Conference Coverage

Second-generation hydrogel surpasses platinum for brain aneurysm closure



– A second-generation hydrogel coil that’s already approved for U.S. marketing proved superior to bare platinum wire for durably embolizing brain aneurysms in a multicenter, randomized trial with 600 patients.

Dr. Bernard R. Bendok, professor of neurosurgery, Mayo Clinic, Phoenix Mitchel L. Zoler/MDedge News

Dr. Bernard R. Bendok

For the study’s primary endpoint of recurrent intracranial aneurysm during follow-up as long as 18-24 months, the 297 patients treated with the hydrogel coil had a recurrence rate of 4%, compared with a 15% rate among patients treated with platinum wire, Bernard R. Bendok, MD, said at the International Stroke Conference sponsored by the American Heart Association. The hydrogel coil materials were also relatively easy to use – much easier than the first-generation hydrogel materials, according to Dr. Bendok – and the adverse event rate using the hydrogel coils was similar to the rate using platinum wire, the standard material for brain aneurysm embolization.

Given the similar safety and ease of use and superior efficacy, clinicians treating brain aneurysms may now increasingly use hydrogel coil. “I think these results will change practice. It’s compelling data,” Dr. Bendok predicted in an interview. “The problem with platinum is it is not conducive to healing.” When an aneurysm is “closed” by insertion of platinum wire, in reality most of the space within the aneurysm remains unfilled by metal. In contrast, animal models suggest that when hydrogel fills an aneurysm it forms a matrix for collagen deposition that further fills the aneurysm space in a wound-healing process, thereby making recurrence less likely, said Dr. Bendok, professor and chair of neurosurgery at the Mayo Clinic in Phoenix.

The HEAT (Hydrogel Endovascular Aneurysm Treatment) trial enrolled patients at 46 centers in the United States and Canada during June 2012–January 2016. Enrolled patients had a ruptured or unruptured brain aneurysm 3-14 mm in diameter, and averaged 57 years old. A blinded core laboratory reviewed brain scans to identify recurrent aneurysms. Of the 297 patients randomized to hydrogel coil treatment, 254 underwent follow-up at 3-12 months and 222 had additional follow-up at 18-24 months, the study’s prespecified time for the primary endpoint. Among 303 patients treated with platinum, 258 had follow-up after 3-12 months and 231 had follow-up at 18-24 months.

Among patients who entered the study with an unruptured aneurysm (nearly three-quarters of enrolled patients), the recurrence rate was 12% with platinum and 3% with hydrogel. Among the patients with a ruptured aneurysm, the recurrence rate was 24% with platinum and 8% with hydrogel. Adverse events occurred in 25% of those treated with platinum and 22% of those treated with hydrogel coil. Mortality during follow-up was 3% in the platinum arm and 2% in the hydrogel coil arm. The two groups also had similar outcomes as measured by the modified Rankin Scale and by quality-of-life measures.

HEAT was sponsored by MicroVention, the company that markets the tested hydrogel coil. Dr. Bendok had no personal disclosures.

SOURCE: Abi-Aad KR et al. ISC 2019, Abstract LB20.

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