Kallmes, David F

Background Delayed aneurysm rupture (DAR) is a potentially devastating complication after flow-diverters (FD) deployment and their exact mechanisms are still unclear. The purpose of this meta-analysis is to synthesize the latest evidence on DAR after FD treatment and identify predictive factors. Methods A systematic review and meta-analysis were conducted according to established protocols. Searches were conducted in PubMed, Scopus, Web of Science, and Embase databases up to June 2024 using variations of “aneurysm “and “delayed aneurysm rupture” terms. Original studies reporting DAR and including more than five patients were included. All analyses were conducted in R software (version 4.4.2), employing the “meta” and “tableone” packages. Results 64 studies with 9820 patients were included, large aneurysm size (OR=1.08, 95% CI (1.02, 1.14), P value=0.008), intra-aneurysmal thrombus (OR=1.05, 95% CI (1.01, 1.09), P value=0.010) and posterior circulation location (OR=1.02, 95% CI (1.00, 1.04), P value=0.014) were significant risk factors for DAR. The pooled prevalence of DAR was 1.40%, with a rate of 1.18% after removing outliers. DAR occurred within 30 days in 66.7% of cases, with a mortality rate of 73.3% at discharge. Conclusion DAR following flow diversion treatment is an uncommon but devastating complication and remains a limitation of the technique. It is influenced by factors such as large aneurysm size, intra-aneurysmal thrombosis, and posterior circulation involvement. The first 30 days post-procedure represent a particularly high-risk period. Despite advancements in FD technology, significant gaps remain, highlighting the need for further research to improve risk assessment and treatment strategies.

Background Advancement in neurointervention is frequently driven by the introduction of new technology and devices that improve procedural efficacy and patient outcomes. For physician-innovators, customer discovery—or the process of directly engaging with end users to explore workflows and associated challenges—offers a structured way to identify meaningful problems and guide early innovation. This primer aims to outline stepwise guidance for conducting customer discovery within neurointervention to characterize key areas of unmet need. Methods We detail stepwise guidance for conducting customer discovery founded on foundational business literature. To illustrate this process, we conducted five interviews with expert neurointerventionalists engaged in clinical innovation. Interview transcripts were reviewed and analyzed to track emerging themes, and responses were synthesized into a neurointerventionalist customer profile. Results Responses from interviewed neurointerventionalists suggested that safer vascular access, tools to support treatment prognostication, and condition-specific device design are unmet areas of need. Moreover, interviews revealed broader concerns about stagnation in device innovation and barriers within regulatory and institutional pathways. Conclusions Structured customer discovery identifies unmet needs that may be overlooked when device development is solely driven by technical breakthroughs or published outcomes. By outlining an actionable framework for customer discovery in neurointervention, we provide a practical model for aligning future innovation with real-world clinical challenges.

Background Mechanical thrombectomy (MT) is a well-established treatment for acute ischemic stroke (AIS) due to large vessel occlusion (LVO). However, its role in cervical artery dissection-related (CeAD) LVO remains debated due to anatomical complexities and procedural challenges. This systematic review and meta-analysis aims to evaluate the safety, efficacy, and clinical outcomes of MT in patients with AIS due to CeAD-related LVO compared with other AIS etiologies. Methods PubMed, Embase, and Scopus were systematically searched from inception to March 2025. Comparative observational studies evaluating the use of MT in adult patients with AIS due to LVO were included, specifically those comparing outcomes in patients with CeAD versus non-CeAD etiologies. Results MT for CeAD-related AIS showed no statistically significant difference in successful recanalization compared with non-CeAD cases (OR 0.81 (95% CI 0.63 to 1.04), P=0.10). However, patients with CeAD-related AIS had significantly higher rates of 90-day functional independence (modified Rankin Scale score 0–2) (OR 2.17 (95% CI 1.55 to 3.05), P<0.01) and lower 90-day mortality (OR 0.34 (95% CI 0.22 to 0.53), P<0.01). Rates of distal embolization (OR 1.60 (95% CI 0.69 to 3.70), P=0.27), symptomatic intracranial hemorrhage (OR 0.84 (95% CI 0.51 to 1.38), P=0.49), or iatrogenic dissection (OR 1.58 (95% CI 0.59 to 4.22), P=0.36) did not differ significantly between patient groups. Conclusions MT in patients with CeAD-related LVO is safe, effective, and associated with improved functional outcomes and lower mortality compared with patients with non-CeAD acute ischemic causes.

