Abstract WP36: Thrombus Composition and Success of Thrombectomy in Acute Ischemic Stroke Patients: A Histopathological Analysis

Background: Thrombus composition may vary among acute ischemic stroke patients. Thrombus composition is a key factor in determining susceptibility to mechanical and pharmacological thrombus disruption and thus the degree of successful recanalization. Many studies have reported the correlation between thrombus components and parameters such as stroke etiology, treatment outcome but there is still a lack of information due to a small sample size. We determined the relationship of thrombus composition on the success of thrombectomy in this multicenter study. Methods: We analyzed the data on 111 acute stroke patients, treated with mechanical thrombectomy, taken from 3 different stroke centers. Retrieved clots underwent semiquantitative proportion analysis by pathologists blinded to patient characteristics and imaging findings. Thrombus type was classified as erythrocyte rich, fibrin-rich and mixed type. Primary outcome assessment was the effect of clot composition on recanalization attempts. Multivariate analysis was performed to identify predictors of attempt number. Successful recanalization is defined as thrombolysis in cerebral infarction (TICI) scale 2b and 3. The good functional outcome is defined as modified Rankin Scale (mRS) 0-2 at 3 months. Results: Successful recanalization was achieved in 86 of 111 patients who underwent acute thrombectomy. Pathological characteristics did not differ significantly when compared to the number of attempts for recanalization (p = 0.469). Symptom recanalization time was shorter for patients recanalized with fewer attempts (p=0.0027). National Institute of Health Stroke Scale (NIHSS) or Stroke Etiologic Subtype was not correlated significantly with thrombectomy attempts ( p=0.76 and 0.22, respectively) as well. There was a no significant trend for good functional outcome with fewer attempts (p=0.10). There was no predictor of the number of attempts in multivariate analysis. Conclusions: In our study, histological thrombus composition had no impact on the number of attempts of thrombectomy done in acute ischemic stroke patients.