PF4 and Venous thrombosis: Key features of VITT are unusual site venous thrombosis, predominantly cerebral venous sinus (CVST) and splanchnic vein thrombosis (SVT), frequently accompanied by multiple venous and/or arterial clots, severe thrombocytopenia, a striking rise in D-dimer levels with signs of disseminated intravascular coagulation (DIC) associated with the presence of anti-platelet factor 4 (PF4)/heparin complex antibodies in the absence of prior exposure to heparin, occurring 5–30 days after anti-SARS-CoV-2 vaccination [3,12,19].