Background For large vessel occlusion (LVO) ischemic strokes, three major techniques of mechanical thrombectomy (MT) have demonstrated efficacy. Here we compare the safety and efficacy of stent retrievers (SR), contact aspiration (Asp), and a combined mechanical thrombectomy (cMT) for LVO ischemic stroke. Methods Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we queried the PubMed, EMBASE, Scopus, and Web of Science databases for studies published prior to December 2024 describing patients with ischemic stroke who underwent MT using SR, Asp, or cMT. Results Twnety-four studies comprising a total of 12 845 patients were included in the analysis. Compared with cMT, Asp was associated with a lower rate of first pass effect (FPE) (risk ratio (RR) 0.67; 95% CI 0.46 to 0.96), shorter procedure duration (mean difference (MD) −13.35 min; 95% CI −20.83 to –5.87), and lower risk of arterial dissection (RR 0.50; 95% CI 0.29 to 0.87). Additionally, SR use was linked to a higher procedure duration compared with Asp (MD 13.39 min; 95% CI 5.55 to 21.22) and a lower symptomatic intracranial hemorrhage rate (RR 0.75; 95% CI 0.59 to 0.96). No significant differences were observed between groups in terms of number of passes, successful recanalization, 90-day functional outcomes, mortality, arterial perforation, or embolization to new territory. Conclusions All three techniques demonstrated similar recanalization rates and functional outcomes. However, Asp was associated with shorter procedure times and fewer arterial dissection complications, while cMT showed a higher FPE. Given the comparable overall efficacy, the choice of technique should be guided by the physician’s preference, expertise, and confidence, tailored to the individual patient’s profile.

Background The hypoperfusion intensity ratio (HIR) has emerged as a vital measure of tissue-level collateral blood flow, helping to identify patients who are likely to benefit from mechanical thrombectomy (MT). We aimed to assess the HIR’s predictive accuracy for clinical outcomes following MT in patients with acute ischemic stroke. Methods PubMed, Embase, and Scopus were searched to identify studies comparing good versus poor HIR groups based on studies’ reported cut-offs. We pooled binary outcomes to calculate odds ratios (OR) and continuous outcomes to calculate mean differences (MD) with 95% confidence intervals (95% CI) using random-effects models. PROSPERO registration code: CRD42024609185. Results 14 studies with 2987 patients, 1553 with good HIR and 1434 with poor HIR, were included in this meta-analysis. Patients with poor HIR exhibited a significantly higher baseline infarct volume compared with those with good HIR (MD 30.6 mL, 95% CI 20.8 mL to 40.3 mL, P<0.01), though baseline National Institutes of Health Stroke Scale (NIHSS) (P=0.12) and Alberta Stroke Program Early CT Score (ASPECTS) (P=0.35) were comparable between groups. The rates of infarct growth (MD 22.4 mL, 95% CI 6.7 mL to 38.0 mL, P<0.01) and 3-month mortality (OR 2.18, 95% CI 1.04 to 4.58, P=0.04) were higher among the poor HIR group and good functional recovery (modified Rankin Scale 0–2 at 3 months) was lower (OR 0.58, 95% CI 0.42 to 0.80, P<0.01). The rates of symptomatic intracranial hemorrhage (P=0.37) and successful reperfusion (P=0.47) were comparable among groups. Conclusion This meta-analysis highlights the significant negative impact of poor HIR on patient outcomes. These findings emphasize the need for personalized treatment strategies for patients with poor HIR.

Background: Variability in recanalization success during endovascular treatment for acute ischemic stroke (AIS) has led to increased interests in thrombus composition and associated cellular materials. While evidence suggests that bacteria may influence thrombus characteristics, limited data exist on microbiological profiles of thrombi in stroke patients. Objectives: Characterization of bacterial communities present in thrombi of AIS patients undergoing mechanical thrombectomy, providing insights into microbial contributions to stroke pathogenesis and treatment outcomes. Methods: Thrombi were collected from 20 AIS patients. After extracting metagenome, 16S rDNA sequencing was performed. Bioinformatic analysis included taxonomy and diversity assessments. The presence of bacterial DNA and viable bacteria in thrombi was validated using polymerase chain reaction (PCR) and bacterial culturing followed by matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) analysis, respectively. Results: 16S rDNA was amplified in 19/20 thrombi (95%). Analysis identified a diverse microbial community, with Corynebacterium spp. as the most prevalent genus, followed by Staphylococcus spp., Bifidobacterium spp., Methylobacterium spp., and Anaerococcus spp. Alpha diversity analyses (Shannon index: 4.0–6.0 and Simpson index: 0.8–1.0) revealed moderate to high microbial diversity across samples; beta diversity demonstrated distinct clustering, indicating inter-patient variability in microbial profiles. PCR confirmed the presence of DNA specific to dominant bacterial taxa identified through sequencing. Culturing showed the presence of Staphylococcus epidermidis and Enterococcus faecalis in some clots as identified through MALDI analysis. Conclusions: This study shows bacterial communities present in AIS patients’ thrombi, suggesting a potential link between microbial signatures and thrombus characteristics.

