Outcomes Following Mechanical Thrombectomy in Different Etiological Subtypes of Acute Basilar Artery Occlusion

Background and Purpose Vertebrobasilar occlusion stroke (VBOS) is innately associated with high morbimortality despite advances in endovascular thrombectomy (EVT). Nonetheless, notable outcome dissimilarities exist between angiographically categorized stroke subtypes. We aim to evaluate potential differences concerning clinical angiographic outcomes among etiological subtypes of VBOS based on the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. Methods We retrospectively reviewed prospective EVT databases at two tertiary care stroke centers for consecutive patients with VBOS who had preinterventional MRI and underwent EVT from January 2015 to December 2019. We identified three groups: large artery atherosclerosis (LAA), cardioembolic stroke (CES), and embolic stroke of undetermined source (ESUS). The primary endpoints were the rates of poor outcome (identified as 90-day modified Rankin scale score of 3–6) and mortality, while the secondary endpoint included the rates of incomplete reperfusion (identified as modified treatment in cerebral infarction scale mTICI 0–2b), and periprocedural symptomatic intracranial hemorrhage. We evaluated the association between the etiology and clinical angiographic outcomes through stepwise logistic regression analysis. Results Out of 1823 patients, 139 (91 men; median age, 69 (61–76) years) with VBOS were qualified for the final analysis with incidence as follows: LAA (41%, n = 57), CES (35%, n = 48), and ESUS (24%, n = 34). Overall, incomplete reperfusion was realized in 41% (57/139) of the patients, a poor outcome in 65% (90/139), and mortality in 40% (55/139). Longer puncture to reperfusion interval (aOR 1.0182 [95% CI: 1.008–1.029]; p < 0.001) and utilization of combined aspiration-retriever technique (aOR 0.1998 [95% CI: 0.066–0.604]; p = 0.004) were associated with a greater likelihood of incomplete reperfusion (mTICI 0–2b) irrespective of the stroke etiology. After adjustment for confounding factors in the regression analysis, ESUS was an independent predictor of poor outcome (aOR 5.315 [95% CI: 1.646–17.163]; p = 0.005) and mortality (aOR 4.667 [95% CI: 1.883–11.564]; p < 0.001) at 90 days following EVT. Conclusion The functional outcome following EVT for VBOS might depend on stroke etiology. According to our results, ESUS seems to be associated with the worst outcome, which needs further investigation to tailor the appropriate therapeutic plan.