Introduction: The rapid advancement of artificial intelligence (AI) technologies holds promise for improving healthcare outcomes. RapidAI is a software solution that utilizes AI to rapidly analyze imaging data to identify vascular occlusions and salvageable tissue. Physicians receive notifications and can review source images on the Rapid mobile app (RMA). Methods: Data for this study were obtained from the Get with the Guidelines Stroke database. The study focused on adult patients (18 years or older) admitted to Alexian Brothers Medical Center in Illinois between 2019-2022 who were diagnosed with acute ischemic stroke. Primary outcomes were the number of AIS patients treated with thrombolysis (IV tPA or IV TNK) and/or mechanical thrombectomy (MT) and time to treatment. Door to MT puncture times for transfer patients were analyzed separately from direct presentation patients. Discharge Modified Rankin score (mRS) was assessed as a secondary clinical outcome. Results: This analysis included 1,732 patients, 1,193 prior to installation of the RapidAI platform and 539 after installation of Rapid CTP, CTA, ASPECTS, LVO and RMA. Median door to femoral puncture time for MT cases decreased from 2 hr 28 min to 1 hr 58 min (p=0.012) post-Rapid for non-transfer patients. Door to femoral puncture times for transfer patients were unchanged. MT procedure volume increased from 9.6% to 14.5% (p=0.007). IV tPA/TNK volume and door-to-needle (DTN) times were unchanged; 15% treated with tPA/TNK pre-Rapid and 14% post-Rapid, DTN 48 vs 47 min. There was an improvement in the distribution of discharge mRS scores in post-Rapid patients (p<0.0001). Discussion: Following implementation of the AI software platform there was a significant increase in patients treated with MT, faster door to MT times for non-transfer patients, and improved discharge mRS scores. These data support future studies expanding the use of AI technology to improve stroke outcomes.

At the time of this writing, the coronavirus disease 2019 pandemic continues to be a global threat, disrupting usual processes, and protocols for delivering health care around the globe. There have been significant regional and national differences in the scope and timing of these disruptions. Many hospitals were forced to temporarily halt elective neurointerventional procedures with the first wave of the pandemic in the spring of 2020, in order to prioritize allocation of resources for acutely ill patients and also to minimize coronavirus disease 2019 transmission risks to non-acute patients, their families, and health care workers. This temporary moratorium on elective neurointerventional procedures is generally credited with helping to “flatten the curve” and direct scarce resources to more acutely ill patients; however, there have been reports of some delaying seeking medical care when it was in fact urgent, and other reports of patients having elective treatment delayed with the result of morbidity and mortality. Many regions have resumed elective neurointerventional procedures, only to now watch coronavirus disease 2019 positivity rates again climbing as winter of 2020 approaches. A new wave is now forecast which may have larger volumes of hospitalized coronavirus disease 2019 patients than the earlier wave(s) and may also coincide with a wave of patients hospitalized with seasonal influenza. This paper discusses relevant and practical elements of cessation and safe resumption of nonemergent neurointerventional services in the setting of a pandemic.