Background Carotid artery tortuosity (CAT) may complicate mechanical thrombectomy (MT), potentially causing delays or preventing recanalization. However, the relationship between CAT and MT outcomes remains largely unexplored. This systematic review aims to evaluate the existing evidence regarding the impact of CAT on MT outcomes. Methods Following PRISMA guidelines, a systematic literature search was conducted using MEDLINE, EMBASE, Web of Science, Cochrane, and Scopus databases. Studies providing data for MT outcomes based on CAT status were included. Outcomes of interest included successful recanalization, first-pass efficacy (FPE), procedure time, functional independence, and procedure-related complications. Results Our search identified nine studies with 2737 patients. Three studies employed DSA to assess tortuosity, whereas the remaining six studies preferred CTA. In seven studies, CAT was associated with prolonged procedure times. In five studies, successful recanalization rates were significantly lower in CAT patients as compared to patients with non-tortuous arteries. Two studies showed that CAT could alter FPE or successful recanalization rates of first-line MT techniques. No study found statistically significant relationships between CAT and functional independence. Three studies examined the association between CAT and safety outcomes, and only one study found increased intracranial hemorrhage rates in patients with CAT. All nine studies employed different CAT criteria. Conclusions Despite the vast MT literature, the number of studies reporting CAT status remains low. CAT may affect procedure time and technical outcomes of MT. Therefore, employing a uniform CAT definition and reporting CAT more frequently can provide insights into management of patients with acute large vessel occlusions.

Background: Identifying optimal candidates for endovascular treatment (EVT) remains an ongoing priority to maximize treatment efficacy. The recent large core trials have called into question the use of infarct volume alone for selecting patients. This study aimed at exploring the feasibility of using routinely acquired Computed Tomography Perfusion (CTP) to capture how lesion location impacts brain connectivity and how this in turn affects the ability to benefit from EVT. Methods: Consecutive patients from a multi-centric stroke imaging registry were included in this study if they had a proven anterior circulation large vessel occlusion (LVO) and available baseline CTP data. Hypoperfusion (Tmax >6 seconds) and ischemic core (relative cerebral blood flow <30%) maps were automatically generated using e-CTP (Brainomix, UK) and used to derive disconnection maps via a DTI template. A voxel-based, multivariate method (Sparse Canonical-Correlation-Analysis – LESYMAPS) was used to explore associations between disconnection maps and NIHSS subitems in recanalized patients. The mismatch between Tmax and core disconnection volumes (disconnection mismatch volume) (Figure 1) was used to predict modified Rankin Scale (mRS) at 3-months using an ordinal shift regression adjusted for age, recanalization status and infarct volume. Results: One-hundred and seventy-one patients were included. The median NIHSS was 16 (11.5 to 22). The total NIHSS was associated with disconnection predominantly within the left basal ganglia, brainstem and corpus callosum. Upper and lower limb deficits (NIHSS 5a, 5b, 6a, 6b) were associated with corticospinal tract disconnection, with negative correlations within the contralateral tracts (Figure 2). Language deficits were associated with left hemisphere tract disconnection, also showing negative correlations within the contralateral tracts. The disconnection mismatch volume was an independent predictor of functional outcome at 3-months (Table 1). Conclusion: The results from this study showed that it is possible to use routinely acquired CTP to capture the effects of stroke lesion on brain connectivity and its impact on functional outcome following recanalization treatment. Such an approach could enable more nuanced treatment selection for patients based on specific neurological deficits.

Background: Acute stroke lesions become more hypodense on non-contrast CT as the ischemic injury matures. Lesions transition to established infarcts at which time recanalization treatment is thought to be futile, if not harmful. As it is not possible to directly quantify the degree of injury progression, eligibility for treatment is determined using temporal criteria. In this study we used an AI approach to segment and quantify the degree of hypoattenuation of acute stroke lesions on baseline CTs, and explored its impact on clinical outcome following mechanical thrombectomy. Methods: Imaging was collected from a multicentric registry (across 4 US and 5 EU sites) of consecutive large vessel occlusion (LVO) stroke patients who underwent mechanical thrombectomy. Baseline NCCT scans were processed using Brainomix 360 to automatically segment the ischemic core. Lesion hypoattenuation was then quantified by in-house software using the mean Net-Water-Uptake (NWU). Multivariate models were used to explore the association between NWU and clinical outcome (3-month modified Rankin scale–mRS), controlling for e-ASPECTS scores, age, and recanalization status. Interaction models were also used to examine the relationship between NWU e-ASPECTS scores. Results: Of the 1363 patients included (age: median 70, IQR: 50-79; 571 females), successful recanalization (mTICI 2b-3) was achieved for 1119 patients. Multivariate analysis found NWU (p=<.001, t=4.62; Fig1) to remain an independent predictor of outcome. There was a significant interaction effect between and ASPECTS score (p=0.029, Fig 2), suggesting that degree of hypoattenuation played a larger role in patients with lower aspects value. In subgroup analysis, NWU was not a significant predictor of outcome in patients that did not achieve successful recanalizion (mTICI 0-2a). Conclusions: These findings suggest that stroke lesion hypodensity measured using NWU might help identify patients at risk of futile recanalization, and that incorporating this information might be more relevant in patients with lower ASPECTS. The ability to determine treatment eligibility using information extracted from routine imaging would allow safe extension of treatment to patients with unclear onset time, and would account for differences in rates of infarct progression.