Evaluation of Apixaban safety and effectiveness in morbidly obese patients with atrial fibrillation: a retrospective cohort study.

BACKGROUND: The benefit of apixaban to reduce stroke risk in morbidly obese patients with nonvalvular atrial fibrillation (AF) is still undetermined. The International Society of Thrombosis and Hemostasis recommends avoiding the use of direct oral anticoagulants (DOAC)s in morbidly obese patients (body mass index > 40 or weight > 120 kg) because of limited clinical data. This exploratory study aims to evaluate the effectiveness and safety of using apixaban in morbidly obese (body mass index (BMI) ≥ 40) patients with AF. METHODS: An exploratory retrospective cohort study was conducted at a single-center, including adult patients with non-valvular AF using apixaban between 01/01/2016 and 31/12/2019. Patients were excluded if they were known to have liver cirrhosis Child-Pugh C, mechanical valve, serum creatinine > 1.5 mg/dL, follow up < 3 months, or using apixaban with a dose of ≤5 or > 10 mg/day. Included patients were categorized into two groups based on their BMI (BMI<40 Vs. BMI ≥ 40). The primary outcome was all thrombotic events, while the secondary outcomes were major and minor bleeding after apixaban initiation. Propensity score (PS) matching was used (1:1 ratio) based on the patient's age, gender, and HAS-BLED score. RESULTS: A total of 722 patients were eligible; 254 patients were included after propensity score matching based on the selected criteria. The prevalence of all thrombotic events was similar between the two groups in the first year of apixaban initiation (OR (95%CI): 0.58 (0.13, 2.5), p-value = 0.46). In addition, the odds of developing major and minor bleeding were not statistically significant between the two groups (OR (95%CI): 0.39 (0.07, 2.03), p-value = 0.26 and OR (95%CI): 1.27 (0.56, 2.84), p-value = 0.40), respectively). CONCLUSION: This exploratory study showed similar effectiveness and safety of apixaban use in both morbid and non-morbid obese patients with non-valvular AF. However, a larger randomized controlled trial with a longer follow-up period needs to confirm our findings.

Evaluation of Apixaban in Patients With Antiphospholipid Syndrome: A Case Series and Review of Literature.

Several guidelines endorsed the indefinite use warfarin or heparin-containing products for acute venous thromboembolism (VTE) treatment and secondary prevention and discouraged the use of direct oral anticoagulants (DOAC) for patients diagnosed with antiphospholipid syndrome (APS). However, adequate anticoagulation despite warfarin therapy remains a challenge in APS patients. Using DOACs in APS patients is seen in clinical practice, despite the lack of evidence to support their use in this population. In this case series, we aim to evaluate the safety and effectiveness of apixaban use in nine patients with primary or secondary APS at King Abdulaziz Medical City (Riyadh, Saudi Arabia). All patients presented with APS and received apixaban with or without concomitant antiplatelet. Three patients had double positivity, and two patients had triple positivity of antiphospholipid antibodies (aPL). Some patients tolerated apixaban during the follow-up period, but recurrent VTE and stroke were reported in some of them. Bleeding complications were evident in some cases as well. In conclusion, warfarin remains the best choice to prevent VTE recurrence in patients with APS. On the other side, apixaban use in patients with APS may have some safety and effectiveness concerns evidenced by VTE recurrence and bleeding complications. The safety and effectiveness of utilizing apixaban in APS patients need to be assessed in well-controlled randomized trials.

Apixaban Use in Patients with Protein C and S Deficiency: A Case Series and Review of Literature.

Background: Historically, warfarin was the mainstay anticoagulant agent to manage patients presenting with thrombotic disorders caused by Protein C or S deficiency. Several direct oral anticoagulants (DOACs) were introduced over the past decade. They showed superiority over warfarin in patients with venous thromboembolism in many landmark trials. Insufficient data are available that examine the outcome of utilizing apixaban in patients with protein S deficiency induce thrombosis. Cases Presentation: We reported the clinical outcomes of utilizing apixaban in four patients with systemic thrombosis caused by protein C or S deficiency who presented to a tertiary hospital in Riyadh, Saudi Arabia. Four patients exhibited typical features of thrombotic events. After confirming the diagnosis, one patient was initially started on apixaban, and the other three patients were converted from warfarin to apixaban. Three of the four patients tolerated the apixaban during the follow-up period. Additionally, they did not have any bleeding or thrombotic complications. However, one patient developed recurrent thrombotic events despite switching to different type of DOAC and was ultimately transitioned back to warfarin. Conclusion: Based on the available emerging evidence and our case series, the use of apixaban could be effective in preventing recurrent thrombotic events in patients with inherited thrombophilia without safety concerns. Further, large studies are warranted to investigate the safety and efficacy of apixaban in these population.