A99 Mechanical thrombectomy for basilar artery occlusion through a type 2 persistent proatlantal artery

<h3>Introduction</h3> The persistent proatlantal artery (PPA) is one of the rare types of persistent primitive carotid-vertebrobasilar anastomoses. While the PPA itself is an uncommon anatomical variant, basilar artery occlusion (BAO) occurring in the setting of a PPA is extremely rare. <h3>Aim of Study</h3> To present a rare case of acute basilar artery occlusion successfully treated by mechanical thrombectomy through a Type 2 PPA, and to review relevant literature on this unusual vascular anomaly. <h3>Method</h3> A 50-year-old male patient presented with left-sided motor weakness. Preprocedural MRI revealed an acute infarction in the pons and basilar artery occlusion. Cerebral angiography showed absence of both proximal vertebral arteries and the presence of a Type 2 persistent proatlantal artery originating from the left external carotid artery. Mechanical thrombectomy was performed via the PPA using a contact aspiration technique, achieving successful recanalization of the basilar artery. <h3>Results</h3> The patient showed a favorable clinical course with a modified Rankin Scale score of 2 at 90 days. <h3>Conclusion</h3> In patients with acute vertebrobasilar occlusion and absent vertebral arteries, the possibility of a persistent primitive carotid-vertebrobasilar anastomosis, such as a Type 2 persistent proatlantal artery, should be considered. Recognition of such rare anatomical variants is essential for planning effective endovascular treatment. <h3>Conflict of Interest</h3> No