乌鸦传媒

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BARCELONA -- Cardiologists who have switched atrial fibrillation patients awaiting elective cardioversion to a novel oral anticoagulant (NOAC) such as rivaroxaban (Xarelto) may find reassurance in the results of , which found that 20 mg of rivaroxaban was as safe as warfarin in that setting.

Patients randomized to rivaroxaban were half as likely to have a stroke or a heart attack during cardioversion than warfarin patients, 0.51% versus 1.02% (relative risk 0.50, 95% CI 0.15-1.73). Rivaroxaban patients were also less likely to develop major bleeding, 0.61% versus 0.80% (RR 0.76, 95% CI 0.21-2.67) -- but as study leader , of the University of Milan, pointed out, "there were very few events in both arms and the trial was not powered to produce a statistically significant difference."

In the rivaroxaban group, four patients died versus two patients in the control group, but again the difference was not statistically significant.

Cappato reported the results of X-VeRT (eXplore the efficacy and safety of once-daily oral riVaroxaban for the prevention of caRdiovascular events in patients with nonvalvular aTrial fibrillation scheduled for cardioversion) at the final Hot Line session of the European Society of Cardiology annual meeting.

The study was simultaneously published online in the .

The trial recruited patients from 141 centers and 16 countries, who were scheduled to undergo either electrical (97.6%) or pharmacological (2.4%) cardioversion.

Patients were randomized to rivaroxaban 20 mg (15 mg if creatine clearance was impaired) or to dose-adjusted warfarin in a 2:1 ratio; thus, 978 patients were assigned to the rivaroxaban arm versus 492 patients in the warfarin arm.

Two cardioversion strategies were used based on physician choice: early, which was 1 to 5 days after randomization, or delayed, 3 to 8 weeks after randomization. Slightly more than half of the patients (58%) were assigned to early cardioversion.

Although there was no significant difference in time to cardioversion between rivaroxaban and warfarin-treated patients in the early cardioversion group, there was a significant time difference among patients who received delayed cardioversion. Rivaroxaban therapy, Cappato said, was associated with shorter time to cardioversion: median time of 22 days versus 30 days, P<0.001.

Current guidelines recommend anticoagulation for a minimum of 3 weeks before cardioversion and 4 weeks after cardioversion. Use of heparin plus transesophageal echocardiography to rule out left atrial thrombus can speed time to cardioversion.

In X-VeRT, anticoagulation was confirmed by pill counts for rivaroxaban patients and by INR for warfarin patients.

In the delayed cardioversion group, 77% of the rivaroxaban patients were successfully cardioverted as scheduled versus 36.3% in the warfarin group.

director of the New England Cardiac Arrhythmia Center and a professor at Tufts Medical Center in Boston, told 乌鸦传媒 that the results from X-VeRT were reassuring "because we don't see any immediate signal of harm and no increase in bleeding."

, of the University Medical Center of Nijmegen in the Netherlands, noted that X-VeRT was the first prospective, randomized trial of cardioversion with a NOAC and that "there was no difference, but the NOAC was at least as safe as warfarin."

Verheugt, who c0-chaired the Hot Line press briefing on X-VeRT, said that lack of a difference "is reassuring."

Cappato agreed with that assessment, adding that "many people are already switching to NOACs without evidence."

a past president of the American College of Cardiology, told 乌鸦传媒 that X-VeRT offers useful information that can influence practice, especially since it appears that with a "NOAC we can cardiovert the patient more quickly, without waiting 30 days as we do with warfarin."