Sex-related differences in outcomes after mechanical thrombectomy (MT) for distal medium vessel occlusion (DMVO) stroke remain uncertain. While unadjusted differences have been reported in stroke populations, it is unclear whether biological sex independently influences outcomes after accounting for major prognostic factors. We performed a retrospective, multicenter analysis of the MAD-MT registry. Patients with acute DMVO who underwent MT were included. Propensity score matching (PSM) was employed. The primary outcome was functional independence (modified Rankin Scale [mRS] score 0–2) at 90 days. Secondary outcomes included excellent outcome (mRS 0–1), day 1 NIHSS shift, and reperfusion success. Safety outcomes included mortality and symptomatic intracerebral hemorrhage. Before matching, 1147 females and 1062 males were included. After 1:1 PSM (748 patients in each group), the groups were balanced in baseline characteristics. The median age was 75 years in both groups. At 90 days, 51

Optimal treatment for acute ischemic stroke due to distal medium-vessel occlusion (DMVO) in the middle cerebral artery (MCA) remains uncertain. While mechanical thrombectomy (MT) may pose higher risks in DMVO, intra-arterial thrombolysis (IAT)—with or without intravenous thrombolysis (IVT)—could be a safer alternative. To compare functional outcomes and safety profiles of IAT versus MT in acute ischemic stroke caused by MCA DMVO (M2–M4 segments). We performed a retrospective, propensity score-matched study across 37 centers (Asia, Europe, North America) using the MAD-MT registry. Patients with MCA DMVO (M2–M4) treated with IAT or MT (with/without IVT) were included. Propensity score matching adjusted for confounders. The primary outcome was excellent functional outcome (modified Rankin Scale [mRS] 0–1 at 90 days). After matching, 184 patients were analyzed (19 IAT, 165 MT). Baseline characteristics were balanced. At 90 days, excellent functional outcomes occurred in 38

BackgroundEndovascular therapy (EVT) for stroke due to distal or medium vessel occlusion (DMVO) is safe. Due to the distinct anatomical characteristics of DMVOs, further evaluation of EVT is crucial to determine which devices may yield better outcomes.MethodsA retrospective analysis of adults with DMVO treated in 37 centers (11 countries) was queried. The primary outcome of favorable shift in 90-day modified Rankin Scale (mRS) was compared between patients treated with Trevo versus other devices on first pass using 1:1 propensity score matching (PSM) with multivariable adjustment. Secondary outcomes included the number of pass attempts, final thrombolysis in cerebral infarction (TICI) score 2b-3, symptomatic intracranial hemorrhage (sICH), improvement in National Institutes of Health Stroke Scale (NIHSS) at 24h, and 90-day mortality.ResultsOf the 1115 included patients, 264 (24%) were treated with Trevo (PSM cohort of 261 per group). Trevo use was not associated with a favorable 90-day mRS shift (proportional odds ratio [OR] 1.10, 95% confidence interval [CI] 0.80-1.51). Trevo was associated with fewer passes (adjusted β=-0.25, 95% CI -0.48 - -0.03), higher odds of TICI 2b-3 (adjusted OR 1.97, 95% CI 1.11-3.49), and a greater 24h NIHSS improvement (adjusted β= -1.74, 95% CI -3.11 - -0.36), with no difference in sICH or mortality (p>0.05). Results were similar in sensitivity analyses.ConclusionsWe observed no safety concerns with Trevo as compared to other EVT devices for DMVO recanalization. There was a signal of better technical efficacy and early clinical improvement.

