Safety and Feasibility of Reconstructing Dissection Tandem Lesions with Flow Diverter Stents during Mechanical Thrombectomy for Acute Ischemic Stroke: A Multicenter Retrospective Case Series

BACKGROUND Patients with acute ischemic stroke due to large vessel occlusion may present with concomitant carotid dissections that make the technical approach for their treatment challenging. The purpose of this study was to determine the safety and feasibility of flow diverter (FD) stents to treat carotid artery dissections in tandem lesions of acute ischemic stroke patients during mechanical thrombectomy. METHODS A retrospective review of all patients in which a carotid artery dissection was treated with an FD during endovascular treatment of acute ischemic stroke between 2018 and 2020 was conducted in 5 high‐volume Comprehensive Stroke Centers. Patient clinical and angiographical characteristics, postoperative outcome, and follow‐up were recorded. RESULTS A total of 12 patients (mean age: 54.18±14.74 years, median Alberta Stroke Program Early CT Score: 10 [interquartile range 9–10]) were included. Successful FD stenting with immediate patency of the dissected segments and successful intracranial recanalization modified thrombolysis in cerebral infarction score 2b‐3 after thrombectomy was achieved in all patients. A good outcome (modified Rankin scale 0–2 at 90 days) was achieved in 66% (8/12) of patients. In 25% (3/12) of patients, an additional self‐expanding carotid stent was used to anchor the FD proximally at the carotid bulb level. Complications included 1 symptomatic intracranial hemorrhage after procedure (24–48 hours) and 2 in‐stent stenoses at follow‐up. CONCLUSIONS In this small case series, the treatment of carotid artery dissection with FD stents was safe and technically feasible during mechanical thrombectomy of acute ischemic stroke patients with tandem lesions and resulted in a high rate of good clinical outcome. These results may provide the basis for designing larger prospective studies to assess the efficacy and safety of FD stents in selected patients with carotid tandem lesions.

The Q and A—The MIVI Q Catheters for Aspiration Thrombectomy—Initial Experience from London

Background: Aspiration thrombectomy is a widely accepted treatment option for large vessel occlusion (LVO). The MIVI aspiration system has a novel design to maximize the lumen size. We present the results of our initial experience with this innovative aspiration thrombectomy system. Materials and Methods: Retrospectively, we reviewed our database to find all cases of LVO treated with the MIVI Q system (February 2019 and July 2020). In addition, we recorded the baseline demographics, NIHSS, ASPECT, mTICI scores, procedural time, complications, and 90 day mRS. Results: Herein, we identified 25 patients with an average age of 65.3 ± 19.3 years (range 19–89), majority of whom were female (n = 14, 56%). The average NIHSS was 16.9 ± 6.7 (range 6–30), and the average CT ASPECT was 7.9 ± 1.4 (range 5–10). The most common clot location was the M1 segment of the MCA (n = 16, 64%). Four of the patients had tandem lesions (16%). The average clot length was 21.7 ± 31 mm (range 2–130 mm). Of the 23 cases where the Q catheter reached the proximal clot face, mTICI ≥ 2b was achieved on the first pass in 11 cases (44%), and at the end of the ‘Q aspiration’ only the procedures with 16 patients achieved mTICI ≥ 2b recanalization (64%). Stent-retrievers were used in 13 cases (52%). At the end of the procedure, 24 patients (96%) achieved mTICI ≥ 2b with 18 patients (72%) achieving mTICI ≥ 2c. The average number of passes with the Q catheter, including when it was used for SOLUMBRA, was 2.1 ± 2.2 (range 1–10). The mean procedure time was 69 ± 32 mins (range 7–116 mins). No complications were associated with the MIVI Q. Conclusions: The MIVI aspiration system is a novel technology with regards to aspiration mechanical thrombectomy. The system is easy to use with early results comparable to other large-bore catheter systems. However, further studies are needed.

