International guidelines recommend direct oral anticoagulants (DOACs) over warfarin to prevent stroke for most patients with atrial fibrillation (AF). However, a substantial portion of patients in Canada, who would benefit from anticoagulation, do not receive it adequately or at all.

Experts review the evidence for the use of DOACs in the  Canadian Journal of Cardiology , discuss reasons for the large gap between guidelines and clinical practice, including policy and funding barriers, and propose strategies for the future.

AF affects about 350,000 patients in Canada and about 10 times as many in the United States. AF is the most common heart rhythm disorder in the world with major impact on public health, especially due to increased risk of stroke.

Anticoagulation drug therapy

Stroke due to AF still comprises up to 15% of all stroke cases, and disabling stroke remains disproportionately more common in patients with AF than in patients without. Although anticoagulation drug therapy is an effective treatment, its use in Canada is slow to reflect evidence-based guidelines.

"Despite the evidence and unanimity of clinical practice guidelines, these drugs go unprescribed for many, perhaps even most, patients," lead lead author Chris S. Simpson, MD, of the Queen's University-Kingston Health Science Center, Kingston, ON , Canada. "The result is that many preventable strokes are still happening every day in Canada."

DOAC indications for stroke risk reduction were initially incorporated into the Canadian Cardiovascular Society (CCS) guidelines in 2010. This recommendation has been included in the guidelines of other major societies such as the European Society of Cardiology (ESC) and the American Heart Association. AHA).

The CCS then recommended a preference for damage over warfarin because of dabigatran's greater efficacy and safetyThe authors call attention to patient-physician factors in DOAC decision-making and identify barriers to using DOACs in Canada:

1. Perceived cost is a major, if not the main barrier to prescribing DOACs.

2. High initial cost due to temporary gap between guidelines recommendation and funding approval.

3. Antiquated perception among physicians that aspirin is a suitable alternative to DOAC, lack of experience in managing DOAC, and fear of moving disorders.

4. Mandatory trial with warfarin in some Canadian provinces.

5. Lack of experience and limited availability of specific reversal agents to manage bleeding.

6. Lack of patient awareness of stroke risk in AF and information about DOAC usage and access.

7. Concurrent release of multiple DOACs and patient-targeted information on DOAC profiles and dosing schedules may delay patient-physician decision to start DOAC.

8. Limited use coverage that denies patients who are eligible based on guidelines, forcing suboptimal therapy or paying out of pocket if not covered by private insurance.

9. Physicians required to justify clinical decision in providing evidence-based guideline-recommended treatment.

10. Physicians' lack of guideline awareness contributing to reduced confidence in starting DOAC therapy. Guideline awareness may be part of the reason why cardiologists (more than other specialists) are more likely to start DOAC treatment.