BACKGROUND AND OBJECTIVES:Recent trials have shown the efficacy of endovascular thrombectomy (EVT) in patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO) and large infarcts on admission. However, many patients still experience poor outcomes despite treatment. The aim of this study was to investigate whether quantitative ischemic lesion net water uptake (NWU) on noncontrast head CT (NCCT) could identify AIS-LVO patients with large baseline infarcts who may require constant care or die despite successful EVT. METHODS:This retrospective study included AIS-LVO patients with large baseline infarcts (Alberta Stroke Program Early CT Score ≤5) and occlusion of the intracranial internal carotid artery or first (M1) or second (M2) segments of the middle cerebral artery. Patients underwent EVT in 2 centers between 2012 and 2020. NWU was assessed on admission CT images by comparing density measurements of the ischemic core with the matching area of the contralateral hemisphere. The primary end point was a very poor outcome determined by functional neurologic status at 90 days on the modified Rankin Scale (mRS, score 5 or 6). Statistical analyses included group comparisons and evaluation of the predictive accuracy of an NWU ≥11.5% for very poor outcomes. RESULTS:A total of 103 patients with AIS-LVO were included, of whom 57.3% were female, with a mean age of 72.1 years. Among patients with NWU ≥11.5%, 85% experienced very poor outcomes, compared with 51.8% of patients with an NWU <11.5% (p = 0.007). Patients with very poor outcomes had higher mean NWU compared with those without very poor outcomes (10.3% vs 6.0%, p < 0.001). An NWU threshold of 11.5% showed high specificity (93.0%, 95% CI 81.4-97.6) and positive predictive value (85%, 95% CI 64.0-94.8) for predicting very poor outcomes, which increased after combining it with other clinical and imaging parameters. DISCUSSION:Elevated ischemic lesion NWU (≥11.5%) on admission NCCT was strongly associated with very poor functional outcomes at 90 days in AIS-LVO patients with large baseline infarcts treated by EVT. NWU assessment may serve as a valuable imaging biomarker for identifying patients who are likely to require constant care or die despite EVT.

Mechanical thrombectomy (MT) efficacy in medium vessel occlusion (MeVO) stroke, particularly in patients with low Alberta Stroke Program Early Computed Tomography Score (ASPECTS), remains less explored. This retrospective study analyzed data from 443 AIS patients treated with MT for MeVO and low ASPECTS (4–7) at 37 centers across North America, Asia, and Europe, from September 2017 to July 2021. Patients were categorized into ASPECTS of 4–5 and 6–7. Of 443 patients, 51 (12

BackgroundAcute ischemic stroke (AIS) caused by distal medium vessel occlusions (DMVOs) represents a significant proportion of overall stroke cases. While intravenous thrombolysis (IVT) has been a primary treatment, advancements in endovascular procedures have led to increased use of mechanical thrombectomy (MT) in DMVO stroke patients. However, symptomatic intracerebral hemorrhage (sICH) remains a critical complication of AIS, particularly after undergoing intervention. This study aims to identify factors associated with sICH in DMVO stroke patients undergoing MT.MethodsThis retrospective analysis utilized data from the Multicenter Analysis of Distal Medium Vessel Occlusions: Effect of Mechanical Thrombectomy (MAD-MT) registry, involving 37 centers across North America, Asia, and Europe. Middle cerebral artery (MCA) DMVO stroke patients were included. The primary outcome measured was sICH, as defined per the Heidelberg Bleeding Classification. Univariable and multivariable logistic regression were used to identify factors independently associated with sICH.ResultsAmong 1708 DMVO stroke patients, 148 (8.7%) developed sICH. Factors associated with sICH in DMVO patients treated with MT included older age (adjusted odds ratio (aOR) 1.01, 95% confidence interval (95% CI) 1.00 to 1.03, P=0.048), distal occlusion site (M3, M4) compared with medium occlusions (M2) (aOR 1.71, 95% CI 1.07 to 2.74, P=0.026), prior use of antiplatelet drugs (aOR 2.06, 95% CI 1.41 to 2.99, P<0.001), lower Alberta Stroke Program Early CT Scores (ASPECTS) (aOR 0.75, 95% CI 0.66 to 0.84, P<0.001), higher preoperative blood glucose level (aOR 1.00, 95% CI 1.00 to 1.01, P=0.012), number of passes (aOR 1.27, 95% CI 1.15 to 1.39, P<0.001), and successful recanalization (Thrombolysis In Cerebral Infarction (TICI) 2b-3) (aOR 0.43, 95% CI 0.28 to 0.66, P<0.001).ConclusionThis study provides novel insight into factors associated with sICH in patients undergoing MT for DMVO, emphasizing the importance of age, distal occlusion site, prior use of antiplatelet drugs, lower ASPECTS, higher preoperative blood glucose level, and procedural factors such as the number of passes and successful recanalization. Pending confirmation, consideration of these factors may improve personalized treatment strategies.

