Revisiting 'progressive stroke': incidence, predictors, pathophysiology, and management of unexplained early neurological deterioration following acute ischemic stroke.

Early neurological deterioration (END) following acute ischemic stroke is a serious clinical event strongly associated with poor outcome. Regarding specifically END occurring within 24 h following stroke onset, apart from straightforward causes such as symptomatic intracranial haemorrhage and malignant edema, the cause of END remains unclear in more than a half of cases. In the latter situation, patients are often referred to as 'progressive stroke', a default clinical category that does not imply underlying mechanisms, precluding informed management. In this review article, we summarize the available evidence on the incidence, predictors, and associated factors of unexplained END, and discuss its underlying pathophysiology. We particularly address the hemodynamic and thrombotic mechanisms that likely play a critical role in unexplained END, and in turn highlight potential new avenues to prevent and manage this ominous event.