Cancer Prediction With Machine Learning of Thrombi From Thrombectomy in Stroke: Multicenter Development and Validation.

BACKGROUND: We aimed to develop and validate machine learning models to diagnose patients with ischemic stroke with cancer through the analysis of histopathologic images of thrombi obtained during endovascular thrombectomy. METHODS: This was a retrospective study using a prospective multicenter registry which enrolled consecutive patients with acute ischemic stroke from South Korea who underwent endovascular thrombectomy. This study included patients admitted between July 1, 2017 and December 31, 2021 from 6 academic university hospitals. Whole-slide scanning was performed for immunohistochemically stained thrombi. Machine learning models were developed using transfer learning with image slices as input to classify patients into 2 groups: cancer group or other determined cause group. The models were developed and internally validated using thrombi from patients of the primary center, and external validation was conducted in 5 centers. The model was also applied to patients with hidden cancer who were diagnosed with cancer within 1 month of their index stroke. RESULTS: The study included 70 561 images from 182 patients in both internal and external datasets (119 patients in internal and 63 in external). Machine learning models were developed for each immunohistochemical staining using antibodies against platelets, fibrin, and erythrocytes. The platelet model demonstrated consistently high accuracy in classifying patients with cancer, with area under the receiver operating characteristic curve of 0.986 (95% CI, 0.983-0.989) during training, 0.954 (95% CI, 0.937-0.972) during internal validation, and 0.949 (95% CI, 0.891-1.000) during external validation. When applied to patients with occult cancer, the model accurately predicted the presence of cancer with high probabilities ranging from 88.5% to 99.2%. CONCLUSIONS: Machine learning models may be used for prediction of cancer as the underlying cause or detection of occult cancer, using platelet-stained immunohistochemical slide images of thrombi obtained during endovascular thrombectomy.

Intensive vs Conventional Blood Pressure Lowering After Endovascular Thrombectomy in Acute Ischemic Stroke: The OPTIMAL-BP Randomized Clinical Trial.

Importance: Optimal blood pressure (BP) control after successful reperfusion with endovascular thrombectomy (EVT) for patients with acute ischemic stroke is unclear. Objective: To determine whether intensive BP management during the first 24 hours after successful reperfusion leads to better clinical outcomes than conventional BP management in patients who underwent EVT. Design, Setting, and Participants: Multicenter, randomized, open-label trial with a blinded end-point evaluation, conducted across 19 stroke centers in South Korea from June 2020 to November 2022 (final follow-up, March 8, 2023). It included 306 patients with large vessel occlusion acute ischemic stroke treated with EVT and with a modified Thrombolysis in Cerebral Infarction score of 2b or greater (partial or complete reperfusion). Interventions: Participants were randomly assigned to receive intensive BP management (systolic BP target <140 mm Hg; n = 155) or conventional management (systolic BP target 140-180 mm Hg; n = 150) for 24 hours after enrollment. Main Outcomes and Measures: The primary outcome was functional independence at 3 months (modified Rankin Scale score of 0-2). The primary safety outcomes were symptomatic intracerebral hemorrhage within 36 hours and death related to the index stroke within 3 months. Results: The trial was terminated early based on the recommendation of the data and safety monitoring board, which noted safety concerns. Among 306 randomized patients, 305 were confirmed eligible and 302 (99.0%) completed the trial (mean age, 73.0 years; 122 women [40.4%]). The intensive management group had a lower proportion achieving functional independence (39.4%) than the conventional management group (54.4%), with a significant risk difference (-15.1% [95% CI, -26.2% to -3.9%]) and adjusted odds ratio (0.56 [95% CI, 0.33-0.96]; P = .03). Rates of symptomatic intracerebral hemorrhage were 9.0% in the intensive group and 8.1% in the conventional group (risk difference, 1.0% [95% CI, -5.3% to 7.3%]; adjusted odds ratio, 1.10 [95% CI, 0.48-2.53]; P = .82). Death related to the index stroke within 3 months occurred in 7.7% of the intensive group and 5.4% of the conventional group (risk difference, 2.3% [95% CI, -3.3% to 7.9%]; adjusted odds ratio, 1.73 [95% CI, 0.61-4.92]; P = .31). Conclusions and Relevance: Among patients who achieved successful reperfusion with EVT for acute ischemic stroke with large vessel occlusion, intensive BP management for 24 hours led to a lower likelihood of functional independence at 3 months compared with conventional BP management. These results suggest that intensive BP management should be avoided after successful EVT in acute ischemic stroke. Trial Registration: ClinicalTrials.gov Identifier: NCT04205305.

