Abstract 1122‐000138: De Novo Intracranial Stenosis after Mechanical Thrombectomy with Stent Retrievers

Introduction : Increased vascular damage with the use of stent‐retrievers (SR) has been shown on histopathological analysis of the vascular tissue immediately after mechanical thrombectomy (MT) in animal models. We hypothesized that intraoperative endovascular damage‐intimal injury could result in fibrosis and de novo vascular stenosis (dnVS). The purpose of the study is to identify de novo or worsening intracranial stenosis (wICS) of the treated vessel(s) on patients who underwent MT for the treatment of acute ischemic stroke with SR, on follow‐up vascular imaging (FVI). Methods : This was a retrospective chart review. Patients who underwent MT with SR at two centers from January 2015‐December 2020, who had FVI (CTA, MRA or cerebral angiogram) were included. Patient characteristics, procedural details, timing for FVI and clinical outcomes were collected. Two neuroradiologists reviewed baseline angiograms and FVI to assess for the presence of dnVS or wICS, and graded each stenosis and collateral scores (CS), when stenosis was present. CS were calculated using the multiphase CT angiography collateral score (mCTA). Fischer exact test and Mann‐Whitney U test were used to assess for differences in categorical and continuous variables, respectively. Statistical analysis was performed using SPSS 28.0 (IBM Corp.). Results : Forty‐six patients within this cohort had FVI with 9 patients developing dnVS or wICS in the follow‐up period (19.6%) with a median follow‐up of 113 days. Five of these patients demonstrated a complete occlusion of the target vessel on FVI. Of the remaining 4 patients, mean degree of stenosis was 55%. Only 2 of these patients had underlying stenosis on baseline post‐treatment angiogram: one with 44% stenosis which progressed to 95% in 2 months. Another with mild stenosis that progressed to complete occlusion in 50 days. Adequate revascularization, defined as TICI score >2b was achieved in 88.8% of patients with dnVS or wICS, and in 89.2% of patients with stable FVI. No significant differences were observed in baseline demographics, NIHSS score at presentation or initial ASPECTS. Median number of passes was identical between patients who developed dnVS or wICS (median 1, IQR [1, 2], p = 0.683). Mean CS for dnVS or wICS was 3. No significant differences were observed in discharge or follow‐up NIHSS scores, mRS, mortality, or recurrent stroke or TIA between the two cohorts. Conclusions : MT with SR can be associated with dnVS or wICS in some patients. The number of passes with SR did not seem to have an impact on this. Patients with dnVS or wICS did not have a higher incidence of recurrent stroke or TIA. This could be due to the development of new collaterals in this population. Our study is limited by a small cohort, however, larger studies might be challenging as standardized radiological follow up of these patients has not been implemented.

Abstract 1122‐000095: Revisiting the Role of Angioplasty and Stenting for Symptomatic Intracranial Stenosis ‐ A Case Series

Introduction : Early and long‐term results of the SAMMPRIS trial showed superiority of aggressive medical management over stenting in patients with symptomatic intracranial stenosis, in part due to the high risk of periprocedural complications. However, even with maximal medical management, the risk of recurrent TIA or stroke in patients with high‐grade stenosis often remains elevated. Methods : A review of our stroke database was conducted, identifying three relevant cases. Results : CASE 1: A 69 year‐old man with multiple vascular risk factors and atrial fibrillation on apixaban presented with several months of multiple stereotyped episodes of limb‐shaking TIAs affecting the left leg, often leading to falls. CT angiogram revealed 70–80% stenosis of A2 segment of right ACA. Symptoms completely resolved after stenting with Neuroform Atlas stent. Repeat angiogram at 6 months showed excellent vessel caliber. CASE 2: A 78 year‐old man with hypertension, DM, CAD, and known left ICA occlusion presented with recurrent episodes of aphasia and right arm weakness while on maximal medical therapy. CT angiogram showed severe right supraclinoid ICA stenosis which was corrected with Resolute Onyx DES stent with improvement of symptoms. CASE 3: A 77 year‐old with hypertension, DM, CAD and aortic dissection on dual antiplatelet therapy and high‐intensity statin was admitted with stereotyped, blood pressure‐dependent episodes of aphasia and right face/arm weakness secondary to high‐grade stenosis of both M2 divisions of the left MCA. Successful angioplasty and Y‐stenting with Neuroform EZ and Wingspan stents led to complete resolution of symptoms. Conclusions : At high‐volume centers and with newer interventional devices and techniques, intracranial angioplasty and stenting should be considered as a valuable therapeutic option in patients with symptomatic intracranial stenosis refractory to maximal medical therapy.

Value of vessel wall magnetic resonance imaging in the diagnosis and management of cerebrovascular diseases

Background Intracranial atherosclerosis, one of the leading causes of ischemic stroke, is associated with an increased risk for recurrent stroke and dementia. Objective This work was carried out to assess suspicious lesions detected by Magnetic Resonance Angiography (MRA) and Computed Tomgraphy Angiography (CTA) for further evaluation by vessel wall MRI . Patients and methods This study was conducted on 16 patients who were admitted to Ain Shams University Specialized Hospital with establilished diagnosis of stroke (11 patients with intracranial atherosclerosis, 3 patients with CNS vasculitis and 2 patients with Moya-moya disease ) performing MRI brain including magnetic resonance angiography (MRA) that showed intracranial stenosis, who then referred to Misr Radiology Center for the evaluation of intracranial vasculopathies by vessel wall MR Imaging using 3.0-tesla (T) field strengths. Results The results showed statistically significant difference between groups as regard to significant intracranial stenosis (>50%). It was prominent among moya moya disease group (100.0%) followed by intracranial atherosclerotic groups (81.8%), whereas CNS vasculitis group shows mild intracranial stenosis (0.0%). Conclusion Intracranial vessel wall MR imaging is an adjunct to conventional angiographic imaging