The objective of the study is to evaluate the safety and efficacy of the Adient absorbable filter for the prevention of pulmonary embolism (PE: blood clot in the lungs). PE claims the lives of over 100,000 Americans each year, more than breast cancer, traffic fatalities and HIV combined.

Pharmaceutical anticoagulation (blood thinners) that reduce blood clot formation represent the standard of care for treating patients at risk for PE. However, for people who are temporarily unable to use anticoagulants, such as those who have suffered major trauma or those who are scheduled for surgical procedures, inferior vena cava (IVC) filters are used to help protect against PE. These blood filters prevent large blood clots that originate in the deep veins of the legs (deep vein thrombosis (DVT)) from reaching your lungs causing a potentially life-threatening PE.

Conventional metal IVC filters have been proven effective at reducing the incidence of PE, however, most require retrieval. If not retrieved within a timely manner (months), they can perforate the IVC, impale nearby organs with their barbed struts, and cause blood clots.

In contrast, the Adient absorbable filter traps blood clots similar to conventional metal IVC filters, but following the 8 week protection period, the filter itself breaks down into carbon dioxide and water. Hence no filter retrieval is required and complications are less likely due to the shortened indwell time. Once blood clots are trapped in the absorbable filter, the body's thrombolytic enzymes dissolve the clots within weeks while the filter itself resorbs in 6 to 8 months. The absorbable filter is braided from absorbable suture that has been proven safe over 4 decades.

The question being addressed with the randomized controlled trial portion is whether the placement of the absorbable filter in addition to current best practice PE prevention (sequential compression machines, compression stockings, and anticoagulants when indicated) significantly reduces the incidence of clinically significant PE in high risk subjects.

The absorbable filter will be indicated for the temporary prevention of PE in patients with transient high risk for venous thromboembolism (DVT and/or PE) with or without venous thromboembolic disease and as an enhancement to pharmaceutical anticoagulation and mechanical prophylaxis.

INCLUSION CRITERIA:

Aged 18 years or older

Willing to comply with the specified follow-up requirements including contrast enhanced CTs for the 9-month duration of the study

For female subjects of childbearing potential: a negative pregnancy test within 48 hours prior to the implantation procedure

For the prophylactic cohort, high risk VTE denoted by either:

Caprini score > 8 for surgical ICU, Parvizi score ≥ 150 for TKA (total knee replacement), ISS score ≥ 24 for trauma.

For the therapeutic cohort, documented VTE per the following:

Pulmonary thromboembolism when anticoagulants are contraindicated, Failure of anticoagulant therapy in thromboembolic diseases, Emergency treatment following massive pulmonary embolism where anticipated benefits of conventional therapy are reduced.

Requirement of temporary PE protection (8 weeks) based on clinical judgment

Fully informed subject or caretaker consent having executed an Institutional Review Board (IRB) or approved informed consent.

EXCLUSION CRITERIA:

Expected high VTE risk to extend beyond 8 weeks.

Vena cava filter currently implanted

History of abdominal or pelvic radiation therapy

Previous IVC filter placement/retrieval within 6 months prior to randomization

Confirmed positive blood cultures within the last 48 hours if there is bacteremia

Known sensitivity to radiographic contrast medium that cannot be adequately prophylactically pre-medicated

Known allergy or intolerance to IVC filter materials (i.e. PDSII absorbable suture)

Pregnant, lactating, or plans to become pregnant during investigation follow-up period

Renal insufficiency (GFR < 60) or requiring renal replacement therapy

IVC effective diameter (D) <16 mm or >28 mm anywhere within L1-L4, D = √(AP*Lat)

Less than 7cm from inferior-most renal vein to the iliac vein confluence

Duplication of the IVC

Any thrombus or occlusion in IVC on pre-procedural CT cavogram

Life expectancy of < 12 months

Simultaneous participation in another investigative drug or device trial that has not reached its primary endpoint

Other co-morbid condition that, in the opinion of the Investigator, could limit the subject's ability to participate in or would affect the scientific integrity of the study

Previously enrolled in a clinical investigation of the Adient filter.

For Roll In, patient has advanced heart failure or recent (6 weeks) myocardial infarction. - - -

Advanced heart failure is defined by NYHA class IV or AHA/ACC/HFSA stage D or LVEF < 40%. Subjects with MI diagnosed with ECG alone without MI history and symptoms are not excluded.

Data will be reviewed by the Outcomes Assessor for futility at 25% and 50% enrollment. Subsequently at 75% enrollment, the Outcomes Assessor will conduct an interim assessment for potentially stopping the study with overwhelming efficacy of the filter cohort.