Collateral Grade Research Articles

Collateral status and recanalization after endovascular treatment for acute ischemic stroke

BackgroundSuccessful recanalization and good collateral status are associated with good clinical outcomes after endovascular treatment (EVT) for acute ischemic stroke, but the relationships among them are unclear.ObjectiveTo assess if collateral...

Early plasma D-dimer as a predictor of acute intracranial atherosclerosis-related large vessel occlusion in acute ischemic stroke.

Intracranial atherosclerosis-related large vessel occlusion (ICAS+LVO) poses an important technical challenge for endovascular thrombectomy (EVT). To evaluate the value of D-dimer in predicting ICAS+LVO alone and in combination with other clinical and imaging predictors. Consecutive patients who underwent EVT at our center between January 2018 and June 2021 were retrospectively reviewed. Patients were classified to the ICAS+LVO or ICAS-LVO group according to angiographic findings. Collateral gradings were evaluated based on computed tomography angiography and categorized as follows: score 0-1 unfavorable collaterals and score 2-3 favorable collaterals. Receiver operating characteristic curve was analyzed to evaluate the predictive value of D-dimer and the combination of other predictors for ICAS+LVO. A total of 374 patients were enrolled, among them, 107 (28.6%) had an ICAS+LVO, while ICAS-LVO was determined in 267 (71.4%) patients. Median D-dimer levels were lower (0.36 vs. 1.18 mg/L; P < 0.001) while the proportion of favorable collaterals was higher (85.0% vs. 22.5%; P < 0.001) in the ICAS+LVO group than the ICAS-LVO group. After multivariable analysis, D-dimer (adjusted odds ratio [OR]=0.32, 95% confidence interval [CI]=0.21-0.50; P < 0.001) and collaterals (adjusted OR=16.25, 95% CI=7.58-34.84; P < 0.001) remained independent predictors of ICAS+LVO. The area under the curve of D-dimer, collaterals, and combination for identification of ICAS+LVO was 0.82, 0.85, and 0.92, respectively. Low early plasma D-dimer levels are a significant and independent predictor of ICAS+LVO, and predictive value strengthens when in a combined model using D-dimer and collateral grading.

Association of Systolic Blood Pressure and Cerebral Collateral Flow in Acute Ischemic Stroke by Stroke Subtype.

Background and PurposeCollateral flow in acute ischemic stroke is known as a predictor of treatment outcome and long-term prognosis. However, factors determining the initial collateral flow remain unclear. We investigated factors related to collateral flow in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO) and further analyzed the results according to stroke etiology.MethodsThis was a retrospective study using prospective stroke registry data from a single university hospital from October 2014 to May 2021. AIS-LVO with middle cerebral artery M1 occlusion identified by pre-treatment multiphasic computed tomography angiography was included. Collateral flow score was graded on a 6-point ordinal scale according to pial arterial filling.ResultsA total of 74 patients [cardioembolism (CE): 57; large artery atherosclerosis (LAA): 17] was included. The mean age of all patients was 72.2 ± 11.7 years, and 37.8 % (n = 28) were men. Multivariate regression analysis showed that initial SBP [odds ratio (OR): 0.994; 95% confidence interval (CI): 0.990–0.998; p = 0.002] and stroke etiology (OR: 0.718; 95% CI: 0.548–0.940; p = 0.019) were independent factors of the collateral flow grade. Collateral flow grade was independently associated with initial SBP in the CE group (OR: 0.993; 95% CI: 0.989–0.998; p = 0.004) but not in the LAA group (OR: 0.992; 95% CI: 0.980–1.004; p = 0.218). Initial SBP was significantly correlated with NIHSS score in the CE group but not in the LAA group (r2= 0.091, p = 0.023; r2 = 0.043, p = 0.426, respectively).ConclusionsElevated initial SBP was associated with poor cerebral collateral flow and more severe symptoms in the CE group, but not in the LAA group in patients with AIS-LVO. These findings suggest differential effects of initial SBP elevation on collateral flow by stroke subtypes.

Correlation of serum vascular endothelial growth factor and cardiovascular risk factors on collateral formation in patients with acute coronary artery syndrome.

