Kallmes, David F.

Background The Woven EndoBridge (WEB) device is used to treat wide-neck bifurcation aneurysms (WNBAs). We conducted a systematic review and meta-analysis to determine the retreatment rate strategies following aneurysmal recurrence of WEB device treated WNBAs. Methods This study is reported following the PRISMA 2020 guidelines. We conducted a systematic review of the literature using PubMed, Scopus, Embase, and Web of Science. Data were pooled using a random-effects model. We calculated pooled prevalence and corresponding 95% confidence intervals (CI). Results We included 11 studies. The overall retreatment rate was 171/1875 aneurysms (10.3%; 95% CI = 8.3–12.9). Stent-assisted coiling was used to treat 59 aneurysms (36.7%; 95% CI = 26.4–48.5), and flow diverters were used to treat 44 aneurysms (18.7%; 95% CI = 9.9–32.5). Following retreatment, the complete occlusion rate was 57/91 aneurysms (62.8%; 95% CI = 48.2–75.3) and the adequate occlusion rate was 24/91 aneurysms (26.4%; 18.4%–36.4%). The most common aneurysmal recurrence site was the anterior communicating artery (44/136 aneurysms, 32.4%; 95% CI = 25.0–40.7). Conclusions Roughly 10% of WNBAs initially treated with the WEB device will undergo retreatment. Retreatment is an effective strategy for WEB-treated aneurysms, with high rates of adequate and complete occlusion. Future studies should work to identify risk factors for aneurysmal recurrence.

Background Smoking represents a leading risk factor for acute ischemic stroke (AIS). Previous literature has described a “smoking paradox”, wherein smokers experience better outcomes following intravenous thrombolysis for AIS. It is unclear whether such a phenomenon exists in smokers undergoing endovascular therapy (EVT) for AIS. To assess outcomes in smokers following EVT for AIS, we conducted a systematic review and meta-analysis. Methods Following the PRISMA guidelines, a systematic literature review of the English language literature was conducted using PubMed, Embase Web of Science, and Scopus. Outcomes of interest included 90-day modified Rankin Scale (mRS) 0–2, thrombolysis in cerebral infarction (TICI) score 2b-3, symptomatic intracranial hemorrhage (sICH), and mortality. We calculated mean difference (MD), pooled odds ratios (ORs) and their corresponding 95% confidence intervals (CI). Results Eight studies with 2633 patients comprised our analysis. On average, smokers were 10.14 years (MD = 10.14, [95% CI = −14.49 to −5.79], P-value < 0.001) younger than non-smokers. Smokers achieved mRS 0–2 (OR = 1.82, [95% CI, 1.34–2.48], P-value < 0.001) and TICI 2b-3 (OR = 1.61, [95% CI, 1.19–2.19], P-value = 0.002) at a higher rate than non-smokers. sICH rates were comparable between smokers and non-smokers (OR = 1.07, [95% CI, 0.62–1.85], P-value = 0.81). Smokers had a lower rate of 90-day mortality than non-smokers (OR = 0.54, [95% CI, 0.41–0.71], P-value < 0.001). Conclusions In this meta-analysis of eight studies, we found that smokers with AIS undergoing EVT experienced better 90-day outcomes and higher rates of TICI 2b-3. This may be due to baseline differences between smokers and non-smokers, but future studies should explore alternative reasons that could explain this relationship between smoking and AIS treated with EVT.

Background Studies during the COVID-19 pandemic have demonstrated an association between COVID-19 virus infection and the development of acute ischemic stroke, particularly large vessel occlusion (LVO). Studying the characteristics and immunohistochemistry of retrieved stroke emboli during mechanical thrombectomy for LVO may offer insights into the pathogenesis of LVO in COVID-19 patients. We examined retrieved COVID-19 emboli from the STRIP, EXCELLENT, and RESTORE registries and compared their characteristics to a control group. Methods We identified COVID-positive LVO patients from the STRIP, RESTORE, and EXCELLENT studies who underwent mechanical thrombectomy. These patients were matched to a control group controlling for stroke etiology based on Trial of Org 10172 in Acute Stroke Treatment criteria. All clots were stained with Martius Scarlet Blue (MSB) along with immunohistochemistry for interleukin-6 (IL-6), C-reactive protein (CRP), von Willebrand factor (vWF), CD66b, fibrinogen, and citrullinated Histone H3. Clot composition was compared between groups. Results Nineteen COVID-19-positive patients and 38 controls were included. COVID-19-positive patients had a significantly higher percentage of CRP and vWF. There was no difference in IL-6, fibrin, CD66b, or citrullinated Histone H3 between groups. Based on MSB staining, there was no statistically significant difference regarding the percentage of red blood cells, white blood cells, fibrin, and platelets. Conclusions Our study found higher concentrations of CRP and vWF in retrieved clots of COVID-19-positive stroke patients compared to COVID-19-negative controls. These findings support the potential role of systemic inflammation as indicated by elevated CRP and endothelial injury as indicated by elevated vWF as precipitating factors in thrombus development in these patients.

