Background: An in situ thromboocclusion (IST) is defined as an infarct extensively involving all or most of a stenosed arterial territory, which is one major stroke mechanism related to intracranial atherosclerosis (ICAS). We focused on ISTs occurring in major cerebral arteries and analyzed their rate of instant reocclusion during mechanical thrombectomy (MT) compared with non-ISTs. Also, we introduced a treatment strategy of low-dose intra-arterial tirofiban administration to prevent such reocclusion following repeat recanalization, and evaluated its safety and efficacy. Methods: We analyzed 168 consecutive patients treated with MT over a 2-year period from May 2011 to April 2013. During MT, if angiography following a successful recanalization showed stenosis at the occlusion site, we performed additional angiographic runs every 10 min for 30 min after the recanalization. Then, if angiography revealed reocclusion, we performed a repeat recanalization, using the same MT technique but additionally followed by low-dose intra-arterial tirofiban infusion. Time-of-flight MR angiography or CT angiography was performed to confirm any underlying ICAS at the occlusion site 5-7 days after the procedure. The patients who had confirmed underlying ICAS were included in the IST cohort. Results: Of 168 enrolled patients, we excluded 36 who could not be checked for underlying ICAS at the occlusion site for one of the following reasons: recanalization failure (n = 11), rescue stenting after tirofiban failure (n = 5) and lack of follow-up vascular imaging (n = 20). The incidence of IST was 30.3% (40/132). All IST patients were confirmed to have underlying ICAS by follow-up vascular imaging. Instant reocclusion after successful recanalization was significantly more frequent in the IST cohort [26/40 (65%) vs. 3/92 (3.3%); p < 0.001]. Regarding the efficacy of low-dose intra-arterial tirofiban infusion, 85.7% of the reocclusion patients finally achieved a thrombolysis in cerebral infarction score 2/3 recanalization, but in the remaining 14.3% of the cases, the condition was refractory to the procedure and required rescue stenting. There were no cases of symptomatic intracranial hemorrhage following the procedure. Conclusions: In situ thromboocclusion was characterized by a significantly higher chance of instant reocclusion during MT. In such cases, low-dose intra-arterial tirofiban administration may be effective and safe. However, future confirmation by prospective multicenter trials seems necessary.

BACKGROUND AND PURPOSE: Although intracranial atherosclerotic disease is often encountered during endovascular treatment for acute vertebrobasilar occlusions, its clinical implication is not well-known. We aimed to evaluate whether intracranial atherosclerotic disease influences the clinical outcomes following endovascular treatment of acute vertebrobasilar occlusive stroke. MATERIALS AND METHODS: Fifty-one patients with acute vertebrobasilar occlusive stroke were included. The onset-to-groin puncture time was ≤12 hours, and aspiration- or stent-based thrombectomy was used as the primary treatment method. Following primary endovascular treatment, intracranial atherosclerotic disease (IAD group) was angiographically diagnosed when a fixed focal stenosis was observed at the occlusion site, whereas embolism (embolic group) was diagnosed if no stenosis was observed. Clinical and treatment variables were compared in both groups, and IAD was evaluated as a prognostic factor for clinical outcomes. RESULTS: The baseline NIHSS score tended to be lower (14 versus 22, P = .097) in the IAD group (n = 19) than in the embolic group (n = 32). The procedural time was longer in the IAD group (96 versus 61 minutes, P = .002), despite similar rates of TICI 2b–3 (89.5% versus 87.5%, P = 1.000). The NIHSS score at 7 days was higher (21 versus 8, P = .060) and poor outcomes (mRS 4–6 at 3 months) were more frequent in the IAD group (73.7% versus 43.8%, P = .038). IAD (odds ratio, 5.469; 95% CI, 1.09–27.58; P = .040) was independently associated with poor outcomes. CONCLUSIONS: An arterial occlusion related to IAD was associated with a longer procedural time and poorer clinical outcome. Further studies are warranted to elucidate the appropriate endovascular strategy.

