VenaTech Convertible Vena Cava Filter U.S. Multi-Center Clinical Trial

The investigation was designed as a multi-center, prospective, single-arm, historical (literature) controlled clinical study of VenaTech Convertible filter safety and performance in 75 subjects in whom the filter has been implanted, converted, and followed for 6-months. The study could enroll up to 323 patients to ensure 75 converted subjects with 6 months of follow-up data. Converted subjects were followed at 30-days, 3-months, and 6-months post conversion. Subjects that were unable to undergo conversion were followed at 6-months post filter implant (permanent filtration subjects).

Study subjects were to be identified from the pool of candidates with a time-limited risk for pulmonary embolism. Subjects who signed the informed consent were evaluated to determine eligibility for the study based on the inclusion and exclusion criteria. Following completion of baseline procedures including a bilateral Doppler ultrasound of the legs to assess for baseline DVT and contrast venacavography to assess baseline IVC diameter, subjects underwent implantation of the VenaTech Convertible filter.

After device implant, a clinical assessment was completed to determine eligibility for filter conversion. This assessment was done at an interval post-implant and frequency per the investigator's discretion, often with input from the primary care physician. If the clinician determined the subject was no longer at risk for pulmonary embolism, there was no thrombus in or below the filter, and there was no clinically significant deep vein thrombosis (DVT) in the legs, the filter could be converted. After conversion, subjects were followed at 30 days and 3-months by telephone, and at a 6-months post-conversion office visit with imaging (KUB or spot film and Doppler or CT).

If during the conversion clinical assessment(s), the subject remained at risk for pulmonary embolism, additional conversion assessment(s) were completed per the investigator's discretion until the filter was either converted or the subject was determined to require permanent filtration.

At 6-months post-implant, if a study subject's filter had not been converted, no further conversion assessments were to be performed and no attempts were to be made to convert the filter as part of the study. The 6-month post filter implant visit was the final follow-up for nonconverted subjects, which also included imaging (KUB or spot film and Doppler or CT). The study protocol allowed the investigators flexibility as to the best IVC imaging modality based on the condition and anatomy of the subject.

The core laboratory reviewed all screening/baseline, filter implantation, conversion eligibility assessment, conversion, and 6-month follow-up images, with the exception of the ultrasounds. (The core laboratory recommended ultrasound images be evaluated by the expert sonographers at the sites). Additionally, any images taken as a result of a suspected filter-related adverse event or technical complication, with the exception of ultrasounds, were also sent to the core laboratory for review.

Inclusion criteria

• The subject is 18 years of age or older
• The subject is at a time-limited risk of pulmonary embolism as judged by the implanting or referring physician
• In the physician's judgment, the subject requires prevention of pulmonary embolism and placement of a vena cava filter is indicated because anticoagulants are contraindicated, or the subject has experienced failure of anticoagulant therapy in thromboembolic diseases in the past, or the subject requires emergency treatment following massive pulmonary embolism where anticipated benefits of conventional therapy are reduced
• The subject, or their legal representative, is willing and able to provide informed consent
• The subject is willing and able to comply with the requirements of the study protocol, including the predefined follow-up visit evaluations
• The subject's vena cava diameter is ≤ 28 mm as evaluated by contrast venacavography and corrected for magnification

Exclusion criteria

• The subject is a female of childbearing potential and known to be, or suspected to be, pregnant (verified with a urine/blood pregnancy test), or unwilling to use an acceptable form of birth control for as long as the device is implanted
• The subject is severely disabled and his/her life expectancy appears limited according to the investigator's opinion (≤ 6 months)
• The subject already has an implanted vena cava filter
• The subject has contrast allergy to both iodinated contrast and non-iodinated contrast materials
• The subject has a duplicated IVC
• The subject is bacteremic
• The subject has an active malignancy with associated hypercoagulability or mortality likely preventing the VenaTech Convertible filter from being converted within 6 months of implant
• The subject would be unavailable for follow-up
• Filter implantation using the right internal jugular or femoral veins is not possible
• There is no location available in the infrarenal inferior vena cava for placement of the VenaTech Convertible vena cava filter (assessed using contrast venacavography)
• The subject is currently participating in another clinical study or has participated in one within the last 30 days or plans to participate in one during the next 6 months