Background Randomized trials have shown equivocal outcomes between a direct aspiration as first-pass technique (ADAPT) and stent retriever (SR) stroke thrombectomy, yet whether specific patient subgroups benefit differentially from one technique over the other remains unknown. Methods In this retrospective multicenter cohort study, patients with large vessel occlusion were included, and those who underwent ADAPT versus SR first-pass thrombectomy (either as standalone or combined with aspiration) were compared. The primary outcome was a composite of first-pass effect (FPE, modified Thrombolysis In Cerebral Infarction (mTICI) 2c or better with one attempt) with no symptomatic intracranial hemorrhage (sICH). A causal forest model was used to estimate the conditional average treatment effect (CATE) for each patient, with larger CATEs indicating that ADAPT is expected to be more advantageous. Patients were stratified by CATEs, and outcomes were compared between treatment groups. Results Among 6700 included patients, ADAPT (n=3695, 55%) was associated with a higher rate of FPE with no sICH (39.9% vs 26.9%; adjusted OR (aOR) 2.07, 95% CI 1.77 to 2.41, P<0.001). The causal forest identified significant treatment effect heterogeneity (interaction P<0.001), where ADAPT was more advantageous in more recent years and among patients with M1 occlusions presenting in earlier time windows. Low-CATE patients showed no statistically significant difference between techniques (aOR 0.91, 95% CI 0.57 to 1.45, P=0.70), while medium- and high-CATE patients demonstrated progressively larger ADAPT advantages (aOR 2.06, 95% CI 1.67 to 2.55, and aOR 2.99, 95% CI 2.24 to 3.98, respectively, both P<0.001). Conclusions ADAPT may be superior to SR for a majority of patients, particularly in recent years, and among patients with M1 occlusions presenting in earlier time windows.
Procedure duration predicts outcomes more than prehospital delay in endovascular stroke treatment
Background Endovascular thrombectomy (EVT) has transformed acute ischemic stroke (AIS) care, with onset-to-puncture (OTP) time widely recognized as a critical determinant of outcome. However, emerging evidence suggests that in-hospital procedure time (PT)—from arterial puncture to final recanalization—may have an equally or more significant impact. This study examines the relative contribution of PT versus OTP to functional outcomes in patients with AIS undergoing EVT. Methods A retrospective analysis was conducted of 6644 patients with AIS treated at 44 international stroke centers from the Stroke Thrombectomy and Aneurysm Registry (STAR; 2016–2023). Multivariable regression, time-equivalence analysis, and marginal effects modeling were used to assess associations between PT, OTP, and 90-day modified Rankin Scale (mRS) outcomes. Centers were stratified by procedural efficiency and compared using propensity score matching (PSM). Mediation analysis evaluated whether PT accounted for inter-center differences. Results PT and OTP were independently associated with functional outcomes; however, PT had a significantly stronger effect (adjusted OR for mRS 0–2: PT=0.56 vs OTP=0.96 per hour). Each 5 min increase in PT was equivalent to 78–100 min of additional OTP in outcome impact. Centers with faster average PT had higher rates of functional independence (number needed to treat (NNT)=10), fewer complications, and lower symptomatic intracranial hemorrhage rates. PT significantly mediated the relationship between center tier and outcomes (Sobel’s P<0.001). Conclusion While minimizing OTP remains important, PT exerts a greater influence on outcomes after EVT. Procedural efficiency should be emphasized in stroke systems of care and included in center performance metrics to improve patient outcomes.
Safety and efficacy of preoperative embolization in the treatment of brain arteriovenous malformations with perinidal aneurysms and single draining vein: a multicenter study with propensity score-weighting
Background and objectives Arteriovenous malformations (AVMs) with perinidal aneurysms and single draining vein are associated with an elevated risk of rupture and increased procedural complexity. The role of preoperative embolization in this high-risk anatomical subset remains unclear. This study aimed to evaluate the safety and efficacy of microsurgery with preoperative embolization, compared with microsurgery alone in patients with such AVMs. Methods We conducted a multicenter retrospective analysis of an AVM registry from the MISTA (Multicenter International Study for Treatment of Brain AVMs) consortium and included AVMs with perinidal aneurysms and a single draining vein. Baseline characteristics, angiographic outcomes, functional outcomes, and complication rates were compared. Propensity score weighting (PSW) using the covariate balancing method was applied to adjust for baseline differences. Results Out of a total of 1919 patients, 65 met the inclusion criteria; 45 patients underwent preoperative embolization followed by microsurgery, and 20 underwent microsurgery alone. After adjustment, complete obliteration rates were similar between groups (OR 0.87, 95% CI 0.04 to 16.33, P=0.92), as were rates of functional independence at discharge and follow-up. Overall complication, symptomatic complication, and mortality rates did not differ significantly between groups. However, permanent complications were significantly lower in patients with preoperative embolization (OR 0.06, 95% CI 0.004 to 0.84, P=0.03). Discussion In patients with AVMs featuring perinidal aneurysms and single draining vein, preoperative embolization followed by microsurgery was associated with fewer permanent complications and no increase in adverse outcomes compared with microsurgery alone. However, given the small number of events, this finding should be interpreted cautiously.