BACKGROUND AND PURPOSE: Although the PS has been the most promising mechanical thrombectomy device in terms of recanalization rates, even the PS cannot recanalize all cases of occlusion. Under such circumstances, we simply modified the PS, identified certain advantages, and applied this modification as a primary technique for recanalization. Here we describe and discuss the technical details and results of our preliminary experience. MATERIALS AND METHODS: This study included 22 consecutive patients with acute ischemic stroke secondary to large-artery occlusion who underwent modified thrombectomy by using the PS for recanalization. Direct wedging between the tip of the reperfusion catheter and the proximal part of the clot followed by forceful suction by using a 20- or 50-mL syringe is a unique feature of this technique. What is distinctive is that this does not require use of a separator or aspiration pump. RESULTS: All treated vessels (100%) were successfully recanalized. A TICI scale of 2b or 3 was achieved in 81.9% of patients. A 3-month favorable functional outcome (mRS score, 0–2) was achieved in 45.5% of patients. The only procedural complication was a transient dissection of the proximal ICA, which developed while advancing the guide catheter. CONCLUSIONS: Forced-suction thrombectomy is a simple modification of the PS. On the basis of our data, this technique allows safe and effective revascularization in acute large-vessel occlusion. Thus, for achieving the best outcome, the modified PS technique is proposed as a viable option for acute stroke management, either by itself or in conjunction with other devices or drugs.

Little is known about prognosis after endovascular therapy (EVT) for acute large artery occlusion (LAO) caused by underlying intracranial atherosclerotic stenosis (ICAS). Therefore, we investigated the prognosis following EVT according to the underlying etiology of LAO. Patients from the Acute Stroke due to Intracranial Atherosclerotic occlusion and Neurointervention-Korean Retrospective (ASIAN KR) registry (n=720) were included if their occlusion was in the intracranial anterior circulation and their onset-to-puncture time was <24 hours. Occlusion was classified according to etiology as follows: no significant stenosis after recanalization (Embolic group), and fixed significant focal stenosis in the occlusion site with flow impairment or re-occlusion observed during EVT (ICAS group). Patients were excluded when significant extracranial carotid lesions existed, and when the intracranial occlusion was intractable to EVT so that the etiology was undetermined. The effect of angiographic etiologic classification on outcomes was evaluated using multivariable analysis that was adjusted for potential confounders. Among eligible patients (n=520), 421 and 99 were classified in the Embolic and ICAS groups, respectively. Patients in the Embolic and ICAS groups had similar successful reperfusion rates with EVT (79.6% vs. 76.8%, P=0.537) and 3-month functional independence (54.5% vs. 45.5%, P=0.104). In multivariable analysis, ICAS-related occlusion (odds ratio, 0.495; 95% confidence interval, 0.269 to 0.913; P=0.024) showed poorer 3-month functional independence compared to embolic occlusion. s After EVT, patients with acute ICAS-related occlusion have relatively poor functional outcomes compared to those with embolic occlusion. Novel strategies need to be developed to improve EVT outcomes for ICAS occlusion.

Background and Purpose—: Acute intracranial occlusion can be associated with in situ thrombo-occlusion in relation to preexisting intracranial atherosclerotic disease. We aimed to assess residual stenosis at the site of a target arterial lesion (TAL) to determine whether residual stenosis at the TAL is associated with underlying intracranial atherosclerotic disease. Methods—: One hundred and sixty-three patients who underwent endovascular therapy for M1 middle cerebral artery occlusion and achieved angiographic reperfusion were selected for analysis. The presence of residual stenosis at the TAL was classified using the Arterial Occlusive Lesion (AOL) scale at postprocedural angiography, and the severity of stenosis was grouped into none, mild (<50%), moderate (50%–69%), severe (70%–99%), and occlusion on postprocedural and follow-up angiography. We also recorded the incidence of instant reocclusion occurring during the procedure and delayed reocclusion detected on follow-up angiography. Results—: Seventy-four patients (45.5%) showed target arterial residual stenosis (AOL 2). As to the TAL pathogenesis, 40 patients were classified into in situ thrombo-occlusion (54.1% of AOL 2 and 24.5% of M1 occlusion). The occurrence of instant or delayed reocclusion was independently associated with a low chance of favorable 3-month outcome. Furthermore, the occurrence of delayed reocclusion was associated with excellent pretreatment collateral flow and early neurological worsening, but not the severity of residual stenosis at the TAL. Conclusions—: In population with a high prevalence of intracranial atherosclerotic disease, residual stenosis may be attributed to in situ thrombo-occlusion with underlying intracranial atherosclerotic disease in ≈25% of cases, hindering functional recovery via the occurrence of instant or delayed reocclusion.