Williamson, Richard

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.

Introduction: Endovascular thrombectomy (EVT) is an effective treatment for basilar artery occlusion (BAO) stroke in select patients. While there is a growing body of literature suggesting that advanced imaging modalities such as computed tomography perfusion (CTP) and magnetic resonance (MR) may not be necessary for selecting anterior circulation large vessel occlusion stroke patients for EVT, whether advanced imaging may be superior to conventional imaging (non-contrast CT and CT angiography) in identifying good treatment candidates among BAO patients is less clear. Patients and methods: This was a multicenter retrospective cohort study of BAO EVT patients treated from 2013 to 2022 in the Stroke Thrombectomy and Aneurysm Registry. Patients selected for EVT by advanced imaging (CTP or MR) were matched with those selected by conventional imaging using propensity score matching (PSM) accounting for possible confounders. Primary outcome was functional independence at 90 days. Other outcomes include bedridden state or death at 90-days and symptomatic intracranial hemorrhage (sICH). Results: 268 patients were included. 150 patients were selected for BAO EVT by conventional imaging, 86 by CTP, and 32 by MR. Patients selected by advanced imaging were significantly older than those selected by conventional imaging (median age 71 vs 64 years, p = 0.001); patient characteristics were otherwise similar between cohorts. After PSM, 90-day outcomes were similar between the two cohorts ( p = 0.56), with similar rates of functional independence (39.4% vs 35.1%, p = 0.65), bedridden state or death (40.4% vs 44.7%, p = 0.66), and sICH (3.3% vs 5.7%, p = 0.49) for conventional and advanced imaging groups, respectively. Results were similar across treatment time windows (all p > 0.05). Conclusions: Selecting patients for basilar EVT using conventional versus advanced imaging did not result in different clinical outcomes, regardless of treatment time windows. Conventional imaging appears sufficient as a first-line tool for selecting basilar EVT patients in routine clinical practice.

Background The effectiveness of endovascular thrombectomy (EVT) for low Alberta Stroke Program Early CT score (ASPECTS) stroke patients with occlusion of the second segment of the middle cerebral artery (M2) is unclear. Methods This was a multicenter retrospective study. Patients with M1 or M2 occlusions and low ASPECTS (<6) who underwent successful EVT (modified treatment in cerebral ischemia score of 2b or higher) were included. Primary outcome was futile EVT reperfusion (defined as 90-day modified Rankin scale of 5 or 6). Other outcomes of interest include acceptable outcomes (modified Rankin scale of 3 or less) and intracranial hemorrhage (ICH), and all-cause 90-day mortality. Outcomes for M1 patients were compared to M2 patients with multivariable logistic regression models accounting for potential confounders. Results 173 patients with M1 or M2 occlusions and low ASPECTS (<6) who underwent successful EVT were identified. After multivariable adjustments, M2 patients had significantly higher odds of futile reperfusion (OR 5.48 [95%CI 1.91 to 15.7], p = 0.002), lower odds of acceptable outcomes (OR 0.33 [95%CI 0.12 to 0.89], p = 0.028), and higher odds of all-cause mortality (OR 4.90 [95%CI 1.65 to 14.5], p = 0.004). These findings suggest that EVT's efficacy for low-ASPECTS stroke patients may be diminished for patients with M2 occlusions. M2 occlusion was not significantly associated with ICH. Conclusions Among low-ASEPCTS stroke patients who underwent successful EVT, those with M2 occlusions had significantly higher odds of poor outcome compared to those with M1 occlusions.

BACKGROUND AND OBJECTIVES: It remains unclear whether decompressive craniectomy (DC) is beneficial in patients who suffer symptomatic intracerebral hemorrhage (sICH) after acute ischemic stroke (AIS). We sought to study the effect of DC on functional outcomes in patients with sICH after AIS who underwent mechanical thrombectomy (MT). METHODS: Patients with AIS from anterior circulation large vessel occlusion who underwent MT and subsequently developed sICH were identified from the Stroke Thrombectomy and Aneurysm Registry database. The primary outcome was acceptable 90-day functional neurological outcome, defined as modified Rankin scale (mRS) 0-3. Multivariable logistic regression and propensity-score matching were used to identify and quantify risk factors. RESULTS: Of 464 patients identified with sICH after AIS after MT, 97 patients (20.9%) underwent DC. Patients who underwent DC were more likely to be female ( P < .001), younger ( P < .001), have a measured medical comorbidity, have higher baseline mRS ( P = .02), and have higher-grade hemorrhages ( P = .01). At 90 days, 14% of patients had the primary outcome of mRS 0-3 and 56% had died. The primary outcome was observed in 11 patients who underwent DC (11%) and 55 (15%) of those without DC (odds ratio [OR] 0.7, 95% CI 0.4-1.4, P = .40). DC did not affect mRS shift at 90 days ( P = .10) but was associated with lower mortality (OR 0.5, 95% CI 0.3-0.8, P = .01). Multivariable analysis demonstrated that DC decreased the odds of primary outcome (adjusted OR 0.2, 95% CI 0.02-0.9, P = .045), but did not affect mortality ( P = .94), mRS shift ( P = .50), or length of stay ( P = .90). Propensity-matched analysis similarly demonstrated that non-DC patients were more likely to achieve the primary outcome (24% vs 8%, P = .045). CONCLUSION: In patients with sICH after AIS after MT, those selected for DC had less favorable outcomes and similar rates of mortality at 90 days.

