Background: Mechanical thrombectomy (MT) of basilar artery occlusions (BAO) is a subject of debate. We investigated the clinical outcome of MT in BAO and predictors of a favorable outcome.
Material and methods: A total of 104 MTs of BAO (carried out between 2010 and 2016) were analyzed. Favorable outcome as a modified Rankin scale (mRS) ≤ 2 at 90 days was the primary endpoint. The influence of the following variables on outcome was investigated: number of detectable posterior communicating arteries (PcoAs), patency of basilar tip, completeness of BAO and posterior circulation Alberta Stroke Program early computed tomography score (PC-ASPECTS). Secondary endpoints were technical periprocedural parameters including symptomatic intracranial hemorrhage (sICH).
Results: The favorable clinical outcome at 90 days was 25% and mortality was 43%. The rate of successful reperfusion, i.e. modified thrombolysis in cerebral infarction (mTICI) ≥ 2b was 82%. Presence of bilateral PcoAs (area under the curve, AUC: 0.81, odds ratio, OR: 4.2, 2.2-8.2; p < 0.0001), lower National Institute of Health Stroke Scale (NIHSS) on admission (AUC: 0.74, OR: 2.6, 1.3-5.2; p < 0.01), PC-ASPECTS ≥ 9 (AUC: 0.72, OR: 4.2, 1.5-11.9; p < 0.01), incomplete BAO (AUC: 0.66, OR: 2.6, 1.4-4.8; p < 0.001), and basilar tip patency (AUC: 0.66, OR: 2.5, 1.3-4.8; p < 0.01) were associated with a favorable outcome. Stepwise logistic regression analysis revealed that the strongest predictors of favorable outcome at 90 days were bilateral PcoAs, low NIHSS on admission, and incomplete BAO (AUC: 0.923, OR: 7.2, 3-17.3; p < 0.0001).
Conclusion: The use of MT for BAO is safe with high rates of successful reperfusion. Aside from baseline NIHSS and incomplete vessel occlusion, both known predictors of favorable outcome in anterior circulation events, we found that collateral flow based on the presence or absence of PcoAs had a decisive prognostic impact.
Keywords: Cerebral Stroke; Cerebrovascular Occlusion; Collateral Circulation; Embolectomy; Intracranial Thrombosis.