Coronary collaterals serve as an alternative source of blood flow in obstructive coronary heart disease. Coronary collateral development is induced by various angiogenic growth factors, including vascular endothelial growth factor-A (VEGF-A). Cardiovascular risk factors strongly associated with coronary artery disease include age, sex, elevated serum cholesterol, disturbed carbohydrate metabolism, and elevated blood pressure. A better understanding of the effects of these cardiovascular risk factors and serum VEGF-A level on collateral recruitment is necessary for a better prognosis in coronary artery diseases and new insight for further therapeutic promotion of coronary collaterals.220 consecutive patients undergoing coronary angiography with a mean age of 61 ± 9.83 were selected for the analysis. Two milliliters of blood were taken from the patients for analysis. The blood serum VEGF concentration was quantified via the ELISA method. Angiograms and other clinical reports were collected. Significant coronary artery disease was diagnosed in those with ≥ 70% of stenosis in at least one of the coronary arteries. The angiographic and clinical data were documented. The collateral grading was done according to the Rentrop Scoring system. The serum vascular endothelial growth factor level was correlated with the collateral score and cardiovascular risk factors like age, sex, type II diabetes, blood pressure, and cholesterol level. An increase in the level of the collateral score was noted with an increase in the level of VEGF in blood serum. A significant association was founded between serum VEGF level and cardiovascular risk factors on collateral formation in patients with diabetes and hypertension.

The Potential Mechanism Behind Native and Therapeutic Collaterals in Moyamoya

Background and PurposeTo explore the genetic basis and molecular mechanism of native arteriogenesis and therapeutic synangiosis in moyamoya disease (MMD).MethodsAn angiography-based study using patients from a prospective trial of encephaloduroarteriosynangiosis (EDAS) surgery was performed. The spontaneous collaterals grades were evaluated according to the system described by a new grading system. Blood samples were collected from all the recruited patients before EDAS and during the second hospitalization 3 months post-EDAS. We performed Boolean analysis using a combination of specific cell surface markers of CD34briCD133+CD45dimKDR+. Genotyping of p.R4810K was also performed. The correlation of age, sex, initial symptoms at diagnosis, collateral grade, Suzuki stages, the RNF213 genotype, time to peak (TTP), and endothelial progenitor cell (EPC) count with good collateral circulation was evaluated.ResultsEighty-five patients with MMD were included in this study. The mutation rate of RNF213 p.R4810K in our study was 25.9% (22/85). The heterozygous mutations were occurred significantly more frequently in the cases that were presented with infarction, worse neurological status, severe posterior cerebral artery (PCA) stenosis, and longer TTP delay. Further, the heterozygous mutations occurred significantly more frequently in the poor collateral stage group. Lower grades were significantly correlated with severe ischemia symptoms, worse neurological status, and a longer TTP delay. The post-operative angiographic findings showed that a good Matsushima grade was correlated with heterozygous mutations, a lower collateral stage, and a longer TTP delay. The CD34briCD133+CD45dimKDR+ cell count in patients 3 months post-EDAS was significantly higher as compared to the count before EDAS in the good Matsushima grade group. However, this change was not observed in the poor Matsushima grade group.ConclusionsThese data imply that mutations of RNF213 p.R4810K affect the establishment of spontaneous collateral circulation, and EPCs are involved in the process of formation of new EDAS collaterals.

Prognostic accuracy and impact of cerebral collateral status on clinical and safety outcomes in acute ischemic stroke patients receiving reperfusion therapy: a systematic meta-analysis.

Cerebral collateral status has a potential role in mediating postreperfusion clinical and safety outcomes in acute ischemic stroke (AIS). To investigate the prognostic accuracy and impact of collateral status on clinical and safety outcomes in patients with AIS receiving reperfusion therapy. Studies with AIS patients treated with reperfusion therapy, collateral status assessed using Tan, ASITN/SIR, or similar collateral grading methods and data stratified according to collateral status were included. Relevant data on clinical outcomes, such as functional outcome at 90 days, mortality at 90 days, angiographic reperfusion, symptomatic intracerebral hemorrhage (sICH) and hemorrhagic transformation (HT), were collated and analyzed. A meta-analysis of 18 studies involving 4132 patients with AIS was conducted. Good collateral status was significantly associated with angiographic reperfusion (odds ratio [OR]=1.97, 95% confidence interval [CI]=1.38-2.80; P < 0.0001), sICH (OR=0.67, 95% CI=0.46-0.99; P = 0.042), and 90-day functional outcome (OR=3.05, 95% CI=1.78-5.24; P < 0.0001). However, its association with HT (OR=0.76, 95% CI=0.38-1.51; P = 0.425) and three-month mortality (OR=0.53, 95% CI=0.17-1.69; P = 0.280) did not reach statistical significance. The prognostic accuracy of collaterals for predicting angiographic reperfusion, HT, functional outcome (at 90 days), and mortality (at 90 days) were 63%, 49%, 66%, and 48%, respectively. Cerebral collaterals are significantly associated with clinical and safety outcomes, albeit with a prognostic accuracy range of 48%-66%; thus, evaluation of their patency is a useful prognostic tool in patients with AIS receiving reperfusion therapy.

