The effect of Clot Burden Score on clinical outcomes in acute ischemic stroke patients with atrial fibrillation treated with endovascular thrombectomy.

Background: The Clot Burden Score (CBS) is used to assess thrombus length. The influence of CBS on functional outcome was barely analyzed in patients with acute ischemic stroke (AIS) with atrial fibrillation (AF).

Purpose: To assess the association between CBS and clinical outcomes in large vessel occlusion (LVO)-related patients with AF who have undergone endovascular thrombectomy (EVT).

Material and methods: A total of 160 patients with AF were enrolled between January 2021 and April 2023. The CTA-CBS score was used to quantify the thrombus burden. The primary outcome was the modified Rankin scale (mRS) score at 90 days. A multivariate logistic regression model was used to identify prognostic predictors and determine the correlation between CTA-CBS and clinical outcomes.

Results: In the multivariable logistic regression, younger age, smaller clots, and better collateral status were the favorable prognosis factors. The odds ratios (OR) were 0.956 (95% confidence interval [CI] = 0.924-0.988, P = 0.008), 1.29 (95% CI = 1.110-1.499, P < 0.001), and 1.706 (95% CI = 1.065-2.731, P = 0.026), respectively. A smaller clot correlated with better outcomes OR of 1.29 (95% CI = 1.110-1.499, P < 0.001) for the entire cohort, 1.395 (95% CI = 1.142-1.702, P < 0.001) for bridging the EVT subgroup, and 1.171 (95% CI = 0.866-1.582, P = 0.305) for direct EVT subgroup.

Conclusions: In LVO-related AIS patients with AF treated with EVT, lower CBS is associated with poorer functional outcomes. Notably, CBS acts as a prognostic imaging biomarker in the direct EVT subgroup and does not in bridging the EVT subgroup.