Endovascular treatment of a basilar tip aneurysm via a persistent primitive proatlantal intersegmental artery

Abstract

Background: A proatlantal intersegmental artery is an anastomosis between the carotid and vertebrobasilar arterial systems that exists in the developing fetus to temporarily maintain the posterior cerebral circulation. Failure of this artery to obliterate once the vertebral arteries are developed results in a persistent primitive proatlantal intersegmental artery (PPPIA). We present a patient with a basilar tip aneurysm that was exclusively supplied by a PPPIA, serving as the only corridor to accessing the aneurysm endovascularly. We report the first case of an elective endovascular stent-assisted coiling of a basilar tip aneurysm via a PPPIA and review this rare anatomic variant in a clinical setting. Case report: The patient is a 60-year-old Caucasian male who presented with recurrent headaches and blurry vision after sustaining mild head trauma. Imaging revealed a basilar tip aneurysm, and the patient elected for endovascular treatment. He was furthermore found to have an anatomic variant of a proatlantal artery in the context of bilateral vertebral artery hypoplasia, thus his posterior circulation was entirely supplied by the fetal remnant vessel. The patient underwent a successful stent-assisted coil embolization of the aneurysm. Conclusion: PPPIA is a rare vascular anomaly that may be associated with intracranial vascular pathology. Awareness and intricate understanding of the anatomy of embryologic remnants such as the PPPIA is central to planning neuro-interventional access and avoiding complications. Keywords: Aneurysm, Basilar tip, Congenital, Proatlantal, Endovascular, Stent-assisted coiling