Characterization of the ‘White’ Appearing Clots that Cause Acute Ischemic Stroke

Most clots retrieved from patients with acute ischemic stroke are ‘red’ in color. ‘White’ clots represent a less common entity and their histological composition is less known. Our aim was to investigate the composition, imaging and procedural characteristics of ‘white’ clots retrieved by mechanical thrombectomy. Seventy five ‘white’ thrombi were selected by visual inspection from a cohort of 760 clots collected as part of the RESTORE registry. Clots were evaluated histopathologically. Quantification of Martius Scarlett Blue stain identified platelets/other as the major component in ‘white’ clots’ (mean of 55% of clot overall composition) followed by fibrin (31%), red blood cells (6%) and white blood cells (3%). ‘White’ clots contained significantly more platelets/other (p