Variability of Fibrinolytic Activity in Pregnant Patients Exposed to Tissue Plasminogen Activator: An In Vitro Study Utilizing Rotational Thromboelastometry

( Int J Obstet Anesth . 2024:59:103994. doi: 10.1016/j.ijoa.2024.103994) Fibrinolysis is the process of breaking down blood clots and is caused by the conversion of plasminogen to plasmin by tissue plasminogen activator (tPA), resulting in the cleavage of a fibrin clot into fibrin degradation products (FDPs). Pregnancy causes many physiological changes in the body, among which are changes to the fibrinolytic system; in some cases, alterations can cause conditions like hyperfibrinolysis, which is an excessive activity of clot breakdown. Previous literature has evaluated fibrinolysis extensively in the context of trauma patients, but the obstetric population is understudied in this area; this is surprising given the impact of fibrinolysis on bleeding and its potential to impact postpartum hemorrhage (PPH) patients. This study was designed to assess the variability of fibrinolysis with the addition of exogenous tPA, with the hypothesis that some patients will respond more and thus have a higher risk of PPH.