Post-thrombectomy intracranial hemorrhages (PTIH) are dangerous complications of acute
ischemic stroke (AIS) following mechanical thrombectomy. We aimed to investigate if
S100b levels in AIS clots removed by mechanical thrombectomy correlated to increased
risk of PTIH.We analyzed 122 thrombi from 80 AIS patients in the RESTORE Registry
of AIS clots, selecting an equal number of patients having been pre-treated or not
with rtPA (40 each group). Within each subgroup, 20 patients had developed PTIH and
20 patients showed no signs of hemorrhage. Gross photos of each clot were taken and
extracted clot area (ECA) was measured using ImageJ. Immunohistochemistry for S100b
was performed and Orbit Image Analysis was used for quantification. Immunofluorescence
was performed to investigate co-localization between S100b and T-lymphocytes, neutrophils
and macrophages. Chi-square or Kruskal-Wallis test were used for statistical analysis.PTIH
was associated with higher S100b levels in clots (0.33 [0.08-0.85] vs. 0.07 [0.02-0.27]
mm2, H1 = 6.021, P = 0.014*), but S100b levels were not significantly affected by
acute thrombolytic treatment (P = 0.386). PTIH was also associated with patients having
higher NIHSS at admission (20.0 [17.0-23.0] vs. 14.0 [10.5-19.0], H1 = 8.006, P =
0.005) and higher number of passes during thrombectomy (2 [1-4] vs. 1 [1-2.5], H1
= 5.995, P = 0.014*). S100b co-localized with neutrophils, macrophages and with T-lymphocytes
in the clots.Higher S100b expression in AIS clots, higher NIHSS at admission and higher
number of passes during thrombectomy are all associated with PTIH. Further investigation
of S100b expression in AIS clots by neutrophils, macrophages and T-lymphocytes could
provide insight into the role of S100b in thromboinflammation.
