The Efficacy and Safety of Oral Rivaroxaban in Patients with Permanent Inferior Vena Cava Filter: A Pilot Case-Control Study

Aim: to evaluate the efficacy and safety of direct oral anticoagulant Rivaroxaban in patients with permanent Inferior Vena Cava (IVC) filter.

Methods. This was a prospective case-control study involving 30 patients with acute DVT after implantation of IVC filter. The indication for temporary IVC filter implantation was proximal deep vein thrombosis (DVT) with ≥ 4 cm free-floating head. In the study were included patients in whom IVC filter was not removed 3 weeks after implantation because of technical failure (66.7%), persistence of irreversible risk factors or free-floating head (23.3% and 10%). After IVC filter implantation all patients were initially treated with low molecular weight heparins for 48 hours and then assigned to a standard anti-vitamin K therapy (AVK). Those who refused standard anticoagulation were allowed to choose a new oral anticoagulant and some of them were treated with Rivaroxaban 15 mg twice daily for the first 3 weeks, followed by 20 mg once daily. Totally 15 patients were treated with oral Rivaroxaban on their own: 8 men and 7 women, 35-87 years old (mean - 65.6±15.2) with 1-6 individual risk factors for venous thromboembolism (mean - 2.9±1.4). For each case patient the control one treated with AVK was matched by age (±5 years), sex and the number of individual risk factors (±1). Matching was successful in 100%.

Patients were evaluated at 6^th, 12^th, 18^th and 24^th month after intervention with clinical examination, duplex ultrasound of IVC system and inspection of medical records. The endpoints of the study were: the patency of IVC filter, the rates of recurrent DVT, pulmonary embolism (PE) and bleeding.

Results. During 12 month we followed up all 30 patients, during 18 month we followed up 9 cases and 14 controls and during 24 month - 2 cases and 6 controls. We found no IVC filter obstruction or PE in all patients treated with Rivaroxaban or AVK during the whole time of observation. At 6^th month after intervention, we found no recurrent DVT. Hemorrhagic complications were found in one case and two controls (6.6% vs 13.3%, n.s.). At 12^th month after intervention, we found one recurrent DVT in control patient (0% vs 6.6%, n.s.). New hemorrhagic complications were found in one case and one control. Totally hemorrhagic complications during first year of observation were found in 2 patients at Rivaroxaban and 3 patients at AVK without any statistically significant difference (13.3% vs 20.0%), but in controls they were more severe: one intracranial hemorrhage and two skin hemorrhage versus one skin and one gingival hemorrhage. During the second year of observation we found no new cases of DVT or bleeding.

Conclusion. Using of oral Rivaroxaban in patients with permanent IVC filter seems to be not less effective and safe as standard therapy with AVK and does not lead to filter obstruction. These findings need to be confirmed in a randomized controlled trial.