Impact of Renal Function on Short-Term Outcome After Reperfusion Therapy in Patients With Ischemic Stroke.

BACKGROUND: A high and low estimated glomerular filtration rate (eGFR) could affect outcomes after reperfusion therapy for ischemic stroke. This study aimed to determine whether renal function based on eGFR affects mortality risk in patients with ischemic stroke within 6 months following reperfusion therapy. METHODS: This prospective registry-based cohort study included 2266 patients who received reperfusion therapy between January 2000 and September 2019 and were registered in the SECRET (Selection Criteria in Endovascular Thrombectomy and Thrombolytic Therapy) study or the Yonsei Stroke Cohort. A high and low eGFR were based on the Chronic Kidney Disease Epidemiology Collaboration equation and defined, respectively, as the 5th and 95th percentiles of age- and sex-specific eGFR. Occurrence of death within 6 months was compared among the groups according to their eGFR such as low, normal, or high eGFR. RESULTS: Of the 2266 patients, 2051 (90.5%) had a normal eGFR, 110 (4.9%) a low eGFR, and 105 (4.6%) a high eGFR. Patients with high eGFR were younger or less likely to have hypertension, diabetes, or atrial fibrillation than the other groups. Active cancer was more prevalent in the high-eGFR group. During the 6-month follow-up, there were 24 deaths (22.9%) in the high-eGFR group, 37 (33.6%) in the low-eGFR group, and 237 (11.6%) in the normal-eGFR group. After adjusting for variables with P<0.10 in the univariable analysis, 6-month mortality was independently associated with high eGFR (hazard ratio, 2.22 [95% CI, 1.36-3.62]; P=0.001) and low eGFR (HR, 2.29 [95% CI, 1.41-3.72]; P=0.001). These associations persisted regardless of treatment modality or various baseline characteristics. CONCLUSIONS: High eGFR as well as low eGFR were independently associated with 6-month mortality after reperfusion therapy. Kidney function could be considered a prognostic factor in patients with ischemic stroke after reperfusion therapy.

Immediate and Long-Term Outcomes of Reperfusion Therapy in Patients With Cancer.

Background and Purpose: Patients with acute stroke are often accompanied by comorbidities, such as active cancer. However, adequate treatment guidelines are not available for these patients. The purpose of this study was to evaluate the association between cancer and the outcomes of reperfusion therapy in patients with stroke. Methods: We compared treatment outcomes in patients who underwent reperfusion therapy, using a nationwide reperfusion therapy registry. We divided the patients into 3 groups according to cancer activity: active cancer, nonactive cancer, and without a history of cancer. We investigated reperfusion processes, 24-hour neurological improvement, adverse events, 3-month functional outcome, and 6-month survival and related factors after reperfusion therapy. Results: Among 1338 patients who underwent reperfusion therapy, 62 patients (4.6%) had active cancer, 78 patients (5.8%) had nonactive cancer, and 1198 patients (89.5%) had no history of cancer. Of the enrolled patients, 969 patients received intravenous thrombolysis and 685 patients underwent endovascular treatment (316 patients received combined therapy). Patients with active cancer had more comorbidities and experienced more severe strokes; however, they showed similar 24-hour neurological improvement and adverse events, including cerebral hemorrhage, compared with the other groups. Although the functional outcome at 3 months was poorer than the other groups, 36.4% of patients with active cancer showed functional independence. Additionally, 52.9% of the patients with determined stroke etiology showed functional independence despite active cancer. During the 6-month follow-up, 46.6% of patients with active cancer died, and active cancer was independently associated with poor survival (hazard ratio, 3.973 [95% CI, 2.528­6.245]). Conclusions: In patients with active cancer, reperfusion therapy showed similar adverse events and short-term outcomes to that of other groups. While long-term prognosis was worse in the active cancer group than the nonactive cancer groups, not negligible number of patients had good functional outcomes, especially those with determined stroke mechanisms.

Effect of Cumulative Case Volume on Procedural and Clinical Outcomes in Endovascular Thrombectomy.

