Background Brain atrophy is associated with an inferior functional outcome in patients undergoing mechanical thrombectomy (MT) for acute ischemic stroke. We hypothesized that brain atrophy determined from pre-interventional non-contrast-enhanced CT scans would also be linked to increased mortality in this cohort.

Methods A total of 204 patients treated with MT for acute occlusions of the internal carotid artery (ICA) or the M1 segment of the middle cerebral artery (M1) at Tampere University Hospital, Finland between 2013 and 2017 were retrospectively studied. Brain atrophy index (BAI), masseter muscle surface area and density, chronic ischemic lesions, and white matter lesions were evaluated from pre-interventional CT studies. Logistic regression was applied in analyzing the association of BAI with 3-month mortality.

Results Median age at baseline was 69.9 years (IQR 15.6) and mortality at 3 months was 13.2% (n=27). BAI, measured with excellent reproducibility (intraclass correlation coefficient ≥0.894, p<0.001), was significantly associated with age (r=0.54), white matter lesions (r=0.43), dental status (r=−0.31), masseter area (r=−0.24), masseter density (r=−0.28), and chronic ischemic lesions (r=0.24) (p≤0.001 for all). In univariable analysis, BAI demonstrated a strong association with mortality (OR 2.02, 95% CI 1.34 to 3.05, per 1 SD increase), and none of the other factors associated with mortality remained as significant when included in the same multivariable model. The results remained similar when extending the follow-up up to 2.5 years.

Conclusions Brain atrophy predicts 3-month mortality after MT of the ICA or the M1 independent of age, masseter sarcopenia, chronic ischemic lesions, or white matter lesions.