Venous thrombo-embolism during immune-mediated thrombotic thrombocytopenic purpura is prevalent in patients with a prolonged treatment with therapeutic plasma exchange

Thrombotic thrombocytopenic purpura (TTP) is a devastating disease characterized by disseminated microvascular thrombosis. Despite pro-thrombotic predisposing conditions, the prevalence of macrovascular venous thrombosis event (VTE) in immune-mediated TTP (iTTP) has rarely been assessed. We reviewed data of all iTTP patients of the French reference Center for thrombotic microangiopathies registry prospectively enrolled through a 10-year period, between 2008 and 2018. Venous thrombosis included either thrombosis of central venous catheter, symptomatic deep venous thrombosis of the limbs or pulmonary embolism. Forty-eight (12.7%) VTE were diagnosed. VTE was diagnosed after a median time of 7 [IQR, 3-16] days following the first therapeutic plasma exchange (TPE) and consisted mainly in catheter-related thrombosis (73%), and to a lesser extend symptomatic deep venous thrombosis (16%), proximal pulmonary embolism (8%) and splanchnic vein thrombosis (2%). Cases with VTE (VTE+ cases), required more TPE to achieve remission (P