Angiographic Collaterals Research Articles

Identification of the optimal thresholds for the hypoperfusion intensity ratio in moyamoya disease.

The authors' objective was to retrospectively compare two methods for defining the hypoperfusion intensity ratio (HIR) in moyamoya disease (MMD) by using hypoperfused volumes calculated from time to maximum of the residue function (Tmax) thresholds of 10 seconds/4 seconds and 10 seconds/6 seconds. All hemispheres were categorized into normal, ischemic, and hemorrhagic groups. Hypoperfused volumes were calculated using Tmax thresholds of 10 seconds, 6 seconds, and 4 seconds. HIR was computed as Tmax > 10 seconds/Tmax > 4 seconds (HIR10/4) and Tmax > 10 seconds/Tmax > 6 seconds (HIR10/6). Angiographic collaterals were assessed using CT perfusion (CTP)-sourced images (CTP-sis). The 3-month clinical follow-up included primary outcomes (survival or death) and secondary outcomes (modified Rankin Scale [mRS] and Katz activities of daily living [ADL] scale scores). Multivariate logistic regression and correlation analyses were conducted. Thirty patients (54 hemispheres) were included. Patients with poor primary outcomes exhibited higher rates of hypertension (p = 0.015), larger hypoperfused volumes, and elevated HIR10/4 and HIR10/6 (p < 0.001). The regression model with HIR10/4 outperformed that with HIR10/6 for predicting primary outcomes (Z = 2.02, p = 0.044). Both HIR10/4 and HIR10/6 correlated with mRS and ADL scores (p < 0.05). Although there was no correlation between HIR and CTP-sis when all hemispheres were included, a significant association was found between HIR10/4 and CTP-sis when hemispheres with hemorrhagic lesions were excluded (p = 0.013). HIR10/4 exhibited a superior predictive value for primary outcomes in MMD compared to HIR10/6. Additionally, HIR10/4 showed a significant association with angiographic collaterals, particularly in ischemic MMD cases. This study suggested that HIR defined as Tmax > 10 seconds/Tmax > 4 seconds may be more suitable than Tmax > 10 seconds/Tmax > 6 seconds in MMD.

Abstract WP140: Perfusion Collateral Index Predicts Infarct Growth in Successfully Reperfused Patients With Acute Ischemic Stroke

Introduction: Robust collaterals are associated with lower rates of infarct growth and improved clinical outcomes in patients with acute ischemic stroke. Perfusion Collateral Index (PCI) and Hypoperfusion Intensity Ratio (HIR) have been shown to correlate with angiographic collaterals. We aimed to assess and compare the ability of PCI and HIR to predict infarct growth in anterior circulation large vessel occlusion (AC LVO) patients who underwent successful reperfusion. Methods: In this retrospective study, AC LVO stroke patients were included if they had pretreatment perfusion (CT or MR), successful reperfusion (mTICI &gt; 2b), and follow up MRI within 24 hours from treatment. HIR (defined as volume of Tmax &gt;10 sec/volume of Tmax &gt;6 sec) was calculated by RAPID software (Version 5.0.4). PCI (defined as volume of delay 2-6 seconds x rCBV) was calculated using Olea software (SP.23). Infarct growth was calculated by subtracting baseline ischemic core (ADC &lt;620 х 10 –6 mm2/s on MRI or rCBF &lt;30% on CTP) from post-treatment MRI volume of DWI hyperintensity. Results: A total of 80 patients were included; 46 female, age (mean + SD): 70.2 + 13.1 years, NIHSS (median, IQR): 14, 8-19, and time from stroke-onset to reperfusion (mean + SD): 389 + 236 minutes. The infarct growth volume was 27 + 52 mL (mean + SD); 47 patients (58.7%) had infarct growth &gt; 10 mL. ROC analysis for prediction of infarct growth &gt; 10 mL revealed AUC/sensitivity/specificity of 0.70/55.3/84.8 for PCI at threshold &lt;60, which was significantly higher (P=0.006) than HIR at threshold of &gt;0.4 (0.50/74.5/24.2) (Figure). Multivariate logistic regression showed PCI (p=0.004) and time-to treatment (p=0.024) were the only independent variables to predict infarct growth. Conclusion: In conclusion, in patients with AC LVO stroke, poor baseline collateral perfusion defined by PCI &lt;60 predicts infarction growth &gt; 10 mL despite successful reperfusion. PCI was superior to HIR in the prediction of infarct growth.