Abstract 1122‐000085: Endovascular Treatment of Acute Extracranial ICA Strokes – A Systematic Review and Pooled Analysis

Introduction : Ischemic stroke secondary to acute extracranial internal carotid artery (EC‐ICA) occlusion with a concurrent intracranial anterior circulation large vessel occlusion (tandem lesions) account for approximately 20% of all stroke cases. Endovascular management includes acute carotid artery stenting (CAS) with or without balloon angioplasty for pure EC‐ICA occlusions and concurrent mechanical thrombectomy (MT) for tandem lesions. In lieu of the scarcity of randomized data and abundance of observational studies, we intend to perform a systematic review and pooled analysis of the data over the past decade to evaluate clinical outcomes, safety and feasibility of endovascular management of acute EC‐ICA strokes. Methods : Systematic search of the Pubmed, MEDLINE, and EMBASE databases was conducted based on Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. We performed a systematic review of all acute EC‐ICA stroke papers (including tandem lesions) published between January 2010 and December 2020. A pooled analysis of the extracted data was performed. Results : Data from 1153 patients from 22 studies were pooled and analyzed. Mean age after pooling was 66.9 years, mean NIHSS at admission was 15.9, % IV tPA use before endovascular intervention was seen 56.1% of studies. 82.8% of subjects had a tandem lesion involving both Extracranial and intracranial part of ICA and only 17.2% had a pure and isolated EC‐ICA lesion. Angioplasty + stenting (both) was done in 77.6% of cases. Pooling was also done for any and all approaches taken in case of a tandem lesion i.e. anterograde or retrograde. Anterograde approach was taken in 61.7% of cases whereby CAS was performed first followed by MT. Outcome measures were reported as successful recanalization (TICI ≥ 2B) in 80.0% of cases, with good outcome (90‐day mRS <2) in 49.6% and a mortality rate of 12.9%. Conclusions : Our systematic review for endovascular treatment of EC‐ICA strokes found a high rate of good outcomes and an impressive rate for recanalization, with low mortality rates. Since these results are from observational, retrospective studies, more rigorous randomized trials are required to establish the best approach.

Abstract 1122‐000101: First‐in‐Human Experience Using the Millipede 088 Aspiration Catheter in Stroke Thrombectomy

Introduction : Studies have suggested that closely matching the catheter size to the vessel size may improve the effectiveness of clot aspiration in stroke thrombectomy. A new category of “super‐bore” aspiration catheters with 8Fr OD and 0.088in ID has recently been developed to further improve reperfusion success. In this work we report on early clinical experience using a CE Marked device called Millipede 088 developed by Perfuze (Galway, Ireland). Methods : The clinical, procedural, and radiological data were reviewed for consecutive cases in which Millipede 088 was used. Millipede 088 was navigated to the target vessel over a 6F intermediate catheter with or without a microcatheter and microwire, at the discretion of the physician. Performance was evaluated in terms of successful intracranial navigation and reperfusion measured using the mTICI scale. Results : Ten patients (age 55–89 years, 50% male) with intracranial large vessel occlusions (LVOs) were treated ‐ 4 ICA and 6 M1 LVOs. In two cases, the patients had concomitant tandem lesions requiring additional treatment. Millipede 088 was delivered intracranially in all cases, and to the target vessel in 8 cases. In two cases in which Millipede 088 was not advanced to the target vessel, it was placed intracranially for distal flow control, and an intermediate catheter was used for clot aspiration. In one case, following mTICI 2b reperfusion after aspiration, a stentriever was deployed via Millipede 088 to retrieve a distal M2 clot. Excellent reperfusion (mTICI 2c‐3) at the end of the procedure, was achieved in all (100%) of patients. First‐pass mTICI 2c‐3 was achieved in 5 patients (50%). No sICH or other complications were reported. Conclusions : In this first in man experience, aspiration thrombectomy using the Millipede 088 proved to be technically feasible and safe. Excellent reperfusion was achieved in all patients. The Millipede 088 represents a promising option for stroke thrombectomy.

Evidence-Based Updates to Thrombectomy: Targets, New Techniques, and Devices

Endovascular thrombectomy (EVT) has been validated in several randomized controlled trials in recent years for its efficacy in the treatment of acute ischemic strokes (AIS) and is now the standard of care according to international guidelines. However, in about 20% of EVT procedures, recanalization is not achieved, and over 50% of patients who undergo EVT still do not have good functional outcome. In this article, we provide an extensive review of the latest evidence and developments in the field of EVT, with particular focus on the factors that improve patient outcomes. These factors include new and adjunctive techniques such as combination of direct aspiration and stent retriever, intra-arterial urokinase or 2b/3a inhibitors, rescue stenting, as well as novel devices including balloon guide catheters and the newer generations of aspiration catheters and stent retrievers. We also examined the latest notion of using first-pass effect (FPE) as the target to achieve during EVT, which has been associated with an improved functional outcome. While the field of EVT has been rapidly evolving, further research is required in specific AIS patient populations such as those with large ischemic core, late presentation beyond 24 h, posterior circulation strokes, and with distal medium vessel occlusion or tandem lesions to better assess its efficacy and safety.