Background and Purpose- Mechanical thrombectomy (MT) devices have led to improved reperfusion and clinical outcomes in acute ischemic stroke patients with emergent large vessel occlusions; however, less than one-third of patients achieve complete reperfusion. Use of intraarterial thrombolysis in the context of MT may provide an opportunity to enhance these results. Here, we evaluate the use of intraarterial rtPA (recombinant tissue-type plasminogen activator) as rescue therapy (RT) after failed MT in the North American Solitaire Stent-Retriever Acute Stroke registry. Methods- The North American Solitaire Stent-Retriever Acute Stroke registry recruited sites within North America to submit data on acute ischemic stroke patients treated with the Solitaire device. After restricting the population of 354 patients to use of RT and anterior emergent large vessel occlusions, we compared patients who were treated with and without intraarterial rtPA after failed MT. Results- A total of 37 and 44 patients was in the intraarterial rtPA RT and the no intraarterial rtPA RT groups, respectively. Revascularization success (modified Thrombolysis in Cerebral Infarction ≥2b) was achieved in more intraarterial rtPA RT patients (61.2% versus 46.6%; P=0.13) with faster times to recanalization (100±85 versus 164±235 minutes; P=0.36) but was not statistically significant. The rate of symptomatic intracranial hemorrhage (13.9% versus 6.8%; P=0.29) and mortality (42.9% versus 44.7%; P=0.87) were similar between the groups. Good functional outcome (modified Rankin Scale score of ≤2) was numerically higher in intraarterial rtPA patients (22.9% versus 18.4%; P=0.64). Further restriction of the RT population to M1 occlusions only and time of onset to groin puncture ≤8 hours, resulted in significantly higher successful revascularization rates in the intraarterial rtPA RT cohort (77.8% versus 38.9%; P=0.02). Conclusions- Intraarterial rtPA as RT demonstrated a similar safety and clinical outcome profile, with higher reperfusion rates achieved in patients with M1 occlusions. Prospective studies are needed to delineate the role of intraarterial thrombolysis in MT.

BackgroundThe DEFUSE 3 and DAWN trials have shown the benefit of thrombectomy beyond 6 hours of stroke symptom onset in carefully selected patients.ObjectiveTo evaluate the real-world outcomes of stent retriever thrombectomy beyond 6 hours of stroke onset using combined individual patient data from the North American Solitaire Stent Retriever Acute Stroke (NASA) and Trevo Stent-Retriever Acute Stroke (TRACK) registries.MethodsPooled analysis of individual patient data of all cases of anterior circulation acute ischemic stroke (AIS) from NASA and TRACK was performed to compare outcomes of patients presenting within the first hours 6 or beyond 6 hours of stroke symptom onset.ResultsOf 830 patients with anterior circulation AIS from the NASA and TRACK registries, 32.7% (271 patients) underwent thrombectomy beyond the first 6 hours of symptom onset. The rates of good clinical outcome (modified Rankin scale score of 0–2 at 90 days), mortality, and symptomatic intracranial hemorrhage were similar: 48.1%, 20.6%, and 8.0% within 0–6 hours, 46.2%, 21.6%, and 10.9% within 6–16 hours, and 38.9%, 33.3%, and 5% within 16–24 hours (p=0.8, 0.6, and 0.5, respectively). The rates of successful recanalization (Thrombolysis in Cerebral Infarction 2b/3) were 79.4% in patients with stroke within 0–6 hours, 72.6% within 6–16 hours, and 85.0% within 16–24 hours (p=0.04).ConclusionsReal-world experience with patients with anterior circulation AIS treated with the Solitaire and Trevo thrombectomy devices beyond the first 6 hours of symptom onset proved to be equally safe and effective as for patients with symptom onset within the first 6 hours.

Background and Purpose— In acute ischemic stroke, fast and complete recanalization of the occluded vessel is associated with improved outcomes. We describe a novel measure for newer generation devices: the first pass effect (FPE). FPE is defined as achieving a complete recanalization with a single thrombectomy device pass. Methods— The North American Solitaire Acute Stroke Registry database was used to identify a FPE subgroup. Their baseline features and clinical outcomes were compared with non-FPE patients. Clinical outcome measures included 90-days modified Rankin Scale score, National Institutes of Health Stroke Scale score, mortality, and symptomatic intracranial hemorrhage. Multivariate analyses were performed to determine whether FPE independently resulted in improved outcomes and to identify predictors of FPE. Results— A total of 354 acute ischemic stroke patients underwent thrombectomy in the North American Solitaire Acute Stroke registry. FPE was achieved in 89 out of 354 (25.1%). More middle cerebral artery occlusions (64% versus 52.5%) and fewer internal carotid artery occlusions (10.1% versus 27.7%) were present in the FPE group. Balloon guide catheters were used more frequently with FPE (64.0% versus 34.7%). Median time to revascularization was significantly faster in the FPE group (median 34 versus 60 minutes; P =0.0003). FPE was an independent predictor of good clinical outcome (modified Rankin Scale score ≤2 was seen in 61.3% in FPE versus 35.3% in non-FPE cohort; P =0.013; odds ratio, 1.7; 95% confidence interval, 1.1–2.7). The independent predictors of achieving FPE were use of balloon guide catheters and non-internal carotid artery terminus occlusion. Conclusions— The achievement of complete revascularization from a single Solitaire thrombectomy device pass (FPE) is associated with significantly higher rates of good clinical outcome. The FPE is more frequently associated with the use of balloon guide catheters and less likely to be achieved with internal carotid artery terminus occlusion.

