Thrombocyte-thrombocyte aggregates (proxy) in HIs and patients, and correlation with EASIX and PBR. (A) Gating strategy for identifying thrombocyte-thrombocyte aggregates (Thr_Thr, proxy) and leukocyte-thrombocyte aggregates (Leuko_Thr) by flow cytometry. Thr_Thr aggregates (proxy), identified as CD45⁻CD41⁺ platelets exceeding 2 standard deviations (>2σ) above the mean FSC, indicating larger platelet aggregates. Leuko_Thr aggregates, defined as CD45⁺CD41⁺ double-positive cells, further classified by CD14 expression to differentiate monocyte-platelet subtypes. (B) Box plots comparing Thr_Thr aggregate levels (proxy) between HIs and patients, showing a trend toward higher levels in patients (P = value from Kruskal-Wallis test). (C-D) Linear regression analyses showing correlations between (C) platelet aggregates (proxy) and EASIX (C) and platelet aggregates (proxy) and PBR (mean values across VDs 8-25 μm) (D). These findings suggest a link between platelet activation, systemic endothelial stress, and glycocalyx degradation. FSC, forward scatter; PBMCs, peripheral blood mononuclear cells.