Platelets and von Willebrand factor (vWF) are key factors in thrombosis and thus are
likely key components of acute ischemic stroke (AIS) emboli. We aimed to characterize
platelet and vWF levels in AIS emboli and to assess associations between their expression
levels and clinical and procedural information.Histopathological and immunohistochemical
analysis of emboli collected as part of the multi-institutional RESTORE registry was
performed. The composition of the emboli was quantified using Orbit Image Analysis
machine learning software. Correlations between clot components and clinical and procedural
information were assessed using the χ2 test.Ninety-one emboli samples retrieved from
63 patients were analyzed in the study. The mean platelet (CD42b) content of the clots
was 33.9% and the mean vWF content of the clots was 29.8%. There was a positive correlation
between platelet and vWF levels (ρ=0.564, p<0.001*, n=91). There was an inverse correlation
between both platelets and vWF levels and percentage of red blood cells (RBCs) in
the emboli (CD42b vs RBC: ρ=-0.535, p<0.001*, n=91; vWF vs RBC: ρ=-0.366, p<0.001*,
n=91). Eighty-one percent of patients in the low platelet group had a good revascularization
outcome (Thrombolysis in Cerebral Infarction 2c/3) compared with 58% in the high platelet
group (χ2=5.856, p=0.016).Platelet and vWF levels in AIS emboli correlate with each
other and both have an inverse relationship with RBC composition. Patients with platelet-rich
clots have poorer revascularization outcomes.