Background and Purpose— In acute ischemic stroke, fast and complete recanalization of the occluded vessel is associated with improved outcomes. We describe a novel measure for newer generation devices: the first pass effect (FPE). FPE is defined as achieving a complete recanalization with a single thrombectomy device pass. Methods— The North American Solitaire Acute Stroke Registry database was used to identify a FPE subgroup. Their baseline features and clinical outcomes were compared with non-FPE patients. Clinical outcome measures included 90-days modified Rankin Scale score, National Institutes of Health Stroke Scale score, mortality, and symptomatic intracranial hemorrhage. Multivariate analyses were performed to determine whether FPE independently resulted in improved outcomes and to identify predictors of FPE. Results— A total of 354 acute ischemic stroke patients underwent thrombectomy in the North American Solitaire Acute Stroke registry. FPE was achieved in 89 out of 354 (25.1%). More middle cerebral artery occlusions (64% versus 52.5%) and fewer internal carotid artery occlusions (10.1% versus 27.7%) were present in the FPE group. Balloon guide catheters were used more frequently with FPE (64.0% versus 34.7%). Median time to revascularization was significantly faster in the FPE group (median 34 versus 60 minutes; P=0.0003). FPE was an independent predictor of good clinical outcome (modified Rankin Scale score ⩽2 was seen in 61.3% in FPE versus 35.3% in non-FPE cohort; P=0.013; odds ratio, 1.7; 95% confidence interval, 1.1–2.7). The independent predictors of achieving FPE were use of balloon guide catheters and non-internal carotid artery terminus occlusion. Conclusions— The achievement of complete revascularization from a single Solitaire thrombectomy device pass (FPE) is associated with significantly higher rates of good clinical outcome. The FPE is more frequently associated with the use of balloon guide catheters and less likely to be achieved with internal carotid artery terminus occlusion.

Background Limited post-marketing data exist on the use of the Solitaire FR device in clinical practice. The North American Solitaire Stent Retriever Acute Stroke (NASA) registry aimed to assess the real world performance of the Solitaire FR device in contrast with the results from the SWIFT (Solitaire with the Intention for Thrombectomy) and TREVO 2 (Trevo versus Merci retrievers for thrombectomy revascularization of large vessel occlusions in acute ischemic stroke) trials. Methods The investigator initiated NASA registry recruited North American sites to submit retrospective angiographic and clinical outcome data on consecutive acute ischemic stroke (AIS) patients treated with the Solitaire FR between March 2012 and February 2013. The primary outcome was a Thrombolysis in Myocardial Ischemia (TIMI) score of ≥2 or a Treatment in Cerebral Infarction (TICI) score of ≥2a. Secondary outcomes were 90 day modified Rankin Scale (mRS) score, mortality, and symptomatic intracranial hemorrhage. Results 354 patients underwent treatment for AIS using the Solitaire FR device in 24 centers. Mean time from onset to groin puncture was 363.4±239 min, mean fluoroscopy time was 32.9±25.7 min, and mean procedure time was 100.9±57.8 min. Recanalization outcome: TIMI ≥2 rate of 83.3% (315/354) and TICI ≥2a rate of 87.5% (310/354) compared with the operator reported TIMI ≥2 rate of 83% in SWIFT and TICI ≥2a rate of 85% in TREVO 2. Clinical outcome: 42% (132/315) of NASA patients demonstrated a 90 day mRS ≤2 compared with 37% (SWIFT) and 40% (TREVO 2). 90 day mortality was 30.2% (95/315) versus 17.2% (SWIFT) and 29% (TREVO 2). Conclusions The NASA registry demonstrated that the Solitaire FR device performance in clinical practice is comparable with the SWIFT and TREVO 2 trial results.

