Salvage flow diverter stent across the posterior communicating artery for persistent retrograde filling of a giant internal carotid artery aneurysm after parent vessel occlusion

Giant internal carotid artery (ICA) aneurysms are complex vascular lesions which are difficult to treat with open as well as endovascular surgery. Parent vessel occlusion is a well-established treatment option for such aneurysms. However, there have been a few reported cases of ruptured aneurysms related to the persistent retrograde filling after parent vessel occlusion. We report a case which highlights the usage of the flow diverter stent as a potential treatment strategy for the management of retrograde filling of aneurysms. A 54-year-old female was found to have a giant left ICA aneurysm on a brain magnetic resonance imaging during workup for headaches. She underwent occlusion of the left ICA proximal to the aneurysm using multiple coils. However, follow up angiograms after 6 months and 2 years demonstrated persistent retrograde filling of the left ICA aneurysm through the posterior communicating (PCOM) artery. Eventually, she was successfully treated with a flow diverter stent across the PCOM artery into the distal ICA. Follow up angiogram after 6 months showed patent flow in the PCOM artery and the distal ICA. with complete occlusion of the aneurysm. Using a flow diverter stent after insufficient parent vessel occlusion for giant intracranial aneurysms may be a feasible treatment option and an addition to the neurovascular treatment armamentarium.