Independent Significance of Visual Assessment of Perfusion CT Maps in Anterior Circulation Stroke Patients Treated with Mechanical Thrombectomy.

In the absence of an automated software analysis, the role of computed tomography perfusion (CTP) in a real time clinical practice is not well established. We evaluated the clinical significance of a widely accessible and simple visual grading scale of CTP in the anterior circulation of acute ischemic stroke (AIS) patients treated with mechanical thrombectomy (MT). The single center consecutive CT investigations of AIS patients treated with MT in the anterior circulation have been evaluated retrospectively. ASPECT score and collateral circulation evaluation based on the Maas score were determined. Time to peak parametric maps, derived from CTP, were graded into four categories, from least to most favorable. The primary endpoint was functional outcome evaluated as modified Rankin Scale (mRS) ≤ 2 at 90days after MT. We included 318 patients in the analysis; 142 (45%) patients had mRS ≤ 2 after 90days, mortality rate was 24%. Higher CTP and Maas score were significantly correlated with better clinical outcome (Pearson χ2 25.0 and 37.7, respectively; p < 0.01). Collateral circulation and CTP grades were strongly interrelated (Pearson χ2 78.6; p < 0.01). The CTP grade demonstrated statistically significant independent correlation with the clinical outcome irrespective of the collateral circulation grade, ASPECT score and age (OR 2.5; p = 0.011). The correlation was more pronounced in patients with normal collateral circulation (OR 3.27; p = 0.029). We demonstrated that both visually graded CTP and collateral circulation grade strongly correlated with the clinical outcome of MT in the anterior circulation of AIS patients. Importantly, CTP correlated with the clinical outcome independent of the collateral circulation.

Leukocytes in Cerebral Thrombus Respond to Large-Vessel Occlusion in a Time-Dependent Manner and the Association of NETs With Collateral Flow.

Thrombus components are dynamically influenced by local blood flow and blood immune cells. After a large-vessel occlusion stroke, changes in the cerebral thrombus are unclear. Here we assessed a total of 206 cerebral thrombi from patients with ischemic stroke undergoing endovascular thrombectomy. The thrombi were categorized by time to reperfusion of <4 h (T4), 4–8 h (T4–8), and >8 h (T8). The cellular compositions in thrombus were analyzed, and relevant clinical features were compared. Both white blood cells and neutrophils were increased and then decreased in thrombus with time to reperfusion, which were positively correlated with those in peripheral blood. The neutrophil extracellular trap (NET) content in thrombus was correlated with the degree of neurological impairment of patients. Moreover, with prolonged time to reperfusion, the patients showed a trend of better collateral grade, which was associated with a lower NET content in the thrombus. In conclusion, the present results reveal the relationship between time-related endovascular immune response and clinical symptoms post-stroke from the perspective of thrombus and peripheral blood. The time-related pathological changes of cerebral thrombus may not be the direct cause for the difficulty in thrombolysis and thrombectomy. A low NET content in thrombi indicates excellent collateral flow, which suggests that treatments targeting NETs in thrombi might be beneficial for early neurological protection.

