Citations

Background Flow diverter stents (FDSs) are widely used to treat aneurysms in the clinic. However, even the same flow diverter (FD) use on different patients’ aneurysm sites can cause unexpected hemodynamics at the aneurysm region yielding low success rates for the overall treatment. Therefore, the present study aims to unfold why FDs do not work as they are supposed to for some patients and propose empirical correlation along with a contingency table analysis to estimate the flow stasis zones in the aneurysm sacs. Methods The present work numerically evaluated the use of FRED4518 FDS on six patients’ intracranial aneurysms based on patient-specific aneurysm geometries. Computational fluid dynamics (CFD) simulation results were further processed to identify the time evolution of weightless blood particles for six patients’ aneurysms. Results Stagnation zone formation, incoming and outgoing blood flow at the aneurysm neck, and statistical analysis of six patients indicated that FRED4518 showed a large flow stasis zone for an aspect ratio larger than 0.75. However, FRED4518, used for aneurysms with an aspect ratio of less than 0.65, caused small stagnant flow zones based on the number of blood particles that stayed in the aneurysm sac. Conclusion A patient-specific empirical equation is derived considering aneurysms’ morphological characteristics to determine the amount of stagnated fluid flow zones and magnitude of the mean aneurysm velocity in the aneurysm sac for FRED4518 based on weightless fluid particle results for the first time in the literature. As a result, numerical simulation results and patient data-driven equation can help perceive stagnated fluid zone amount before FRED4518 placement by shedding light on neuro-interventional surgeons and radiologists.

Background In 2015, mechanical thrombectomy (MT) was deemed the standard of care for acute ischemic stroke (AIS) in the anterior circulation due to large vessel occlusion (LVO). To determine if outcomes in patients treated with MT have changed, we conducted a systematic review and meta-analysis of published randomized controlled trials (RCTs). Methods A systematic literature review of the English language literature was conducted using PubMed. We included RCTs that focused on patients with AIS treated with MT. The primary outcome of interest was good functional outcome defined as modified Rankin Scale (mRS) 0–2 at 90 days. Safety outcomes included rates of symptomatic intracranial hemorrhage (sICH) and mortality at 90 days. Using Joinpoint Regression Analysis Program, we calculated the average annual percent change (AAPC) for the outcomes of interest. Results We included 23 RCTs with 5784 patients. The years of mid-enrollment among the included RCTs ranged from 2012–2020. There was an AAPC of +3.82% between 2012 and 2020 (95% CI 0.4 to 7.3; P -value = 0.033) in rates of good functional outcome. There was an AAPC of +6.98% between 2012 and 2020 (95% CI 0.5 to 13.9; P -value = 0.039) in rates of sICH. There was an AAPC of −0.49% between 2012 and 2020 (95% CI −4.4 to 3.5; P -value = 0.77) in rates of mortality. Conclusion Between 2012 and 2020, rates of good functional outcome and sICH increased, while rates of mortality remained consistent in RCTs investigating MT for AIS. Multiple factors likely influenced our results, including increased use of MT and utilization of adjunctive therapies alongside MT.

Background Endovascular coil embolization (ECE) for intracranial aneurysms has been proven as an effective minimally invasive treatment. However, the aneurysm recanalization after coiling is a serious complication of this technique. Among all the proposed factors associated with recanalization, the impact of packing density (PD) is still controversial. Objective To clarify the role of PD in the aneurysm recanalization following ECE, via conducting a systematic review and meta-analysis. Methods A systematic literature search was conducted using PubMed, Scopus, Embase, and Web of Science databases, until November 28, 2022, by adhering to the Preferred Reporting Items for Systematic Review and Meta-Analyses statement guidelines. Considering the eligibility criteria, all the studies reporting the outcomes of interest were included. Data elements of interest were extracted and analyzed using R software version 4.2.1. Results The pooled analysis of the 17 eligible papers revealed a 29% higher PD of the nonrecanalized aneurysms (ROM = 1.29, 95% confidence interval [CI] = 1.18–1.40, p < 0.001), even after removing outlier studies to reduce heterogeneity. However, the pooled estimates from multivariable regression models within nine included studies showed no significant effect of PD on recanalization odds when incorporated into a multivariable model with other predictors (odds ratio [OR] = 0.93, 95% CI = 0.84–1.02, p = 0.126), even after removing outlier studies. Conclusion The current literature does not support PD as a significant predictor of aneurysm treatment outcomes, especially with adjusting for other variables. This finding necessitates further prospective multicenter studies with a larger sample size to overcome the current methodological shortcomings.