Circulating secretoneurin level reflects angiographic coronary collateralization in stable angina patients with chronic total occlusion

ObjectiveTo investigate the association between circulating secretoneurin (SN) and angiographic coronary collateralization in stable angina patients with chronic coronary total occlusion (CTO).MethodsSN concentrations in serum were measured in 641 stable angina patients with CTO by radioimmunoassay. The status of coronary collaterals from the contra-lateral vessel was visually estimated using the Rentrop grading system, and was categorized into poor (grade 0 or 1) or good (grade 2 or 3) collateralization.ResultsSerum SN levels were significantly higher in patients with good coronary collaterals compared to those with poor collaterals (175.23 ± 52.09 pmol/L vs. 143.29 ± 42.01 pmol/L, P < 0.001). Serum SN increased stepwise across Rentrop score 0 to 3 (P < 0.001), and increasing SN tertiles were associated with higher proportion of good coronary collateralization (OR, 1.907; 95% CI, 1.558 ~ 2.335, P < 0.001). After adjustment for confounding variables, serum SN (per tertile) remained an independent factor for predicting good coronary collaterals (OR, 1.870; 95% CI, 1.515 ~ 2.309; P < 0.001). Moreover, the diagnostic value of serum SN (per tertile) was consistent after stratifying patients based on gender, age, body mass index, hypertension, diabetes, history of smoking, severity of coronary artery disease and kidney function (OR: 1.511 ~ 2.680, P interaction ≥ 0.327).ConclusionElevated circulating SN reflects good angiographic coronary collaterals in stable angina patients with CTO. The findings may provide insight into decision-making for these patients.

Hypoperfusion Intensity Ratio Correlates with Angiographic Collaterals and Infarct Growth in Acute Stroke with Thrombectomy.

The assessment of collaterals before endovascular thrombectomy (EVT) therapy play a pivotal role in clinical decision-making for acute stroke patients. To investigate the correlation between hypoperfusion intensity ratio (HIR), collaterals on digital subtraction angiography (DSA), and infarct growth in acute stroke patients who underwent EVT therapy. Patients with acute ischemic stroke (AIS) who underwent EVT therapy were enrolled retrospectively. HIR was assessed through magnetic resonance imaging (MRI) and was defined as the Tmax > 10 s lesion volume divided by the Tmax > 6 s lesion volume. Collaterals were assessed on DSA using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale. Good collaterals were defined as ASITN/SIR score 3-4 and poor collaterals were defined as ASITN/SIR score 0-2. Spearman's rank correlation analysis was used to evaluate the correlation between HIR, collaterals, infarct growth, and functional outcome. A total of 115 patients were included. Patients with good collateral (n = 59) had smaller HIR (0.29 ± 0.07 vs. 0.52 ± 0.14; t = 10.769, P < 0.001) and infarct growth (8.47 ± 2.40 vs. 14.37 ± 5.28; t = 7.652, P < 0.001) than those with poor collateral (n = 56). The ROC analyses showed that the optimal cut-off value of HIR was 0.40, and the sensitivity and specificity for predicting good collateral were 85.70% and 96.61%, respectively. With the optimal cut-off value, patients with HIR < 0.4 (n = 67) had smaller infarct growth (8.86 ± 2.59 vs. 14.81 ± 5.52; t = 6.944, P < 0.001) than those with HIR ≥ 0.4 (n = 48). Spearman's rank correlation analysis showed that HIR had a correlation with ASITN/SIR score (r = -0.761, P < 0.001), infarct growth (r = 0.567, P < 0.001), and mRS at 3 months (r = -0.627, P < 0.001). HIR < 0.4 is significantly correlated with good collateral status and small infarct growth. Evaluating HIR before treatment may be useful for guiding EVT and predicting the functional outcome of AIS patients.

The risk and outcome of malignant brain edema in post-mechanical thrombectomy: acute ischemic stroke by anterior circulation occlusion

Background and purposeMalignant brain edema (MBE) occurring after mechanical thrombectomy (MT) in acute ischemic stroke (AIS) could lead to severe disability and mortality. We aimed to investigate the incidence, predictors, and clinical outcomes of MBE in patients with AIS after MT.MethodsThe clinical and imaging data of 155 patients with AIS of anterior circulation after MT were studied. Standard non-contrast CT was used to evaluate baseline imaging characteristics at admission. Clinical outcomes were measured using the 90-day modified Rankin Scale (mRS) score. Based on the follow-up CT scans performed within 72 h after MT, the patients were classified into MBE and non-MBE group. MBE was defined as a midline shift of ≥ 5 mm with signs of local brain swelling. Univariate and multivariate regression analyses were used to analyze the relationship between MBE and clinical outcomes and identify the predictors that correlate with MBE.ResultsMBE was observed in 19.4% of the patients who underwent MT and was associated with a lower rate of favorable 90-day clinical outcomes. Significant differences were observed in both MBE and non-MBE groups: baseline Alberta Stroke Program Early CT (ASPECT) score, hyperdense middle cerebral artery sign (HMCAS), baseline signs of early infarct, angiographic favorable collaterals, number of retrieval attempts, and revascularization rate. Multivariate analysis indicated that low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count, and poor revascularization independently influenced the occurrence of MBE in AIS patients with anterior circulation after MT.ConclusionMBE was associated with a lower rate of favorable 90-day clinical outcomes. Low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count and poor revascularization were independently associated with MBE after MT.

