Common Questions in Anticoagulation Management in Atrial Fibrillation

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Key points

  • Until recently, the only oral options for chronic anticoagulation were the vitamin K antagonists (VKAs), but their various limitations promoted the development of novel oral anticoagulants (NOACs), with a specific target.

  • To assess the probability of good or poor anticoagulation control while taking VKAs, a new score (the SAMe-TT2R2 score) has been developed to help identify patients who are likely to be in the therapeutic range for a long time.

  • Not every patient is suitable for NOACs, including

Who should switch?

Patients with difficulties in achieving a stable anticoagulation will benefit from NOACs. In fact, patients with TTR less than 55% or who are treated with interfering drugs proven to cause INR fluctuations might benefit from switching to NOACs.8 However, such patients should also be carefully considered before switching. Indeed, drug compliance and treatment adherence needs to be assured by focusing on patients’ education so they understand which factors under their control might affect

Previous Gastrointestinal Bleeding

A recent meta-analysis12, 13 comparing main trials on dabigatran, rivaroxaban, and apixaban suggests that new oral anticoagulants lower the risk for intracranial bleeding; the data on overall risk of bleeding were inconclusive. In contrast, it suggests an increased risk for gastrointestinal bleeding associated with the new agents (especially dabigatran and apixaban) probably was related to their local absorption. Therefore, patients with previous gastrointestinal bleeding should perhaps stay

Scheduled Surgery

Some invasive procedures might require the temporary discontinuation of anticoagulation. Both surgery and patient characteristics (eg, age, kidney function, concomitant medication) need to be taken into account when discontinuing and restarting NOACs. Bridging therapy is considered in patients at high risk of thromboembolism. However, NOACs allow a predictable waning of the anticoagulation effect, thus short-term cessation can be accurately timed (Table 2).10, 21

Urgent Surgery

NOACs should be discontinued,

How to assess an anti-coagulation effect?

Unlike warfarin, knowing the exact time lapse between drug intake and coagulation assessment is mandatory because the impact on a coagulation test varies roughly with the peak level.10, 22 Moreover, the high variability in reagent sensitivity leads to a lack of standard measures to quantify the effect, which depends on the specific coagulometer and reagent used in each laboratory23; although assay-specific calibrators and calibration curves should be made at each center.10

NOACs prolong some

How to deal with systemic thrombolysis for ischemic stroke or ST elevation MI?

AF-complicating ACS (with and without ST elevation) and vice versa is not only relatively frequent, but also associated with significantly higher mortality rates. Moreover, AF patients with ACS receive fewer evidence-based therapies or procedures, and antithrombotic cocktails vary considerably.10 The anticoagulation state or intensity is difficult to interpret through the usual tests: INR, TT, and APTT. This is especially so if other antithrombotics have been administered (eg, bivalirudin,

How to deal with adherence problems?

Nonadherence in patients older than 65 years, with chronic conditions such as AF is estimated to range from 40% to 75%.8 Once-daily regimens are usually associated with greater adherence than are twice daily regimens.10 Patients with poor compliance or low treatment adherence may not achieve their underprotection against stroke because the anticoagulant effect of NOACs lasts only for 12 to 24 hours after intake.9 Therefore, patient education (as well as family member involvement) is extremely

Follow-up

The follow-up of patients taking NOACs is vital, and should be carefully specified and communicated among all involved healthcare staff. Indeed, all anticoagulants have some drug interactions so new prescriptions should be carefully considered. Moreover, routine follow-up increases patient adherence, which is crucial. Therefore, compliance should be periodically checked. Renal function should be assessed frequently because as patients become older some renal impairment may appear. The European

Elderly

OAC underuse is particularly pronounced in elderly patients (>80 years). The elderly progressively own certain particular characteristics that make data extrapolation more difficult; therefore, they are often excluded from clinical trials.

The elderly are more prone to achieve high INR levels with low doses of VKA and have a greater likelihood of labile INRs. Given the lower rates of serious bleeding, some physicians may prescribe NOACs to the elderly.28 Nonetheless, NOACs should be used as they

How to manage bleeding?

Bleeding remains the main complication of OACs and the fear of bleeding among physicians has long led to a lack of prescription and reduced uptake particularly when treating patients who may otherwise benefit greatly from its use.31, 32, 33, 34 Although not conclusive, NOACs might have a generally safer profile, with some reduction in all-bleeding rates. However, as NOACs prescriptions increase clinicians need to be prepared to deal with bleeding complications.

While bleeding events are a known

Summary

The widespread use of NOACs has highlighted important management questions. Bleeding remains the main complication of all OACs. Although clinical trials of stroke prevention in AF have shown a significant reduction in hemorrhagic stroke and intracranial bleeding with the NOACs, as prescriptions increase clinicians need to be prepared to manage bleeding complications if they occur. More guidance on how to manage patients who require urgent surgery or systemic thrombolysis for ischemic stroke or

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    The authors have nothing to disclose.

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