Abstract 1122‐000192: Transient Blood Flow Reversal in The Vertebral Artery As an Embolic Protection Method During Angioplasty/Stenting

Introduction : Approximately 20% of all acute ischemic strokes occur in the vertebrobasilar (VB) circulation. Similar to carotid stenosis, symptomatic vertebral artery (VA) stenosis is associated with a high risk of stroke recurrence. The use of embolic protection devices for recanalization in the setting of carotid stenosis in order to improve clinical outcomes is well established. Recent randomised trials have failed to demonstrate improvement of clinical outcomes in VB stroke patients treated with stenting. To our knowledge, these studies did not require the use of embolic protection devices or techniques. This may be due to several factors. Firstly, since the caliber of the stenotic segment of VA is not large enough to safely allow the protection device delivery system to pass through, initial angioplasty without protection is needed. Secondly, the most common segment of VA to become stenotic is its origin, and usually after stenting of this segment, the edge of the stent is protruding into the SCA. When the angle of the VA relative to the SCA is acute, passing the filter capture catheter through this protruded stent is very difficult and dangerous. Methods : We are introducing a VA reversal blood flow technique for prevention of emboli through the VB system in the setting of symptomatic extracranial VA stenosis. In this technique, we used a balloon tip guide catheter in order to transiently occlude the proximal segment of the SCA, causing flow arrest. We then evaluated the presence of blood flow reversal in the VA. Theoretically, this induction of blood flow reversal in the VA can be considered protective because it washes the embolic particles into the distal SCA. Results : Of the 11 cases of VA origin symptomatic stenosis, 4 had desirable VA blood flow reversal after balloon occlusion trial. These patients had successful angioplasty‐stenting of the VA origin using balloon mounted stent without major complications such as ischemic stroke in the posterior circulation territory. Conclusions : This study demonstrates the feasibility of proximal SCA balloon occlusion to cause transient flow reversal in the VA during angioplasty +/‐ stenting of the proximal VA. Future studies are required to determine the effectiveness of this approach in the setting of extracranial VA stenosis due to atherosclerosis, especially at its proximal segment.

Abstract 1122‐000174: Stroke Risk of Carotid Artery Stenting Using Balloon‐Guide Catheter Versus Distal Embolic Protection Devices

Introduction : Prevention of distal embolization during carotid artery stenting (CAS) is a key element of procedural technique and is standardly performed using distal protection devices (DPDs). Data in support of DPDs, however, are limited. Here, we present our experience of proximal occlusion using a balloon guide catheter (BGC) during CAS as the primary method of distal embolic protection. Methods : We conducted a retrospective review of patients undergoing CAS at our healthcare system between January of 2018 to March of 2021. Procedures were categorized by embolic protection strategy: DPD or BGC (with or without DPD). Emergent cases were defined as patients receiving CAS within <24 hours of presenting with an ischemic stroke or TIA ipsilateral to the carotid disease side. Severe stenosis was defined as 70–99% per NASCET criteria. The primary outcome was rate of procedural ischemic stroke between the DPD and BGC groups, and was defined as acute focal neurological deficit lasting for ≥ 24 hours following CAS related to an embolic event during the procedure. Results : A total of 126 CAS procedures were performed during the study period. 91 cases were performed under proximal BGC protection (of which 24 also included DPD usage) and 35 CAS cases via DPD as a primary mean for embolic protection. The median age for the cohort was 68 [IQR 62‐76], 37% females, 31% (n = 39) cases were treated emergently, and elective cases were 69% (n = 87). Baseline characteristics were similar in both groups except for hyperlipidemia (BGC vs DPD, 71.4% vs 42.9%; p = 0.003) and history of smoking (BGC vs DPD, 56% vs 34.4%; p = 0.029). Severe carotid stenosis was present in 80.2% BGC group and 77.1% in DPD (p = 0.573). Post‐stenting balloon angioplasty was more frequent in the BGC group as compared with DPD (54% vs. 26%, BGC vs. DPD, p = 0.005). Procedural embolic stroke rates were low in both groups, and not significantly different (1.1% vs. 2.9%, BGC vs. DPD, p = 0.48). Conclusions : CAS with BGC as the primary means of distal embolic protection showed comparable, low rates of procedural embolic ischemic events compared to those with DPD. These findings suggest BGC embolic strategies may be a viable alternative to DPD usage.