Acute ischemic stroke (AIS) due to distal, medium vessel occlusion (DMVO) is increasingly recognized as the next frontier for mechanical thrombectomy. Distal, medium vessel occlusions are typically defined as an occlusion in the following arteries: anterior cerebral artery, M2–M4 segments of the middle cerebral artery, posterior cerebral artery, posterior inferior cerebellar artery, anterior inferior cerebellar artery, and superior cerebellar artery. It is estimated that 25–40% of all AIS is due to DMVO. Because of the large burden of DMVO, the frequency of literature published regarding these occlusions has greatly increased in recent years. Furthermore, treatment modalities have been created specifically for DMVOs. Due to the rapidly evolving literature on this topic, remaining up to date on DMVO definitions, anatomy, management, imaging, and clinical course is difficult. In this review article, we synthesized existing literature regarding the aforementioned topics and discussed future directions.

Background Chronic subdural hematoma (cSDH) is a challenging and common neurosurgical condition. Our goal is to demonstrate that middle meningeal artery (MMA) embolization combined with surgical evacuation can be a promising adjuvant option for treatment of cSDHs and prevent recurrence in symptomatic patients who require surgical treatment. Method We retrospectively collected data from patients who underwent MMA embolization using polyvinyl alcohol particles and surgical evacuation with burr hole or craniotomy in a single center for the treatment of new and recurrent cSDHs. The primary outcome was recurrence of cSDH requiring surgical rescue during follow up, and secondary outcomes were defined as >50% decrease in the maximum width of cSDHs on the longest follow-up computed tomography (CT) scan, complications following procedure, and improvement in modified Rankin scale (mRS) score. Results A total of 51 patients successfully underwent 72 MMA embolization procedures (96% of the total 75 cases in the cohort) combined with surgical evacuation. Seventy cases (93.3%) achieved at least 50% reduction in the size of the cSDHs on the last CT imaging. A surgical evacuation was required in five cases (6.7%) due to cSDH recurrence during the follow-up period. There were three complications (6.0%) related to embolization procedure. Forty patients (78.4%) showed improvement in mRS score. There was one mortality (2%) regardless of the embolization and evacuation. Conclusions Our study demonstrates the safety and efficacy of adjunct MMA embolization in significantly reducing size and recurrence of cSDHs.

Background Vertebrobasilar junction (VBJ) aneurysms represent a relatively rare and often anatomically complex subgroup of saccular aneurysms. This systematic review and meta-analysis aimed to assess the safety and efficacy of endovascular treatment (EVT) of VBJ aneurysms. Methods PubMed, Web of Science, Ovid Medline, Ovid Embase, and Scopus were searched from inception to 20 December 2022. We included primary studies assessing the long-term clinical and angiographic outcomes for VBJ aneurysms treated with endovascular techniques. We excluded surgically managed studies. All data were analyzed using R software version 4.2.1. We calculated pooled prevalence rates and their corresponding 95% confidence intervals (CI). Results In this meta-analysis, a total of 76 VBJ aneurysms from seven studies were included for quantitative analysis. The results showed that the rate of adequate occlusion (complete + near complete occlusion) was 94.1% (95% CI = 76.71–98.71), and the rate of complete occlusion was 77.7% (95% CI = 63.07–87.65). A modified Rankin Scale (mRS) score of 0–2 was achieved in 93.9% of patients (95% CI = 67.65–99.14). The mortality rate was found to be 5.9% (95% CI = 0.97–28.55), and the retreatment rate was 4.6% (95% CI = 1.50–13.36). The overall ischemic complication rate was 4.7% (95% CI = 0.73–25.4), while the overall hemorrhagic complication rate was 4.6% (95% CI = 1.5–13.36). Conclusions The treatment of VBJ aneurysms with EVT is effective in achieving curative treatment and is associated with good clinical outcomes and low mortality rates. These findings provide important insights into the clinical and angiographic outcomes and the complication rates of EVT for VBJ aneurysms.