OBJECTIVE The definitive influence of prestroke disability on outcomes in patients with a low Alberta Stroke Program Early CT Score (ASPECTS) treated with endovascular thrombectomy (EVT) for acute ischemic stroke (AIS) due to large-vessel occlusion (LVO) remains unknown. This study aimed to investigate the impact of prestroke disability on outcomes in this specific population. METHODS Data from 32 international centers for AIS-LVO patients with a low ASPECTS who underwent EVT between January 2013 and December 2022 were analyzed retrospectively. Low ASPECTS and prestroke disability were defined as ASPECTS values of 2–5 and prestroke modified Rankin Scale (mRS) score ≥ 2. The primary outcome was a return to the prestroke mRS score at 90 days. Secondary outcomes were independent ambulation (mRS scores of 0–3) or a return to the prestroke mRS score at 90 days, good functional outcome (mRS scores of 0–2) or a return to the prestroke mRS score at 90 days, successful recanalization, and 90-day mortality. Safety outcomes were any intracranial hemorrhage or symptomatic intracranial hemorrhage. A symptomatic intracranial hemorrhage was defined as an intracranial hemorrhage with an associated worsening of ≥ 4 points in the National Institutes of Health Stroke Scale score. Outcomes were compared between patients with and without prestroke disability. RESULTS Of 293 patients, 50 (17.1%) had a prestroke disability. Of 50 patients, 20 (40.0%), 24 (48.0%), and 6 (12.0%) had prestroke mRS scores of 2, 3, and 4, respectively. The primary outcome showed no significant difference between the two groups. Compared with patients without prestroke disability, those with prestroke disability had a significantly smaller proportion of independent ambulation or return to prestroke mRS score (adjusted OR 0.13, 95% CI 0.03–0.53) and good functional outcome or return to prestroke mRS score (adjusted OR 0.21, 95% CI 0.05–0.91). Other secondary and safety outcomes showed no significant difference between the two groups. CONCLUSIONS The present study indicated that prestroke disability was not associated with a return to the prestroke mRS score at 90 days or intracranial hemorrhage. Physicians should not routinely exclude AIS-LVO patients with a low ASPECTS who have prestroke disability from EVT based on prestroke disability alone.

BACKGROUND AND OBJECTIVES: We aimed to develop and validate a prediction score for futile recanalization (FR) for large vessel occlusion (LVO) presenting low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) for patients who underwent endovascular thrombectomy (EVT). METHODS: Patients with anterior circulation LVO with low ASPECTS (<6) who underwent successful EVT (modified treatment in cerebral ischemia score ≥2b) from Stroke Thrombectomy and Aneurysm Registry were retrospectively analyzed. FR was defined as 90-day modified Rankin Scale (mRS) scores ≥4 despite successful EVT. Multivariable logistic regression was used to identify independent predictors of FR, and they were used to create a clinical score. The performance of the score was assessed by receiver operating characteristic curve analyses. RESULTS: Of 219 patients, 170 and 49 patients were randomly assigned to the training and validation cohort, respectively. Independent predictors of FR identified in the training cohort were used to construct the SNAP score: site of occlusion (middle cerebral artery = 0, internal carotid artery = 1), National Institutes of Health Stroke Scale score at admission (≤10 = 0, 10 to 19 = 1, ≥20 = 2), age (<75 = 0, ≥75 = 2), and prestroke mRS score (0-3). Receiver operating characteristic curve analyses of the SNAP score in the training and validation cohorts showed areas under the curve of 0.79 (95% CI 0.72-0.86) and 0.79 (95% CI 0.65-0.92) for predicting FR, respectively. A SNAP score ≥5 had a positive predictive value of 92.1% [95% CI 78.8%-97.3%] for FR. CONCLUSION: The SNAP score may be useful in predicting FR after EVT in low-ASPECTS patients with LVO. It can provide patients, family members, and physicians with reliable outcome expectations among patients with acute ischemic stroke with large infarcts.

