Supplementary Material for: Revisiting the predictive role of truncal-type occlusion sign for acute large vessel stroke treated by endovascular thrombectomy: A scoping review

Abstract Background and purpose The truncal type occlusion (TTO) sign observed during endovascular thrombectomy (EVT) is thought to predict the etiology and prognosis of acute ischemic stroke (AIS) due to large vessel occlusion (LVO). However, the interpretation of the present results and the clinical utility of this sign needs further investigation. This scoping meta-review aimed to assess the predictive value of the TTO sign, thus identifying methodological limitations in current study designs. Methods Studies published up to January 2023 were identified by systematically searching PubMed, Embase, and Web of Science. A meta-analysis was performed to quantitatively synthesize the evidence on the predictive value of the TTO sign. An 8-point scale was introduced to narratively summarize the current evidence level and methodological quality of included studies. Results We included 10 studies in this review. For the prediction of intracranial atherosclerotic stenosis, the sensitivity, specificity, PLR and NLR of the TTO sign were 0.73, 0.87, 5.5 and 0.31, respectively (all p<0.05). For recanalization failure after primary thrombectomy, the sensitivity, specificity, PLR and NLR were 0.44, 0.91, 4.9 and 0.61, respectively (all p<0.05). The strength of evidence was low due to the methodological limitations and lack of adjustment for potential confounders. Conclusion The predictive values of the TTO sign for the etiology of LVO-AIS was considerable but seemed limited for current interpretation. Several confounders could influence the determination and predictive value of the TTO sign, requiring methodological adjustments in future research. Endovascular practitioners encountering this sign during thrombectomy should draw specific attention to stroke etiology, thus promoting timely adjustment of intra- and postprocedural strategies.