Prognostic Accuracy of N20 Somatosensory Potential in Patients With Acute Ischemic Stroke and Endovascular Thrombectomy

BACKGROUND: Somatosensory evoked potentials may add substantial prognostic value in patients with acute ischemic stroke and contribute to the selection of patients who may benefit from revascularization therapies beyond the accepted therapeutic time windows. We aimed to study the prognostic accuracy of the N20 somatosensory evoked potential component of the ischemic hemisphere in patients with anterior large-vessel occlusion undergoing endovascular thrombectomy (EVT). METHODS: Presence and amplitude of the N20 response were recorded before and after EVT. Its adjusted predictive value for functional independence (modified Rankin scale score, <= 2) at day 7 was analyzed by binary logistic regression adjusting by age, mean arterial blood pressure, National Institute of Health Stroke Scale, Alberta Stroke Program Early CT Score, and serum glucose. N20 predictive power was compared with that of clinical and imaging models by using receiver operating characteristics curve analysis. RESULTS: A total of 223 consecutive patients were studied (mean age, 70 years; median National Institute of Health Stroke Scale score, 18). Somatosensory evoked potential recordings identified the presence of N20 in 110 (49.3%), absence in 58 (26%), and not assessable in 55 patients due to radiofrequency interferences in the angiography room. Before EVT, N20 predicted functional independence with a sensitivity of 93% (95% CI, 78%-98%) and negative predictive value of 93% (95% CI, 80%98%). The adjusted odds ratio for functional independence was 9.9 (95% CI, 3.1-44.6). In receiver operating characteristics curve analysis, N20 amplitude showed a higher area under the curve than prehospital or in-hospital variables, including advanced imaging. Sensitivity increased to 100% (95% CI, 0.85-1) when N20 was present after EVT. CONCLUSION: Somatosensory evoked potential monitoring is a noninvasive and bedside technique that could help eligibility of patients with acute ischemic stroke for EVT and predict functional recovery.