Persistent primitive trigeminal artery in stroke: A review and clinical insights

The persistent primitive trigeminal artery is the most common remnant of the embryonic carotid-basilar connection. While its anatomy is well documented, its clinical significance in strokes remains debated. Some studies suggest it predisposes ischemia through altered hemodynamics, whereas others report a protective role via collateral circulation. This review summarizes the current knowledge on the anatomy, imaging, and clinical implications of the persistent primitive trigeminal artery in strokes. A literature search of PubMed, Scopus, and Embase up to March 2025 identified relevant case reports, imaging studies, and clinical series. The artery typically arises from the cavernous segment of the internal carotid artery, courses alongside the trigeminal nerve, and terminates in the posterior circulation. Classification systems describe variations in its termination, course, and vascular supply. Magnetic resonance and computed tomography angiography are key diagnostic tools, each with their advantages and limitations. Evidence shows two opposing roles: either as a conduit for steal phenomena, turbulent flow, and thromboembolism or as a collateral channel that preserves cerebral perfusion during carotid or vertebrobasilar occlusion. Understanding this vessel's anatomy and potential hemodynamic effects are critical for accurate diagnoses, risk assessments, and treatment planning. Its dual nature highlights the importance of individualized evaluations and further research to clarify its role in strokes.