Perfusion Collateral Index versus Hypoperfusion Intensity Ratio in Assessment of Collaterals in Patients with Acute Ischemic Stroke.

Perfusion-based collateral indices such as the perfusion collateral index and the hypoperfusion intensity ratio have shown promise in the assessment of collaterals in patients with acute ischemic stroke. We aimed to compare the diagnostic performance of the perfusion collateral index and the hypoperfusion intensity ratio in collateral assessment compared with angiographic collaterals and outcome measures, including final infarct volume, infarct growth, and functional independence. Consecutive patients with acute ischemic stroke with anterior circulation proximal arterial occlusion who underwent endovascular thrombectomy and had pre- and posttreatment MRI were included. Using pretreatment MR perfusion, we calculated the perfusion collateral index and the hypoperfusion intensity ratio for each patient. The angiographic collaterals obtained from DSA were dichotomized to sufficient (American Society of Interventional and Therapeutic Neuroradiology [ASITN] scale 3-4) versus insufficient (ASITN scale 0-2). The association of collateral status determined by the perfusion collateral index and the hypoperfusion intensity ratio was assessed against angiographic collaterals and outcome measures. A total of 98 patients met the inclusion criteria. Perfusion collateral index values were significantly higher in patients with sufficient angiographic collaterals (P < .001), while there was no significant (P = .46) difference in hypoperfusion intensity ratio values. Among patients with good (mRS 0-2) versus poor (mRS 3-6) functional outcome, the perfusion collateral index of ≥ 62 was present in 72% versus 31% (P = .003), while the hypoperfusion intensity ratio of ≤0.4 was present in 69% versus 56% (P = .52). The perfusion collateral index and the hypoperfusion intensity ratio were both significantly predictive of final infarct volume, but only the perfusion collateral index was significantly (P = .03) associated with infarct growth. Results show that the perfusion collateral index outperforms the hypoperfusion intensity ratio in the assessment of collateral status, infarct growth, and determination of functional outcomes.

Predictors of tissue infarction from distal emboli after mechanical thrombectomy

BackgroundDistal embolization after endovascular thrombectomy (EVT) is common. We aimed to determine factors associated with tissue infarction in the territories of distal emboli.MethodsThis is a retrospective cohort study of consecutive...

The association of collaterals with myocardial ischemia and viability in chronic total occlusions.

Collateral development in chronic total occlusions (CTO) is crucial to perfuse the distal myocardium and its angiographic evaluation is frequently used to assess the need for revascularization. We aimed to analyse the association between the presence of ischemia and hibernating myocardium, evaluated by cardiac [13N]NH3/2-[18F]FDG PET-CT, and the angiographic characterization of the collateral circulation. Prospective study including patients with a CTO who underwent a [13N]NH3 and, when deemed necessary, 2-[18F]FDG PET-CT. Well developed (WD) collaterals were defined as a concomitant angiographic Rentrop grade 3 and Werner collateral connection score 2 or 3, whereas the remaining as poorly developed (PD). 2% thresholds used to identify prognostic benefit of revascularization were applied: ischemia > 10% and hibernating myocardium > 7%. Fifty-nine patients (age 62.9±9.1 years, 58 male) were recruited, WD collaterals were present in 28 (47.5%). No significant differences were found in ischemia (WD 6.4±4.3 vs. PD 7.0±4.1, p = 0.64) and hibernation (WD 1.8±1.9 vs. PD 3.1±3.3, p = 0.18) scores. Most CTO territories demonstrated ischemia, but only 19 (46.3%) were associated with an area > 10% (WD 47.6% vs. PD 45.0%, p = 0.58). Scared non-viable myocardium was limited to 9 (15.3%) patients and was not associated with PD collaterals. Hibernating myocardium was frequent (54.2%), but just 6 (10.2%) CTO patients had an area of > 7% (WD 3.6% vs. PD 16.1%, p = 0.20). Collateral assessment by angiography has a poor association with the ischemic burden and hibernation state of CTO territories. Myocardial viability was present even in most CTO with angiographic PD collaterals.