BackgroundTime to reperfusion following endovascular treatment (ET) predicts outcomes after acute ischemic stroke (AIS).ObjectiveTo assess the time–outcome relationship within reperfusion grades in the North American Solitaire Acute Stroke registry.MethodsWe identified patients given ET for anterior circulation ischemic stroke within 8 h from onset and in whom reperfusion was achieved. Together with clinical and outcome data, site-adjudicated modified Thrombolysis in Cerebral Ischemia (TICI) was recorded. We assessed the impact of time to reperfusion (onset to procedure completion time) on good outcome (modified Rankin Scale 0–2 at 3 months) in patients who achieved TICI 2 or higher reperfusion in multivariable models. We further assessed this relationship within strata of reperfusion grades. A p<0.05 was considered significant.ResultsIndependent predictors of good outcome at 3 months among those achieving TICI ≥2a reperfusion (n=188) were initial National Institutes of Health Stroke Scale score (adjusted OR=0.90, 95% CI 0.85 to 0.95), symptomatic hemorrhage (adj. OR=0.16, 95% CI 0.05 to 0.60), TICI grade (TICI 3: adj. OR=11.52, 95% CI 3.34 to 39.77; TICI 2b: adj. OR=5.14, 95% CI 1.61 to 16.39), and time to reperfusion per 30 min interval (adj. OR=0.91, 95% CI 0.82 to 0.99). There was an interaction between final TICI grade and 30 min time to reperfusion intervals (p=0.001) such that the effect of time was strongest in TICI 2a patients.ConclusionsTime to reperfusion was a strong predictor of outcome following ET for AIS. However, the effect varied by TICI grade such that its greatest effect was in those achieving TICI 2a reperfusion.

Background: Various techniques are used to enhance the results of mechanical thrombectomy with stent-retrievers, including proximal arrest with balloon guide catheter (BGC), conventional large bore proximal catheter (CGC), or in combination with local aspiration through a large-bore catheter positioned at the clot interface (Aspiration-Retriever Technique for Stroke [ARTS]). We evaluated the impact of ARTS in the North American Solitaire Acute Stroke (NASA) registry. Summary: Data on the use of the aspiration technique were available for 285 anterior circulation patients, of which 29 underwent ARTS technique, 131 CGC, and 125 BGC. Baseline demographics were comparable, except that ARTS patients are less likely to have hypertension or atrial fibrillation. The ARTS group had more ICA occlusions (41.4 vs. 22% in the BGC, p = 0.04 and 26% in CGC, p = 0.1) and less MCA/M1 occlusions (44.8 vs. 68% in BGC and 62% in CGC). Time from arterial puncture to reperfusion or end of procedure with ARTS was shorter than with CGC (54 vs. 91 min, p = 0.001) and was comparable to the BGC time (54 vs. 67, p = 0.11). Final degree of reperfusion was comparable among the groups (TICI [modified Thrombolysis in Cerebral Infarction] score 2b or higher was 72 vs. 70% for CGC vs. 78% for BGC). Procedural complications, mortality, and good clinical outcome at 90 days were similar between the groups. Key Messages: The ARTS mechanical thrombectomy in acute ischemic stroke patients appears to yield better results as compared to the use of CGCs with no significant difference when compared to BGC. This early ARTS technique NASA registry data are limited by the earlier generation distal large bore catheters and small sample size. Future studies should focus on the comparison of ARTS and BGC techniques.

