Circulating numbers of platelet-monocyte aggregates (Panel A) were increased post-operatively in patients with VTE (+ VTE, n=13), compared to patients without VTE (- VTE, n=19). In comparison, neither platelet surface p-selectin expression (Panel B) nor integrin αIIbβ3 activation (Panel C) predicted the development of VTE. Similarly, neither d-dimer (Panel D) nor fibrinogen (Panel E) predicted VTE (bars show mean±SEM).