Background and Purpose- The effect of endovascular thrombectomy (EVT) cumulative case volume (EVT-CCV) on outcomes of acute stroke patients has not been studied. This study investigated whether EVT-CCV was associated with outcomes. Methods- We identified all patients who underwent EVT for anterior circulation large vessel occlusion. Patients who met enrollment criteria were grouped into 5 based on the number of previous cases at each hospital. The number of cases that were recruited from each hospital and then assigned to each group (n) was designed to increase by the function of 10×2(n-1); group 1 consisted of cases 1 to 10 at each hospital, group 2 was cases 11 to 30, group 3 was cases 31 to 70, group 4 was cases 71 to 150, and group 5 was cases ≥151. We tested whether EVT-CCV group was associated with procedural and clinical outcomes. Results- Nine hundred fifty-five patients fulfilled the enrollment criteria. Recanalization and good outcome positively correlated with EVT-CCV group ( P<0.001 [correlation coefficient, r=0.122] for recanalization; P=0.002 [ r=0.099] for good outcome), whereas symptomatic intracranial hemorrhage and mortality negatively correlated ( P=0.039 [ r=-0.067] for symptomatic intracranial hemorrhage; P=0.016 [ r=-0.078] for mortality). EVT-CCV group was independently associated with recanalization (odds ratio, 1.182; 95% CI, 1.029-1.358) and good outcome (odds ratio, 1.187; 95% CI, 1.053-1.337). Conclusions- With increased EVT-CCV, recanalization and good outcome increased, whereas symptomatic intracranial hemorrhage and mortality decreased. Increased EVT-CCV was independently associated with recanalization and good outcome.

Balloon Guide Catheter Is Beneficial in Endovascular Treatment Regardless of Mechanical Recanalization Modality.

Background and Purpose- Based on its mechanism, the use of balloon guide catheters (BGCs) may be beneficial during endovascular treatment, regardless of the type of mechanical recanalization modality used-stent retriever thrombectomy or thrombaspiration. We evaluated whether the use of BGCs can be beneficial regardless of the first-line mechanical endovascular modality used. Methods- We retrospectively reviewed consecutive acute stroke patients who underwent stent retriever thrombectomy or thrombaspiration from the prospectively maintained registries of 17 stroke centers nationwide. Patients were assigned to the BGC or non-BGC group based on the use of BGCs during procedures. Endovascular and clinical outcomes were compared between the BGC and non-BGC groups. To adjust the influence of the type of first-line endovascular modality on successful recanalization and favorable outcome, multivariable analyses were also performed. Results- This study included a total of 955 patients. Stent retriever thrombectomy was used as the first-line modality in 526 patients (55.1%) and thrombaspiration in 429 (44.9%). BGC was used in 516 patients (54.0%; 61.2% of stent retriever thrombectomy patients; 45.2% of thrombaspiration patients). The successful recanalization rate was significantly higher in the BGC group compared with the non-BGC group (86.8% versus 74.7%, respectively; P<0.001). Furthermore, the first-pass recanalization rate was more frequent (37.0% versus 14.1%; P<0.001), and the number of device passes was fewer in the BGC group (2.5±1.9 versus 3.3±2.1; P<0.001). The procedural time was also shorter in the BGC group (54.3±27.4 versus 67.6±38.2; P<0.001). The use of BGC was an independent factor for successful recanalization (odds ratio, 2.18; 95% CI, 1.54-3.10; P<0.001) irrespective of the type of first-line endovascular modality used. The use of BGC was also an independent factor for a favorable outcome (odds ratio, 1.40; 95% CI, 1.02-1.92; P=0.038) irrespective of the type of first-line endovascular modality used. Conclusions- Regardless of the first-line mechanical endovascular modality used, the use of BGC in endovascular treatment was beneficial in terms of both recanalization success and functional outcome.

Outcomes of Endovascular Treatment for Acute Intracranial Atherosclerosis-Related Large Vessel Occlusion.

Background and Purpose- Endovascular treatment for acute intracranial atherosclerosis-related large vessel occlusion (ICAS [+]-LVO) is one of the challenging issues in modern mechanical thrombectomy era. We evaluated procedural and clinical outcomes of endovascular treatment for the ICAS (+)-LVO. We also compared their outcomes with those of large vessel occlusion not associated with intracranial atherosclerosis (ICAS [-]-LVO). Methods- We retrospectively reviewed consecutive patients with acute stroke who underwent endovascular treatment for LVO. Patients were assigned to the ICAS (+)-LVO group or the ICAS (-)-LVO group primarily based on catheter angiogram. Procedural and clinical outcomes were compared between the ICAS (+)-LVO and ICAS (-)-LVO groups. Results- The present study included 318 patients. Fifty-six patients (17.6%) had an ICAS (+)-LVO. Recanalization was achieved in 45 patients in the ICAS (+)-LVO group (80.4%), which was comparable with the ICAS (-)-LVO group (88.5%; P=0.097). However, recanalization using a stent retriever was less successful in the ICAS (+)-LVO (28.9%) than the ICAS (-)-LVO group (93.5%). Of the remaining patients in the ICAS (+)-LVO group, 84.3% of patients required specific rescue treatments appropriate for ICAS, including balloon angioplasty, stenting, and intra-arterial glycoprotein IIb/IIIa inhibitor infusion. The rates of favorable outcomes (46.4% versus 46.9%), death, and symptomatic intracranial hemorrhage were not significantly different between the 2 groups. Glycoprotein IIb/IIIa inhibitor use was not significantly associated with symptomatic intracranial hemorrhage. Conclusions- ICAS (+)-LVO was often refractory to mechanical thrombectomy. With specific rescue treatments appropriate for ICAS, patients in the ICAS (+)-LVO group had a recanalization rate comparable with patients in the ICAS (-)-LVO. With comparable recanalization rate, the clinical outcomes did not differ between patients with ICAS (+)-LVO and ICAS (-)-LVO.

