The success of endovascular therapies depends on a number of factors including flow dynamics proximal and distal to the occlusion. The evaluation of antegrade flow distal to the occluded segment is currently a readily available, yet unexplored, option during stentriever-mediated thrombectomy. In this study, we retrospectively evaluated presence of contrast stasis and absence of capillary blush on angiograms obtained by selective injections into the distal site of occlusive thrombi, prior to deployment of stentrievers, in patients undergoing endovascular treatment for acute MCA occlusion. The role of this novel angiographic strategy assessing distal antegrade flow in predicting procedural and clinical outcome was compared to previously defined, prognostic angiographic characteristics. A total of 7 (21%) out of 34 patients had contrast stasis and lack of capillary blush downstream to the injection site. None of these patients with angiographic features suggestive of microcirculatory obstructions achieved a satisfactory outcome in terms of reperfusion (TICI grade 2B-C) and clinical outcome (90-day mRS 0-2), while the corresponding figures were 78% (p < 0.001) and 48% (p = 0.029), respectively, among patients with substantial capillary filling. These findings highlight the potentially detrimental impact of impaired microcirculatory flow on tissue and clinical outcome after recanalization/reperfusion efforts in acute ischemic stroke.
Keywords: Angiography; Capillaries; Collaterals; Reperfusion; Thrombectomy.