SENTRY: Bioconvertible IVC filter tied to low pulmonary embolism at 1 year

Michael D. Dake

LAS VEGAS — Use of a bioconvertible inferior vena cava filter successfully prevented new-onset pulmonary embolism in high-risk patients and was bioresorbed within 1 year in most cases, according to new data from the SENTRY study.

IVC filters, when used properly, protect patients at risk from transient PE; however, some conventional filters are associated with high rates of complications due to device design or being left in too long. The FDA issued a warning to health care professionals to remove conventional filters when risk has passed, which is typically after 30 days, Michael D. Dake, MD, the Thelma and Henry Doelger professor of cardiovascular surgery and medical director of the catheterization and angiography laboratories at Stanford Health Care, said during a press conference.

The SENTRY study was conducted to evaluate the novel bioconvertible IVC filter (Sentry, Novate Medical), which is designed to protect from PE during the transient risk period and then bioconvert to leave an unobstructed IVC lumen, removing the need for retrieval. The device received FDA clearance in February.

The device has “a rather unique design,” Dake said. “It has a stable frame with filters held together by a bioresorbable filament. It reduces IVC filter complication by this design. It’s almost impossible to have tilt or migration. There’s an automatic bioconversion when this filament is resorbed. The filter arms retract into the IVC wall, leaving a patent lumen. This reduces the risk of any subsequent IVC occlusion and removes the requirement for the retrieval of a filter, and the attendant risks and costs associated with that.”

The SENTRY researchers enrolled 129 patients requiring temporary protection from PE at 23 sites. Approximately two-thirds of patients had PE or deep vein thrombosis; the rest received the device prophylactically for impending surgery when anticoagulation was not possible, Dake said.

The composite primary endpoint was technical success, freedom from symptomatic PE during the 30-day protection period and freedom from IVC-related complications at 6 months.

All patients received the device successfully; one case required two tries, Dake said.

None of the patients in the study had new symptomatic PE at 30 days or 12 months, according to Dake.

The rate of freedom from IVC-related complications at 6 months was 98.2%, as 1.8% of patients had symptomatic caval thrombosis, all of which were treated successfully, he said.

There were no cases over 12 months of filter tilting, migration, embolization, fracture, IVC perforation or device-related death, he said.

Bioconversion occurred in 95.7% of patients at 6 months and 96.4% at 12 months, which is much higher than published retrieval rates, Dake said.

“IVC filters are somewhat controversial, but this offers a new design and a new perspective on IVC filtration,” he said at the press conference. “Bioconversion did not result in symptomatic PE. We feel this represents an important paradigm shift, and we will have to see how physicians and patients receive this new idea.”

The device may be most appropriate for use in “those who have a contraindication to anticoagulation and have an ongoing problem with venous thromboembolic disease,” Dake said. “Patients who have PE associated with surgery or trauma are a good group to consider” for the device.

Two-year follow-up is underway. – by Erik Swain

Reference:

Dake MD, et al. Late-Breaking Clinical Trials. Presented at: VIVA 17; Sept. 11-14, 2017; Las Vegas.

Disclosures: The study was funded by Novate Medical. Dake reports he receives honoraria from Bard Peripheral Vascular, Cook Medical and W.L. Gore and Associates; consults for Cook Medical, Novate and W.L. Gore and Associates; and receives research funding from Cook Medical, Manta, Novate, Shockwave Medical and W.L. Gore and Associates.