Abstract TP76: Medium-Term Angiographic Follow-up and Packing Density Analysis in a Series of 67 Consecutive Intracranial Aneurysms Treated Endovascularly with a Single Coil

Abstract

Purpose: To determine the medium-term angiographic outcome and packing density threshold for complete aneurysm occlusion at follow-up in a series of cerebral aneurysms treated with a single coil. Methods: We retrospectively identified all cerebral aneurysms treated with a single coil at our institution from July 1997 until September 2011. We recorded aneurysm dimensions, neck size, packing density, and follow-up catheter or MR angiograms to determine the angiographic outcome at last follow-up according to the Raymond scale. We then performed receiver operating characteristic (ROC) analysis of the likelihood of complete aneurysm occlusion at follow-up to determine the packing density maximum operating point (MOP). Results: Eighty-one aneurysms in 79 patients were treated with a single coil at our institution during the study period. Sixty-four patients were female (81%) and mean age was 53 years (range 23-87 years). Mean maximum aneurysm dimension was 2.8mm (range 1.6-4.8mm), and mean dome-to-neck ratio was 1.3 (median 1.3, range 0.8-1.9). Mean aneurysm packing density was 35.3% (median 32.8%, range 10.2-94.3%). Three patients with ruptured aneurysms died during the hospitalization (7.7%), and follow-up angiographic examinations were performed in 65 patients with 67 aneurysms (85.9%). Mean time to last angiographic follow-up was 26.4 months (range 4-102 months). Complete aneurysm occlusion at last follow-up was present in 46 aneurysms (68.7%), a neck remnant in 16 aneurysms (23.9%) and sac recanalization in 5 aneurysms (7.4%). ROC analysis of the likelihood of complete aneurysm occlusion at last follow-up yielded a packing density MOP of >36.3%, with a specificity of 85.7%, sensitivity of 47.8%, and an area under the curve of 0.61 (95%CI 0.49-0.73). There was a statistically-significant difference in the likelihood of complete aneurysm occlusion at last follow-up between the 25 aneurysms with a packing density >36.3% (88%), and the 42 aneurysms with a packing density ≤36.3% (57.1%, OR 5.5 [95%CI 1.4-21.3], p-value 0.009). Conclusion: Achieving a packing density >36.3% predicts a significantly higher likelihood (88%) of complete aneurysm occlusion at medium-term angiographic follow-up in cerebral aneurysms treated with a single coil.