Thrombus Volume as a Predictor of Nonrecanalization After Intravenous Thrombolysis in Acute Stroke.

Background and Purpose- We investigated whether measuring the volume and density of a thrombus could predict nonrecanalization after intravenous thrombolysis. Methods- This study included a retrospective cohort to develop a computed tomography marker of thrombus for predicting nonrecanalization after intravenous thrombolysis and a prospective multicenter cohort for validation of this marker. The volume and density of thrombus were measured semiautomatically using 3-dimensional software on a baseline thin-section noncontrast computed tomography (1 or 1.25 mm). Recanalization was assessed on computed tomography angiography or magnetic resonance angiography immediately after intravenous thrombolysis or conventional angiography in patients who underwent further intra-arterial treatment. Nonrecanalization was defined as a modified Thrombolysis in Cerebral Infarction grade 0, 1, 2a. Results- In the retrospective cohort, 162 of 214 patients (76.7%) failed to achieve recanalization. The thrombus volume was significantly larger in patients with nonrecanalization than in those with successful recanalization (149.5±127.6 versus 65.3±58.3 mm3; P<0.001). In the multivariate analysis, thrombus volume was independently associated with nonrecanalization ( P<0.001). The cutoff for predicting nonrecanalization was calculated as 200 mm3. In the prospective multicenter validation study, none of the patients with a thrombus volume ≥200 mm3 among 78 enrolled patients achieved successful recanalization. The positive and negative predictive values were 95.5 and 29.4 in the retrospective cohort 100 and 23.3 in the prospective validation cohort, respectively. The thrombus density was not associated with nonrecanalization. Conclusions- Thrombus volume was predictive of nonrecanalization after intravenous thrombolysis. Measurement of thrombus volume may help in determining the recanalization strategy and perhaps identify patients suitable for direct endovascular thrombectomy.

Number of Stent Retriever Passes Associated With Futile Recanalization in Acute Stroke.

Background and Purpose- Stent retriever (SR) thrombectomy has become the mainstay of treatment of acute intracranial large artery occlusion. However, it is still not much known about the optimal limit of SR attempts for favorable outcome. We evaluated whether a specific number of SR passes for futile recanalization can be determined. Methods- Patients who were treated with a SR as the first endovascular modality for their intracranial large artery occlusion in anterior circulation were retrospectively reviewed. The recanalization rate for each SR pass was calculated. The association between the number of SR passes and a patient's functional outcome was analyzed. Results- A total of 467 patients were included. Successful recanalization by SR alone was achieved in 82.2% of patients. Recanalization rates got sequentially lower as the number of passes increased, and the recanalization rate achievable by ≥5 passes of the SR was 5.5%. In a multivariable analysis, functional outcomes were more favorable in patients with 1 to 4 passes of the SR than in patients without recanalization (odds ratio [OR] was 8.06 for 1 pass; OR 7.78 for 2 passes; OR 6.10 for 3 passes; OR 6.57 for 4 passes; all P<0.001). However, the functional outcomes of patients with ≥5 passes were not significantly more favorable than found among patients without recanalization (OR 1.70 with 95% CI, 0.42-6.90 for 5 passes, P=0.455; OR 0.33 with 0.02-5.70, P=0.445 for ≥6 passes). Conclusions- The likelihood of successful recanalization got sequentially lower as the number of SR passes increased. Five or more passes of the SR became futile in terms of the recanalization rate and functional outcomes.

Rescue Stenting for Failed Mechanical Thrombectomy in Acute Ischemic Stroke: A Multicenter Experience.

