Baseline sPECAM-1 plasma levels (ng/mL) in study patients. Box plots illustrating baseline sPECAM-1 levels (ng/mL) in patients with subsequent PTS vs patients without PTS (shown on the left side of the figure; P = .007). The 2 box plots on the right side of the figure show sPECAM-1 levels (ng/mL) in patients with subsequently delayed thrombus resolution (Δ thrombus score <4), compared with patients undergoing normal thrombus resolution (Δ thrombus score ≥4; P < .001).