No-reflow phenomenon after vessel recanalization in acute ischemic stroke: mechanisms, diagnosis, and treatment directions.

Reperfusion therapy is the main treatment strategy for acute ischemic stroke (AIS). The no-reflow phenomenon (NRP) refers to the persistent impairment of microvascular tissue reperfusion after successful recanalization of large blood vessels, which significantly increases the risk of poor clinical outcomes in patients. Its prevalence after reperfusion therapy ranges from 3.3% to 63%. NRP is mainly caused by intraluminal occlusion and extraluminal constriction, involving multiple mechanisms such as distal embolization of emboli and microthrombus formation. Additionally, inflammatory responses, cerebral edema, and abnormal interactions among components of the neurovascular unit (NVU) are also involved. Clinically, various preventive and therapeutic strategies have been explored, including targeted therapy, pericyte modulators, post-ischemic conditioning, and traditional Chinese medicine. Meanwhile, multiple clinical, imaging, and other methods are used for the identification of NRP. This article focuses on the pathological mechanisms, diagnostic evaluation, and therapeutic directions of NRP, aiming to clarify the orientation for the diagnosis and treatment of AIS patients after recanalization therapy and related future research.