I n cerebral ischemia due to large-vessel occlusion, cell viability depends on the collateral perfusion status (1,2). Infarction might be complete in less than 1 hour or may not be complete for hours or days depending on the collateral perfusion status, which varies among patients (3,4). Therefore, recanalization and reperfusion treatment can be futile or even dangerous when performed in the standard optimal time window, but could be useful if performed in a later time window (5)(6)(7)(8). Studies have shown that a large ischemic core combined with poor collaterals is a strong predictor of an unfavorable response to endovascular treatment and poor functional outcomes. Hence, the exclusion of patients with a large ischemic core and poor collateral circulation could prevent administration of futile and dangerous recanalization therapy. Conversely, good collateral circulation can limit ischemic core expansion and prolong the time the penumbral tissue at risk remains salvageable until reperfusion therapy. Some studies have suggested that the time window for endovascular treatment can be successfully extended in patients with good collaterals (9-14). These results demonstrate the importance of accurately estimating the collateral perfusion status to enable patientspecific application of treatment, thereby improving functional outcomes among patients with acute ischemic stroke due to large-vessel occlusion.Recently, researchers have developed dynamic collateral imaging methods such as multiphase CT angiography and collateral flow maps derived from dynamic susceptibility contrast material-enhanced perfusion MRI (15,16). Studies evaluating these collateral imaging approaches have shown that collateral status is a strong predictor of final infarct size and functional outcomes in patients considered eligible for intra-arterial thrombectomy and intravenous thrombolysis (17,18). For intra-arterial thrombectomy, it

ObjectiveThe outcome evaluation for the revascularization of intracranial vascular stenoses has not been fully described due to the highly technical nature of the procedure. We report here on the early and late clinical outcomes of angioplasty and/or stenting of symptomatic severe intracranial vascular stenoses at a single institute.Materials and MethodsSince 1995, we have treated 35 patients with symptomatic intracranial vascular stenosis (more than 70% stenosis, mean stenosis: 78.6% ± 6.2%). Angioplasty (n = 19) was performed for the horizontal segment of the middle cerebral artery (M1) (n = 16) and the basilar artery (BA) (n = 1), the intradural vertebral artery (VA) (n = 1), and the cavernous internal carotid artery (ICA) (n = 1). Stenting (n = 16) was performed for the cavernous or petrous ICAs (n = 9), the intradural VA (n = 3), BA (n = 2), and M1 (n = 2) artery. We assessed the angiographic success (defined as residual stenosis < 50%) rate, the periprocedural complications during the 30-day periprocedural period, the symptomatic recurrence and restenosis during a mean 22-month follow-up (FU) period. The Kaplan-Meier estimate of the cumulative event-free rate of the major cerebrovascular events, i.e. death, stroke or restenosis, was also done.ResultsAngiographic success was achieved in 97% of our patients (34/35). There were four procedure-related complications (11%) including a death and a minor stroke. During the mean 22-month FU, the asymptomatic restenosis rate was 9% and the symptomatic restenosis rate was 6% in the target lesion and 9% in all the vascular territories. The Kaplan-Meier estimate was 70.6% (95% confidence interval = 46.5-94.7) after 33 months of FU.ConclusionIn addition to a high angiographic success rate and an acceptable periprocedural complication rate, intracranial angioplasty and/or stenting revealed a relatively low symptomatic recurrence rate. Hemorrhage is a rare, but the physician must aware that potentially fatal periprocedural complications can occur.