Cerebral Arterial Air Emboli on Immediate Post-Endovascular Treatment CT are Associated with Poor Short- and Long-Term Clinical Outcomes in Acute Ischemic Stroke Patients

PURPOSE: To determine the incidence and predictors of cerebral arterial air emboli (CAAE) on immediate post-endovascular treatment (EVT) dual-energy CT (DECT) in acute ischemic stroke (AIS) patients, and describe their association with clinical outcomes.

METHODS: EVT records from 2010-2019 were screened. Exclusion criteria included intracerebral haemorrhage on post-EVT DECT. In the affected middle cerebral artery (MCA)-territory, circular and linear (length ≥ 1.5*width) CAAE were counted. Clinical data were collected from prospective records. The modified Rankin Scale (mRS) at 90 days was the primary outcome. Multivariable linear, logistic, and ordinal regression were used to analyse the effect of (1) linear CAAE and (2) isolated circular CAAE.

RESULTS: Out of 651 EVT-records, 402 patients were included. In 65 patients (16%), at least one linear CAAE was found in the affected MCA-territory. 17 patients (4%) showed isolated circular CAAE. Multivariable regression showed an association between both the presence and the number of linear CAAE and the mRS at 90 days (presence: adjusted (a)cOR 3.10, 95%CI 1.75-5.50; number: acOR 1.28, 95%CI 1.13-1.44), NIHSS at 24-48h (presence: aβ 4.15, 95%CI 1.87-6.43; number: aβ 0.88, 95%CI 0.42-1.34), mortality at 90 days (presence: aOR 3.34, 95%CI 1.51-7.40; number: aOR 1.24, 95%CI 1.08-1.43) and stroke progression (presence: aOR 4.01, 95%CI 1.96-8.18; number: aOR 1.31, 95%CI 1.15-1.50). Isolated circular CAAE were not significantly associated with any outcome measure.

CONCLUSION: CAAE were found frequently on post-EVT CT imaging. The presence and the number of linear CAAE, but not circular CAAE, are associated with unfavourable short- and long-term clinical outcomes.