Outcomes of medical and surgical management in infectious intracranial aneurysms: a multicenter cohort analysis
Introduction Infectious intracranial aneurysms (IIAs) are rare but serious complications of systemic infections, particularly infective endocarditis. These aneurysms are prone to rupture, leading to significant morbidity and mortality. Management strategies lack consensus due to the rarity of the condition and reliance on small case series. This study examines the clinical management of IIAs using data from a large multicenter cohort. Methods A retrospective registry-based cohort study was conducted across 11 tertiary care centers in the USA between 2018 and 2023. Patients with IIAs were identified based on clinical and radiographic criteria. The primary outcome was treatment failure defined as persistence, growth, or rupture of the aneurysm. Secondary outcomes were mortality and the modified Rankin Scale (mRS) score at 90 days and 1 year. Multivariate logistic regressions were used to identify outcome predictors. Results A total of 104 patients with 166 aneurysms were included, with a median age of 43 years. Medical management was successful in 56% of cases, with failure often within 18 days of initiation. Predictors of failure included younger age, larger aneurysm size, and rupture at presentation. Surgical and endovascular interventions achieved higher success rates with better outcomes. At 90 days, 57% of patients achieved functional independence (mRS 0–2), while the mortality rate was 24%. Conclusion This study highlights the limitations of medical management for IIAs and underscores the need for early surgical or endovascular intervention in high-risk patients. Outcome predictors aid clinical decision-making, optimizing patient management. Further research is needed to standardize management guidelines for IIAs.
Higher risk of recurrence in partially thrombosed cerebral aneurysms post-WEB (Woven EndoBridge) device treatment: insights from the WorldWideWEB Consortium registry
Background The Woven EndoBridge (WEB) device is a prevalent treatment for intracranial aneurysms. While many studies have assessed the obliteration rate post-WEB embolization, few have focused on long-term outcomes in partially thrombosed aneurysms. Objective To assess whether partially thrombosed aneurysms are at higher risk of recurrence or retreatment following WEB embolization compared with non-thrombosed aneurysms. Methods We evaluated data from 22 academic institutions, focusing on previously untreated cerebral aneurysms treated with the WEB device. Logistic regression was utilized to analyze factors predicting long-term aneurysm obliteration and retreatment necessity. Results Among 1303 patients, 26 presented with a partially thrombosed aneurysm. In the partially thrombosed group, the mean aneurysm maximal diameter was 10.7±4 mm with a neck ratio of 1.99±1.19 mm, larger than in the control group where the mean aneurysm maximal diameter was 6.81±2.37 mm with a neck ratio of 1.64±0.51 mm (P<0.001 for both maximal diameter and neck ratio). At the final follow-up, partially thrombosed aneurysms treated by the WEB device had a 38.5% retreatment rate, compared with 7.0% for non-thrombosed aneurysms (P<0.001). Among partially thrombosed aneurysms, the Raymond-Roy type IIIa/b occlusion rate was higher (38.5% vs 9.9%, P<0.001). On multivariate analysis, partially thrombosed aneurysms compared with non-thrombosed aneurysms had an increased rate of retreatment (OR 3.64, 95% CI 1.28 to 10.1). Conclusion Partially thrombosed aneurysms are associated with a poorer occlusion rate and a higher rate of retreatment following WEB embolization. For partially thrombosed aneurysms, the WEB device appears suboptimal as a first-line treatment, and therefore alternative techniques should be prioritized.
