Abstract 2605: Comparison of Intra-Operative Indocyanine Green Angiography and Digital Subtraction Angiography for Clipping of Intracranial Aneurysms

Abstract

BACKGROUND: The presence of residual aneurysm after microsurgical clipping carries a risk of aneurysm growth and rupture. Digital subtraction angiography (DSA) is the gold standard to determine the adequacy of clipping post-operatively. Intra-operative Indocyanine green (ICG) angiography is increasingly utilized to confirm optimal clip positioning across the neck and to evaluate adjacent vasculature. We evaluated the correlation between ICG and DSA in clipped intracranial aneurysms. METHODS: This is a retrospective study of patients who underwent craniotomy and microsurgical clipping of intracranial aneurysms with ICG between January 2010 and May 2011. A chart review was performed to abstract the baseline characteristics and details of presentation of patients, details of the operative reports of clipping were reviewed, and pre and post clipping angiographic images were reviewed to determine the adequacy of clipping. Post-clipping DSA was evaluated by two physicians not involved in the care of the patient for the presence of residual aneurysm and patency of branch vessels/parent artery. RESULTS: Twelve patients (58 % female, mean age 53.6) underwent clipping of intracranial aneurysms with ICG and had post-operative DSA. Operative reports indicated complete clipping of all aneurysms without compromise of branch vessels. Postoperative DSA was performed in follow-up ranging from 1 day to 6 months. Seventeen aneurysms were clipped, seven patients (58.3%) presented with subarachnoid hemorrhage. Thirteen aneurysms were located in the anterior circulation (avg. size 7.3mm) and four in the posterior circulation (avg. size 6.6mm). Four patients had two aneurysms clipped in the same setting. Of the 17 aneurysms treated 5 aneurysms demonstrated a residual on DSA not identified on ICG. The residual sizes ranged from 0.8-4.3 mm with an average size of 1.2mm. There was no apparent predilection to location; three were in the anterior and two in the posterior circulation. Post-operative DSA demonstrated no branch occlusions, two patients demonstrated slow flow in the posterior communicating artery, and there was no compromise of the parent vessel in any cases. CONCLUSION: Intra-operative ICG is useful in the microsurgical clipping of intracranial aneurysms to ensure patency of branch vessels. However, the presence of residual aneurysm and subtle changes in flow in branch vessels is best seen by DSA. This has important clinical implications in regards to immediate post-operative management, the need for delayed follow-up imaging, and decisions to re-treat incompletely clipped aneurysms.