I langt de fleste rapporterede tilfælde havde patienterne i forvejen tendens til blodpropslidelser grundet allerede eksisterende risikofaktorer såsom en nylig operation, en nylig knusningsskade, forsnævrede pulsårer på grund af sygdom, leversygdom og alvorlig blodforgiftning.
In the vast majority of cases reported, the patients were predisposed to thrombotic disorders due topre-existing risk factors such as recent surgery, recent crush injury, arteries narrowed by disease, liver disease and serious blood infection.