Clinical outcome after large-vessel occlusive strokes depends on admitting clinical condition, successful recanalization, and robust collateral circulation. However, predicting successful recanalization and quantifying collateral status in the acute setting remain elusive. Successful recanalization has many predictive factors. Strong evidence supports increasing clot length being associated with poor recanalization. Current imaging techniques completed in the acute setting suggest that clot length can be estimated with a clot burden score. In vitro evidence suggests that clots with more red blood cells and less thrombin lyse more easily after systemic fibrinolysis. Clinical correlations with clot composition have been mixed, although one study suggested that clot composition could be predicted with computed tomography and correlate with successful recanalization. Finally, overwhelming proof shows that robust collateral circulation correlates with improved clinical outcome. Imaging modalities in the acute setting remain promising, with studies suggesting that collaterals can be quantified with computed tomography angiography and perfusion studies. Patients with large-vessel occlusive strokes have variable clinical responses to fibrinolysis and thrombectomy. Independent predictive variables that can possibly alter clinical outcome appear to be successful recanalization and robust collateral circulation. Future studies that allow for better prediction of successful recanalization and quantification of collateral status may help clinical decision-making when evaluating large-vessel occlusions.
Keywords: clot composition; clot length; collateral; ischemic stroke; outcome; recanalization.
© 2014 World Stroke Organization.