Predictors of 90-Day Functional Outcome Following Direct Mechanical Thrombectomy for Anterior Circulation Large Vessel Occlusion: A Prospective Study

Background: Mechanical thrombectomy (MT) is becoming a growing trend in the management of large vessel occlusion (LVO) during the past few decades, although data on the predictors of outcome following MT are scarce. We aimed to study the predictors of 90-day outcome in a cohort of patients with ischemic stroke with large-vessel occlusion. Methods: This was a three-month prospective study of 40 patients with anterior circulation LVO who underwent MT and were followed up for three months with modified Rankin Score (mRS). Results: Of the 40 patients recruited, 55% were men. M1 was the most common vessel occluded (32.5%) followed by internal carotid artery (ICA) and carotid trunk (20%). Tandem occlusion occurred in 25% of the cases. Among the demographic, clinical, radiological, and procedural variables studied, the factors that had a significant impact on the mRS at 3 months were age, diabetes mellitus (DM), hyperlipidemia, stroke mechanism, blood glucose level during procedure, post-procedural National Institutes of Health Stroke Scale (NIHSS), baseline Alberta stroke program early CT score (ASPECT) score, collaterals grade, and procedural thrombolysis in cerebral infarction (TICI) score (P&lt;0.05). On multivariate regression, patients’ age (B: 0.025, 95% CI: 0.001- 0.049, P=0.038), post-procedural NIHSS (B: 0.192, 95% CI: 0.101–0.283, P&lt;0.001), and baseline ASPECT score (B: -0.442, 95% CI: -0.838- -0.046, P=0.03) were the most independent factors to affect the mRS at 3 months. Conclusion: Patients’ age, baseline ASPECT score and post-procedural NIHSS are significant predictors of 90-day outcome of large-vessel occlusion following MT.

Risk factors of unexplained early neurological deterioration after treatment for ischemic stroke due to large vessel occlusion: a post hoc analysis of the HERMES study

BackgroundEarly neurological deterioration (END) after endovascular treatment (EVT) in patients with anterior circulation acute ischemic stroke (AIS) is associated with poor outcome. END may remain unexplained by parenchymal hemorrhage (UnEND)....

Abstract WMP65: Association Of Pre-mechanical Thrombectomy Collateral Scores With Functional Outcome In Short Versus Extended Window For Thrombectomy

Introduction: We aim to determine the association of pre-mechanical-thrombectomy (MT) collateral scores in the short (&lt;6 hours from onset) versus extended (6-24 hours from onset) window for MT with a good functional outcome. Methods: We performed a retrospective chart review of patients who underwent MT for anterior circulation large vessel occlusion at a comprehensive stroke center from 7/2014 to 12/2020. A board-certified neuroradiologist, who was blinded to the clinical outcomes, used collateral grading scales of Miteff (ordinal), Mass (ordinal), and modified-Tan (dichotomous) to designate collateral scores on the pre-MT CT Angiogram. The patients were divided into short (&lt;6 hours from onset) versus extended (6-24 hours from onset) groups depending on their timing of presentation to the emergency department. A binary logistic regression analysis was performed, controlling for age, sex, NIHSS, ASPECTS≥6, TICI score≥2b, recanalization time, mean arterial pressure, blood glucose, location of the occlusion, atrial fibrillation, LDL, hemoglobin-A1C, and administration of intravenous-alteplase, with the pre-MT collateral grading scores as predictors. The primary outcome was a good functional outcome (3-month mRS≤2). Results: 220 patients met the inclusion criteria.162 patients presented in the short window for MT. The pre-MT scales of Mass (OR, 0.35; 95%CI, 0.16-0.78; P 0.01) and modified-Tan (OR, 0.35; 95%CI, 0.16-0.78; P 0.01) were associated with a good functional outcome, unlike the Miteff scale (OR, 0.46; 95% CI, 0.18-1.18; P 0.103). 58 patients met our inclusion criteria for patients who presented in the extended window for MT. The pre-MT scales of Mass (OR, 0.75; 95% CI, 0.23-2.48; P 0.63), Miteff scale (OR, 0.78; 95%CI, 0.17-3.64; P 0.746) and modified-Tan (OR, 1.14; 95%CI, 0.1-12.98; P 0.918) were not associated with a good functional outcome. Conclusions: Our study demonstrates that good collateral grades on Mass and modified-Tan scales are associated with a good functional outcome for patients who present to the ED in the short window for MT. We did not find an association of any pre-MT collateral scores with a good functional outcome for patients presenting in the extended window for MT.

