Anticoagulation under-utilization in atrial fibrillation patients is responsible for a large proportion of strokes...

Atrial fibrillation (AF) is responsible for 30-50% of large strokes requiring endovascular thrombectomy (EVT). Anticoagulation (AC) underutilization is a common source of AF-related stroke. We compared antithrombotic medications among stroke patients with AF that did or did not undergo EVT to determine if AC underutilization disproportionately results in strokes requiring EVT, while quantifying the proportion of likely preventable thrombectomies.

This retrospective single-center cohort included consecutive patients admitted with acute ischemic stroke between 2016 and 2021. Patients were categorized based on the presence of AF, and pre-admission antithrombotic medications were compared between those who underwent EVT and those who didn't. The reason for not being on AC was abstracted from the medical record, and patients were categorized as either AC eligible or AC contraindicated.

Of 3092 acute ischemic stroke patients, 644 had a history of AF, 213 of whom underwent EVT. Patients who required EVT were more likely to not be taking any antithrombotics prior to admission (34% vs 24%, p=0.007) or have subtherapeutic INR on admission if taking warfarin (83% vs 63%; p = 0.046). Among the AF-EVT patients, 44% were taking AC, and only 31% were adequately anticoagulated. Only 8% of AF-EVT patients who were not on pre-admission AC had a clear contraindication, and 94% were ultimately discharged on AC.

Lack of antithrombotic therapy in AF patients disproportionately contributes to strokes requiring EVT. A small minority of AF patients have contraindications to AC, so adequate anticoagulation can prevent a remarkable number of strokes requiring EVT.