Background A higher number of recanalization attempts reduces the efficacy of endovascular thrombectomy (EVT) for acute ischemic stroke secondary to large vessel occlusion (LVO). We assessed the impact of switching EVT techniques after a failed first pass on procedural and clinical outcomes. Methods This multicenter international study, conducted between January 2013 and December 2022, included patients undergoing EVT for anterior circulation LVO (internal carotid artery or M1 segments) with failed first pass recanalization. Propensity score matching identified a 1:1 matched cohort of patients in whom EVT technique was changed after a failed first pass and those with the same technique repeated. The primary outcome was successful recanalization at second attempt defined as Thrombolysis in Cerebral Ischemia (TICI) score of 2B or higher. Secondary outcomes were 90-day modified Rankin Score (mRS) and postprocedural hemorrhage. Results Among 2167 patients, converting to an alternative technique after a failed first pass was associated with higher odds of successful recanalization (adjusted OR (aOR)=1.5, p=0.041), and higher odds of mRS 0–2 at 90 days (aOR=1.6, p=0.005) without additional risk of symptomatic hemorrhage (p=0.379). Using a propensity score matched cohort of 490 patients, technique conversion at second attempt increased odds of successful recanalization at second attempt (aOR=1.32, p=0.006) and 90-day mRS 0–2 (aOR=1.38, p=0.008). Conclusions Early conversion to an alternative EVT technique after a failed first pass recanalization in patients with AIS is associated with better technical success and clinical outcomes.

Background The benefit of intravenous thrombolysis (IVT) is well established. We aim to study the benefits of IVT in acute ischemic stroke (AIS) patients with large vessel occlusion (LVO) who underwent unsuccessful mechanical thrombectomy (MT). Methods We included AIS patients who underwent MT for anterior circulation LVO with failed recanalization (modified treatment in cerebral ischemia [mTICI] score ≤ 2A). Patients who received IVT prior to MT were compared to those who received MT alone. Propensity score matching using demographic, clinical, radiographic and procedural variables was used to match patients with and without IVT. The primary outcome was favorable 90-day good functional outcome (defined as modified Rankin scale of 0–2), and secondary outcomes included intracranial hemorrhage (ICH), symptomatic ICH (sICH), and 90-day mortality. Results Totally, 610 AIS patients with unsuccessful MT were included. After propensity matching, 219 patients were identified in each group. Median age was 70 years and 73 years in the IVT + MT and MT alone groups, respectively. In the IVT + MT group, final mTICI scores of 0, 1, and 2A were achieved in 92 (42.0%), 33 (15.1%), and 94 (42.9%) patients, respectively, versus 76 (34.7%), 29 (13.2%), and 114 (52.1%) in the MT alone group. The IVT + MT group had greater odds of 90-day good functional outcome (adjusted odds ratio 2.54, 95% confidence interval 1.53–4.32). There were no significant differences in secondary outcomes. Conclusions IVT is associated with improved functional outcomes in AIS patients with LVO despite unsuccessful MT.

Background Whereas mechanical thrombectomy (MT) has become standard-of-care treatment for patients with salvageable brain tissue after acute stroke caused by large-vessel occlusions, the results of MT in patients with medium-vessel occlusions (MEVOs), particularly in the posterior cerebral artery (PCA), are not well known. Methods Using data from the international Stroke Thrombectomy and Aneurysm Registry (STAR), we assessed presenting characteristics and clinical outcomes for patients who underwent MT for primary occlusions in the P2 PCA segment. As a subanalysis, we compared the PCA MeVO outcomes with STAR's anterior circulation MeVO outcomes, namely middle cerebral artery (MCA) M2 and M3 segments. Results Of the 9812 patients in STAR, 43 underwent MT for isolated PCA MeVOs. The patients’ median age was 69 years (interquartile range 61–79), and 48.8% were female. The median NIH Stroke Scale score was 9 (range 6–17). After recanalization, 67.4% of patients achieved successful recanalization (modified treatment in cerebral infarction score [mTICI] ≥ 2b), with a first-pass success rate of 44.2%, and 39.6% achieved a modified Rankin score of 0–2 at 90 days. Nine patients (20.9%) had died by the 90-day follow-up. In comparison with M2 and M3 MeVOs, there were no differences in presenting characteristics among the three groups. Patients with PCA MeVOs were less likely to undergo intra-arterial thrombolysis (4.7% PCA vs. 10.1% M2 vs. 16.2% M3, p = 0.046) or to achieve successful recanalization (mTICI ≥ 2b, 67.4%, 86.7%, 82.3%, respectively, p < 0.001); however, there were no differences in the rates of successful first-pass recanalization (44.2%, 49.8%, 52.3%, respectively, p = 0.65). Conclusions We describe the STAR experience performing MT in patients with PCA MeVOs. Our analysis supports that successful first-pass recanalization can be achieved in PCA MEVOs at a rate similar to that in MCA MeVOs, although further study and possible innovation may be necessary to improve successful PCA MeVO recanalization rates.