BACKGROUND AND PURPOSE: Effective rescue treatment has not yet been suggested in patients with mechanical thrombectomy (MT) failure. This study aimed to test whether rescue stenting (RS) improved clinical outcomes in MT-failed patients. METHODS: This is a retrospective analysis of the cohorts of the 16 comprehensive stroke centers between September 2010 and December 2015. We identified the patients who underwent MT but failed to recanalize intracranial internal carotid artery or middle cerebral artery M1 occlusion. Patients were dichotomized into 2 groups: patients with RS and without RS after MT failure. Clinical and laboratory findings and outcomes were compared between the 2 groups. It was tested whether RS is associated with functional outcome. RESULTS: MT failed in 148 (25.0%) of the 591 patients with internal carotid artery or middle cerebral artery M1 occlusion. Of these 148 patients, 48 received RS (RS group) and 100 were left without further treatment (no stenting group). Recanalization was successful in 64.6% (31 of 48 patients) of RS group. Compared with no stenting group, RS group showed a significantly higher rate of good outcome (modified Rankin Scale score, 0-2; 39.6% versus 22.0%; P=0.031) without increasing symptomatic intracranial hemorrhage (16.7% versus 20.0%; P=0.823) or mortality (12.5% versus 19.0%; P=0.360). Of the RS group, patients who had recanalization success had 54.8% of good outcome, which is comparable to that (55.4%) of recanalization success group with MT. RS remained independently associated with good outcome after adjustment of other factors (odds ratio, 3.393; 95% confidence interval, 1.192-9.655; P=0.022). Follow-up vascular imaging was available in the 23 (74.2%) of 31 patients with recanalization success with RS. The stent was patent in 20 (87.0%) of the 23 patients. Glycoprotein IIb/IIIa inhibitor was significantly associated with stent patency but not with symptomatic intracranial hemorrhage. CONCLUSIONS: RS was independently associated with good outcomes without increasing symptomatic intracranial hemorrhage or mortality. RS seemed considered in MT-failed internal carotid artery or middle cerebral artery M1 occlusion.

Collateral status affects the onset-to-reperfusion time window for good outcome.

OBJECTIVE: To characterise the time window in which endovascular thrombectomy (EVT) is associated with good outcome, and to test the differential relationship between functional outcome and onset-to-reperfusion time (ORT), depending on collateral status. METHODS: This was a retrospective analysis of clinical and imaging data of 554 consecutive patients, who had recanalisation success by EVT for anterior circulation large artery occlusion, from the prospectively maintained registries of 16 comprehensive stroke centres between September 2010 and December 2015. The patients were dichotomised into good and poor collateral groups, based on CT angiography. We tested whether the likelihood of good outcome (modified Rankin Scale, 0-2) by ORT was different between two groups. RESULTS: ORT was 298 min±113 min (range, 81-665 min), and 84.5% of patients had good collaterals. Age, diabetes mellitus, previous infarction, National Institutes of Health Stroke Scale, good collaterals (OR 40.766; 95% CI 10.668 to 155.78; p<0.001) and ORT (OR 0.926 every 30 min delay; 95% CI 0.862 to 0.995; p=0.037) were independently associated with good outcome. The drop in likelihood of good outcome associated with longer ORT was significantly faster in poor collateral group (OR 0.305 for every 30 min; 95% CI 0.113 to 0.822) than in good collateral group (OR 0.926 for every 30 min; 95% CI 0.875 to 0.980). CONCLUSIONS: Earlier successful recanalisation was strongly associated with good outcome in poor collateral group; however, this association was weak during the tested time window in good collateral group. This suggests that the ORT window for good outcome can be adjusted according to collateral status.

Delayed Intravenous Thrombolysis in Patients with Minor Stroke.

BACKGROUND: The actions and responses of the hospital personnel during acute stroke care in the emergency department (ED) may differ according to the severity of a patient's stroke symptoms. We investigated whether the time from arrival at ED to various care steps differed between patients with minor and non-minor stroke who were treated with intravenous tissue plasminogen activator (IV tPA). METHODS: We included consecutive patients who received IV tPA during a 1.5 year-period in 5 hospitals. Minor stroke was defined as a National Institutes of Health Stroke Scale (NIHSS) score < 5. We compared various intervals from arrival at the ED to treatment between patients with minor stroke and those with non-minor stroke (NIHSS score ≥5). Delayed treatment was defined as a door-to-needle time > 40 min. RESULTS: During the study period, 356 patients received IV tPA treatment. The median door-to-needle time was significantly longer in the minor stroke group than it was in the non-minor stroke group (43 min [interquartile range [IQR] 35.5-55.5] vs. 37 min [IQR 30-46], p < 0.001). The minor stroke group had a significantly longer door-to-notification time (7 min [IQR 4.5-12] vs. 5 min [IQR 3-8], p < 0.001) and door-to-imaging time (20 min [IQR 15-26.5] vs. 16 min [IQR 11-21], p < 0.001) than did the non-minor stroke group. However, the imaging-to-needle time was not different between the groups. Multivariable analyses revealed that minor stroke was associated with delayed treatment (OR 2.54 [95% CI 1.52-4.30], p = 0.001). CONCLUSIONS: Our findings show that the door-to-needle time was longer in patients with minor stroke than it was in those with non-minor stroke, mainly owing to delayed action in the initial steps of neurology notification and imaging. Our findings suggest that some quality improvement initiatives are necessary for patients with suspected stroke with minor symptoms.