Rationale Efficacy of mechanical thrombectomy for acute stroke due to large vessel occlusion initiated beyond 6 h of time last seen well has not been demonstrated in randomized trials. Aim To establish whether subjects considered to have substantial areas of salvageable brain based on age-adjusted clinical core mismatch who can undergo endovascular treatment within 6–24 h from time last seen well (TLSW) have better outcomes at three months compared to subjects treated with standard medical therapy alone. Age-adjusted clinical core mismatch is defined by age (≤80 or >80 years), baseline National Institutes of Health Stroke Scale (NIHSS) (10–20 or ≥21), and core size (0–20 cm3 in subjects older than 80 and, in subjects younger than 80, 0–30 cm3 with NIHSS 10–20 and 31–50 cm3 with NIHSS ≥21). Design Prospective, randomized, multicenter, Bayesian adaptive-enrichment, open label trial with blinded endpoint assessment. For the purpose of enrolment, ischemic core size will be evaluated by CT perfusion or magnetic resonance imaging-diffusion-weighted imaging measured by automated software (RAPID). Procedures Subjects with acute ischemic stroke due to computed tomography angiography- or magnetic resonance angiogram-proven arterial occlusion of the intracranial internal carotid and/or proximal middle cerebral artery (M1) with age-adjusted clinical core mismatch in whom treatment can be initiated between 6 and 24 h from TSLW are randomized in a 1:1 ratio to receive mechanical embolectomy with the Trevo device or medical management alone. Sequential interim analyses allowing adaptation of enrolment criteria or stopping new enrolment for futility or predicted success will occur in every 50 randomized patients starting at 150 to a maximum of 500 patients. Study outcomes The primary endpoint is the modified Rankin Scale score at 90 days. The primary safety outcome is stroke-related mortality at 90 days. Analysis The primary endpoint, expressed as a utility-weighted modified Rankin Scale score is analyzed using a Bayesian posterior probability with adjustment for ischemic core size. For regulatory reasons, a nested co-primary endpoint analysis was added consisting of the proportion of subjects with modified Rankin Scale 0–2 between the active and control groups also analyzed using a Bayesian model.

Background: The Interventional Management of Stroke III (IMS-III) trial demonstrated no benefit for intravenous recombinant tissue plasminogen activator (IV rt-PA) followed by endovascular therapy versus IV rt-PA alone. However, IMS-III mostly included earlier generation devices. The recent thrombectomy trials have incorporated the stent-retriever technology, but their generalizability remains unknown. Methods: The North American Solitaire Acute Stroke (NASA) registry recruited patients treated with the Solitaire FR™ device between March 2012 and February 2013. The NASA-IMS-III-Like Group (NILG baseline NIHSS score ≥10 who received IV rt-PA) was compared to the IV rt-PA and IV + intra-arterial (IA)-IMS-III groups and the MR CLEAN, ESCAPE, SWIFT Prime, and REVASCAT trial controls to assess the stent-retriever treatment in the ‘real-world' setting. The NILG was also compared to non-IV rt-PA NASA patients to evaluate the impact of IV rt-PA on thrombectomy. Results: A total of 136 of the 354 NASA patients fulfilled criteria for the NILG. Baseline characteristics were well balanced across groups. Time from onset to puncture was higher in NILG than IV+IA-IMS-III patients (274 ± 112 vs. 208 ± 47 min, p < 0.0001). Occlusions involving the intracranial ICA, MCA-M1, or basilar arteries were more common in NILG than IV+IA-IMS-III patients (91.2 vs. 47.2%, p < 0.00001). Modified thrombolysis in cerebral infarction ≥2b reperfusion was higher in NILG than IV+IA-IMS-III patients (74.3 vs. 39.6%, p < 0.00001). A 90-day modified Rankin Scale score ≤2 was more frequent in the NILG than IV+IA-IMS-III patients (51.9 vs. 40.8%, p = 0.03) and MR CLEAN (51.9 vs. 19.1%, p < 0.00001), ESCAPE (51.9 vs. 29.3%, p = 0.0002), SWIFT Prime (51.9 vs. 35.5%, p = 0.02), and REVASCAT (51.9 vs. 28.2%, p = 0.0003) controls. Symptomatic intracranial hemorrhage definitions varied across the different studies with rates ranging from 2.7% (ESCAPE) to 11.9% (NILG). The NILG 90-day mortality (24.4%) was higher than in SWIFT Prime but comparable to all other groups. IV rt-PA was an independent predictor of good outcome in NASA (OR = 2.3, 95% CI 1.2-4.7). Conclusion: Our results support the ‘real-world' applicability of the recent thrombectomy trials.

