Clinical experience with retrievable vena cava filters: results of a prospective observational multicenter study.

Background: Retrievable inferior vena cava (IVC) filters offer the attractive possibility to be definitive or to be removed when they become unnecessary. Objective: The purpose of this study was to evaluate the efficacy and the likelihood to remove the retrievable IVC filter ALN. Methods: A total of 30 patients (13 males and 17 females, mean age 57 ± 15 years) underwent placement of ALN filters. Indications for implantation were acute venous thromboembolism (VTE) with a contraindication to anticoagulation in 26 cases (86%), primary prophylaxis after major trauma in two cases (7%) or before surgery in two patients with very high thromboembolic risk (7%). Results: The filter was successfully placed in all patients. After a median follow-up of 18.2 months, there were three cases (10%) of trapped emboli within the filter, one case (3%) of asymptomatic migration of the filter toward the heart and two patients (7%) had deep vein thrombosis (DVT) recurrences. ALN retrieval was attempted through transjugular approach in 18 patients (60%) and the maneuver was successful in 14 of them (78%); when the decision of removal was taken more than 3 months after the implantation, the retrieval was possible only in four of eight patients (50%). The median implantation period was 123 days (range: 30-345). Conclusions: The present study shows the efficacy of ALN filter; it also demonstrates the feasibility and safety of retrieval after a medium-term period of placement. Removal after 3 months after implantation can be unsuccessful and maximum implantation time requires further studies