Abstract WP368: Thromboelastography for Risk Stratification in Embolic Stroke of Undetermined Source: A Pilot Study

Background: Embolic Stroke of Undetermined Source (ESUS) has diverse potential mechanisms, including occult atrial fibrillation (AF) and hypercoagulable states. Thromboelastography (TEG) is a viscoelastic assay that provides real-time assessment of coagulation and may identify hypercoagulability in stroke patients. This study evaluated the potential role of TEG in detecting hypercoagulable state in ESUS Methods: The study was conducted at 2 academic medical centers in the United States. Adult ESUS patients underwent TEG as part of outpatient post-discharge evaluation. Hypercoagulability was defined using TEG by any of the following: shortened clot initiation time (R time <4.6 min), elevated citrated functional fibrinogen maximum amplitude (CFF MA >32 mm),or elevated citrated rapid TEG maximum amplitude (CRT MA >70 mm). All patients were on antiplatelet (AP) therapy prior to testing and were followed through in-person or virtual visits. The primary objective was to assess TEG and its association with recurrent stroke or death Results: Of 64 patients (median age 61; 52% female), 23% had a patent foramen ovale, 20% with history of or active malignancy, 3% COVID-19 positive test, and 7.8% developed AF during a median 9-month (IQR 6-12) follow-up. Median time from stroke to TEG testing was 2 months (IQR 1-3). Abnormal TEG profiles were detected in 21 patients (33%). Recurrent strokes and deaths each occurred in 3 (4.6%) patients with two patients suffering both stroke and death; all patients with stroke or death had abnormal TEG. All recurrent stroke events occurred in patients with elevated both CFF MA and CRT MA, including two who additionally had shortened R-time. No recurrent strokes occurred in patients with <2 abnormal measures (n=43). In 7 patients who were on anticoagulation therapy after an abnormal TEG, two (29%) had recurrent stroke; in 14 patients who were on AP therapy after an abnormal TEG,1 (7%) had recurrent stroke. Patients with abnormal TEG were more likely to have a history of or active malignancy than those with normal TEG (8/21 vs 5/43 ,p=0.02). None of the 5 malignancy patients with normal TEG had a recurrence Conclusion: Normal TEG was associated with absence of recurrent stroke, whereas abnormal profiles, especially multiple abnormalities, identified patients at higher risk and were associated with history of or active malignancy. These hypothesis-generating findings support further evaluation of TEG-guided antithrombotic strategies in ESUS