Introduction Mechanical thrombectomy (MT) is the standard of care in eligible patients presenting with acute ischemic stroke (AIS). The question of whether intravenous thrombolysis (IVT) improves outcomes in conjunction with MT remains unanswered. We performed a systematic review and meta-analysis of published randomized controlled trials (RCT) to explore outcomes of MT with and without IVT. 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), distal embolization, and mortality. We calculated pooled risk ratios (RRs) and their corresponding 95% confidence intervals (CI). Results Six RCTs with 2334 patients compared outcomes of patients treated with MT alone and MT with IVT. Both treatments resulted in comparable rates of mRS 0–2 (RR = 0.96, 95% CI = 0.88–1.04; p -value = 0.282), sICH (RR = 0.80, 95% CI = 0.55–1.17; p -value = 0.253), mortality at 90-days (RR = 1.06, 95% CI = 0.88–1.28; p -value = 0.529), and distal embolization (RR = 1.10, 95% CI = 0.79–1.52; p -value = 0.572). MT alone was associated with a lower rate of TICI 2b-3 compared to MT with IVT (RR = 0.96, 95% CI = 0.93–0.99; p -value = 0.006). Conclusions In this meta-analysis of six RCTs, MT alone was comparable to MT plus IVT for mRS 0–2, sICH, mortality, and distal embolization; however, MT alone resulted in lower rates of TICI 2b-3. Further trials are needed to determine which patient populations benefit from MT plus IVT and to increase the power of future meta-analyses.

Background Computed tomography (CT) angiography collateral score (CTA-CS) is an important clinical outcome predictor following mechanical thrombectomy for ischemic stroke with large vessel occlusion (LVO). The present multireader study aimed to evaluate the performance of e-CTA software for automated assistance in CTA-CS scoring. Materials and Methods Brain CTA images of 56 patients with anterior LVO were retrospectively processed. Twelve readers of various clinical training, including junior neuroradiologists, senior neuroradiologists, and neurologists graded collateral flow using visual CTA-CS scale in two sessions separated by a washout period. Reference standard was the consensus of three expert readers. Duration of reading time, inter-rater reliability, and statistical comparison of readers’ performance metrics were analyzed between the e-CTA assisted and unassisted sessions. Results e-CTA assistance resulted in significant increase in mean accuracy (58.6% to 67.5%, p = 0.003), mean F1 score (0.574 to 0.676, p = 0.002), mean precision (58.8% to 68%, p = 0.007), and mean recall (58.7% to 69.9%, p = 0.002), especially with slight filling deficit (CTA-CS 2 and 3). Mean reading time was reduced across all readers (103.4 to 59.7 s, p = 0.001), and inter-rater agreement in CTA-CS assessment was increased (Krippendorff's alpha 0.366 to 0.676). Optimized occlusion laterality detection was also noted with mean accuracy (92.9% to 96.8%, p = 0.009). Conclusion Automated assistance for CTA-CS using e-CTA software provided helpful decision support for readers in terms of improving scoring accuracy and reading efficiency for physicians with a range of experience and training backgrounds and leading to significant improvements in inter-rater agreement.