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.

BACKGROUND AND PURPOSE:Endovascular thrombectomy is a standard treatment for acute ischemic stroke due to large-vessel occlusions (AIS-LVO), but a large minority of patients do not achieve successful reperfusion. This study aimed to investigate the hypoperfusion intensity ratio (HIR) as a prognostic biomarker in unsuccessfully reperfused patients with AIS-LVO. MATERIALS AND METHODS:A multicenter retrospective cohort study was conducted at 2 comprehensive stroke centers, involving patients with AIS-LVO who underwent endovascular thrombectomy but did not achieve successful reperfusion, defined as a modified TICI score of 0-2a. HIR, derived from CT or MR perfusion imaging, was analyzed for its association with favorable clinical outcomes (90-day mRs score of 0-2). The optimal HIR threshold predictive of favorable outcomes was identified through receiver operating curve analysis. RESULTS:Of 129 patients included, 20 (15.5%) achieved favorable outcomes. HIR of <0.4 significantly predicted favorable outcomes with a sensitivity of 66% and specificity of 80%. Patients with an HIR of <0.4 demonstrated better clinical and imaging profiles, including lower admission NIHSS scores and smaller ischemic core volumes. Multivariable logistic regression confirmed HIR, along with age and the presence of hemorrhagic transformation, as independent predictors of favorable outcomes. CONCLUSIONS:In unsuccessfully reperfused patients with AIS-LVO, an HIR of <0.4 is associated with favorable outcomes, emphasizing on the importance of robust collateral circulation. This finding suggests that perfusion imaging and HIR evaluation could guide clinical decision-making and prognostication in this challenging patient subset.

For patients with symptomatic acute occlusions of the internal carotid artery below the circle of Willis, endovascular and best medical treatment were both effective and safe therapeutic options.

BackgroundThe efficacy of endovascular treatment (EVT) in acute ischaemic stroke due to distal medium vessel occlusion (DMVO) remains uncertain. Our study aimed to evaluate the safety and efficacy of EVT compared with the best medical management (BMM) in DMVO.MethodsIn this prospectively collected, retrospectively reviewed, multicentre cohort study, we analysed data from the Multicentre Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy registry. Patients with acute ischaemic stroke due to DMVO in the M2, M3 and M4 segments who underwent EVT or received BMM were included. Primary outcome measures comprised 10 co-primary endpoints, including functional independence (mRS 0–2), excellent outcome (mRS 0–1), mortality (mRS 6) and haemorrhagic complications. Propensity score matching was employed to balance the cohorts.ResultsAmong 2125 patients included in the primary analysis, 1713 received EVT and 412 received BMM. After propensity score matching, each group comprised 391 patients. At 90 days, no significant difference was observed in achieving mRS 0–2 between EVT and BMM (adjusted OR 1.00, 95% CI 0.67 to 1.50, p>0.99). However, EVT was associated with higher rates of symptomatic intracerebral haemorrhage (8.4% vs 3.0%, adjusted OR 3.56, 95% CI 1.69 to 7.48, p<0.001) and any intracranial haemorrhage (37% vs 19%, adjusted OR 2.61, 95% CI 1.81 to 3.78, p<0.001). Mortality rates were similar between groups (13% in both, adjusted OR 1.48, 95% CI 0.87 to 2.51, p=0.15).ConclusionOur findings suggest that while EVT does not significantly improve functional outcomes compared with BMM in DMVO, it is associated with higher risks of haemorrhagic complications. These results support a cautious approach to the use of EVT in DMVO and highlight the need for further prospective randomised trials to refine treatment strategies.

