Predictors of spontaneous and early recanalization in stroke patients eligible for endovascular treatment

INTRODUCTION: Large vessel occlusion (LVO) recanalization before endovascular thrombectomy (EVT) is known as spontaneous recanalization (SR) or early recanalization (ER) after treatment with intravenous thrombolysis. In this study, we aim to investigate predictors for SR/ER and evaluate its association on functional outcomes. METHODS: Patients with an anterior circulation LVO who received groin puncture for intended EVT between 2014 and 2019 were included from the MR CLEAN (Multicenter Randomized Clinical trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry. SR/ER was defined as a presence of a LVO CTA but recanalized on first run of digital subtraction angiography. Multivariable logistic regression was used to evaluate the association between predictor variables and SR/ER. Additionally, we evaluated the association of SR/ER with functional outcomes (modified Rankin Scale [mRS] at 90 days, mortality, and National Institutes of Health Stroke Scale [NIHSS] scores at 24 hours), and performed multivariable ordinal, binary, and linear regression, where appropriate. RESULTS: SR/ER occurred in 251/4448 (5.6%) of patients. Multivariable logistic regression identified male sex (aOR 1.41, 95%CI 1.07-1.84), treatment with intravenous thrombolysis (aOR 3.19, 95%CI 2.03-5), and M2 occlusions (aOR 1.96, 95%CI 1.45-2.66), as independent predictors for higher odds of SR/ER. Higher NIHSS (aOR 0.94, 95%CI 0.92-0.96), use of direct oral anticoagulation (aOR 0.12, 95%CI 0.02-0.91), presence of hyperdense artery sign (aOR 0.62, 95%CI 0.47-0.83), and ICA-T occlusion (aOR 0.18, 95%CI 0.08-0.41), were significant independent predictors for a lower odds of SR/ER. SR/ER resulted in a lower NIHSS at 24 hours (aβ -1.95, 95%CI -3.08- -0.83), a shift towards a lower mRS (acOR 0.67, 95%CI 0.53-0.86), and less mortality (aOR 0.53, 95%CI 0.34-0.82). When compared to patients who achieved successful recanalization through EVT these associations lost significance. CONCLUSION: SR/ER is associated with male sex, treatment with intravenous thrombolysis, baseline NIHSS, direct oral anticoagulation medication use, hyperdense artery sign, and ICA-T and M2 occlusions. Patients with SR/ER achieved significant better functional outcomes compared to all patients achieving successful recanalization through EVT.