LAA ablation may raise risk for stroke, TIA

Aneesh S. Dhore

SAN FRANCISCO — Among patients who underwent catheter ablation for atrial fibrillation, those who had left atrial appendage ablation with or without isolation had elevated risk for ischemic stroke or transient ischemic attack, according to a single-center study presented at the Heart Rhythm Society Annual Scientific Sessions.

The researchers analyzed 350 patients (mean CHA₂DS₂-VASc score, 2.9) who underwent catheter ablation at MetroHealth Medical Center in Cleveland.

The primary endpoint was ischemic stroke or TIA. Mean follow-up was 5.3 years.

According to the researchers, 38% of patients had pulmonary vein isolation alone and the remainder had left atrial ablation beyond pulmonary vein isolation. Among the patients in the latter group, 43% had additional ablation on the posterior wall and 37% had additional ablation on the anterior wall.

Ohad Ziv

“We decided to do this study to look for the stroke risk associated with ablation beyond pulmonary vein isolation,” Aneesh S. Dhore, MBBS, MD, internal medicine resident at MetroHealth Medical Center, told Cardiology Today.

Among the cohort, 7.7% had LAA ablation without complete isolation and 5.9% had LAA isolation.

“Our experience is that there are a number of patients who desperately need to be in sinus rhythm and require not only pulmonary vein isolation but extensive left atrial ablation, which can include a number of different locations, such as the left atrial appendage in some situations,” Ohad Ziv, MD, director of electrophysiology at MetroHealth Medical Center, said in an interview. “We have seen cases where we have completely isolated the left atrial appendage, which is known to be a risk for clot formation, but also cases where we have to perform ablation in the left atrial appendage but don’t completely isolate it so that clot formation may be reduced. This was an attempt to look back at our data set to see what were the clinical outcomes and whether we can make any conclusions about the association with stroke with locations of ablation.”

Long-term anticoagulation was required in 66.9% of the entire cohort, 79% of those who had LAA ablation without complete isolation and 75% of those who had LAA isolation.

Dhore and colleagues determined the risk for ischemic stroke or TIA was 1.45 per 100 patient-years in the overall cohort, 4.34 per 100 patient-years in those who had LAA ablation without complete isolation and 3.82 per 100 patient-years in those who had LAA isolation.

After adjustment for anticoagulation use and CHA2DS2-VASc score, the independent predictors of increased stroke/TIA risk were LAA ablation without complete isolation (HR = 4.1; P = .003) and LAA isolation (HR = 5.8; P = .0002), according to the researchers. Dhore said in an interview that the stroke/TIA risk was increased in the two LAA groups independent of each other.

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“The risk seemed to be highest in patients with subtherapeutic anticoagulation,” he said. “The most common reason for these patients to be off anticoagulation was a low CHA₂DS₂-VASc score. It’s reasonable to assume that these patients who had left atrial appendage ablation with or without isolation should not be taken off anticoagulation, given the increased risk of ischemic events.”

Given that many patients from the LAA ablation groups had events despite anticoagulation, it raises the question “whether closing the left atrial appendage in some way soon after ablation might be wise,” Ziv said. “We have to be careful about making sweeping conclusions based on a retrospective study, but it plants the seed that if a patient requires left atrial appendage ablation or isolation, the LAA may have to be closed off down the road. Maybe closure needs to be thought of more often in these patients.” – by Erik Swain

Reference:

Dhore AS, et al. Abstract S-PO01-043. Presented at: Heart Rhythm Society Annual Scientific Sessions; May 8-11, 2019; San Francisco.

Disclosure: Dhore and Ziv report no relevant financial disclosures.