BACKGROUND:Isolated anterior cerebral artery occlusions (ACAo) in patients with acute ischemic stroke present significant challenges due to their rarity. The efficacy and safety of endovascular therapy (EVT) in comparison with best medical therapy (BMT) for ACAo remains unclear. This study aimed to assess the outcomes of these treatments. METHODS:This multinational, multicenter study analyzed data from the MAD-MT registry. Data were collected retrospectively from 37 sites across North America, Asia, and Europe. Inverse probability of treatment weighting (IPTW) was applied to balance confounding variables. The primary outcome was functional independence (modified Rankin Scale (mRS) scores of 0-2) at 90 days. Secondary outcomes included excellent outcomes (mRS 0-1), mortality at 90 days, and NIH Stroke Scale (NIHSS) score on day 1 post treatment. RESULTS:Of the 108 patients, 36 received BMT and 72 underwent EVT. The median age was 75 years, and 56% were male. At 90 days, 40% of patients achieved mRS 0-2, with no significant difference between EVT and BMT (38% vs 45%, p=0.46). Procedural success (mTICI 2b-3) was 91% in the EVT group, with a sICH rate of 2.9%. IPTW-adjusted analysis showed no significant difference between EVT and BMT for functional independence (OR 1.17, 95% CI 0.23 to 6.02, p=0.85), mortality (25% vs 21%, p=0.71) or day 1 NIHSS scores (Beta 2.2, 95% CI -0.51 to 4.8, p=0.11). CONCLUSIONS:EVT showed high procedural success but did not significantly improve functional outcomes or mortality compared with BMT in patients with ACAo. Further randomized trials are needed to clarify EVT's role in ACAo.

INTRODUCTION:The venous outflow profile (VOP) is a crucial yet often overlooked aspect affecting stroke outcomes. It plays a major role in the physiopathology of acute cerebral ischemia, as it accounts for both the upstream arterial collaterals and cerebral microperfusion. This enables it to circumvent the limitations of various arterial collateral evaluation systems, which often fail to consider impaired autoregulation and its impact on cerebral blood flow at the microcirculatory levels. In this narrative review, we will highlight the different parameters and modalities used to assess the VOP in acute ischemia. VO ASSESSMENT WITH DIFFERENT MODALITIES:CT parameters include cortical vein opacification score, interhemispheric difference of composite scores of the draining veins classifications on single-phase CT angiography (CTA), as well as the extent and velocity of optimal cortical venous filling on multiphase CTA. Differences in contrast administration and acquisition time render the single-phase CTA parameters less reliable. Perfusion parameters are semiautomated, thus offering greater reproducibility. These include time to peak and prolonged venous transit. Finally, the venous transit time is an MRI parameter. ASSOCIATIONS AND PROGNOSTIC IMPLICATIONS:VOP parameters' significance lies in their potential to predict tissue fate and, subsequently, clinical outcomes. Recent studies indicate that favorable VOP is independently associated with slower rates of infarct edema progression, smaller infarct volumes, and higher rates of functional independence after 90 days. Moreover, it is considered a predictor of recanalization success and the first-pass effect during mechanical thrombectomy. Conversely, an unfavorable VOP predicts futile recanalization and indicates a higher risk of reperfusion hemorrhage. Our aim is to explore these prognostic implications and their relevance in determining the utility of intracranial intervention.

