Advances in no-reflow after stroke reperfusion therapy.

Representing a standard treatment for acute ischemic stroke, reperfusion therapy encompasses intravenous thrombolysis (IVT) and endovascular therapy (EVT). Although EVT achieves a high rate of complete large vessel recanalization, more than 50 % of patients who have successful reperfusion (modified Thrombolysis in Cerebral Infarction score of 2b-3) still don't have favorable outcomes. Therefore, futile reperfusion (FR) refers to the treatment failure to achieve favorable outcomes despite successful recanalization of occluded arteries and subsequent reperfusion of the downstream blood flow. FR may attribute to numerous causes including microvascular no-reflow, early arterial re-occlusion, hemorrhagic transformation, cerebral edema, irreversible infarction, evolution of infarction, and suboptimal post-reperfusion management. No-reflow may be an important pathophysiological mechanism of FR in stroke. The prevalence of no-reflow is relatively high in ischemic stroke patients with reperfusion therapy. However, there is currently no universally accepted effective treatment for it in stroke, largely due to the lack of imaging diagnostic standards. Thus, no-reflow after reperfusion therapy is still a pressing clinical challenge in stroke management that demands immediate resolution. In this review, we highlight the definition, pathophysiological mechanisms, imaging evaluation, predictors or markers, and intervention strategies of no-reflow in stroke as well as making research prospects.