Use of Non-Vitamin K Antagonist Oral Anticoagulants in Special Patient Populations with Nonvalvular Atrial Fibrillation: A Review of the Literature and Application to Clinical Practice

Thrombocytopenia Induced by Direct Oral Anticoagulants: a Clinical Case and Literature Review

The last decade has dramatically changed the strategy of anticoagulant therapy in patients with atrial fibrillation. Direct oral anticoagulants have replaced vitamin K antagonists: either direct thrombin blockers (dabigatran) or factor IIa blockers (apixaban, rivaroxaban, edoxaban). According to the regulatory domestic and foreign documents, the use of direct oral anticoagulants in patients with atrial fibrillation has priority in comparison with vitamin K antagonists, since they have a predictable anticoagulant effect, the possibility of taking fixed doses without the need for routine anticoagulant monitoring, rapid onset and termination of action, relatively low potential for food and drug interactions. Direct oral anticoagulants are used for the prevention of thromboembolic complications in patients with atrial fibrillation, for the prevention of deep vein thrombosis in patients who have undergone surgery on the knee or hip joints, for emergency treatment and secondary prevention of deep vein thrombosis and pulmonary embolism. Alertness to side effects tends to focus on the likelihood of bleeding, with the possibility of other side effects of direct oral anticoagulants receiving less attention or going unnoticed. These mainly include liver damage, kidney damage and a number of other rare adverse reactions. The finding of isolated thrombocytopenia in patients taking direct oral anticoagulants may be associated with a high risk of life-threatening bleeding. The article analyzes published data on the occurrence of thrombocytopenia associated with the intake of direct oral anticoagulants, and presents a clinical case of thrombocytopenia while taking apixaban.

Changes in primary care management of atrial fibrillation patients following the shift from warfarin to non-vitamin K antagonist oral anticoagulants: a Norwegian population based study

Background

To assess baseline characteristics, drug utilisation and healthcare use for oral anticoagulants (OACs) following the introduction of non-vitamin K antagonist oral anticoagulants among patients with atrial fibrillation in primary care in Norway.

Methods

In this retrospective longitudinal cohort study, 92,936 patients with atrial fibrillation were identified from the Norwegian Primary Care Registry between 2010 and 2018. Linking to the Norwegian Prescription Database, we identified 64,112 patients (69.0%) treated with OACs and 28,824 (31%) who were untreated. Participants were followed until 15 May 2019, death, or loss to follow-up, whichever came first. For each OAC, predictors of initiation were assessed by modelling the probability of initiating the OAC using logistic regression, and predictors of the first switch after index date were assessed using multivariable Cox proportional hazards models. The numbers of primary care visits per quarter by index OAC were plotted and analysed with negative binomial regression analyses offset for the log of days at risk.

Results

Patients treated with OACs were older, had more comorbidities, and higher CHA₂DS₂-VASc scores than untreated patients. However, the mean CHA₂DS₂-VASc in the non-OAC group was 1.58 for men and 3.13 for women, suggesting an indication for OAC therapy. The percentage of patients with atrial fibrillation initiating OACs increased from 59% in 2010 to 79% in 2018. Non-vitamin K antagonist oral anticoagulant use increased throughout the study period to 95% of new OAC-treated patients in 2018, and switches from warfarin to non-vitamin K antagonist oral anticoagulants were common. The persistence of OAC treatment was > 60% after four years, with greatest persistence for apixaban. Patients treated with non-vitamin K antagonist oral anticoagulants had fewer primary care visits compared with those treated with warfarin (incidence rate ratio: 0.73, 95% confidence interval 0.71 to 0.75).

Conclusion

In this Norwegian primary care study, we found that the shift from warfarin to non-vitamin K antagonist oral anticoagulants was successful with 95% use in patients initiating OACs in 2018, and associated with fewer general practitioner visits. Persistence with OACs was high, particularly for apixaban. However, many patients eligible for treatment with OACs remained untreated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-022-01824-6.

Periprocedural management of patients receiving novel oral anticoagulants

Background

Non-vitamin K oral antagonists are being increasingly used. However, broad clinical experience with them is lacking.

Objectives

To review guidelines and evidence for the use of non-vitamin K oral antagonists in the periprocedural environment.