Objective: The benign nature of perimesencephalic subarachnoid hemorrhage (pmSAH) can be challenged by the occurrence of complications. Given the limited prognostic value of established clinical parameters for the development of complications in patients with pmSAH, this study evaluates the potential of volumetric hemorrhage quantification for risk assessment and the evaluation of the clinical outcome. Material and Methods: In this retrospective single-center study, we analyzed all consecutive patients diagnosed with pmSAH between 2010 and 2023 at a tertiary care academic medical center in Germany. The volumetric quantification of the hemorrhage in cm3 was performed using non-contrast CT imaging. The occurrence of clinical complications, including hydrocephalus, vasospasm, and delayed cerebral ischemia (DCI), were assessed. Clinical outcomes were determined by the Glasgow Outcome Scale (GOS) at discharge. Multivariable logistic regression models were used to assess the correlation between quantified hemorrhage volumes and the occurrence of complications and clinical outcomes (GOS) controlled for other variables such as age, sex, cardiovascular risk factors, clinical symptoms, and the modified Fisher scale. Results: A total of 82 patients (58.5% male, 54.8 ± 12.1 years) were enrolled. The median World Federation of Neurosurgical Societies (WFNS) score for all patients at admission was 1.0 (IQR 1.0–1.0). During the clinical course, hydrocephalus occurred in 29%, vasospasm in 14.6%, and DCI in 8.5% of all patients. Hemorrhage volume quantification was found to be the strongest independent predictor for hydrocephalus (OR 1.28; 95% CI 1.02–1.61; p = 0.032) and vasospasm (OR 1.25; 95% CI 1.07–1.46; p = 0.007) and showed a high predictive accuracy in ROC analyses (AUC = 0.77 and 0.76, respectively). Conversely, neither clinical parameters nor the modified Fisher scale were associated with these complications. A higher hemorrhage volume was also significantly correlated with a worse functional outcome (GOS; β = –0.07, CI: −0.12–−0.02, p = 0.021). Conclusions: In patients with pmSAH, the volumetric quantification of hemorrhage may be an adequate prognostic parameter regarding the occurrence of hydrocephalus and vasospasm. In addition, the quantitative assessment of hemorrhage volumes was strongly associated with clinical outcomes in these patients. Despite the generally benign nature of pmSAH, this imaging biomarker could improve individualized clinical management strategies and inform about the risk for the occurrence of complications.

Perimesencephalic subarachnoid hemorrhage (pmSAH) is a rare, typically benign subtype of non-aneurysmal subarachnoid hemorrhage (SAH). While the majority of patients demonstrate a positive recovery trajectory, a subset of patients experiences complications, including vasospasm, hydrocephalus, or delayed cerebral ischemia (DCI). Reliable imaging markers for risk stratification are lacking. This study evaluates whether volumetric CT-based biomarkers—validated in aneurysmal SAH (aSAH)—are also predictive for pmSAH. In this retrospective single-center study, 72 patients with confirmed pmSAH between 2011 and 2024 were analyzed. The automated volumetric segmentation was performed using 3D Slicer and TotalSegmentator to quantify intracranial volume (ICV), brain volume (BV), cerebrospinal fluid (CSF), and selective sulcal volume (SSV). The associations between volumetric parameters and clinical presentation, complications, and functional outcome (Glasgow Outcome Scale, GOS) were assessed using non-parametric statistics and Spearman correlation. The median intracranial volume was 1352.7 mL, brain volume 1247.3 mL, cerebrospinal fluid volume 95.9 mL, and selective sulcal volume 19.4 mL. Vomiting at presentation was associated with higher CSF and SSV values (p = 0.04 and p = 0.005, respectively), but no significant volumetric differences were found regarding other symptoms or complications (vasospasm, hydrocephalus, DCI). GOS scores were uniformly high (median = 5), and none of the volumetric markers significantly correlated with outcome or complication rate (all p > 0.05). In contrast to aSAH, volumetric CT biomarkers such as ICV, BV, CSF, and SSV do not offer predictive value in patients with pmSAH. Risk stratification should continue to rely on initial hemorrhage pattern and volume, clinical monitoring, and individualized assessment rather than other volumetric parameters.

The efficacy and safety of intravenous thrombolysis (IVT) in acute ischemic stroke (AIS) patients undergoing mechanical thrombectomy (MT) for distal, medium vessel occlusions (DMVO) is not well established. This study investigates whether IVT impacts outcomes in DMVO patients, particularly in those with unsuccessful or partial recanalization after MT. We conducted a retrospective, multicenter study using data from the Multicenter Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy (MAD-MT) registry. The study population included AIS patients with DMVO in the M2, M3, and M4 segments of the MCA, treated with or without IVT followed by MT and a final modified Thrombolysis in Cerebral Infarction (mTICI) score of 0, 1, or 2a. The primary outcome was functional independence, assessed by the 90-day modified Rankin Scale (mRS) of 0–1 or 0–2. The study comprised 210 patients with final mTICI 0 to 2a, with 130 undergoing MT alone and 80 receiving IVT followed by MT. Logistic regression analysis revealed no significant differences in clinical outcomes between groups. The odds ratios (ORs) for achieving a 90-day mRS of 0–1 and 0–2 were 1.55 (95

