Hydrogel-coated coils for the treatment of cerebral aneurysms: preliminary results

The authors present a retrospective analysis of their initial experience with the recently developed MicroVention HydroCoil to treat patients with cerebral aneurysms. Unlike the bare metal coils initially available for endovascular treatment of aneurysms, HydroCoils have a layer of hydrogel polymer surrounding a platinum metallic core. The hydrogel polymer expands soon after making contact with blood. The expanded hydrogel polymer provides increased volumetric filling compared with bare metal coils and offers a more biocompatible surface, as demonstrated in animal models.

Over a 17-month period, the authors used HydroCoils to treat 30 patients with 33 aneurysms. All patients had been treated at least 6 months prior to data analysis. Initial treatment results as well as records of clinical and angiographic follow up were reviewed. Six-month posttreatment angiograms were available for 25 patients.

The HydroCoils were implanted with few complications. On angiographic follow up, a clearly defined radiolucent separation of the coils from the parent artery was noted in many of the aneurysms treated. The authors have not previously observed angiographically demonstrated lucencies separating the coils from the parent artery. This frequent, but not consistent, appearance on follow-up angiograms obtained in this study indicates that HydroCoils support significant neointimal formation across the neck of treated aneurysms. The preliminary results indicate that HydroCoils can be used safely and effectively to treat aneurysms and that these devices may allow for improved aneurysm filling.