PF4 and laryngotracheoesophageal cleft: Several studies have shown that microclots were identified in the plasma of patients with LC, carrying altered levels of coagulation and fibrinolysis proteins, which are involved in endothelial injury, platelet activation, coagulation and fibrinolysis, such as increased von Willebrand factor (vWF), platelet factor 4, fibrinogen chains α and β, factor XIII, plasminogen and antiplasmin (α2AP), and decreased plasma kallikrein [203,204].