Blood Blister−Like Aneurysms at the Junction of the Internal Carotid and Posterior Communicating Artery: Characteristics and Treatment Strategies

Abstract

Blood blister-like aneurysms (BBAs) usually arise from the anterior walls of the internal carotid artery (ICA), and such lesions at the junction of ICA and posterior communicating artery (PCoA) have not been reported to date. Here, we firstly report our experiences of BBAs at PCoA, and studied their clinical and angiographical characteristics including internal carotid (IC)-PCoA angle, an indicator of hemodynamic stress at the bifurcation. Three patients with BBAs located at the origin of PCoA were studied. Wrap-clipping was adopted as the first-line therapy, but direct clipping was conducted when difficult. All patients were elderly females (mean age 81.3 years), and BBAs were very small in size (mean maximum diameter 1.5 mm), which arose at the origins of wide-angled fetal-type PCoAs (mean IC-PCoA angle 37.8 degrees). All the lesions were treated by surgery (direct clipping 2, wrap-clipping 1), and severe atherosclerotic changes were observed at adjacent arterial walls in all cases. Ordinary wrap-clipping using a polytetrafluoroethylene membrane via the trans-Sylvian approach was difficult due the limited working space, requiring some special techniques such as usage of fenestrated clips, polyglycolic acid sheets, and combined approach with subtemporal craniotomy. Good clinical outcomes were achieved in two patients. BBAs at PCoA were predominantly occurred as the very small bulges at the origins of wide-angled fetal-type PCoAs in elderly females. Hemodynamic stress and atherosclerosis would contribute to the aneurysmal formation. Wrap-clipping or direct clipping with additional techniques would be useful for this rare condition.