Abstract 77: Collateral Status And Recanalization After Endovascular Treatment For Acute Ischemic Stroke

Background: Successful recanalization and good collateral status are associated with good clinical outcome in patients with acute ischemic stroke treated with endovascular treatment, but the relationships among them are unclear. Methods: We analysed data from the MR CLEAN Registry, a multicenter prospective cohort study of patients with acute ischemic stroke who underwent endovascular treatment in the Netherlands. Collateral status was assessed using a common 4-point visual grading scale. Successful recanalization was defined as an extended Thrombolysis in Cerebral Infarction score ≥ 2B. Functional outcome at 90 days was determined with the modified Rankin Scale score. We assessed, in multivariable (ordinal) logistic regression models, the associations between 1) collateral status and successful recanalization, 2) successful recanalization and functional outcome, 3) collateral status and functional outcome. An interaction term (successful recanalization*collateral grade) was added to the latter model, to assess effect modification. Subgroup analyses were performed for patients treated with intravenous thrombolysis. Results: We included 2717 patients, 1898 (70%) with successful recanalization. There was no relationship between collateral status and successful recanalization. Successful recanalization (acOR 2.15, 95% CI 1.84-2.52) and better collateral grades (Grade 1, acOR 2.12, 95% CI 1.47-3.05; Grade 2, acOR 3.46, 95% CI 2.43-4.92; Grade 3, acOR 4.16, 95% CI 2.89-5.99) were both associated with a shift towards better functional outcome. There was no significant interaction between collateral status and successful recanalization. Results were similar for patients treated with intravenous thrombolysis. Conclusions: Collateral status is not associated with the probability of successful recanalization after endovascular treatment and does not modify the association between successful recanalization and functional outcome.

Abstract TP149: Association Of 24-hour Blood Pressure Parameters Post-thrombectomy With Functional Outcomes According To Collateral Status

Introduction: Higher blood pressure (BP) most post mechanical thrombectomy (MT) can influence perfusion in the ischemic brain tissue depending on collateral status. We aim to determine the association of 24 hour post MT BP parameters with the functional outcome depending on the pre MT collateral status. Methods: We performed a retrospective chart review of patients who underwent MT at a comprehensive stroke center from 7/2014 to 12/2020. The patients were divided into two groups (good versus bad) depending on collateral status. A board certified neuroradiologist, who was blinded to the clinical outcomes, used collateral grading scales of Mass ≥3 and modified-Tan&gt;50% to designate good collaterals on the pre MT CT Angiogram. A binary logistic regression analysis was performed, controlling for age, sex, NIHSS, ASPECTS≥6, TICI score≥2b, time to thrombectomy, LDL, Hemoglobin A1C, intravenous alteplase, with the 24 hour post MT BP parameters as the predictors. The outcomes were good functional outcome (90 day mRS≤2) and mortality. Results: 220 patients met the inclusion criteria. Lower 24 hour BP parameters of standard deviation (SD) SBP (OR,1.16; 95% CI,1.01-1.33; P 0.047) and maximum DBP (OR,1.05; 95% CI,1.01-1.09; P 0.036) were associated with good functional outcome, while higher values of SD SBP (OR,1.15; 95% CI,1.01-1.31; P 0.045), coefficient variation (CV) SBP (OR,1.19; 95% CI,1.01-1.41; P 0.043), SBP range (OR,1.04; 95% CI,1.01-1.07; P 0.046), maximum DBP (OR,0.95; 95% CI,0.91-0.99; P 0.016), pulse pressure (OR,1.09; 95% CI,1.02-1.16; P 0.022) and SBP≥140 (OR,5.85; 95% CI,1.11-30.85; P 0.038) were associated with mortality in patients with good collaterals according to Mass grading. Higher values of BP parameters of SD SBP (OR,1.13; 95% CI,1.04-1.24; P 0.007), CV SBP (OR,1.18; 95% CI,1.05-1.32; P 0.006), SBP range (OR,1.04; 95% CI,1.01-1.06; P 0.008) and maximum DBP (OR,0.97; 95% CI,0.94-1; P 0.02) were associated with mortality in patients with good collaterals according to modified-Tan grading. There was no such association in patients with bad collaterals. Conclusion: Various higher 24 hour BP parameters post MT are associated with a bad functional outcome or mortality in patients with good collaterals, unlike in patients with bad collaterals.

Association of BIRC5 Gene Polymorphism with the Collateral Circulation and Severity of Large Artery Atherosclerotic Stroke.

