Abstract
Introduction:
Emboli retrieved from stroke patients undergoing mechanical thrombectomy vastly differ in histopathologic appearance, likely reflecting varying etiologies of stroke. We investigated whether clot components correlated with clinical features and thrombectomy outcomes.
Methods:
Retrieved thrombi from endovascular thrombectomy in consecutive AIS-LVO patients at 2 academic medical centers were fixed in formalin and sections stained by hematoxylin and eosin. The RBC, WBC and fibrin percentages of the clot were quantified by a neuropathologist blinded to the clinical details. We evaluated the association of these clot components, patient demographic and clinical features, with TICI score (both ordinal and dichotomized at 2c), AOL score, number of thrombectomy passes, and first-pass substantial recanalization (≥TICI 2b result on the first thrombectomy device pass). Non-parametric values were computed via Spearman correlation and pairwise interaction of clinical features was analyzed by ordinal logistic regression.
Results:
Among the 75 analyzed patients, mean age was 71.4 (SD 17.7), 50.7% were female and presenting NIHSS mean was 16.1 (SD 7.6). Devices employed were stent retrievers in 71% of patients, aspiration in 10%, and both stent retrievers and aspiration in 19%. Number of passes per procedure was mean 2.16 (SD 1.21). Substantial reperfusion (TICI 2B-3) was achieved in 88% and excellent reperfusion (TICI 2C-3) in 44%. In retrieved thrombi, mean RBC% was 44.8% (SD 31.9) and mean fibrin% was 49.8% (SD 31.4). Rates of first-pass substantial reperfusion, final substantial reperfusion, and final excellent reperfusion were homogenous across wide ranges of retrieved thrombus RBC% and fibrin% in correlation analysis.
Conclusion:
RBC and fibrin composition range widely among retrieved thrombi causing acute ischemic stroke. Current generation thrombectomy devices perform well across a broad range of clot compositions.