Assessment of Hypercoagulability in Splanchnic Vein Thrombosis by Measurement of the Hemostasis Enzymes Thrombin and Activated Protein C

Splanchnic vein thrombosis (SVT), which is particularly prevalent in myeloproliferative neoplasms (MPNs), has a multifactorial pathomechanism involving the anticoagulant protein C (PC) pathway. To better characterize the hypercoagulable state in SVT we assessed its key enzymes thrombin and activated PC (APC). The study population included 73 patients with SVT, thereof 36 MPN+, confirmed by bone marrow biopsy, 37 MPN-, and 30 healthy controls. Direct measurement of the active enzyme forms of thrombin and APC in the circulation was achieved by using oligonucleotide-based enzyme capture assays (OECA). Additionally, activation markers of coagulation and fibrinolysis were measured. Plasma levels of free thrombin and APC were higher in the MPN+ than in the MPN- cohort, with 0.49 vs.