Results

Despite the clear advantages of vitamin K oral antagonists, their use can entail risks owing to the scarcity of reversal agents. Consensus has been reached about postoperative resumption, which is recommended at 24 hours and 48-72 hours, respectively, after low-risk and high-risk bleeding surgery. Bridging with heparin is recommended in patients with a high risk of thrombosis. Urgent interventions should ideally take place 24 hours after the last dose intake. Major discrepancies exist between the American and the European recommendations for neuraxial procedures. The American proposals recommend suspending the drug for five half-lives, whereas the European approaches suggest suspension of just two half-lives. Suggestions for perioperative discontinuation vary widely. Some authors recommend a longer time of resumption for patients with renal impairment. All agree that there should be an increase in the number of days of interruption in high-risk bleeding procedures versus low-risk bleeding procedures.

Conclusions

A diverse number of approaches have been suggested for perioperative management of novel oral antagonists. American recommendations tend to be more rigorous than those of Europe. A need for more studies that measure health outcomes after the use of these drugs would be indispensable.

Assessment of Oral Anticoagulant Use in Residents of Long-Term Care Homes: Evidence for Contemporary Suboptimal Use

Objective: To describe the quality of warfarin use in residents of long-term care facilities and investigate potential predictors oral anticoagulant use. Design: Retrospective chart review (August 2013 to September 2014). Setting: Thirteen long-term care (LTC) and assisted living facilities (ALF). Participants: Residents from LTC or ALF settings who ( a) received warfarin or direct-acting oral anticoagulants (DOACs) and ( b) residents with a valid indication for oral anticoagulants such as atrial fibrillation, venous thromboembolism, but were not receiving these drugs. Primary Outcome: Time in therapeutic international normalized ratio (INR) range (TTR). Results: A total of 563 residents (70% female) with an average age of 85 years were identified. Participants had an average of 7.5 comorbidities and 9 medications. A total of 391 (69%) residents with indications for OACs were receiving such medications. Indications were atrial fibrillation (63%), venous or pulmonary embolism (16%), cardiac valves (0.4%); 26% did not have documented indications. Warfarin and DOACs were prescribed for 213 (38%) and 178 (32%) respectively, and 172 (31%) received no OACs The TTR ranged from 56%-75% (mean 63%). The frequency of INR determinations ranged from every 7 to 20 days, (mean 13 days) with no apparent relationship between frequency of testing and TTR. Conclusion: The TTR was higher (63.8%) than literature average (50%), but remains suboptimal given expected benefits of TTRs >75% versus TTRs circa 60%. Documentation of indications for OACs needs improvement, and it is possible that OACs are underused. Further work is necessary to understand how OAC use may be optimized in these facilities.

Drug interactions with aprepitant or fosaprepitant: Review of literature and implications for clinical practice

Purpose Aprepitant and its parenteral formulation fosaprepitant are widely used for the prevention of chemotherapy-induced nausea and vomiting. Aprepitant exerts modest inhibitory effect on CYP3A4 and modest inductive effect on CYP2C9 substrates such as some antineoplastics and multiple other medications. This article is aimed to provide pharmacists and other healthcare professionals with an updated summary of drug-drug interactions of aprepitant/fosaprepitant and implications for clinical practice. Method We reviewed publications reporting drug-drug interactions between aprepitant/fosaprepitant and other medications. Results Coadministration of aprepitant with antineoplastics or opiods may result in significant elevations in the serum levels of the agents metabolized via CYP3A4, with the best documentation for cyclophosphamide, ifosfamide, erlotinib and oxycodone. These alterations did not translate into adverse outcomes and/or necessitate dosing adjustments. The levels of warfarin were significantly decreased by aprepitant requiring prolonged monitoring after discontinuation of aprepitant. Among direct oral anticoagulants, a theoretical interaction between aprepitant and rivaroxaban or apixaban exists. Interactions between aprepitant and quetiapine or diltiazem or sirolimus required dose reductions to avoid adverse outcomes. The intravenous route had a weaker inhibitory effect on CYP3A4 than the oral pathway. Conclusion The evidence on drug interactions of aprepitant with other medications is limited, and the impact on therapeutic outcomes remains to be determined. The intravenous regimen may be a preferred option. As utilization of aprepitant is expanding, practitioners and patients need to be educated about the potential for drug interactions and a need for careful monitoring of patients concurrently receiving aprepitant and CYP2C9 or CYP3A4 substrates, especially those with a narrow therapeutic window.