Durability of aneurysm embolization with matrix detachable coils

OBJECTIVE: Matrix detachable coils (MDC; Boston Scientific/Target, Fremont, CA) are platinum coils coated with a bioabsorbable polymeric material (polyglycolic-polylactic acid). In animal models, the introduction of polyglycolic-poly lactic acid-coated coils into experimental aneurysms resulted in a cellular reaction which promoted stable intra-aneurysmal scar tissue formation. The current study was undertaken to assess the durability of aneurysm occlusion after embolization with MDC. METHODS: All patients undergoing embolization were prospectively enrolled in an endovascular database at our institution. All coils used for embolization were recorded in the operative notes for the procedure. Only aneurysms embolized with 50% or greater length of MDC were included. All patients with Neuroform stents (Boston Scientific/Target, Fremont, CA) were excluded from the study. Patients were followed with conventional angiography and magnetic resonance angiography. RESULTS: During a 20-month period, 131 aneurysms were embolized with MDC. Follow up data (average, 6.9 mo; range, 1.5-22 mo) were available for 82 aneurysms (61 with conventional angiography, 21 with magnetic resonance angiography only). Of the aneurysm patients with follow-up available, 65 had small aneurysms with small necks, three were small aneurysms with wide necks, 12 were large aneurysms, and two were giant aneurysms. Overall, there were 30 (36.6%) recanalizations, 19 (23.1%) of which required retreatment. In two additional patients, retreatment was either recommended (n = 1) or attempted unsuccessfully (n = 1). Fifty-two aneurysms were unchanged or demonstrated progressive thrombosis (63.4%). The recanalization rate for small aneurysms with small necks was 26.1% (17 out of 65) with a 13.8% retreatment rate (9/65). The recanalization rate for large aneurysms was 75% (9 out of 12) with seven requiring retreatment. CONCLUSION: In the absence of Neuroform stent support, aneurysms embolized with the MDC system demonstrated a significant rate of recanalization. Many of the recanalizations were of sufficient size to warrant retreatment. The rates of recanalization observed in the present series were comparable to, or worse than, those reported for bare platinum coils.