Multicenter analysis of flow diversion for recurrent/persistent intracranial aneurysms after stent-assisted coiling
Background Flow-diverter stents (FDS) have become the standard of care for a wide range of intracranial aneurysms, but their efficacy/safety in the context of recurrent/recanalized aneurysms following stent-assisted coiling (SAC) is not well established. We evaluate the outcomes of FDS retreatment in a large multicenter cohort. Methods We retrospectively analyzed data from 118 patients across 22 institutions who underwent FDS retreatment for recurrent/persistent aneurysms after SAC (2008–22). The primary outcome was angiographic occlusion status at last follow-up, categorized as complete (100%), near-complete (90–99%), or incomplete (<90%) occlusion. Secondary outcomes included procedural complications and clinical outcomes measured by the modified Rankin Scale (mRS). Results A total of 118 patients (median age 57, 74.6% female) with median follow-up of 15.3 months were identified. Complete occlusion was achieved in 62.5% and near-complete occlusion in 25%. FDS deployment within the pre-existing stent was successful in 98.3% of cases. Major complications occurred in 3.4% of cases, including postoperative aneurysmal rupture with resultant mortality (1.6%) and thromboembolic events with long-term disability (1.6%). Favorable clinical outcomes (mRS 0–2) were observed in 95.1% of patients. Wider aneurysm neck diameter was a significant predictor of incomplete occlusion (adjusted OR (aOR) 1.23 per mm, P=0.044), with male sex trending towards association with non-occlusion (aOR 3.2, P=0.07), while baseline hypertension was associated with complete occlusion (aOR 0.32, P=0.048). Conclusions FDS treatment for recurrent/residual aneurysms after SAC represents a viable treatment option for these challenging cases with acceptable safety and reasonable occlusion rates, although lower than de novo FDS occlusion rates.
Minimal clinical impact of embolization to new territory on outcomes in medium vessel occlusion strokes treated with mechanical thrombectomy: a retrospective multicenter study
Background Mechanical thrombectomy (MT) is established as an effective treatment for large vessel occlusion strokes, but its efficacy and safety for medium vessel occlusions (MeVOs) remain less clear. This study examines the impact of periprocedural embolization to a new vascular territory (ENT) on clinical outcomes in patients with MeVO stroke treated with MT. Methods A multicenter, retrospective analysis was conducted using the MAD-MT (Multicenter Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy) registry, including 2122 patients with MeVO stroke who underwent MT between September 2017 and July 2023. ENT was defined as filling defects in previously unaffected territories, excluding embolization near the original occlusion, observed on final angiographic runs after retrieval of the primary thrombus. The associations between ENT, procedural variables, and 90-day clinical outcomes were evaluated, including functional independence (modified Rankin Scale (mRS) scores of 0–2), excellent outcomes (mRS 0–1), mortality, and hemorrhagic complications. Results ENT occurred in 2.9% (63/2122) of patients. Longer onset-to-arterial puncture time (adjusted OR 1.03; 95% CI 1.01 to 1.05; P=0.002) and a greater number of passes (adjusted OR 1.15; 95% CI 1.01 to 1.32; P=0.032) were associated with increased ENT risk, while excellent recanalization (thrombolysis in cerebral infarction (TICI) scale score 2c–3) was associated with reduced ENT risk (adjusted OR 0.41; 95% CI 0.23 to 0.72; P=0.002). ENT was not associated with poorer functional independence, mortality, or hemorrhagic complications. Conclusions ENT during MT for MeVO stroke occurs infrequently and does not significantly affect the clinical outcomes. These findings suggest ENT risk should not deter clinicians from performing MT in patients with MeVO. Further prospective studies are needed to validate these results.
Comparative efficacy and safety of stent retrievers as a bailout strategy following failed contact aspiration technique in acute stroke thrombectomy
Background The contact aspiration (CA) technique is often used to perform endovascular thrombectomy (EVT) for acute ischemic stroke (AIS); however, rescue strategies are necessary if CA fails to achieve recanalization. This study investigates the outcomes of incorporating stent retriever (SR) thrombectomy in the rescue strategy following failed CA. Methods EVT patients with failed CA attempts were identified from a large multicenter registry and stratified by rescue technique: CA alone or incorporating SR in the rescue strategy. Outcomes included successful recanalization, 90-day functional outcomes (defined by the modified Rankin Scale (mRS) score), symptomatic intracranial hemorrhage (sICH), and 90-day mortality. Results Among 1885 patients with failed CA attempts, conversion to SR was associated with higher recanalization rates (85.2% vs 80.6%; p=0.03), higher rates of second-pass recanalization (31.2% vs 23.4%; p<0.001), and better 90-day outcomes (mRS 0–2: 35.2% vs 29.9%; p=0.04) when compared with repeated CA attempts. Trevo SRs showed higher odds of successful recanalization (adjusted odds ratio (aOR)=1.9; p=0.02), second-pass recanalization (aOR=1.7; p=0.01), and reduced odds of sICH (aOR=0.3; p=0.02). EmboTrap SRs were associated with higher odds of 90-day mortality (aOR=2.6; p=0.004) and sICH (aOR=2.9; p=0.04) and lower odds of recanalization (aOR=0.5; p=0.03). Conclusions Incorporating SR in the rescue strategy after a failed CA improves recanalization rates and functional outcomes. Trevo SRs demonstrated superior efficacy and safety when incorporated into the rescue strategy.