Importance Patients with atrial fibrillation (AF) treated with mechanical thrombectomy (MT) for acute ischemic stroke (AIS) have been reported to experience worse outcomes compared with patients without AF. Objective To assess differences between patients with AF and their counterparts without AF treated with MT for AIS, focusing on safety outcomes, clinical outcomes, and baseline characteristics in both groups. Data Sources A systematic literature review of the English language literature from inception to July 14, 2022, was conducted using Web of Science, Embase, Scopus, and PubMed databases. Study Selection Studies that focused on patients with and without AF treated with MT for AIS were included. Multiple reviewers screened studies to identify studies included in analysis. Data Extraction and Synthesis Data were extracted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline to ensure accuracy. Data were pooled using a random-effects model. Main Outcomes and Measures The primary outcome of interest was rate of modified Rankin Scale (mRS) scores of 0 to 2 at 90 days. Secondary outcomes of interest included rates of successful reperfusion, defined as thrombolysis in cerebral infarction (TICI) scores of 2b to 3, 90-day mortality, symptomatic intracranial hemorrhage (SICH), and baseline patient characteristics. Results Of 1696 initially retrieved studies, 10 studies were included, with 6543 patients. Patients with AF were a mean of 10.17 (95% CI, 8.11-12.23) years older ( P &amp;lt; .001) and had higher rates of hypertension (OR, 1.89 [95% CI, 1.57-2.27]; P &amp;lt; .001) and diabetes (OR, 1.16 [95% CI, 1.02-1.31]; P = .02). Overall, there were comparable rates of mRS scores of 0 to 2 between patients with AF and patients without AF (odds ratio [OR], 0.72 [95% CI, 0.47-1.10]; P = .13), with significant heterogeneity among the included studies. After sensitivity analysis, the rate of mRS scores of 0 to 2 was significantly lower among patients with AF (OR, 0.65 [95% CI, 0.52-0.81]; P &amp;lt; .001). Successful reperfusion rates were similar between the groups (OR, 1.11 [95% CI, 0.78-1.58]; P = .57). The rate of SICH was similar between groups (OR, 1.05 [95% CI, 0.84-1.31]; P = .68). Mortality was significantly higher in the AF group (OR, 1.47 [95% CI, 1.12-1.92]; P = .005). Conclusions and Relevance In this systematic review and meta-analysis, patients with AF experienced worse 90-day outcomes, even in the setting of similar rates of successful reperfusion. This was likely associated with greater age and greater rates of comorbidities among patients with AF.

Background Delayed neurological improvement (DNI) is a phenomenon that involves patient improvement in the absence of early neurological change following treatment for acute ischemic stroke. The patient characteristics associated with this condition are largely unexplored. Methods Following the PRISMA guidelines, a systematic review of the English language literature was conducted using PubMed, Embase, Web of science, and Scopus. We calculated pooled odds ratios (ORs), mean differences (MDs), and their corresponding 95% confidence intervals (CIs) to test the association between patient characteristics and achievement of DNI. Results Seven studies, with 3266 patients, were included in our analysis. All studies reported a different definition of DNI, with five studies focusing on rates of good functional outcome at 90 days post-treatment in the absence of early neurological improvement. Use of intravenous thrombolytics was associated with increased rates of DNI (OR 1.96, 95% CI 1.28 to 3.00; p = 0.002). Atrial fibrillation was associated with decreased rates of DNI (OR 0.69, 95% CI 0.57 to 0.82; p < 0.001), as was hypertension (OR 0.66, 95% CI 0.53 to 0.83, p < 0.001), and diabetes mellitus (OR 0.71, 95% CI 0.56 to 0.90; p = 0.005). On average, patients who achieved DNI were 6.30 years younger than their non-DNI counterparts ( MD −6.30, 95% CI −9.19 to −3.41; p < 0.001). There were modest associations between male sex and DNI (OR 1.36, 95% CI 1.01 to 1.74, p = 0.042), and smoking and DNI (OR 1.28, 95% CI 1.03 to 1.59, p = 0.027). Conclusions DNI is a phenomenon that is not presently well understood. Lack of uniformity among definitions of DNI hinders efforts to explore DNI and the factors associated with its occurrence. Future studies should work to establish a consensus definition of DNI to determine its causes and significance more accurately.

