Canadian Cardiovascular Society advocate using new anticoagulants instead of warfarin


In updated guidelines, published in the Canadian Journal of Cardiology, the Canadian Cardiovascular Society (CCS) recommend that if oral anticoagulation therapy is indicated in patients with atrial fibrillation, most patients should receive one of the three new anticoagulants (once approved) rather than warfarin.

Allan Skanes, Arrhythmia Service, University of Western Ontario, London, Canada, and other members of the CCS Atrial Fibrillation (AF) Guidelines Committee wrote that since the publication of the last CCS atrial fibrillation guidelines at the beginning of 2011, three pivotal atrial fibrillation trials (ROCKET-AF, ARISTOTLE, and PALLAS) have shown “major implications” for the management of atrial fibrillation. They reported: “After reviewing these three trials and other emergent data, the CCS-AF Guidelines Committee has recommended important changes to the guidelines, specifically with respect to stroke prevention and rate and rhythm control.”

et al advised that patients with atrial fibrillation should be stratified for their risk of stroke using the CHADS2 scoring system and for their risk of bleeding using the HAS-BLED scoring system (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile INR, elderly (age over 65), and drugs/alcohol concomitantly). Patients who have a CHADS2 score of one or two, providing that their HAS-BLED score is acceptable, should receive oral anticoagulant therapy in the form of one of the new anticoagulants (once they are approved by Health Canada): dabigatran (Pradaxa, Boehringer Ingelheim), rivaroxaban (Xarelto, Bayer), and apixaban (Eliquis, Bristol-Myers Squibb, Pfizer).

According to the authors, their preference for the new anticoagulants is because they placed “relatively high value” on comparisons between these drugs and warfarin that showed them to have greater (dabigatran and apixaban) or similar efficacy (rivaroxaban), less intracranial bleeding, and be much similar to use. Skanes et al added that they put less value on some of warfarin’s benefits compared with the new drugs: the long clinical experience of using warfarin, the availability of an antidote, and the availability of a simple and standardised test for intensity of anticoagulant effect with warfarin. However, they wrote: “The preference for one of the new oral anticoagulants is less marked among patients already receiving warfarin with stable INR and no bleeding complications.”

For patients who have a CHADS2 score of 0, Skanes et al recommended further risk stratification by assessing their additional risk factors for stroke. They then advised that aspirin should be prescribed for patients who are female or who have vascular disease and oral anticoagulant therapy should be prescribed if patients are 65 or older or are female and have vascular disease. They also claimed aspirin is a “reasonable alternative” to oral anticoagulation therapy in some patients with a CHADS2 score of one or a CHADS2 score of 0 and aged 65 or older or are female and have vascular disease.

As well as updating its recommendations on anticoagulation therapy, as reported by Skanes et al, the CCS-AF Guideline Committee has also updated its recommendations on dronedarone (Multaq, Sanofi-Avenits) following the PALLAS study. It recommended that the drug should not be used in patients with permanent atrial fibrillation or a history of heart failure or reduced left ventricular ejection fraction (≤40), and should be used with caution with patients on digoxin.