Objectives The collateral circulation near the cerebral artery occlusion can contribute to the relief of the symptoms and signs of stroke. Genetic factors play a decisive role in the difference in collateral circulation. Survivin, encoded by the baculoviral inhibitor of apoptosis (IAP) repeat-containing 5 gene (BIRC5), plays an important role in maintaining long-term endothelial integrity and homeostasis and as an angiogenic factor in the treatment of vascular diseases. We hypothesized that genetic variations in the BIRC5 gene may contribute to severity by influencing the collateral circulation. This study aimed at examining how the polymorphism of the BIRC5 gene correlated with the collateral circulation and severity of large artery atherosclerotic stroke. Methods This study enrolled 428 patients with large artery atherosclerotic stroke. There are no statistical differences in age, sex, social behavior, such as smoking and drinking, between the groups classified by the collateral circulation and by the severity of stroke (P > 0.01). Direct sequencing was performed for the genotyping of single nucleotide polymorphism (SNP) of BIRC5 (rs2071214). The enrolled patients were divided into several subgroups based on the collateral flow grading system from the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR), the results of the National Institutes of Health Stroke Survey (NIHSS) (6 as a threshold), and the score of the modified Rankin scale (mRS) (for the prediction of prognosis, 2 as a threshold). Differences among subgroups were identified through logistic regression. Results The analysis of collateral circulation revealed the significant correlation of SNP of rs2071214 with the development of poor collateral circulation of large artery atherosclerotic stroke in the additive model (GG vs. AA, odds ratio (OR) = 3.592, 95% confidence interval (CI) = 1.410–9.150, and P=0.007) and the recessive model (GG vs. AA/GA, OR = 3.313, 95% CI = 1.420–7.727, and P=0.006). The analysis of stroke severity exposed the significant role of the SNP of rs2071214 in increasing stroke severity in the dominant model (GA/GG vs. AA, OR = 1.658, 95% CI = 1.017–2.703, and P=0.043) and the additive model (GA vs. AA, OR = 1.717, 95% CI = 1.021–2.888, and P=0.042). However, the analysis of the short-term outcome indicated that three genetic models were not associated with short-term outcomes in the additive model (GA vs. AA, P=0.815, GG vs. AA, and P=0.336), the dominant model (GA/GG vs. AA and P=0.589), and the recessive model (GG vs. AA/GA and P=0.342). Conclusion Our findings identified the SNP of rs2071214 of the BIRC5 gene as a risk factor for the poor compensatory ability of collateral circulation and a predictor of stroke severity in large artery atherosclerotic stroke, which suggested that the SNP of rs2071214 can serve as an innovative therapeutic target for patients with acute ischemic stroke.

Imaging Findings of Knee Trauma on Magnetic Resonance Imaging

Background: Knee is one of the major joints involved in kinesis. With increasing involvement in sports related activities especially in young people, Trauma related knee pathologies have increased. An accurate diagnosis regarding the type and extent of injuries is essential for early operative as well as non-operative treatment. Methods:This prospective study included total of 82 cases. The patients were referred to the department of Radiodiagnosis from indoor and outdoor departments of Guru Nanak Dev Hospital, Amritsar with suspicion of internal derangement of the knee and with history of knee trauma.Results:The most common age group involved was young males between 15-34 years. In all age groups most of the patients were males. Most common ligament to be injured was Anterior Cruciate Ligament (ACL). Partial tears were more common than complete tears. Posterior Cruciate Ligament (PCL) tears were less common. Medial Collateral Ligament (MCL) tears outnumbered Lateral Collateral Ligament (LCL) tears and grade 2 tears were more common in both. Among the meniscal injuries Medial Meniscus (MM) tears were more common than LM and grade 3 signal was more common in both. Most of the patellar retinaculum injuries were associated with Anterior Cruciate Ligament ACL tears.Conclusions:Post-traumatic pre-arthroscopic MR imaging evaluation has proved to be cost-effective. MRI is an accurate imaging modality complementing the clinical evaluation and providing a global intra-articular and extra-articular assessment of the knee.

Ischemic Burden Assessment Using Single Photon Emission Computed Tomography in Single Vessel Chronic Total Occlusion of Coronary Artery.

