The Clinical Application And Observation Of The VenaTech Convertible Filter

Objective:To evaluate the effectiveness and safety of Vena Tech convertible vena cava filters to prevent pulmonary embolism by following up patients with deep venous thrombosis of the lower extremity implanted with the Vera Tech convertible filter.Methods: It is a retrospective clinical observation study of the inpatient and outpatient follow-up data of 102 patients with Vena Tech convertible filters implanted in Vascular Surgery,First Affiliated Hospital of Chongqing Medical University from April 2017 to December 2018.The follow-up time was arranged at 30 days,3 months,6 months,12 months and 2 years after surgery.We statistically analyzed the medical records and follow-up results of patients with Vena Tech convertible filters.The outpatient follow-up methods are mainly telephone follow-up visits and IVC ultrasound,CT,DSA and other imaging examinations.Through the statistical analysis of the data,the effectiveness and safety of the Vena Tech convertible filter in clinical application are evaluated.Results:This clinical study successfully followed up 102 patients with an average follow-up time of 12.4 months(5.1-19.6 months).102 cases ofVena Tech convertible vena cava filters were all successfully placed in the predetermined position.The location of the filter included 99 cases of inferior vena cava below the renal vein and 3 cases of the vena cava above the renal vein.Of the 102 patients,46(45.1%)tried to convert the filter,44(95.7%)had a successful conversion,and 2 failed to snare the conversion hook.The average time from filter insertion to filter conversion is 68.8 days(5-198 days).During the filter conversion process,26 cases(59.1%)of patients removed the conversion hook,the filter feet were not fully deployed,and assistant equipment was used.All 102 patients underwent IVC ultrasonography,of which 81(79.4%)patients underwent IVC ultrasonography,39 patients completed abdominal enhanced CT evaluation,and 46 patients underwent ISA under DSA.During the follow-up period,no obvious symptomatic pulmonary embolism occurred after the filter was inserted.Three patients(2.9%)reported death.The cause of death was not related to the Vena Tech convertible filter or PE.Imaging examination revealed inferior vena cava thrombosis in 6 patients(5.9%),among which 3 patients had thrombosis in the filter,2 patients had IVC perforation,and 5 patients(4.9%)had a severely inclined tip of the filter near the IVC wall.Seven patients(6.9%)relapsed DVT.No filter displacement or filter rupture was found in all patients.Conclusion:The Vena Tech convertible filter is a special type of vena cava filters,which can effectively prevent pulmonary embolism.Short-term follow-up shows highsafety and low complication rate.This conversion time can be extended according to clinical needs,and in theory is not limited by time.So it is more advantageous for DVT patients with uncertain pulmonary embolism risk period.Nevertheless,the use of convertible filters still requires strict indications,and more prospective,long-term follow-up high-quality studies are needed to evaluate their long-term effectiveness and safety.