RESUMEN
In seventy-two patients hospitalized for clinical suspicion of pulmonary embolism [PE], level of antithrombin III [AT III], heparin cofactor II [HC II] and histidine-rich glycoprotein [HRGP] were determined. Forty-four patients were positive for PE and twenty-nine received standard heparin. HC II and HRGP did not show any statistically significant variation between patients who were positive or negative for PE. Moreover, presence or absence of heparin therapy in these patients did not modify the level of these two proteins. In contrast, AT III showed a statistically significant reduction in PE than non-PE. Since AT III is one of the most powerful inhibitors against serine protease enzymes of coagulation cascade, it is possible that low levels in patients with PE could be considered as the expression of consumption to prevent further thrombus formation