Middle Cerebral Artery Occlusion: M1 Occlusion, Low NIHSS Score, and Good Collaterals, Treated with Bridging Therapy with Excellent Results: Is Thrombectomy Necessary?

Recent trials have established that endovascular thrombectomy (EVT) is the standard of care for patients with acute ischemic stroke (AIS) with large vessel occlusion (LVO) in the anterior circulation. However, these trials only included patients with a National Institute of Health Stroke Scale (NIHSS) score 6. The benefit of mechanical thrombectomy (MT) in patients with AIS due to LVO and an NIHSS <6 remains uncertain. Many AIS patients with LVO presenting with NIHSS <6 can end up with disabling strokes, and there is no current consensus on how best to manage these patients. A mild neurological deficit may not justify an EVT based on an individual riskbenefit ratio. While these patients are perceived to have good outcomes irrespective of intervention, many may worsen and eventually have poor outcomes. Furthermore, the belief that patients with mild strokes should be protected from the complications of invasive procedures dissuades clinicians from pursuing aggressive interventions such as EVT. We present the case of an 81-year-old man with a history of multiple vascular risk factors who was admitted due to a left hemispheric stroke with a baseline NIHSS of 5. The patient was last seen without symptoms 1.5 h before admission. Noncontrast cranial CT was unremarkable, with baseline Alberta Stroke Program Early CT Score (ASPECTS) 10. CT angiography (CTA) showed a cutoff in the M1 segment of the left MCA and retrograde filling of the distal MCA branches. CTP images revealed a sizeable ischemic penumbra with a volume of 111 ml. The patient received recombinant tissue plasminogen activator (rtPA) and then underwent successful endovascular revascularization of the left M1 occlusion in an uneventful procedure. Follow-up cranial CT did not show any new lesions, and his ASPECTS remained 10. Paroxysms of atrial fibrillation were registered during admission, and apixaban 2 x 5 mg PO daily was started. The patient was discharged with NIHSS 0 and an mRS of 0. This case supports previous observations regarding the safety and efficacy of mechanical thrombectomy in patients with LVOandmild neurological deficit. The necessity and feasibility of endovascular treatment in this cohort of patients is the main topic of this chapter.