Distal posterior cerebral artery revascularization for a fusiform PCA aneurysm: A lesson learned.

The need for revascularization with proximal posterior cerebral artery occlusion in the treatment of giant and fusiform aneurysms is unclear. While early series demonstrated only about a 10% chance of infarction following posterior cerebral artery occlusion, recently several authors have advocated a bypass prior to parent vessel sacrifice in all cases. We present the case of an adult man with a fusiform aneurysm of the right posterior cerebral artery at the P2-P3 junction. He clinically failed a balloon test occlusion preoperatively and therefore underwent an occipital artery to distal posterior cerebral artery bypass with subsequent endovascular occlusion of the parent vessel and aneurysm. Despite the fact that the immediate and 6 month follow up cerebral angiography confirmed a patent bypass, the patient still developed a posterior cerebral artery territory stroke. We believe this case demonstrates that successful distal revascularization in the setting of proximal posterior cerebral artery occlusion does not guarantee against cerebral ischemia and infarction even in those patients that fail a test occlusion.