BACKGROUND:Mechanical thrombectomy with stent-retrievers results in higher recanalization rates compared with previous devices. Despite successful recanalization rates (Thrombolysis in Cerebral Infarction (TICI) score ≥2b) of 70-83%, good outcomes by 90-day modified Rankin Scale (mRS) score ≤2 are achieved in only 40-55% of patients. We evaluated predictors of poor outcomes (mRS >2) despite successful recanalization (TICI ≥2b) in the North American Solitaire Stent Retriever Acute Stroke (NASA) registry. METHODS:Logistic regression was used to evaluate baseline characteristics and recanalization outcomes for association with 90-day mRS score of 0-2 (good outcome) vs 3-6 (poor outcome). Univariate tests were carried out for all factors. A multivariable model was developed based on backwards selection from the factors with at least marginal significance (p≤0.10) on univariate analysis with the retention criterion set at p≤0.05. The model was refit to minimize the number of cases excluded because of missing covariate values; the c-statistic was a measure of predictive power. RESULTS:Of 354 patients, 256 (72.3%) were recanalized successfully. Based on 234 recanalized patients evaluated for 90-day mRS score, 116 (49.6%) had poor outcomes. Univariate analysis identified an increased risk of poor outcome for age ≥80 years, occlusion site of internal carotid artery (ICA)/basilar artery, National Institute of Health Stroke Scale (NIHSS) score ≥18, history of diabetes mellitus, TICI 2b, use of rescue therapy, not using a balloon-guided catheter or intravenous tissue plasminogen activator (IV t-PA), and >30 min to recanalization (p≤0.05). In multivariable analysis, age ≥80 years, occlusion site ICA/basilar, initial NIHSS score ≥18, diabetes, absence of IV t-PA, ≥3 passes, and use of rescue therapy were significant independent predictors of poor 90-day outcome in a model with good predictive power (c-index=0.80). CONCLUSIONS:Age, occlusion site, high NIHSS, diabetes, no IV t-PA, ≥3 passes, and use of rescue therapy are associated with poor 90-day outcome despite successful recanalization.

Background: Time to reperfusion following endovascular treatment (ET) strongly predicts outcomes after acute ischemic stroke (AIS). However, the impact of time may vary depending on the grade of reperfusion. We sought to assess time-outcome relationship within grades of reperfusion in the North American Solitaire Acute Stroke (NASA) registry. Methods: The investigator-initiated NASA registry recruited 24 clinical sites within North America to submit demographic, clinical, site-adjudicated angiographic, and clinical outcome data on consecutive patients treated with the Solitaire Flow Restoration device. We identified patients treated with anterior circulation ischemic stroke treated within 8 hours. The modified Thrombolysis in Cerebral Ischemia (TICI) was used wherein TICI 2 was divided in TICI 2a (< 50% reperfusion) and TICI 2b (> 50% reperfusion). We assessed the impact of time to reperfusion (onset to procedure completion time) on good outcome (modified Rankin Scale 0-2 at 3 months) in those who achieved at least TICI 2a reperfusion, independent of other relevant covariates using logistic regression analysis. We further assessed this relationship within strata of reperfusion grade. Results: Among 265 eligible patients, 209 (78.9%) had complete data (mean age 68.4 years, median NIHSS score 18). Reperfusion grade was as follows: TICI 3: 35.4%; TICI 2b: 39.7%, TICI 2a: 14.8%; TICI 0-1: 10.0%. Independent predictors of outcome at 3 months among those achieving TICI 2-3 reperfusion were: initial NIHSS score, intravenous tissue plasminogen activator use, symptomatic hemorrhage, and time to reperfusion. For each 30 minutes, the adjusted OR for time to reperfusion was 0.874 (95% CI 0.797-958). There was a significant interaction between final TICI grade and 30-minute time to reperfusion intervals (P=0.001) such that the effect of time was strongest in TICI 2a patients. Conclusions: Time to reperfusion is a strong predictor of outcome following ET for AIS with 13% decreased odds of good outcome per 30-minute delay in achieving TICI 2-3 reperfusion. However, the effect varied by TICI grade such that its greatest effect was in those achieving TICI 2a reperfusion.

