European study shows lower rate of composite adverse events with second-generation coil
In the GREAT trial, a smaller proportion of patients hit the composite adverse event endpoint at 18 months if they were treated with hydrogel coils (19.9% versus 28.7%), Christian Taschner, MD, PhD, of University Hospital Freiburg in Germany, and colleagues reported during a press briefing at the International Stroke Conference.
Physicians traditionally used clips to treat intracranial aneurysm, placed via neurosurgery. That began to change after the ISAT trial showed that using platinum coils, delivered via endovascular therapy, to fill the aneurysm was superior to clipping, Taschner explained.
Still, rates of aneurysm recurrence with the new procedure could be improved, he said, leading to the development of second-generation coils that are filled with a hydrogel. When the gel comes into contact with liquid, its volume increases, boosting the packing density of the coiled aneurysm.
For their study, Taschner and colleagues randomized 513 intracranial aneurysm patients from 22 centers in France and Germany to treatment with either hydrogel coils (MicroVention's HydroSoft or HydroFrame) or standard platinum coils, from October 2009 to January 2014.
The primary endpoint was the composite of four outcomes: major aneurysm recurrence at 18 months, retreatment for major recurrences within 18 months, morbidity that prevented angiographic follow-up, and death.
Overall, they achieved the technical outcome of greater coil volume with the hydrogel versus platinum coils (0.041 cm3 versus 0.038 cm3), as well as a higher mean packing density (39% versus 31%) which was 8 percentage points higher (P=0.0001).
Taschner said this translated to a significant difference in terms of the primary outcome at 18 months, with a significant 8.4% reduction in the proportion of patients having those adverse events if treated with hydrogel coils (95% CI 0.5%-16.2%, P=0.036).
When looking at individual outcomes, he noted that there were higher rates of major recurrence and retreatment for those in the standard coil group, while there were no differences between groups in terms of disability or mortality:
- Major recurrence: 12% versus 18%
- Retreatment: 3% versus 6%
- Modified Rankin Score of 3-5: 1% versus 0
- Modified Rankin Score of 6: 3% versus 4%
First- and second-generation hydrogel coil devices are available in Europe, but are not as commonly used in the U.S., said Mark Alberts, MD, of Hartford Healthcare in Connecticut, who was not involved in the study.
"In the U.S., most patients get the classic coil or the clip," he said during a press briefing. "But this could potentially be an advance."
Alberts referred to presentations from the meeting that highlighted the use of stent diverters to prevent blood from flowing into the occluded aneurysm, in order to let the aneurysm heal better: "Both hydrogel coils and stent diverters are new and advanced technologies that we're hopeful about."
Taschner disclosed financial relationships with MicroVention, Stryker Neurovascular, Avandis, Neuravi, and Covidien.