Mechanical Thrombectomy has been associated with improved neurological outcome in large vessel occlusion (LVO) acute ischemic stroke (AIS) patients. To better understand the relationship of LVO clot composition with vessel recanalization, we analyzed individual clots from 94 retrieval passes in 43 AIS patients (65.4±12.7 years, 17 (39.5%) female) who underwent intra-arterial mechanical thrombectomy procedures over a 2-year period. Rates of successful vessel recanalization (TICI 2B - 3) for each trial and final result were analyzed. Clot composition was analyzed histologically, and the area occupied primarily by red blood cells (RBC), fibrin, or mixed was quantified. Fibrin (44%) occupied the greatest area in retrieved clots, followed by mixed type (34%) and RBCs (22%). Clot composition was compared to recanalization success, first pass efficacy, patient comorbidities, devices or technique used, and carotid tortuosity score. In 43 patients, there were 94 passes (mean 2.14, range 1–6), 20 patients (47%) had first pass successful revascularization, 41 (95%) achieved successful revascularization, and 19 (48%) had a good outcome at 3 months (mRS 0–2). In the univariate analysis, first pass efficacy was associated with RBC composition and Atrial Fibrillation but not with fibrin composition, mixed composition, type of first pass technique employed, distal emboli, good outcome, or carotid tortuosity score. In the multivariate analysis, first pass efficacy was significantly correlated with RBC composition (p=.05) but not with atrial fibrillation (p=0.07) or other factors. Dense MCA sign on initial CT was correlated with mixed clot composition (p=0.025). RBC clot composition is associated with first pass efficacy in patients undergoing mechanical thrombectomy for LVO.

Disclosures J. Johnson: None. A. Srivatsan: None. J. Chueh: None. M. Gounis: 1; C; NIH, NIH NINDS, Various Biomedical Device Industry Grants. A. Puri: None. V. Srinivasan: None. S. Chen: None. J. Burkhardt: None. P. Kan: 1; C; NIH, McDonald Foundation. 2; C; Stryker Neurovascular, Cerenovus, Medtronic.