DOACs may be better than warfarin at preventing thromboembolic events
In patients receiving cardioversion of atrial fibrillation (Afib), direct oral anticoagulants (DOACs) are better than warfarin for the short-term prevention of thromboembolic events, researchers showed in a meta-analysis.
At 30-day follow-up post cardioversion, the rates of combined stroke, systemic embolism, myocardial infarction, and cardiovascular death reached 0.42% among DOAC recipients and 0.98% of those getting warfarin (RR 0.42, 95% CI 0.21-0.86), according to investigators led by Dipak Kotecha, MD, PhD, of England's University of Birmingham Institute of Cardiovascular Sciences.
Stroke and systemic embolism together again gave DOACs the advantage (0.18% versus 0.55%, RR 0.33, 95% CI 0.12-0.91), the group reported in the Journal of the American College of Cardiology.
"We show the safety of DOAC therapy in patients with newly initiated oral anticoagulation, including those requiring rapid cardioversion with imaging guidance, and those undergoing cardioversion after 3 weeks of anticoagulation," said Kotecha and colleagues.
Given that thromboembolic events appear to be halved with DOAC use over warfarin, the latter should be restricted to patients who are not eligible for DOAC therapy -- namely those with mechanical heart valves, moderate to severe mitral stenosis, or severe chronic kidney disease, the authors commented.
The conclusion of the study is "consistent with overall clinical trial data and for many reasons, is not surprising," said Jim Cheung, MD, of Weill Cornell Medicine/New York-Presbyterian Hospital in New York City, who was not involved with the study. Nonetheless, he told MedPage Today, the study was "newsworthy" because the results are so reassuring.
The meta-analysis pooled data from three randomized trials (n=5,203), in which patients were required to use their assigned anticoagulant before and up to 42 days after cardioversion. Kotecha's group noted no heterogeneity between trials for their findings.
Trial participants were an average 65 years old, and 32% were women; more than 70% had CHA2DS2-VASc scores of 2 or higher.
DOAC and warfarin use resulted in similar odds of all-cause mortality (RR 0.58, 95% CI 0.22-1.52) and major bleeding (RR 0.61, 95% CI 0.28-1.34).
"More than 90% of patients underwent electrical cardioversion, and although there is no a priori reason to suspect a difference with pharmacological cardioversion, data in this context are scarce," the investigators acknowledged.
They added that another limitation to the retrospective study was that none of the trials included were individually powered for clinical outcomes.
"Further studies are needed to address the remaining gaps in evidence, including the identification of those at risk of adverse events despite oral anticoagulation, and the optimal timing of both anticoagulant agents and cardioversion to minimize stroke risk," Kotecha's group urged.
Kotecha reported funding from a National Institute for Health Research Career Development Fellowship.
Several of his co-authors reported various ties to industry.
Journal of the American College of Cardiology
Source Reference: Kotecha D, et al "Direct oral anticoagulants halve thromboembolic events after cardioversion of AF compared with warfarin" J Am Coll Cardiol 2018; DOI: 10.1161/j.jacc.2018.07.083.
Read the original article on Medpage Today:Meta-Analysis: Oral Anticoagulant Choice Matters in Afib Cardioversion