Anterior Communicating Artery Aneurysm: Stent-Assisted Anterior Communicating Artery Aneurysm Coil Occlusion – A Duplicated AcomA as a Potentially Dangerous Cause of a Nonexpanding Stent

Abstract

The 55-year-old male patient was already suffering from severe three-vessel atherosclerotic heart disease. In December 2016 he had experienced an embolic stroke to the central territory of the right middle cerebral artery (MCA). The diagnostic work-up at that time revealed a 70% stenosis of the right internal carotid artery (ICA) and an incidental aneurysm of the anterior communicating artery (AcomA) measuring 7 mm in diameter and with a wide neck. The patient was scheduled for stent-assisted endovascular treatment. The endovascular strategy was to bridge the neck of the aneurysm from the right A2 segment to the left A1 segment. While deploying the stent, it became apparent that the distal end of the stent was opening well, but the proximal portion showed insufficient expansion. The stent was resheathed, and during this procedure, we acquired a DSA run in a slightly different projection. This run showed that we had attempted to deploy the stent in a very thin duplication of the AcomA, which had been invisible in the previous DSA runs. After maneuvering the microcatheter through the branch of the AcomA with the aneurysm, the stent could be regularly deployed, and the aneurysm was then completely occluded with detachable coils. Incomplete opening of self-expanding intracranial stents is not a rare observation, especially in the case of tortuous vessel anatomy or if the movement of the stent-bearing wire is restricted. Our example shows that anatomical variations of the AcomA complex also need to be taken into consideration should a self-expanding stent not fully expand. The increasing use of low-profile self-expanding stents and flow diverters that can be advanced through ever thinner microcatheters may facilitate the advancement of the microcatheter into anatomical variants that are so tiny that they may be invisible during standard DSA runs. In our patient, any attempt to open the stent with a balloon, which is often a strategy called upon for an incompletely expanded stent, would have been fatal. Potential complications due to inadvertent deployment of low-profile self-expanding stents into small-caliber intracranial arteries are the main topic of this chapter.