Sepsis-associated thrombotic microangiopathy-like syndrome following cardiac surgery: a case report

Severe sepsis following cardiac surgery may be accompanied by a thrombotic microangiopathy (TMA)-like syndrome distinct from classic immune-mediated thrombotic thrombocytopenic purpura (TTP) and overt disseminated intravascular coagulation (DIC). We report a 62-year-old man who developed sepsis after mitral valve replacement, complicated by thrombocytopenia (nadir 45 × 10⁹/L), microangiopathic hemolysis (2.6% schistocytes), and multiple organ dysfunction. Laboratory findings revealed marked dysregulation of the von Willebrand factor (vWF)/ADAMTS13 axis, with markedly elevated vWF antigen levels (548%), moderately reduced ADAMTS13 activity (32.8%), and negative ADAMTS13 inhibitors. Despite meeting criteria for sepsis-induced coagulopathy (SIC), the patient did not fulfill diagnostic criteria for overt DIC, as fibrinogen levels remained elevated and D-dimer elevation was limited. The patient improved with comprehensive sepsis management and supportive care, including adjunctive plasma infusion. Marked vWF/ADAMTS13 imbalance with preserved fibrinogen and limited D-dimer elevation may help distinguish sepsis-associated TMA-like syndrome from overt DIC.