Stopping Anticoagulation After Ablation Increases Stroke Risk in First 3 Months

May 21, 2015

BOSTON, MA — Patients with atrial fibrillation (AF) frequently stop oral anticoagulation therapy following radiofrequency catheter ablation despite an increased risk for stroke, transient ischemic attack (TIA), or systemic embolism in the first 3 months after the procedure, according to the results of a new analysis[1].

In an analysis of 6886 patients undergoing catheter ablation of AF, just 60.5% of patients continued to take oral anticoagulants at 3 months and just 62.5% of patients considered high risk for stroke—those with a CHA2DS2-Vasc score >2—were on oral anticoagulant therapy at 90 days. For those who stopped oral anticoagulation at any time during the initial 3-month period following the ablation procedure, the risk of stroke was eightfold greater (hazard ratio 8.06; P<0.05) when compared with patients who remained treated with oral anticoagulation during the same time period.

"Everybody should continue to take an oral anticoagulant in the first few months after an ablation," lead investigator Dr Peter Noseworthy (Mayo Clinic, Rochester, MN) told heartwire from Medscape. "If the patient is at a lower risk for stroke, the type of patient that might not need to be anticoagulated to begin with, then the medication can be stopped after 3 months."

Everybody else should remain on oral anticoagulation for at least 12 months after the ablation, he added. At that point, physicians can reassess a patient's risk factors to determine whether the oral anticoagulation should continue.

Noseworthy, who presented the results of the analysis here at the Heart Rhythm Society 2015 Scientific Sessions, said patients as well as physicians will frequently pursue ablation to eliminate AF and its symptoms. However, they should not assume that eliminating AF will also rid the patient of the risk for stroke.

"Patients may have other risk factors for stroke, and these risk factors don't go away simply because the atrial fibrillation is treated with catheter ablation," said Noseworthy. Following an ablation, many patients may stop taking the oral anticoagulants because they no longer have any symptoms associated with the arrhythmia, he added.

The clinical guidelines for the management of patients with atrial fibrillation state that the procedure should not be performed to obviate the use of oral anticoagulants. Noseworthy told heartwire he often consults on cases where the patients and physician want to have an ablation performed because the patient wishes simply to get off the lifelong medication. Ablation, he said, is reserved for improving a patient's quality of life (by reducing symptoms).

In their analysis, which included patients within a large administrative claims database who underwent ablation for AF between 2005 and 2014, the rate of oral anticoagulation discontinuation was greatest among patients at low risk for stroke (CHA2DS2-Vasc score of 0 or 1), but the rate of discontinuation was also high in patients with higher CHA2DS2-Vasc scores.

While all patients were at an increased risk of stroke/TIA/systemic embolism in the first 3 months if they stopped oral anticoagulation, only those with a CHA2DS2-Vasc score >2 were at an increased risk when stopping oral anticoagulation beyond 90 days. These high-risk patients had a 2.5-fold increased risk of stroke/TIA/systemic embolism when stopping oral anticoagulation after 3 months compared with those who did not stop the medication (hazard ratio 2.48; P<0.05).

In the past, Noseworthy said, anticoagulation with warfarin was stopped prior to the ablation—and patients bridged with low-molecular-weight heparin—but data suggest this protocol is associated with an increased risk of complications compared with an uninterrupted anticoagulation approach. As a result, more and more physicians are performing ablations while the patient is still anticoagulated. There are fewer data showing the safety of continuing with the newer oral anticoagulants through the ablation procedure, he noted.

In the present analysis, Noseworthy said the data suggest the newer oral anticoagulants, among them edoxaban (Savaysa, Daiichi-Sankyo), rivaroxaban (Xarelto, Bayer), apixaban (Eliquis, Bristol Myers-Squibb), and dabigatran (Pradaxa, Boehringer Ingelheim), are increasingly being used by physicians. In 2014, 69.8% of patients prescribed an oral anticoagulant in the postablation phase were treated with a newer oral anticoagulant, he said.

Noseworthy reports no relevant financial relationships.

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