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Stroke Risk in AF Patients Undergoing Electrical Isolation of LA Appendage
Study Questions:
What is the long-term thromboembolic risk of stroke and transient ischemic attack (TIA) in atrial fibrillation (AF) patients who have undergone left atrial appendage (LAA) electrical isolation?
Methods:
This is a prospective study of consecutive AF patients who underwent LAA electrical isolation at a single center. Patients with AF recurrence within 6 months of the isolation procedure were excluded. Each patient underwent 6-month transesophageal echocardiography (TEE) and was classified into one of two groups. Patients in Group 1 had normal LAA function: preserved LAA velocity, contractility, and consistent A waves. These patients had oral anticoagulation (OAC) discontinued regardless of CHA2DS2-VASc score. Patients in Group 2 had abnormal LAA function: impaired velocity, contractility, or A-wave consistency. These patients were asked to continue OAC indefinitely. After LAA electrical isolation, all patients had: 1) 5 months of event recorder monitoring; 2) electrocardiograms at 1, 3, 6, and 12 months, and thereafter biannually; and 3) 7-day Holter monitoring at 1, 6, and 12 months. Group 2 patients also underwent a 12-month TEE to assess for LAA thrombus. The authors do not describe how the primary endpoint, incident TIA/stroke, was defined, identified, or adjudicated.
Results:
Of 2,726 patients who underwent LAA electrical isolation, 1,854 (68%) were in sinus rhythm at the 6-month follow-up and were included in this study. Of these, 336 (18%) patients were included in Group 1 and 1,518 (82%) patients were included in Group 2. After a median follow-up of 2.3 years (interquartile range, 1.5-4.2 years), no patients in Group 1 had an incident stroke/TIA, whereas 90 (5.9%) Group 2 patients had TIA/stroke. In Group 2, the incidence of stroke/TIA for patients on OAC was 1.7% (18 of 1,086), and off OAC was 16.7% (72 of 432); p < 0.001.
Conclusions:
The goal of LAA electrical isolation is to reduce the risk of arrhythmia initiation from this structure. In this prospective study, the incidence of TIA/stroke was significantly higher among patients with abnormal LAA function than those with normal LAA function. Among patients with abnormal LAA function, the incidence of TIA/stroke was higher in those who discontinued OAC than in those who did not. The authors contend that if LAA electrical isolation results in impaired LAA function at 6 months, patients should be continued on OAC, whereas if LAA function is normal, OAC may not be needed.
Perspective:
Remarkably, the study authors did not describe how incident TIA/stroke (their primary endpoint) was defined nor identified in their methods, making this study’s results difficult to accept at face value. Surveillance for and adjudication of TIA/stroke may have differed between those with normal LAA function versus those without, and between those on anticoagulation versus those not, potentially biasing these results. Given this significant limitation, this study’s results should not be used to change patient management.
Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Noninvasive Imaging, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Echocardiography/Ultrasound
Keywords: Anticoagulants, Arrhythmias, Cardiac, Atrial Appendage, Atrial Fibrillation, Catheter Ablation, Echocardiography, Transesophageal, Electrocardiography, Electrocardiography, Ambulatory, Ischemic Attack, Transient, Risk, Stroke, Thrombosis, Vascular Diseases
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