“No-Reflow” Phenomenon After Successful Recanalization of a Medium Vessel Occlusion in Late Time Window Stroke

A significant proportion of patients treated with reperfusion therapies continue to have a poor prognosis due to a variety of adverse events. The “no-reflow” phenomenon after successful recanalization is a potentially overlooked aspect of post-stroke pathophysiology. Reduced microvascular reperfusion after complete recanalization primarily affects the precapillary arteriole, capillary, and postcapillary venule. There are several theories regarding its mechanism, and it is not clear which perfusion maps and parameters are best suited to diagnose the no-reflow phenomenon. We describe a representative case of medium vessel occlusion in a 74-year-old female patient with a right frontal branch occlusion of the middle cerebral artery (MCA) with late treatment. MCA reperfusion was performed with a stent retriever. Despite successful recanalization and no progression of the ischemic core, the patient showed no clinical improvement. The “no-reflow phenomenon” is the main topic of this chapter.