Direct Bypass Surgery for Moyamoya and Steno-occlusive Vasculopathy: Clinical Outcomes, Intraoperative Blood Flow Analysis, Long-term Follow-up, and Long-term Bypass Patency in a Single Surgeon Case Series of 162 Procedures

Cerebral extracranial-intracranial (EC-IC) direct bypass is a commonly used procedure for the treatment of cerebral hypoperfusion secondary to chronic steno-occlusive vasculopathy. We sought to determine clinical outcomes, intraoperative blood flow analysis, long term follow up, and long term patency rates from a single surgeon's series of direct cerebral bypass for moyamoya disease, moyamoya syndrome, and steno-occlusive disease. We reviewed clinical, demographic, operative and neuroimaging records for all patients who underwent a direct EC-IC bypass by the senior author between August 1999 and November 2020. Primary outcomes analyzed were functional long-term outcomes (by modified Rankin score [mRS]), surgical complications, and short-term and long-term bypass patency. A total of 162 revascularization procedures in 124 patients were performed. Mean clinical follow up time was 2 years 11 months. The combined immediate and long term postoperative stroke and/or intracerebral hemorrhage rate was 6.2%. There were 17 bypasses (10%) that were found to be occluded at long-term follow-up, all but one were asymptomatic. Long-term graft occlusion was correlated with presence of complete collateralization on preoperative angiography but not cut flow index (CFI). Overall, patients had a significant clinical improvement with a mean mRS score 1.8 preoperatively and 1.2 postoperatively. In our consecutive series of patients treated with direct EC-IC cerebral bypass, there was significant improvement in functional outcome as measured by the mRS. The long term patency rate was 90%. There was a statistically significant correlation between complete or incomplete angiographic collateralization patterns and long-term bypass occlusion. There was no correlation between bypass type, clinical syndrome, or CFI and long-term occlusions. The role of bypass surgery and the need for surgical expertise remain strong in the treatment of moyamoya variants and a select group of atherosclerotic steno-occlusive patients.

Surgical revascularization for pediatric moyamoya: the role of surgical mentorship in sustaining and developing a neurovascular service.

Obtaining operative experience for the treatment of rare conditions in children represents a challenge for pediatric neurosurgeons. Starting in November 2017, a surgeon was mentored in surgical revascularization (SR) for pediatric moyamoya with a view to service development and sustainability. The aim of this audit was to evaluate early outcomes of SR for pediatric moyamoya during and following a surgical mentorship. A retrospective cohort study with chart/database review of consecutive moyamoya surgeries performed by a new attending surgeon (between November 2017 and March 2020) was compared to a previously published cohort from the authors' institution in terms of clinical and angiographic outcomes, complications, operating time, and length of stay. A standardized technique of encephaloduroarteriomyosynangiosis with the superficial temporal artery was used. Twenty-two children underwent 36 indirect SRs during the study period. Patient demographics were similar between cohorts. The first group of 6 patients had 11 SRs performed jointly by the new attending surgeon mentored by an established senior surgeon (group A), followed by 10 patients with 16 SRs performed independently by the new attending surgeon (group B). The last 6 patients had 9 SRs with the new attending surgeon mentoring a senior fellow (group C) in performing SR. Good angiographic collateralization (Matsushima grades A and B) was observed in 80% of patients, with similar proportions across all 3 groups. A total of 18/19 symptomatic patients (95%) derived symptomatic benefit. There was no perioperative death and, compared to the historical cohort, a similar proportion had a recurrent arterial ischemic event (i.e., acute ischemic stroke) necessitating a second SR (1/22 vs 3/73). Operative times were longest in group C, with no difference in length of hospital stay among the 3 groups. Early outcomes demonstrate the feasibility of mentorship for safely incorporating new neurosurgeons in sustaining and developing a tertiary-level surgical service.

Hypoperfusion Intensity Ratio is Associated with Stroke Mechanism in Patients Undergoing Mechanical Thrombectomy