The Protective Effect of Middle Cerebral Artery Calcification on Symptomatic Middle Cerebral Artery Infarction.

BACKGROUND AND PURPOSE: The presence of intracranial artery calcification is associated with an increased risk for stroke. However, calcified atherosclerotic plaques are also known to be less vulnerable to rupture. Given this discrepancy, we investigated whether the vulnerability of intracranial arterial atherosclerosis differed based on the presence or absence of calcification. METHODS: We considered consecutive patients with acute stroke in the unilateral middle cerebral artery (MCA) territory. Patients with any stenotic MCAs were included in this study. Symptomatic MCA was defined as the occurrence of infarctions relevant to the stenotic MCA. The presence of calcification in the MCA was evaluated on noncontrast thin-section computed tomography images using a 3dimensional software package. Generalized estimating equations were used to compare the frequency of calcification between symptomatic and asymptomatic stenosis. RESULTS: Of the 1066 MCAs examined in 533 patients, 645 MCAs were stenotic and were included in the study. Among the 645 stenotic MCAs, 406 MCAs (62.9%) were symptomatic. Calcification was observed in 36 MCAs (5.6%). Calcification in the MCA was more frequently observed in the asymptomatic group (7.9% versus 4.2%; P=0.032). On multivariable analysis, the presence of calcification in MCA atherosclerosis was less frequent in the symptomatic group (odds ratio, 0.46; 95% confidence interval, 0.23-0.92; P=0.027). CONCLUSIONS: This study showed that calcified atherosclerosis in the MCA was less frequently symptomatic.

Predictive Value of Computed Tomography Angiography-Determined Occlusion Type in Stent Retriever Thrombectomy.

BACKGROUND AND PURPOSE: We investigated whether occlusion type identified with computed tomography angiography (CTA-determined occlusion type) could predict endovascular treatment success using stent retriever (SR) thrombectomy. METHODS: Consecutive patients with stroke who underwent CTA and then endovascular treatment for intracranial large artery occlusion were retrospectively reviewed. CTA-determined occlusion type was classified into truncal-type occlusion or branching-site occlusion and compared with digital subtraction angiography-determined occlusion type during endovascular treatment. Three rapidly- and readily-assessable pre-procedural findings (CTA-determined occlusion type, atrial fibrillation, and hyperdense artery sign), which may infer occlusion pathomechanism (embolic versus nonembolic) before endovascular treatment, were evaluated for association with SR success along with stroke risk factors and laboratory results. In addition, the predictive power of the 3 pre-procedural findings for SR success was compared with receiver operating characteristic curve analyses. RESULTS: A total of 238 patients (mean age, 70.0 years; male patients, 52.9%) were included in this study. CTA-determined occlusion type corresponded adequately with digital subtraction angiography-determined occlusion type (P=0.453). Atrial fibrillation (odds ratio, 2.66; 95% confidence interval, 1.25-5.66) and CTA-determined branching-site occlusion (odds ratio, 8.20; confidence interval, 3.45-19.5) were independent predictors for SR success. For predicting SR success, the area under the receiver operating characteristic curve value for CTA-determined branching-site occlusion (0.695) was significantly greater than atrial fibrillation (0.594; P=0.038) and hyperdense artery sign (0.603; P=0.023). CONCLUSIONS: CTA-determined branching-site occlusion was significantly associated with SR success. Furthermore, among the 3 rapidly- and readily-assessable pre-procedural findings, CTA-determined branching-site occlusion had the greatest predictive power for SR success.

Hemorrhagic Transformation After Large Cerebral Infarction in Rats Pretreated With Dabigatran or Warfarin.