Studies evaluating the nature of ischemic burden of chronic total occlusion (CTO) vessels are still lacking. A total of 165 patients with single vessel CTO >2.5 mm in an epicardial coronary artery who underwent single photon emission computed tomography (SPECT) were enrolled in the study. Ischemic burden was calculated with the use of semi-quantitative SPECT analysis, and was defined as the summed difference score (SDS) divided by the maximal limit of the score (=SDS/68). The mean age of the participants was 59.5 years and the CTO of the left anterior descending coronary artery (LAD), left circumplex coronary artery (LCX), and right coronary artery (RCA) accounted for 93 (56.4%), 18 (10.9%), and 54 (32.7%) patients, respectively. The median ischemic burden of the total population was 8.8%, and it was highest in the LAD CTO (10.3%) compared with the LCX (5.9%) and RCA CTO (5.9%, p<0.001). High-ischemic burden (ischemic burden >10%) was observed in 66 patients (40.0%), and in 47 patients (50.5%) of the LAD CTO. Ischemic burden was different according to the CTO location only in LAD CTO. The statistically significant predictors for high-ischemic burden were hypertension, baseline ejection fraction >45%, LAD CTO, proximal CTO location, and de novo CTO. Japanese-CTO score and Rentrop scale collateral grade were not associated with high-ischemic burden. Only 40% of patients with single vessel CTO had ischemic burden >10%. For CTO vessels, measurement of ischemic burden using SPECT prior to revascularization may be helpful in identifying beneficial subjects.

Biomarkers of Technical Success After Embolectomy for Acute Stroke.

Stent retrievers and large-bore aspiration catheters have doubled substantial reperfusion rates compared to first-generation devices. This has been accompanied by a 3-fold reduction in procedural time to revascularization. To measure future thrombectomy improvements, new benchmarks for technical efficacy are needed. This review summarizes the recent literature concerning biomarkers of procedural success and harm and highlights future directions. Expanded Treatment in Cerebral Ischemia (eTICI), which incorporates scores for greater levels of reperfusion, improves outcome prediction. Core laboratory-adjudicated studies show that outcomes following eTICI 2c (90%-99% reperfusion) are superior to eTICI 2b50 and nearly equivalent to eTICI 3. Moreover, eTICI 2c improves scale reliability. Studies also confirm the importance of rapid revascularization, whether measured as first pass effect or procedural duration under 30 minutes. Distal embolization is a complication that impedes the extent and speed of revascularization, but few studies have reported its per-pass occurrence. Distal embolization and emboli to new territory should be measured after each thrombectomy maneuver. Collaterals have been shown to be an important modifier of thrombectomy benefit. A drawback of the currently accepted collateral grading scale is that it does not discriminate among the broad spectrum of partial collateralization. Important questions that require investigation include reasons for failed revascularization, the utility of a global Treatment in Cerebral Ischemia scale, and the optimal grading system for vertebrobasilar occlusions. Emerging data support a lead technical efficacy endpoint that combines the extent and speed of reperfusion. Efforts are needed to better characterize angiographic measures of treatment harm and of collateralization.

Abstract 1122‐000198: Failure of Tenecteplase in Maintaining Collateral Circulation in Large Vessel Occlusion Strokes.

Introduction : Acute administration of alteplase with collateral patency has been systematically evaluated in acute ischemic stroke (AIS) patients. Large studies evaluating alteplase demonstrate a significant association of successful recanalization (TICI score) and good clinical outcome (mRS) with ASITN/SIR collateral grade greater than 2. However there is paucity of data looking at the association between IV tenecteplase (TNK) and acute collateralization. Our objective was to investigate early TNK use association for the degree of collateralization in subjects with AIS secondary to large vessel occlusion (LVO). Methods : Collateralization was assessed on digital subtraction angiography using the American Society of Intervention and Therapeutic Neuroradiology/Society of Interventional Radiology (ASTIN/SIR) scale. Grades were defined by the following: 0 no collaterals to ischemic region; 1 slow collaterals peripherally; 2 rapid collaterals peripherally; 3 slow collaterals within ischemic region; 4 complete retrograde perfusion to ischemic region. Subjects with LVO undergoing mechanical thrombectomy status post TNK as part of the pilot early clinical use of TNK within 4.5 hours of last known well were assigned a grade. Mean ASITN/SIR collateral grade was determined. Spearman’s rho was used to measure association of collateral grade with thrombolysis in cerebral infarction (TICI) score. Patients with TNK‐associated recanalization at time of cerebral angiogram were excluded from study. Social Science Statistics was used for data analysis. Results : From October 2020 to April 2021, 16 subjects (6 females; age, 63.25 95% CI [54.9207, 71.5793]) received TNK and underwent mechanical thrombectomy. From those subjects, 25 % (n = 4) had IV TNK‐associated recanalization with normalization of collateral blood flow and were excluded. Of the rest (n = 12, 75%) had a mean ASITN/SIR collateral grade of 1.08 (95% CI [0.5762, 1.5838]). Association between collateral grade and final TICI score was not statistically significant (rs = ‐0.33576, p = 0.28598) suggesting inability of TNK to result in/maintain a robust collateral flow. Conclusions : Poor correlation of collateral grade and final TICI score may have implications of faster progression in patients with ischemic stroke receiving TNK in the setting of LVO if immediate recanalization is not achieved. Larger prospective studies are needed to evaluate the effect of TNK on collateralization when compared to Alteplase.