Mechanical thrombectomy using retrievable stents or stent retriever devices has become the mainstay of intra-arterial therapy for acute ischemic stroke. The recent publication of a series of positive trials supporting intra-arterial therapy as standard of care for the treatment of large vessel occlusion will likely further increase stent retriever use. Rarely, premature stent detachment during thrombectomy may be encountered. In our multicenter case series, we found a rate of detachment of less than 1% (n = 7/1,067), and all were first-generation Solitaire FR devices. A review of the US Food and Drug Administration database of device experience yielded 90 individual adverse reports of detachment. There were 82, 1 and 7 detachments of Solitaire FR (first generation), Solitaire FR2 (second generation) and Trevo devices, respectively. We conclude with a brief overview of the technical and procedural considerations which may be helpful in avoiding this rare complication.

Background and Purpose— Failure to recanalize predicts mortality in acute ischemic stroke. In the North American Solitaire Acute Stroke registry, we investigated parameters associated with mortality in successfully recanalized patients. Methods— Logistic regression was used to evaluate baseline characteristics and recanalization parameters for association with 90-day mortality. A multivariable model was developed based on backward selection with retention criteria of P <0.05 from factors with at least marginal significance ( P ≤0.10), then refit to minimize the number of excluded cases (missing data). Results— Successfully recanalized patients had lower mortality (25.2% [59/234] versus 46.9% [38/81] P <0.001). There was no difference in symptomatic intracranial hemorrhage between patients with successful versus failed recanalization (9% [21/234] versus 14% [11/79]; P =0.205). However, mortality was significantly higher in patients with symptomatic intracranial hemorrhage (72% [23/32] versus 26% [73/281]; P <0.001). Proximal occlusion (internal carotid artery or vertebrobasilar), initial National Institutes of Health Stroke Scale≥18, use of rescue therapy ( P <0.05), and 3+ passes ( P <0.10) were associated with mortality in recanalized patients. In the multivariate model with good predictive power ( c index=0.72), proximal occlusion, initial National Institutes of Health Stroke Scale≥18, and use of rescue therapy remained significant independent predictors of 90-day mortality. Conclusions— Failure to recanalize and presence of symptomatic intracranial hemorrhage resulted in increased mortality. Despite successful recanalization, proximal occlusion, high National Institutes of Health Stroke Scale, and need for rescue therapy were predictors of mortality.

