Duration of Anticoagulation Therapy in Patients with Genetic Inherited Thrombophilia

Background: Genetic factors play an important role in deep vein thrombosis (DVT). The duration of anticoagulation therapy in patients with verified genetic inheritance and previous events of DVT is still questionable. Case reports: We present three cases of siblings (two brothers and one sister) with verified Venous thromboembolism (VTE) and genetic inheritance. The first case is a 33 y.o. male who was admitted with bilateral massive pulmonary thromboembolism and DVT of the right femoral vein. He had an episode of DVT 4 years ago. Fibrinolytic therapy was introduced immediately. Afterwards, unfractionated heparin was introduced, and then switched to enoxaparin and acenocoumarol. Because of inappropriate INR, it was switched then to rivaroxaban. The imaging methods showed significant improvement, and the patient was discharged from the hospital with rivaroxaban at 2x15 mg/day for another 2 weeks and was instructed to continue 20 mg/day until his next control. In the meantime, the second case, a 36 y.o. male, brother to the first patient, came with vein thrombosis of vena saphena magna of the left leg. Treatment with Acenocoumarol was started and continued for 2 years until complete resolution of the thrombi, and then it was changed to Aspirin. The third case is the sister of the first 2 cases, a 38 y.o female with symptoms and findings almost similar to those in the second case. She was treated with Acenocoumarol for 6 months. Doppler ultrasound showed complete resolution of the thrombosis and anticoagulation therapy was stopped. Genetic investigations for mutation showed presence of homozygous gene mutation for Prothrombin (PTB G20210A) in the first patient, his brother (the second case) was compound heterozygote for PTB and for MTHFR C677T, and his sister (third case) was heterozygous only for the PTB mutation. According to the clinical (recurrent unprovoked DVT with thromboembolic complications) and genetic testing (homozygous gene mutation for PTB) in the first patient, we decided to continue the secondary thromboprophylaxis with rivaroxaban 10 mg/day indefinitely. Conclusion: Testing for genetically inherited thrombophilia should be included in the risk assessment for recurrence, and performed in all patients under 50 y.o. who have a first, non-provoked episode of thrombosis, in order to determine the duration of anticoagulation therapy.