Prognostic accuracy of N20 somatosensory potential in patients with acute ischemic stroke and endovascular thrombectomy

Background Somatosensory evoked potentials (SEP) may add substantial prognostic value in patients with acute ischemic stroke (AIS) and contribute to the selection of patients that may benefit from revascularization therapies beyond the accepted therapeutic time windows. We aimed to study the prognostic accuracy of N20 SEP 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 analysed by binary logistic regression adjusting by age, mean arterial blood pressure, NIHSS, ASPECTS score and serum glucose. N20 predictive power was compared with that of clinical and imaging models by using Receiving Operating Characteristics Curve (ROC) analysis. Results: 223 consecutive patients were studied (mean age, 70y; median NIHSS, 18). SEP recordings identified 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. Prior to EVT, N20 predicted functional independence with a sensitivity of 93% (95%CI, 78-98%) and negative predictive value of 93% (80-98%). The adjusted odds ratio for functional independence was 9.9 (95%CI, 3.1-44.6). In ROC analysis, N20 amplitude showed a higher area under the curve than models using pre-hospital or in-hospital variables, including advanced imaging. Sensitivity increased to 100% (95% CI, 0.85-1) at the end of EVT. Conclusions: SEP monitoring is a non-invasive and bedside technique that could help eligibility of AIS patients for EVT and predict functional recovery.
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