BACKGROUND AND PURPOSE: It is uncertain whether hemorrhagic transformation (HT) after large cerebral infarction is less frequent in dabigatran users than warfarin users. We compared the occurrence of HT after large cerebral infarction among rats pretreated with dabigatran, warfarin, or placebo. METHODS: This was a triple-blind, randomized, and placebo-controlled experiment. After treatment with warfarin (0.2 mg/kg), dabigatran (20 mg/kg), or saline for 7 days, Wistar rats were subjected to transient middle cerebral artery occlusion. As the primary outcome, HT was determined by gradient-recalled echo imaging. For the secondary outcome, intracranial hemorrhage was assessed via gradient-recalled echo imaging in surviving rats and via autopsy for dead rats. RESULTS: Of 62 rats, there were 33 deaths (53.2%, 17 technical reasons). Of the intention-to-treat population, 33 rats underwent brain imaging. HT was less frequent in the dabigatran group than the warfarin group (placebo 2/14 [14%], dabigatran 0/10 [0%], and warfarin 9/9 [100%]; dabigatran versus warfarin; P<0.001). In all 62 rats, compared with the placebo (2/14 [14.3%]), the incidence of intracranial hemorrhage was significantly higher in the warfarin group (19/29 [65.5%]; P=0.003), but not in the dabigatran group (6/19 [31.6%]; P=0.420). Mortality was significantly higher in the warfarin group than the dabigatran group (79.3% versus 47.4%; P=0.022), but not related to the hemorrhage frequency. CONCLUSIONS: The risk of HT after a large cerebral infarction was significantly increased in rats pretreated with warfarin than those with dabigatran. However, the results here may not have an exact clinical translation.

Stenting as a Rescue Treatment After Failure of Mechanical Thrombectomy for Anterior Circulation Large Artery Occlusion.

BACKGROUND AND PURPOSE: We hypothesized that permanent stenting may be a rescue treatment for stentriever-failed anterior circulation large artery occlusion. We compared the outcomes among patients with permanent stenting and those without stenting after stentriever failure. METHODS: We retrospectively evaluated 208 patients who underwent stentriever thrombectomy for anterior circulation large artery occlusion between September 2010 and September 2015. Modified thrombolysis in cerebral ischemia 2b-3 recanalization was achieved with stentriever alone or in combination with Penumbra device in 155 patients (74.5%). An additional 8 patients (3.8%) obtained modified thrombolysis in cerebral ischemia 2b-3 with urokinase or glycoprotein IIb/IIIa inhibitor infusion. Of the remaining 45 patients (21.6%), 17 underwent stenting (stenting group; mean age, 68 years), whereas 28 did not undergo stenting (nonstenting group; mean age, 72 years). The rate of modified thrombolysis in cerebral ischemia 2b-3 in stenting group was assessed, and clinical outcomes were compared between groups. RESULTS: There were no differences in clinical and laboratory findings, initial National Institute of Health Stroke Scale score, location of anterior circulation large artery occlusion, and onset-to-puncture time between groups. Modified thrombolysis in cerebral ischemia 2b-3 was achieved in 14 members (83.3%) of the stenting group. Stenting group had more favorable outcomes (modified Rankin Scale score 0-2, 35.3%) and less cerebral herniation (11.8%) than nonstenting group (modified Rankin Scale score 0-2, 7.1%; cerebral herniation, 42.9%; P<0.05 for both). Symptomatic intracranial hemorrhage and mortality rates did not differ between stenting group (symptomatic intracranial hemorrhage, 11.8%; mortality, 23.5%) and nonstenting group (symptomatic intracranial hemorrhage, 14.3%; mortality, 39.3%). CONCLUSIONS: Permanent stenting may be a rescue modality for stentriever-failed anterior circulation large artery occlusion. A large prospective study is necessary for confirmation because of the small sample size of this study.

Poor Outcome of Stroke Patients With Atrial Fibrillation in the Presence of Coexisting Spontaneous Echo Contrast.

BACKGROUND AND PURPOSE: Spontaneous echo contrast (SEC) is frequently detected in patients with atrial fibrillation (AF). Coexisting SEC in patients with AF may be associated with heightened thrombogenicity, which affects stroke outcomes. METHODS: Consecutive stroke patients with nonvalvular AF who underwent transesophageal echocardiography were included in this study. We compared initial stroke severity and functional outcome at 3 months between the patients with and those without SEC. RESULTS: Of 440 patients with nonvalvular AF who underwent transesophageal echocardiography during a 7-year period, 193 (43.9%) patients had SEC. Stroke was more severe in the patients with SEC than in those without SEC (National Institute of Health Stroke Scale score: median [interquartile range], 5 [2-12] versus 3 [1-8]; P=0.004). The patients with SEC more frequently had poor functional outcomes (modified Rankin scale score of >2) at 3 months than those without SEC (32.3% versus 16.1%; P<0.001). On multivariate analysis, the presence of SEC was an independent factor of poor outcome (odds ratio, 2.09; 95% confidence interval, 1.24-3.53). CONCLUSIONS: In the ischemic stroke patients with nonvalvular AF, coexisting SEC was associated with more severe stroke and was predictive of poor long-term functional outcome.

Coil embolization of overwide and undertall small intracranial aneurysms with double microcatheter technique.