Background Procedural success following mechanical thrombectomy for acute ischemic stroke is assessed using the thrombolysis in cerebral infarction scale. We conducted a systematic review and meta-analysis to determine whether outcomes differed between first pass thrombolysis in cerebral infarction 2b and multiple pass thrombolysis in cerebral infarction 2c-3. Methods We conducted a systematic review of the literature using PubMed, Embase, Scopus, and Web of Science. We included original studies in which outcomes were stratified based on first pass thrombolysis in cerebral infarction 2b and multiple pass thrombolysis in cerebral infarction 2c-3. The primary outcome of interest was the rate of modified Rankin Scale 0-2. Secondary outcomes of interest were rates of modified Rankin Scale 0-1, symptomatic intracranial hemorrhage, and mortality. We calculated odds ratios and corresponding 95% confidence intervals. Results Four studies with 1554 patients were included in the quantitative analysis. Rate of modified Rankin Scale 0–2 (odds ratio = 0.91, 95% confidence interval = 0.70–1.18; P -value = 0.49), modified Rankin Scale 0–1 (odds ratio = 1.21, 95% confidence interval = 0.86–1.71; P -value = 0.27), symptomatic intracranial hemorrhage (odds ratio = 1.36, 95% confidence interval = 0.47–3.98; P -value = 0.57), and mortality (odds ratio = 0.91, 95% confidence interval = 0.67–1.25; P -value = 0.56) did not differ between first pass thrombolysis in cerebral infarction 2b and multiple pass thrombolysis in cerebral infarction 2c-3. There was no heterogeneity among included studies for modified Rankin Scale 0–2, modified Rankin Scale 0–1, or mortality; however, there was moderate heterogeneity among studies for symptomatic intracranial hemorrhage ( I 2 = 53%, P -value = 0.12). Conclusions Clinical and safety outcomes did not differ between first pass thrombolysis in cerebral infarction 2b and multiple pass thrombolysis in cerebral infarction 2c-3. Future prospective studies and clinical trials should determine whether first pass thrombolysis in cerebral infarction 2b is a viable endpoint to thrombolysis in cerebral infarction 2c-3.

Background Collateral blood flow markers have been associated with outcomes after thrombectomy in patients presenting with acute ischemic stroke due to large vessel occlusion (AIS-LVO). Hypoperfusion intensity ratio (HIR), a metric reflecting tissue level collaterals, is one such marker with the potential to delineate patients who do and do not do well after thrombectomy. We determined if HIR correlated with successful reperfusion after thrombectomy. Methods Using Nested Knowledge, we screened literature for studies comparing patients with favorable versus unfavorable HIR, distinguished by a cutoff of 0.4, who underwent thrombectomy triage. The primary outcome was reperfusion success, as measured by thrombolysis in cerebral infarction ≥2b and secondary outcomes included rate of symptomatic intracranial hemorrhage, mortality at 90 days, and modified Rankin scale scores 0–2 at 90 days. A random effects model was used to compute pooled prevalence rates and their corresponding 95% confidence intervals (CI). Results Three studies with 973 patients, 496 with favorable HIR, and 477 with unfavorable HIR were included in this meta-analysis. The odds of reperfusion success were not significantly different between patients who had favorable versus unfavorable HIR (OR 0.96, 95% CI: 0.31–3.04) across two of the studies. Analysis of the remaining outcome variables was precluded by significant heterogeneity in data element reporting. Conclusions This meta-analysis was considerably limited by heterogeneity. Future meta-analyses on this topic, and other topics in the field of neurointervention would benefit from improved harmonization of study design and data element reporting.

Background Flow diverter treatment may inevitably require jailing of the branch vessels. While the patency of covered branch arteries and associated safety risks have been a topic of substantial interest, the question of whether the characteristics of branch vessels affect flow diversion's efficacy remains unanswered. In this study, we aimed to assess the impact of branch arteries on the efficacy of endoluminal flow diverters, specifically focusing on posterior communicating artery (Pcomm) aneurysms. Methods Following PRISMA guidelines, we systematically searched the MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane databases with predefined keywords. Studies providing data for flow diversion outcomes in Pcomm aneurysms were included. Outcomes of interest included complete and adequate aneurysm obliteration, ischemic and hemorrhagic complications, and Pcomm occlusion in the follow-up period. A random or fixed effects model was used to calculate the odds ratios (ORs) and pooled event rates with their corresponding confidence intervals (CI). Results The overall complete and adequate aneurysm occlusion rates were 72.25% (95% CI: 64.46–78.88%) and 88.37% (95% CI: 84.33–92.6), respectively. Fetal-type Pcomm aneurysms had significantly lower complete aneurysm occlusion rates than the nonfetal-type Pcomm aneurysms (OR: 0.12, 95% CI: 0.05–0.29). Overall ischemic and hemorrhagic complication rates were 2.62% (95% CI = 0.71–5.32) and 0.71% (95% CI: 0–2.24), respectively. There were no significant associations between Pcomm morphology and complications (OR: 3.61, 95% CI = 0.42–31.06 for ischemic complications and OR: 2.31, 95% CI = 0.36–14.6 for hemorrhage). Overall Pcomm occlusion rate was 32.04% (95% CI = 19.96–47.13), and the Pcomm patency was significantly lower in nonfetal-type Pcomm aneurysms (OR: 0.10, 95% CI = 0.02–0.44). Conclusion Our meta-analysis suggests that flow diversion is a safe treatment option for Pcomm aneurysms, regardless of fetal-type Pcomm morphology. However, on the other hand, our findings indicate that Pcomm anatomy or the presence of jailed large branches can affect the efficacy of flow diverter treatment.