Comparing Endovascular Treatment Methods in Acute Ischemic Stroke Due to Tandem Occlusion Focusing on Clinical Aspects

Introduction: Acute ischemic strokes (AIS) due to tandem occlusion (TO) of intracranial anterior large vessel and concomitant extracranial internal carotid artery (EICA) are represent in 15–20% of all ischemic strokes. The endovascular treatment (EVT) strategy for those patients is still unclear. Although the intracranial mechanical thrombectomy (MT) is considered as a standard treatment approach, the EICA lesion stent necessity remains a matter of debate. We sought to assess the efficacy and safety of EVT in tandem lesions, particularly the EICA stenting management. Methods: We retrospectively analyzed all patients with anterior circulation stroke associated with EICA lesion and receiving EVT in the three participated stroke centers between November 2017 and December 2020. Patients’ data were collected from our prospective stroke registry (STAY ALIVE). Patients enrolled in our study were divided into two groups depending on whether acute carotid stenting (ACS) or balloon angioplasty only (BAO) technique was used. Our primary outcome was the 90-day functional outcome assessed by modified Rankin scale (mRS). Mortality at 90 days and symptomatic intracranial hemorrhage (sICH) were considered as secondary outcomes. Results: A total of 101 patients (age: 67 ± 10 years, 38.6% female) were enrolled in our study, including 29 (28.3%) BAO cases, and 72 (71.3%) patients treated with ACS. Patients in the BAO group were slightly older (70 ± 9 years vs. 66 ± 10 years, p = 0.054), and had higher prevalence of comorbidities such as hypertension (100.0% vs. 59.4%, p < 0.001). There was no significant difference in favorable outcomes (51.7% vs. 54.4%, p = 0.808) between the groups. However, we observed a trend towards higher rates of sICH (8.3% vs. 3.4%, p = 0.382) and 90-day mortality (23.5% vs. 13.8%, p = 0.278) with significantly higher frequency of distal embolization (39.1% vs. 17.9%, p = 0.043) in patients with ACS. In the overall population age (p = 0.013), atrial fibrillation (AF) (p = 0.008), National Institutes of Health Stroke Scale (NIHSS) baseline (p = 0.029), and successful recanalization (p = 0.023) were associated with favorable outcome. Conclusion: Endovascular approach of EICA in addition to MT was safe and effective in tandem occlusion of anterior circulation. Furthermore, our results suggest that balloon angioplasty technique without acute stenting shows a comparable favorable outcome rate to ACS with moderately less hemorrhagic events and mortality rates.

Cerebral fat embolism in the absence of a long bone fracture: A rare case report

Background: The classic triad of fat embolism syndrome consists of pulmonary distress, mental status change, and petechial rash. Typically, symptoms manifest 24–48 hours after a long bone fracture, but case reports have demonstrated fat embolism syndrome without long bone fracture. These cases are initiated by a stress response, mobilizing free fatty acids into the circulation. Case Description: Herein, we present the case of a 70-year-old male who presented with the left-sided hemiparesis and was subsequently found to have tandem lesions of the right internal carotid artery (ICA) and right middle cerebral artery (MCA) warranting emergent mechanical thrombectomy (MT). The ensuing pathology report determined the source of ischemic stroke to be caused by fat embolism, a rare and intriguing case of cryptogenic large vessel occlusion (LVO) with unique features distinguishing it from other reports in the literature. Conclusion: According to the biochemical theory, a catecholamine surge can precipitate fat globules forming in the circulatory system, leading to tissue hypoxia, injury, and ischemia. While the majority of cerebral fat emboli cause reversible ischemia of small diameter vessels, our case presents with LVO and tandem lesions in both the ICA and MCA resulting in infarct and residual hemiparesis.