BACKGROUND:Patients with acute ischemic stroke secondary to distal and medium vessel occlusion (AIS-DMVO) and minor strokes present a challenge in determining the most appropriate emergent treatment. Factors leading to early neurological deterioration (END) in this patient population are understudied, but END is known to result in poor functional outcomes. Therefore, we aimed to investigate the factors contributing to END in minor AIS-DMVO cases. METHODS:We included patients with AIS-DMVO and minor strokes from 37 sites across North America, Asia, and Europe. Minor stroke was defined as a baseline National Institutes of Health Stroke Scale (NIHSS) score of ⩽5. The primary outcome measure, END, was defined as a shift of ⩾4 points in the NIHSS score at day one after treatment compared to baseline. Univariable and multivariable logistic regression analyses were performed to identify factors associated with END. RESULTS:Among 559 consecutive patients with DMVO and minor strokes, END was reported in 68 patients. In multivariable analysis, mechanical thrombectomy (MT) was independently associated with higher odds of END (adjusted odds ratio [aOR] 2.37, 95% CI 1.12-5.02, p = 0.02), while intravenous thrombolysis (IVT) was associated with lower odds of END (aOR 0.46, 95% CI 0.26-0.81, p = 0.008). However, the association between MT and END was no longer statistically significant in the IPTW-adjusted analysis (OR 1.65, 95% CI 0.69-3.98, p = 0.26). Hypertension and antiplatelet use at baseline were also independently associated with END. Among MT-treated patients, successful and excellent recanalization and first-pass effect were protective against END. CONCLUSION:MT was associated with END in patients with minor AIS-DMVO, although this association was not significant after IPTW adjustment. IVT was independently associated with reduced risk of END. These findings support careful patient selection and further study in randomized trials.

BACKGROUND:Acute ischemic stroke (AIS) from distal medium vessel occlusion (DMVO) presents unique treatment challenges. Mechanical thrombectomy (MT) is emerging as a viable option for these patients, yet the role of pre-stroke aspirin treatment is unclear. This study evaluates the impact of pre-stroke low-dose aspirin on outcomes in DMVO patients undergoing MT. METHODS:We conducted a multinational, multicenter, propensity score-weighted analysis within the Multicenter Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy (MAD-MT) registry. Patients with AIS due to DMVO, treated with MT, were included. We compared outcomes between patients on pre-stroke low-dose aspirin (75-100 mg) and those not on antiplatelet therapy. The primary outcome was functional independence at 90 days (modified Rankin Scale (mRS), 0-2). Secondary outcomes included excellent functional outcome at 90 days (mRS, 0-1), mortality, and day 1 post-MT National Institutes of Health Stroke Scale (NIHSS) score. Safety outcomes focused on hemorrhagic complications, including symptomatic intracerebral hemorrhage (sICH). RESULTS:Among 1354 patients, 150 were on pre-stroke low-dose aspirin. After applying inverse probability of treatment weighting (IPTW), aspirin use was associated with significantly better functional outcomes (mRS, 0-2: odds ratio (OR) = 1.89, 95% confidence interval (CI) = 1.14 to 3.12) and lower 90-day mortality (OR = 0.56, 95% CI = 0.32 to 1.00). The aspirin group had lower NIHSS scores on day 1 (β = -1.5, 95% CI = -2.8 to -0.27). The sICH rate was not significantly different between the groups (OR = 0.92, 95% CI = 0.60 to 1.43). CONCLUSIONS:Pre-stroke low-dose aspirin was associated with improved functional outcomes and reduced mortality in patients with DMVO undergoing MT, without a significant increase in sICH. These findings suggest that low-dose aspirin may be safe and associated with more frequent excellent outcomes for this patient population. Further prospective studies are needed to validate these results and assess long-term outcomes.

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 w-ho 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.