Early results of the Axium MicroFX for Endovascular Repair of IntraCranial Aneurysm (AMERICA) study: a multicenter prospective observational registry

Background Axium MicroFX coils contain polymer (polyglycolic/polylactic acid, PGLA) microfilaments designed to significantly impact intra-aneurysmal flow and to encourage aneurysm thrombosis. To provide preliminary evaluation of the safety and suggested efficacy of the MicroFX design, we performed a multicenter prospective single-arm trial, Axium MicroFX for Endovascular Repair of IntraCranial Aneurysm study (AMERICA). Methods AMERICA is a prospective multicenter 100 aneurysm observational study evaluating the safety and efficacy of Axium MicroFX PGLA coils. Enrollment was started in April 2010 and completed in October 2012. Results 99 patients underwent treatment for 100 aneurysms at 13 centers. Mean age was 60.2 years, most were women (72%) and 18% of patients had previously undergone treatment for a separate aneurysm. 22% of patients underwent treatment after acute aneurysmal subarachnoid hemorrhage (SAH). Of these patients, all were Hunt and Hess grade 1-3. Pre-procedure modified Rankin score (mRS) was 0-2 in 92% of patients. The majority of aneurysms were anterior circulation (86%), with the most common aneurysm locations being the anterior communicating artery (23%) followed by the supraclinoid internal carotid artery and posterior communicating artery (18% each). The mean maximum diameter was 6.5 mm. Axium MicroFX coils could be placed in all but one treatment (99%). Raymond grade at conclusion of coiling was I (complete) in 52%, II (dog ear or residual neck) in 33% and III (residual aneurysm) in 15%. Discharge mRS was significantly worse in patients with SAH (62% mRS 0-2) compared with electively treated aneurysms (mRS 0-2 in 94%, p<001). Major events were uncommon (6% thromboembolic events, 3% intraoperative vessel or aneurysm rupture) and device-related adverse events (AE) were rare (2% of cases). Conclusions This prospective study of Axium MicroFX. coils demonstrates excellent aneurysm occlusion rates. 52% of aneurysms were completely occluded post-procedure. Within the ruptured aneurysm group, post-procedure occlusion rates were 63.6%. Major AE rates were consistent with historical data.