LAUSR

Intravenous tissue plasminogen activator (tPA) thrombolysis remains the only proven pharmacological treatment for acute ischemic stroke [1]. A common clinical scenario is where a patient with atrial fibrillation (AF) on therapeutic anticoagulation presents with an acute ischemic stroke but thrombolysis is absolutely contraindicated due to hemorrhagic risk. Recently, dabigatran reversal with idarucizumab to facilitate thrombolysis in acute stroke patients on dabigatran has been proposed [2]. We present two patients, the first outside Europe, managed with this approach (Fig. 1). Case 1 A well 85-year-old presented with a severe dominant hemispheric stroke with a National Institutes of Health Stroke Scale (NIHSS) of 30 within 17 h of last dabigatran dose. Computed Tomography (CT) with angiogram and perfusion studies showed a tandem left Internal Carotid Artery and Middle Cerebral Artery (ICAMCA) occlusion with minimal established infarction and a large salvageable penumbra. Coagulation studies revealed isolated elevated Thrombin Time ([60 s, normal range \21 s) consistent with active dabigatran anticoagulation. 5 g of idarucizumab followed by tPA were administered at 167 min from symptoms onset. Mechanical thrombectomy was not possible as the patient arrived at an endovascularcapable centre outside the 6 h therapeutic time window after urgent inter-hospital transfer post-thrombolysis. Day1 CT showed a large hemispheric infarct with significant hemorrhage and mass effect. He progressively deteriorated and died on day 4. Case 2 A 46-year-old with AF presented with left hemiparesis (admission NIHSS 5) within 1 h of dabigatran intake. Multimodal CT revealed a right frontal ischemic penumbra without large vessel occlusion or stenosis. Idarucizumab and immediate tPA were administered at 178 min from onset with near-total resolution of symptoms (NIHSS 1). Follow-up CT confirmed a small area of right frontal infarction. At 30 h, he developed a severe contralateral left hemispheric stroke (NIHSS 18) secondary to a left M2 segment MCA thrombus which was too distal for endovascular clot retrieval. With the recent stroke contraindicating further thrombolysis, he was conservatively treated. Subsequent echocardiogram did not reveal intracardiac thromboses or valvular lesions. He remained aphasic and bed-bound for 3 months. Idarucizumab, a humanised monoclonal antibody fragment, was approved by the European Medicine Agency in 2015 as a reversal agent in patients on dabigatran requiring emergency procedures, or with life-threatening bleeding [3]. In-vitro and in vivo studies with healthy controls have shown immediate normalization of dabigatran-induced anticoagulation following idarucizumab without & Felix C. Ng [email protected]