Alteration of Factors Associated with Coagulation in Provoked Pulmonary Embolism

Abstract

Purpose Pulmonary embolism (PE) is regarded as a form of deep vein thrombosis. Although the recurrence rate of venous thrombosis in provoked embolism is lower than it is in unprovoked vein thrombosis, proteins associated with coagulation have not been well studied in provoked PE. This study sought to evaluate factors associated with coagulation between provoked and unprovoked PE. Methods This retrospective cohort study included 207 PE patients. Patients that had transient risk factors at diagnosis were included in the provoked PE group, while all others were classified as unprovoked PE. Evaluation of proteins associated with coagulation included protein C, protein C activity, protein S, protein S free form, protein S activity, antithrombin III, factor VIII, and factor IX. Results Among 207 PE cases, 65 (31.4%) cases were diagnosed as provoked PE. Clinical characteristics were not significantly different between provoked and unprovoked PE. However, RV/LV ratio was significantly higher in provoked PE than it was in unprovoked PE. Proteins and activity associated with coagulation were significantly lower in provoked PE than in unprovoked PE: protein C antigen (33% vs. 54%, P= 0.01), protein S antigen (31% vs. 53%, P= 0.001), protein S activity (55% vs. 71%, P< 0.001), antithrombin III antigen (61% vs. 79%, P< 0.001), and factor VIII (160% vs. 184%, P= 0.01). Conclusion Provoked PE had significantly lower anti-coagulation protein levels and activity than unprovoked PE. Keywords: Pulmonary embolism, Coagulation, Deep vein thrombosis