Endovascular treatment of intracranial aneurysms with matrix detachable coils:: Midterm anatomic follow-up from a prospective multicenter registry

BACKGROUND AND PURPOSE: Polyglycolic/polylactic acid-covered platinum coils have been proposed to reduce the rate of aneurysm recanalization after endovascular treatment. A prospective and multicenter registry was conducted in France to evaluate the safety and short-term and midterm efficacy of Matrix coils. This analysis focused on anatomic midterm results. MATERIALS AND METHODS: Two hundred thirty-six patients harboring 244 ruptured or unruptured aneurysms treated via endovascular approach by using Matrix coils were included in this registry. Treatment was totally or partially performed by using Matrix coils. Anatomic results were evaluated on postoperative and last-follow-up digital subtraction angiography DSA) by using the Raymond scale. "Recanalization" was defined as worsening, and "progressive thrombosis" was defined as improvement on the Raymond scale. RESULTS: Anatomic midterm follow-up was obtained in 165 of 236 patients (70%) harboring 171 aneurysms (range, 6-27 months;mean, 14 +/- 4 months). At midterm follow-up angiography, 79 aneurysms were completely occluded (46.2%), 43 had a neck remnant (25.1%), and 49 had an aneurysm remnant (28.7%). Of 171 aneurysms, recanalization was observed in 44 patients (25.7%), including major recanalization in 18 patients (10.5%). Recanalization was more frequent if the embolized volume of aneurysm was <= 25%. Progressive thrombosis was observed in 52 aneurysms (30%). No bleeding or rebleeding was observed during the period of follow-up. CONCLUSION: The efficacy of Matrix coils in preventing recanalization was not demonstrated in our series. In agreement with previous studies using bare platinum coils, volumic occlusion was an important feature for the prediction of aneurysm recanalization. A high percentage of progressive thrombosis in incompletely treated aneurysms was observed in our series, suggesting a biologic activity of Matrix coils.