OBJECTIVE Bioresorbable flow diverters (BRFDs) could significantly improve the performance of next-generation flow diverter technology. In the current work, magnesium and iron alloy BRFDs were prototyped and compared in terms of porosity/pore density, radial strength, flow diversion functionality, and resorption kinetics to offer insights into selecting the best available bioresorbable metal candidate for the BRFD application. METHODS BRFDs were constructed with braided wires made from alloys of magnesium (MgBRFD) or iron (FeBRFD). Pore density and crush resistance force were measured using established methods. BRFDs were deployed in silicone aneurysm models attached to flow loops to investigate flow diversion functionality and resorption kinetics in a simulated physiological environment. RESULTS The FeBRFD exhibited higher pore density (9.9 vs 4.3 pores/mm2) and crush resistance force (0.69 ± 0.05 vs 0.53 ± 0.05 N/cm, p = 0.0765, n = 3 per group) than the MgBRFD, although both crush resistances were within the range previously reported for FDA-approved flow diverters. The FeBRFD demonstrated greater flow diversion functionality than the MgBRFD, with significantly higher values of established flow diversion metrics (mean transit time 159.6 ± 11.9 vs 110.9 ± 1.6, p = 0.015; inverse washout slope 192.5 ± 9.0 vs 116.5 ± 1.5, p = 0.001; n = 3 per group; both metrics expressed as a percentage of the control condition). Last, the FeBRFD was able to maintain its braided structure for > 12 weeks, whereas the MgBRFD was almost completely resorbed after 5 weeks. CONCLUSIONS The results of this study demonstrated the ability to manufacture BRFDs with magnesium and iron alloys. The data suggest that the iron alloy is the superior material candidate for the BRFD application due to its higher mechanical strength and lower resorption rate relative to the magnesium alloy.

Neurovascular catheter technology has rapidly evolved over the past decade. While performance characteristics are well known to the practitioner, the design features of these new-generation catheters and their implications on performance metrics remain a mystery to most clinicians due to the limited number of available resources. This knowledge gap hampers informed device choices and also limits collaboration between clinicians and engineers. To aid fellow neurointerventionalists, in this primer we have summarized the basic concepts of catheter design and construction.

Background The Contour is a new generation intrasaccular flow disruption tool that aims to cover the aneurysm neck and is sized according to the neck diameter. While several case series have been published, no literature review has been performed on this promising device. Objective To assess the safety and effectiveness profile of the Contour Neurovascular System for wide-necked aneurysms. Methods We followed the recommendations of the PRISMA checklist Four databases were searched with a supplemental manual search. All data were analyzed using R software version 4.2.1. Results We finally included six studies with 131 treated aneurysms. The overall procedural time was 97.27 (95% CI = 70.07–124.47) minutes, ranging from 78.9 to 136.0 min. The pooled adequate occlusion rate was 84.21% (95% CI = 75.45–90.25), and the overall functional independence rate was 94.74% (87.97–97.79). The overall adverse event rate was 4.70 (95% CI = 3.24–6.76), varying among different events from 0.78 to 8.53%. Thromboembolic events were the most commonly encountered in 8.53% of the patients (95% CI = 4.78–14.74), followed by headache and minor stroke with incidence rates of 5.88 (95% CI = 2.83–11.83) and 4.35 (95% CI = 1.41–12.63), respectively. The overall procedural time in studies using the Contour system only was 86.17 (95% CI = 68.70–10.64) minutes, while it was 136 (95% CI = 90.96–181.04) in the Contour-assisted coiling procedures. However, both techniques were comparable regarding adequate occlusion rates and functional independence. Conclusion With the anticipation of future studies, the Contour Neurovascular System is a safe and effective treatment option for wide-necked intracranial aneurysms.