BACKGROUND: Overwide and undertall small intracranial aneurysms remain a challenge for coil embolization. The purpose of this study is to evaluate the feasibility and results of intrasaccular double microcatheter endovascular coil embolization of overwide and undertall small intracranial aneurysms. METHODS: Small (<7 mm), overwide (dome-to-neck ratio [DNR] ≤1.2), and undertall (ASPECT ratio ≤1.2) aneurysms which were treated with double microcatheter technique were selected. For the double microcatheter technique, two microcatheters were selected simultaneously into the aneurysm sac and coil insertion was performed alternatingly. The initial results, ASPECT, DNR ratios, complications, and follow-up results were assessed. RESULTS: Twenty small (mean, 3.8 mm), overwide (mean DNR, 1.1), and undertall (mean ASPECT, 1.0) aneurysms were treated with the double microcatheter technique. Overall, complete or near complete occlusion was achieved in 19/20 cases. This was achieved with only the double microcatheter technique in 16/20 cases (ASPECT mean, 1.0; DNR mean, 1.1). Adjuvant balloon remodeling was performed in 4/20 cases (ASPECT mean, 0.8; DNR mean, 1.1). The ASPECT ratio was significantly lower in the adjuvant balloon remodeling cases (p = 0.027). Coiling failed in one patient with both DNR and ASPECT ratio <1.0. Overall, one patient developed a focal visual field defect after the procedure. No other patients developed neurologically significant complications. CONCLUSIONS: Double microcatheter technique may be a safe and effective method for the treatment of overwide and undertall small intracranial aneurysms.

Traditional Thrombus Composition and Related Endovascular Outcomes: Catching up with the Recent Evidence.

Endovascular thrombectomy is the primary treatment for acute intracranial vessel occlusion and significantly improves recanalization success rate. However, achieving optimal recanalization remains a challenge. The histopathological components of thrombus composition play a crucial role in determining endovascular outcomes. This review aimed to consolidate the recent evidence on the impact of thrombus composition on mechanical properties and endovascular outcomes. The relationship between thrombus composition and mechanical properties was significant, with fibrin and/or platelet-rich thrombi being stiff, tough, elastic, and less deformable; fibrin-rich thrombi were sticky and had higher friction with the vessel wall. Erythrocyte composition was positively associated with successful recanalization, whereas lower platelet composition was associated with specific outcomes, such as the first-pass effect and complete recanalization. The number of thrombectomy device passes was possibly related to erythrocyte, platelet, and fibrin composition, with a smaller number of passes associated with erythrocyte-rich thrombi. Procedural time was consistently related to thrombus composition, with shorter times observed for erythrocyte-rich thrombi. The relationship between thrombus composition and secondary embolism remains inconclusive. Understanding the role of thrombus composition in endovascular outcomes is crucial to optimize stroke treatment. Although evidence suggests a link between thrombus composition and mechanical properties, further research is needed to establish stronger correlations and to reduce study variations. Exploring non-traditional thrombus components such as leukocytes and neutrophil extracellular traps is vital. Thrombus imaging could provide a practical solution for predicting thrombus composition before endovascular procedures. This review highlights the importance of thrombus composition for enhancing endovascular stroke treatment strategies.

Incidence and case fatality of stroke in Korea, 2011-2020.

OBJECTIVES: Stroke remains the second leading cause of death in Korea. This study was designed to estimate the crude, age-adjusted and age-specific incidence rates, as well as the case fatality rate of stroke, in Korea from 2011 to 2020. METHODS: We utilized data from the National Health Insurance Services from January 1, 2002 to December 31, 2020, to calculate incidence rates and 30-day and 1-year case fatality rates of stroke. Additionally, we determined sex and age-specific incidence rates and computed age-standardized incidence rates by direct standardization to the 2005 population. RESULTS: The crude incidence rate of stroke hovered around 200 (per 100,000 person-years) from 2011 to 2015, then surged to 218.4 in 2019, before marginally declining to 208.0 in 2020. Conversely, the age-standardized incidence rate consistently decreased by 25% between 2011 and 2020. When stratified by sex, the crude incidence rate increased between 2011 and 2019 for both sexes, followed by a decrease in 2020. Age-standardized incidence rates displayed a downward trend throughout the study period for both sexes. Across all age groups, the 30-day and 1-year case fatality rates of stroke consistently decreased from 2011 to 2019, only to increase in 2020. CONCLUSIONS: Despite a decrease in the age-standardized incidence rate, the total number of stroke events in Korea continues to rise due to the rapidly aging population. Moreover, 2020 witnessed a decrease in incidence but an increase in case fatality rates.