THROMBOTIC MICROANGIOPATHIES (TMAs) are characterized by intravascular platelet activation, hemolysis, and microvascular thrombosis, causing multiorgan dysfunction. Precipitants include genetic predispositions, acquired immune dysregulation, infection, trauma, medications, organ transplantation, and surgery. Thrombotic microangiopathies include thrombotic thrombocytopenic purpura (TTP), typical (diarrhea-associated) hemolytic uremic syndrome (HUS), atypical (complement-mediated) HUS (aHUS), and TMA from secondary causes. 

TMAs are rare, with incidences ranging from 0.42-to-7.1 cases per million adults per year; however, this increases in select patient populations in whom incidence is 0.8% to 4%. 

TMAs are heterogeneous, with etiology-specific treatment and overlap in presentation. This presents a diagnostic challenge for providers. This case presents a patient with undiagnosed Marfan’s who experienced TMA after ascending aortic grafting, aortic valve replacement, and coronary artery bypass surgery performed with cardiopulmonary bypass under deep hypothermic circulatory arrest.