Background: Recanalization of the occluded artery is a powerful predictor of good outcome in acute ischemic stroke secondary to large artery occlusions. Mechanical thrombectomy with stent-trievers results in higher recanalization rates and better outcomes compared to previous devices. However, despite successful recanalization rates (Treatment in Cerebral Infarction, TICI, score ≥ 2b) between 70 and 90%, good clinical outcomes assessed by modified Rankin Scale (mRS) ≤ 2 is present in 40-50% of patients . We aimed to evaluate predictors of poor outcomes (mRS > 2) despite successful recanalization (TICI ≥ 2b) in the acute stroke patients treated with the Solitaire device of the North American Solitaire Stent Retriever Acute Stroke (NASA) registry. Methods: The NASA registry is a multicenter, non-sponsored, physician-conducted, post-marketing registry on the use of SOLITAIRE FR device in 354 acute, large vessel, ischemic stroke patients. Logistic regression was used to evaluate patient characteristics and treatment parameters for association with 90-day mRS score of 0-2 (good outcome) versus 3-6 (poor outcome) within patients who were recanalized successfully (Thrombolysis in Cerebral Infarction or TICI score 2b-3). Univariate tests were followed by development of a multivariable model based on stepwise selection with entry and retention criteria of p < 0.05 from the set of factors with at least marginal significance (p ≤ 0.10) on univariate analysis. The c-statistic was calculated as a measure of predictive power. Results: Out of 354 patients, 256 (72.3%) were successfully recanalized (TICI ≥ 2b). Based on 90-day mRS score for 234 of these patients, there were 116 (49.6%) with mRS > 2. Univariate analysis identified increased risk of mRS > 2 for each of the following: age ≥ 80 years (upper quartile of data), occlusion site other than M1/M2, NIH Stroke Scale (NIHSS) score ≥ 18 (median), history of diabetes mellitus (DM), TICI = 2b, use of rescue therapy, not using a balloon-guided catheter (BGC) or intravenous tissue plasminogen activator (IV t-PA), and time to recanalization > 30 minutes (all p ≤ 0.05). Three or more passes was marginally significant (p=0.097). In multivariable analysis, age ≥ 80 years, site other than M1/M2, initial NIHSS ≥18, DM, absence of IV t-PA, use of rescue therapy and three or more passes were significant independent predictors of poor 90-day outcome in a model with good predictive power (c-index = 0.80). Conclusions: Age, occlusion site, high NIHSS, diabetes, not receiving IV t-PA, use of rescue therapy and three or more passes, were associated with poor 90-day outcome despite successful recanalization.

BACKGROUND AND PURPOSE:The Solitaire With the Intention for Thrombectomy (SWIFT) and thrombectomy revascularization of large vessel occlusions in acute ischemic stroke (TREVO 2) trial results demonstrated improved recanalization rates with mechanical thrombectomy; however, outcomes in the elderly population remain poorly understood. Here, we report the effect of age on clinical and angiographic outcome within the North American Solitaire-FR Stent-Retriever Acute Stroke (NASA) Registry.METHODS:The NASA Registry recruited sites to submit data on consecutive patients treated with Solitaire-FR. Influence of age on clinical and angiographic outcomes was assessed by dichotomizing the cohort into ≤80 and >80 years of age.RESULTS:Three hundred fifty-four patients underwent treatment in 24 centers; 276 patients were ≤80 years and 78 were >80 years of age. Mean age in the ≤80 and >80 cohorts was 62.2±13.2 and 85.2±3.8 years, respectively. Of patients >80 years, 27.3% had a 90-day modified Rankin Score ≤2 versus 45.4% ≤80 years (P=0.02). Mortality was 43.9% and 27.3% in the >80 and ≤80 years cohorts, respectively (P=0.01). There was no significant difference in time to revascularization, revascularization success, or symptomatic intracranial hemorrhage between the groups. Multivariate analysis showed age >80 years as an independent predictor of poor clinical outcome and mortality. Within the >80 cohort, National Institutes of Health Stroke Scale (NIHSS), revascularization rate, rescue therapy use, and symptomatic intracranial hemorrhage were independent predictors of mortality.CONCLUSION:Greater than 80 years of age is predictive of poor clinical outcome and increased mortality compared with younger patients in the NASA registry. However, intravenous tissue-type plasminogen activator use, lower NIHSS, and shorter revascularization time are associated with better outcomes. Further studies are needed to understand the endovascular therapy role in this cohort compared with medical therapy.