Final Two-Year Outcomes for the Sentry Bioconvertible Inferior Vena Cava Filter in Patients Requiring Temporary Protection from Pulmonary Embolism

Clinical question
What were the clinical outcomes and conversion rates of the Sentry bioconvertible IVC filter?

Take away point
The Sentry filter had a high conversion rate and high clinical success (97%) and no late IVC thrombosis or obstruction after bioconversion.

Reference
Dake, Michael D. et al. Final Two-Year Outcomes for the Sentry Bioconvertible Inferior Vena Cava Filter in Patients Requiring Temporary Protection from Pulmonary Embolism. Journal of Vascular and Interventional Radiology, Volume 31, Issue 2, 221 - 230.e3

Click here for abstract

Study design
Prospective multicenter trial of 129 patients that underwent Sentry filter placement with a 2 year follow up.

Funding Source
BTG vascular

Setting
Multicenter, non-randomized single arm trial in 23 U.S. sites and 3 total countries.





Figure 1.  Clinical and technical outcomes in the 129 patients enrolled in the study that had a 24 month follow up.

Summary

While retrievable IVC filters are proven to provide protection against PE in patients that cannot be anticoagulated, retrieval rates for have rarely surpassed 50%, which may lead to complications such as tilting, fracture, embolization, IVC perforation etc. To this end, the Sentry bioconvertible IVC filter was created. This filter transforms from a filter to a non-filter scaffold after 60 days. This manuscript details the 2 year clinical and technical outcomes.

Patients included in the study had a contraindication to or failure of anticoagulation with a documented PE or DVT (40% had a prophylactic indication). 129 patients were included and followed for 24 months. The filter and its conversion was evaluated with CT and X-rays. At each clinical visit patients were evaluated for signs and symptoms of PE, DVT and adverse events.

There was 96.5% bioconversion of the filter at 24 months. Two patients suffered caval thrombosis within the first month with successful subsequent treatment. There were no instances of IVC thrombosis or obstruction after bioconversion at 24 months. Furthermore, there were no new symptomatic PE’s in the first 24 months. In the 5 patients in which the filter did not bioconvert, there were no instances of new DVT, PE or IVC related complications. While there were new DVTs in the study period, none were considered to be device related.

The authors highlight that the freedom from symptomatic PE was similar to what has been observed with retrievable IVC filter. After conversion, the filter did not cause IVC thrombosis or obstruction, and in patients that had thrombus in the filter prior to conversion did not experience a symptomatic PE after conversion.

The study was limited by the single arm design with its inherent bias. The authors conclude that the Sentry filter has a high rate of clinical and technical success in patients that require temporary PE prevention and are unable to be anticoagulated, with the benefit of not requiring removal to prevent long term complications associated with temporary filters.

Commentary

The study provides data to support the use of the Sentry filter in patients that do not require a permanent filter. In the current atmosphere of negative publicity and litigation against IVC filters, a bioconvertable filter is a viable option that removes the need for a second procedure to remove the filter. The data presented in this manuscript supports the conclusion that this filter provides adequate PE prevention in the first 6 months (before bioconversion) and does not cause mid-term complications related to IVC obstruction/thrombosis (after bioconversion).

Post author
Carlos J. Guevara, MD, FSIR
Assistant Professor of Radiology and Surgery
Department of Radiology, Interventional Radiology Division
Washington University in St. Louis, Mallinckrodt Institute of Radiology,
@CarlosGuevaraIR