Ultra-Early Functional Improvement After Stroke Thrombectomy - Predictors and Implications

Neurocritical care is routinely provided to patients post-endovascular thrombectomy (EVT) for anterior large vessel occlusion strokes. We aim to study the relationship between immediate improvement in National Institutes of Health Stroke Scale (NIHSS) score on outcomes post-EVT and potential implications for postprocedural care.

We performed a retrospective review of anterior circulation large vessel occlusion (internal carotid/proximal middle cerebral artery) patients undergoing EVT. Demographic, clinical, and imaging information was analyzed. Ultra-early functional improvement (UEFI) was defined as NIHSS score <6 within 30 minutes of successful recanalization. We analyzed the incidence and predictors of UEFI, and explored reasons for neurological decline post-UEFI.

Of the 343 anterior large vessel occlusion patients undergoing EVT, mean age was 71 ± 15 and 46% were male. Mean NIHSS was 17 ± 6 and Time Last Known Well (TLKW) to arrival was 9 ± 11 hours. UEFI was observed in 23% (79/343) of patients. Independent predictors of UEFI included lower pretreatment NIHSS, favorable Alberta Stroke Program Early CT Score (ASPECTS), and lower admission systolic blood pressure. Rates of 90-day-modified Rankin scale 0-2 were higher (71% versus 33%, P<0.01) and the rate of mortality (8% versus 28%, P<0.01) was lower in the UEFI group compared with the non-UEFI group. Amongst patients with UEFI, 1.3% (1/79) experienced increase in NIHSS by ≥4 points within 24 hours of EVT. This patient received thrombolysis, achieved TICI-2B recanalization, and follow-up neuroimaging revealed a parenchymal hemorrhage and an infarct volume of 44 mL. None of the patients with UEFI required continuous antihypertensive infusions.

Approximately 1-in-4 of anterior large vessel occlusion stroke patients undergoing EVT have an NIHSS score of <6 within 30 minutes of successful recanalization. Only 1% of them experience significant decline in neurological status within 24 hours of the procedure with the majority achieving functional independence at 90 days. The need for advanced neurocritical care should be reevaluated in these patients.