Collateral estimation by susceptibility-weighted imaging and prediction of functional outcomes after acute anterior circulation ischemic stroke

To determine the value of susceptibility-weighted imaging (SWI) for collateral estimation and for predicting functional outcomes after acute ischemic stroke. To identify independent predictors of favorable functional outcomes, age, sex, risk factors, baseline National Institutes of Health Stroke Scale (NIHSS) score, baseline diffusion-weighted imaging (DWI) lesion volume, site of steno-occlusion, SWI collateral grade, mode of treatment, and successful reperfusion were evaluated by multiple logistic regression analyses. A total of 152 participants were evaluated. A younger age (adjusted odds ratio (aOR), 0.42; 95% confidence interval (CI) 0.34 to 0.77; P < 0.001), a lower baseline NIHSS score (aOR 0.90; 95% CI 0.82 to 0.98; P = 0.02), a smaller baseline DWI lesion volume (aOR 0.83; 95% CI 0.73 to 0.96; P = 0.01), an intermediate collateral grade (aOR 9.49; 95% CI 1.36 to 66.38; P = 0.02), a good collateral grade (aOR 6.22; 95% CI 1.16 to 33.24; P = 0.03), and successful reperfusion (aOR 5.84; 95% CI 2.08 to 16.42; P = 0.001) were independently associated with a favorable functional outcome. There was a linear association between the SWI collateral grades and functional outcome (P = 0.008). Collateral estimation using the prominent vessel sign on SWI is clinically reliable, as it has prognostic value.

Assessment of Collaterals Using Multiphasic CT Angiography in Acute Stroke

The aim of the research was to compare the efficiency of multiphase and single-phase computed tomography (CT) angiography in assessing the leptomeningeal collaterals and in predicting the long-term clinical outcome as well as the risk of hemorrhagic transformation. A prospective study was conducted from October 2016 to May 2018 in consecutive patients who presented within 8 hours of the onset of acute anterior circulation ischemic strokes, with NIHSS (National Institutes of Health Stroke Scale) scores ≥5. They underwent triple-phase cerebral CT angiography, and the collaterals were assessed separately using both single-phase and multiphase techniques. The ability of the collaterals to predict the 24-hour CT ASPECTS (Alberta Stroke Program Early CT score), risk of cerebral hemorrhagic transformation, and 90-day clinical outcome was assessed. Fifty-six patients, which included 42 with an involvement of the middle cerebral artery and 14 with mixed occlusions, were assessed. In the multivariate logistic analysis, multiphase CT angiography collateral grading is one of the independent predictors of favorable outcomes. Area under the curve (AUC) was 0.853 (95% confidence interval [CI; 0.73, 0.97]) for multiphase CT collateral scoring in predicting the long-term functional independence, whereas single-phase CT (sCT) scoring displayed an AUC value of only 0.609 (95% CI [0.43, 0.78]). Eighty-two percent of the patients with good multiphase CT collaterals were functionally independent. CT ASPECTS at 24 hours was significantly better in patients with a good multiphase CT collateral score than in those with a good single-phase score. None of the patients with good collaterals in multiphase CT angiography had a significant hemorrhagic transformation. Good multiphase CT collaterals demonstrated 78% sensitivity, 81% specificity, and 80% accuracy in predicting the functional outcome. Multiphase CT collateral system was superior to single-phase angiography in predicting the long-term functional outcomes. Prediction of the hemorrhagic transformation risk was also observed to be better for multiphase CT.