Stopping Rivaroxaban and Warfarin Temporarily in AF Patients Yields Similar Risks

March 10, 2013

SAN FRANCISCO, California — Patients with atrial fibrillation (AF) at moderate to high risk of stroke who briefly stop oral anticoagulation with rivaroxaban (Xarelto, Bayer/Janssen) have similar risks of clinical events as those treated with warfarin. The temporary interruption resulted in very few strokes or thrombotic events and a low rate of bleeding in both rivaroxaban- and warfarin-treated patients.

"Patients with AF taking oral anticoagulants always end up taking a contraindicated medication or have a surgical procedure that results in a short, temporary interruption of oral anticoagulation therapy," Dr Matthew Sherwood (Duke Clinical Research Institute, Durham, NC) told heartwire . "These patients are at moderate to high risk for having strokes, and that's why they're on oral anticoagulation, so any interruption may expose them to risk, specifically the risk of thrombotic events. That's been borne out in patients treated with warfarin, and we expected the same with the newer anticoagulants."

Presenting the results here today at the American College of Cardiology 2013 Scientific Sessions, Sherwood and colleagues analyzed data from the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibitor Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET-AF) study. In that trial, investigators showed rivaroxaban was noninferior to warfarin in terms of stroke and non–central-nervous-system embolism. On this basis, the drug was approved by the US Food and Drug Administration for the prevention of stroke and systemic embolism in nonvalvular AF.

To heartwire , Sherwood said that ROCKET-AF patients are considered at moderate to high risk of stroke, with an average CHADS2 score of 3.4. In the present analysis, a temporary interruption was defined as three days or more, and investigators assessed the at-risk period of three days after the drug was stopped until three days after the drug was restarted. Of the 14 236 study patients, 2165 receiving rivaroxaban and 2528 receiving warfarin stopped treatment at some point during the trial for an average duration of five days. The most common reason for stopping treatment was surgery or an invasive procedure (39.7%), while one-quarter of patients stopped treatment because of a nonbleeding adverse event. Another 13.2% of patients stopped treatment because of bleeding, and 18.1% of patients erroneously stopped taking their medication for a period of time.

In terms of clinical outcomes, investigators observed no difference in the rate of clinical events in patients treated with rivaroxaban or warfarin who stopped therapy. "If the patients are at high risk, then all of them are at high risk," said Sherwood. "It doesn't matter what their therapy is."

Clinical Outcomes Among Patients With Temporary Interruption of Therapy

Clinical event Rivaroxaban, n=2155 (%) Warfarin, n=2528 (%) p
Stroke/noncentral nervous system embolism 0.2 0.2 0.8
Death 0 0.04 NA
MI 0.2 0.1 0.3
Major/nonmajor clinically relevant bleeding 1.5 1.5 0.9
Major bleeding 0.7 0.7 0.9

To heartwire , Sherwood said that in these patients--especially those with a high CHADS2 score--temporary interruptions should be minimized if possible, and if patients stop treatment, the interruption should be as brief as possible. Clinical guidelines recommend bridging therapy in high-risk patients--those with a CHADS2 score >3. In ROCKET-AF, however, just 7.3% of patients had bridging anticoagulation therapy. Of those who did, the vast majority (86%) were bridged with low-molecular-weight heparin.

"If the patient is at moderate risk for stroke, the guidelines say that we should undertake [bridging] on a case-by-case basis," said Sherwood. "Would the risk of bleeding outweigh the benefit they would get with bridging anticoagulation for the prevention of stroke?"

A National Heart, Lung, and Blood Institute-funded study of bridging patients on long-term anticoagulation is currently under way. More than 3500 patients are expected to be enrolled in study, which will assess the risks and benefits of bridging therapy in patients treated with warfarin who must stop because of surgery. However, this study won't answer how to best bridge patients treated with the new anticoagulants--and more studies for this are needed, said Sherwood.

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