Clinical outcomes of patients with unsuccessful mechanical thrombectomy versus best medical management of medium vessel occlusion stroke in the middle cerebral artery territory
Background Current randomized controlled trials are investigating the efficacy and safety of mechanical thrombectomy (MT) in patients with medium vessel occlusion (MeVO) stroke. Whether best medical management (MM) is more efficient than unsuccessful vessel recanalization during MT remains unknown. Methods This was a retrospective cohort study using data from 37 academic centers across North America, Asia, and Europe between September 2017 and July 2021. Only patients with occlusion of the distal branches (M2 and M3) of the middle cerebral artery territory were included. Unsuccessful MT was defined as a modified Thrombolysis in Cerebral Infarction score of 0–2a. Propensity score matching was used to control for confounders. The primary outcome was functional independence, defined as a modified Rankin Scale (mRS) score of 0–2 at 90 days after treatment. Multivariable regression analysis was used to assess factors associated with the primary outcome. Results Of 2903 patients screened for eligibility, 532 patients were analyzed (266 per group) after propensity score matching. The MM group had superior functional outcomes, with 32% achieving mRS 0–1 at 90 days compared with 21% in the MT group (P=0.011). Patients in the MM group also had significantly lower rates of symptomatic intracranial hemorrhage (sICH) (3.4% vs 16%, P<0.001) and any hemorrhage (18% vs 48%, P<0.001). On multivariable regression, unsuccessful MT was associated with reduced odds of functional independence (OR 0.50, 95% CI 0.29 to 0.85, P=0.011) and increased odds of sICH (OR 4.32, 95% CI 1.84 to 10.10, P<0.001). Mortality rates were similar between groups (27% in MM vs 29% in MT, P=0.73). Conclusion Unsuccessful MT for MeVO was linked to worse outcomes than best MM. These findings highlight the risks of prolonged attempts and emphasize the importance of efficient procedural decision-making to reduce complications and improve patient outcomes.
Comparing stand-alone endovascular embolization versus stereotactic radiosurgery in the treatment of arteriovenous malformations with Spetzler-Martin grades I–III: a propensity score matched study
Background Arteriovenous malformations (AVMs) are uncommon cerebral lesions that can cause significant neurological complications. Surgical resection is the gold standard for treatment, but endovascular embolization and stereotactic radiosurgery (SRS) are viable alternatives. Objective To compare the outcomes of endovascular embolization versus SRS in the treatment of AVMs with Spetzler-Martin grades I–III. Methods This study combined retrospective data from 10 academic institutions in North America and Europe. Patients aged 1 to 90 years who underwent endovascular embolization or SRS for AVMs with Spetzler-Martin grades I–III between January 2010 and December 2023 were included. Results The study included 244 patients, including 84 who had endovascular embolization and 160 who had SRS. Before propensity score matching (PSM), complete obliteration at the last follow-up was achieved in 74.5% of the SRS group compared with 57.8% of the embolization group (OR=0.47; 95% CI 0.26 to 0.48; P=0.01). After propensity score matching, SRS still achieved significantly higher occlusion rates at last follow-up (78.9% vs 55.3%; OR=0.32; 95% CI 0.12 to 0.90; P=0.03). Hemorrhagic complications were higher in the embolization group than in the SRS group, although this difference did not reach statistical significance after PSM (13.2% vs 2.6%; OR=5.6; 95% CI 0.62 to 50.47; P=0.12). Similarly, re-treatment rate was higher in the embolization group (10.5% vs 5.3%; OR=2.11; 95% CI 0.36 to 12.31; P=0.40) compared with the SRS group. Conclusion Our findings indicate that SRS has a significantly higher obliteration rate at last follow-up compared with endovascular embolization. Also, SRS has a higher tendency for fewer hemorrhagic complications and lower re-treatment rate. Further prospective studies are needed.