ABSTRACT
References ................................................................................................................36
The angiographic evaluation during endovascular treatment provides an important contribution to understand the physiopathology of acute ischemic stroke. The site of occlusion, the collateral circulation, and the grade of recanalization achieved may be correlated with the main clinical variables such as the time of ischemia, the depth of ischemia (National Institutes of Health Stroke Scale [NIHSS] score), and the clinical outcome after 3 months (mRS). Therefore, it would be possible to consider the angiographic evaluation as an individual window of observation of the effects of the arterial occlusion and the recanalization, if achieved. Several studies reported a signicant correlation between the successful recanalization (TICI 2b-3), the baseline NIHSS, the hyperglycemia, and the favorable clinical outcome (3 months mRS 0-2) so that these are considered relevant predictors (Wechsler et al., 2003; Bill et al., 2013). However, in some cases, a successful recanalization is not associated with a favorable modication of the clinical course, and some patients may have a good recovery even if an adequate recanalization is not obtained. Following these assumptions, it would be reasonable to argue that there is no linear correlation between the grade of the recanalization and the clinical outcome and that also other factors are involved in the determination of the functional independence. Indeed, the clinical evolution seems to be correlated with the effect of the recanalization on the capillary territory distal to the occlusion (reperfusion) rather than to the ow restoration, since a late recanalization could also be associated with negative clinical outcomes or death (futile recanalization) (Hussein et al., 2010; Meyers et al., 2011; Rai et al., 2012). The recanalization is, indeed, a dynamic event that could be associated with immediate reocclusion of the artery (retrothrombosis) secondary either to the presence of residual embolic material, in case of partial recanalization, or to the presence of an underlying atheromatic lesion. Furthermore, the failed reperfusion of the territory determines the slowdown of the blood ow within the ischemic area that contributes to the process of reocclusion (no-reow phenomenon) (Del Zoppo and Mabuchi, 2003; Adhami et al., 2006; Del Zoppo, 2008). Understanding the dynamic mechanisms of the recanalization and reocclusion is fundamental to establish the principles that should set the strategy of the endovascular treatment of acute ischemic stroke on the biological characteristics of the patient. For this reason, we will consider separately the factors inuencing the recanalization of the occluded artery and those that are involved in the dynamics of the cerebral reperfusion.
