thrombus, and the administration of warfarin was then stopped.

CONCLUSIONS

She was successfully treated with the appropriate start time and control of anticoagulation therapy based on careful evaluation of her general condition.

Direct Oral Anticoagulants for the Management of Thromboembolic Disorders

Anticoagulation therapy is central to the management of thromboembolic disorders, and the use of direct oral anticoagulants offers several advantages over standard therapy with parenteral heparins and vitamin K antagonists. In phase III clinical trials, the direct oral anticoagulants (given once or twice daily) all demonstrated favorable benefit–risk profiles compared with conventional standard therapy for the treatment and secondary prevention of venous thromboembolism and for stroke prevention in patients with nonvalvular atrial fibrillation. In clinical practice, many factors may influence overall clinical outcomes in patients receiving anticoagulant therapy, including adherence and persistence to the prescribed therapy, which becomes particularly important during long-term therapy. When choosing an anticoagulant for an individual patient, the pharmacological and clinical profile of the anticoagulant, its dosing regimen, and the patient’s clinical characteristics (eg, renal function and comorbidities) and preferences should be considered. This review examines the rationale for and clinical evidence of the selected dosing regimens of the direct oral anticoagulants for the treatment of venous thromboembolism and stroke prevention in nonvalvular atrial fibrillation. The potential influence of dosing strategies (eg, once- or twice-daily dosing) and other factors on patient adherence and therapy persistence are also discussed.