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Direct oral anticoagulants (DOACs) bested aspirin for cerebrovascular prevention after left ventricular (LV) arrhythmia ablation, the STROKE-VT trial showed.

The anticoagulants eliminated stroke compared with a 6.5% rate with aspirin through 30 days (P<0.001), reported Dhanunjaya Lakkireddy, MD, of the Kansas City Heart Rhythm Institute, at the hybrid Heart Rhythm Society meeting, being held online and in Boston.

Transient ischemic attacks (TIAs) occurred in 4.9% of the DOAC group compared with 18% on aspirin (P<0.001) in the study, which was simultaneously published in .

In addition, there were fewer subclinical MRI-detected brain lesions with a DOAC at both 24 hours (12% vs 23%, P=0.03) and 30 days (6.5% vs 18%, P=0.006), although the neurocognitive implications of these asymptomatic events are debated.

Bleeding complications and in-hospital mortality were similar between groups.

The results were "striking" for an intractable problem that has defied decades of study, said discussant Mina Chung, MD, of the Cleveland Clinic in Ohio, at the late-breaking clinical trial session.

"I think this could become the standard of care for managing anticoagulation for VT [ventricular tachycardia] and PVC [premature ventricular contractions] left-sided ablations," she said.

The trial is the first ever prospective analysis of thromboembolic prevention strategies in this setting, noted Jeffrey Winterfield, MD, of the Medical University of South Carolina in Charleston, and Usha Tedrow, MD, of Brigham and Women's Hospital in Boston, in an accompanying .

These findings are line with those on left atrial ablation, for which guidelines recommend oral anticoagulation -- rather than single or dual antiplatelet therapy -- for heading off systemic thromboembolism, Lakkireddy's group pointed out.

While there are a number of reasons why the evidence has been slower to accrue for ventricular tachycardia catheter ablation than for atrial fibrillation ablation, the STROKE-VT trial is a good step toward data-driven standards, the editorialists noted.

According to , there is a class IIa recommendation for antiplatelet agents for "less extensive" ablation and class IIb recommendations for any oral anticoagulation after "extensive" ablation.

Those subjective guides for anticoagulation use have led to variable practice, but the STROKE-VT findings could change the guidelines and unify practice, Christine Albert, MD, MPH, of Cedars-Sinai Medical Center in Los Angeles and immediate past president of HRS, said at a press conference.

Getting better answers in VT is important, Lakkireddy's group said: "We believe that the burden of systemic embolism may be significantly higher in VT patients, where a larger area of myocardium is ablated, combined with reduced LV function, myocardial stunning, prolonged periods of hypoperfusion and plaque shift with retrograde-aortic approach."

Their multicenter trial included 246 patients being treated with LV catheter ablation mainly for VT from ischemic or nonischemic cardiomyopathy; 25% were treated for premature ventricular contractions. Idiopathic ventricular arrhythmias were included in the study population.

Participants randomized to aspirin post-ablation received 81 mg daily without a loading dose or, for those on an antiplatelet before entering the trial, returned to their pre-existing regimen. Without a loading dose, "perhaps the delay in achieving the therapeutic effects with de novo ASA [aspirin] initiation could have increased the risk of events as noted in the study," Lakkireddy's group wrote.

The study drug started 3 hours after establishing hemostasis, which "may be a bit earlier than routine practice, but appears to have been safe," Winterfield and Tedrow noted.

The strongest predictor for both cerebrovascular accidents and asymptomatic embolic lesions on multivariate logistic regression analysis was aspirin use post-procedure. Prolonged radiofrequency ablation time, a retrograde aortic approach, and reduced ejection fraction were also associated with higher risk of stroke and TIA.

The retrograde aortic approach findings were possibly even more important than the finding that oral anticoagulation was safe in this population, suggested session study discussant Paul Friedman, MD, of the Mayo Clinic in Rochester, Minnesota.

"It's not hard to imagine that a catheter rubbing along the length of the aorta, where they may be atherosclerotic lesions, could result in many of the findings that were observed," he said.

Lakkireddy agreed that there's a message for clinical practice that the retrograde approach should be avoided whenever possible. For those patients who require it, use long sheaths and make sure to thoroughly anticoagulate them, he recommended.

The 8.9% crossover from aspirin to DOAC after a primary event wasn't notable compared with other trials, the researchers said.

The protocol of brain MRI done within 24 hours of the ablation procedure and at 30 days along with weekly evaluation for symptomatic stroke or TIA likely picked up many more events than seen with routine follow-up, they noted.