Aim: To assess the outcome of deep vein thrombosis in patients with malignancy after 6 months of oral anticoagulant therapy, and to compare it with international normalized ratio (INR).
Method: Thirty-one patients with malignancy (13 with hematological and 18 with solid tumors) and deep vein thrombosis (29 leg thrombosis and 2 upper extremity thrombosis) were included into a prospective cohort study that lasted from March 2000 until May 2001. The presence of malignant tumors was histologically proved and documented, and deep vein thrombosis was proved by ultrasound or venography. Patients were treated with heparin during the acute phase, and with oral anticoagulant therapy during further 6 months. INRs and ultrasound examination performed during the acute event were repeated one month and 6 months afterwards for the needs of analysis.
Results: Twenty-four patients concluded the study. Clot resolution was achieved in 13 patients after 6 months of therapy. The patients with INR>2 (n=10) had better clot resolution than those with INR<2 (n=3); p=0.012. There was no statistically significant difference in the outcome of thrombosis with regard to the INR level after a month of therapy (p=0.555). Three patients experienced bleeding, one patient had recurrent thrombosis, and two patients suffered pulmonary embolism.
Conclusion: Appropriate anticoagulation during 6 months after the acute deep vein thrombosis enhances the rate of the complete clot resolution. The INR values can be used as predictive of complete recovery from the thrombosis. Complications are comparable with those reported for patients without malignancy.