Mohammad Reza Pashaei - Department of internal medicine, Faculty of Medicine, Urmia University of Medical Sciences, Urmia-Iran

Venous thromboembolism (VTE) includes deep vein thrombosis (DVT) and pulmonary embolism (PTE), which requires long-term hospitalization and clinical care. The diagnostic laboratory marker D-dimer for VTE and the International Normalized Prothrombin Time Ratio (PT-INR) is a measure used to assess the function of coagulation factors in patients. This study aimed to evaluate D-dimer negating time and its relationship with PT-INR. Methods: In this cross-sectional study, ۵۰ patients with VTE were included in the study. D-dimer was measured by the ELISA method in patients. The criterion for the D-dimer negating having a level below ۵۰۰ μg in hospitalized patients with pulmonary embolism and DVT. The relationship between D-dimer negating time and INR was analyzed using ANOVA and Pearson correlation tests.Results: The minimum and maximum time for the D-dimer to be negative is seven and ۷۱ days, respectively. The mean duration of D- dimer negating time in all patients was ۲۵.۰۸ ۱۵±۱۵.۲ days. The mean duration of D-dimer negating time was ۲۲.۱۸±۶/۷ days among ۱۲ patients with INR <۲ and ۲۲.۹۲ ± ۱۳.۹ days among ۲۴ patients with INR <۳, and ۳۲/۴۲±۲۱/۲ days among ۱۴ patients with INR ≥۳. There was a statistically significant difference between different INR groups (p-value: ۰.۰۴۹). Conclusion: The results showed a direct relationship between INR in thromboembolic patients and the duration of D-dimer negating time. The correlation of PT-INR and D-dimer negation time in patients of venous thromboembolism was found and thus D-dimer negation time also can serve as another marker of warfarin control.

D-dimer, INR, Venous thromboembolism, Deep vein thrombosis, Pulmonary embolism