BackgroundHypoperfusion Intensity Ratio (HIR), defined as Tmax >10s/Tmax >6s on computed tomography perfusion (CTP), and stroke mechanisms have been independently correlated with angiographic collaterals and patient outcomes. Slowly developing atherosclerotic stenosis may foster collateral development, whereas cardioembolic occlusion may occur before collaterals mature. We hypothesized that favorable HIR is associated with large artery atherosclerosis (LAA) stroke mechanism and good clinical outcome. MethodsRetrospective study of consecutive endovascularly-treated stroke patients with intracranial ICA or MCA M1/M2 occlusions, who underwent CTP before intervention, between January 2018 and August 2021. Patients were dichotomized into LAA+ or LAA- based on presence of LAA on angiography. HIR was dichotomized into favorable (HIR+) or unfavorable (HIR-) groups based on published thresholds. Good early outcome was defined as discharge mRS of 0-2. Bivariate and multivariable logistic regression were performed. Results143 patients met inclusion. 21/143 were LAA+ (15%) and 65/143 (45%) were HIR+. HIR+ was significantly more frequent in LAA+ patients (67% vs. 42%, p= 0.035). Controlling for demographics, stroke severity, imaging findings, and medical comorbidities, LAA+ remained independently associated with HIR+ (OR 5.37 [95% CI 1.43 – 20.14]; p=0.013) as did smaller infarction core volume (<30 mL of CBF <30%: OR 7.92 [95% CI 2.27 – 27.64]; p = 0.001). HIR+ was not associated with good clinical outcome. ConclusionsLarge artery atherosclerosis was independently associated with favorable HIR in patients undergoing mechanical thrombectomy. While favorable HIR was associated with smaller pre-treatment core infarcts, reflecting more robust collaterals, it was not associated with good clinical outcome.

Abstract TMP75: Vasomotor Reactivity As A Predictor Of Angiographic Collateralization And Outcome In Patients Undergoing Extracranial-Intracranial Bypass Surgery

Background: Extracranial-Intracranial (EC-IC) bypass is increasingly used for treatment of hemodynamic failure in Moya-Moya disease (MMD) or syndrome (MMS). No specific imaging parameter has been established to determine bypass patency in these patients. We sought to determine if vasomotor reactivity (VMR) testing could be correlated with pre-operative angiographic data and predict bypass patency. Methods: All available pre-operative VMRs and diagnostic angiograms (DSA) in patients with EC-IC direct bypass surgeries performed at our institution from 2007-2019 were reviewed to determine the degree of pre-procedural hemispheric failure (by VMR to the inhalation of carbon dioxide and hyperventilation, abnormal defined by less than 70%) and collateral compensation (categorized as complete vs. incomplete collaterals by DSA). Bypass patency was assessed on follow-up imaging (either immediate in post-op angiogram and delayed subsequent CTA or DSA). Results: Of the 113 bypass surgeries performed, 68 had pre-operative VMR and DSA. A total of 52 patients were included, in which 16 had both hemispheres operated on (median age 46 [IQR 25], 74% women, 60% with Moya-Moya disease, 51% presented with ischemic stroke, 37% TIA, 10% intracerebral hemorrhage and 1% headache). Pre-operatively, 97% had an abnormal VMR, 24% had incomplete collateralization. A total of 79% had bypass patency (87% immediate, 76% delayed, median time 1 year 8 months [IQR 1 year and 6 months)) on follow up. Patients with patent bypass had significantly lower VMR (27 [SD ± 18.8] vs. mean 36 [SD ± 14.5], p=0.005) and higher likelihood of incomplete collateralization pre-operatively (mean 25.1 [SD ± 16.4] vs. mean 39.2 [SD ± 18.8], p=0.013) as compared to non-patent bypass patients. In multivariate analysis low pre-operative VMR was a significant predictor for bypass patency adjusting for age, presenting stroke type and gender (p=0.01). Conclusion: Vasomotor reactivity is a non-invasive, low-cost test which predicted angiographic vessel collateralization and bypass patency. Bypass patency remains important predictor of outcomes in this population.

Optimal Imaging at the Primary Stroke Center.

Optimal Imaging at the Primary Stroke Center.

Hypoperfusion intensity ratio correlates with angiographic collaterals in acute ischaemic stroke with M1 occlusion

Among patients with an acute ischaemic stroke secondary to large-vessel occlusion, the hypoperfusion intensity ratio (HIR) [time to maximum (TMax)>10volume/TMax>6volume] is a strong predictor of infarct growth. We studied the correlation between HIR and collaterals assessed with digital subtraction angiography (DSA) before thrombectomy. Between January 2014 and March 2018, consecutive patients with an acute ischaemic stroke and an M1 middle cerebral artery (MCA) occlusion who underwent perfusion imaging and endovascular treatment at our center were screened. Ischaemic core (mL), HIR and perfusion mismatch (TMax>6s minus core volume) were assessed through magnetic resonance imaging or computed tomography perfusion. Collaterals were assessed on pre-intervention DSA using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale. Baseline clinical and perfusion characteristics were compared between patients with good (ASITN/SIR score 3-4) and those with poor (ASITN/SIR score 0-2) DSA collaterals. Correlation between HIR and ASITN/SIR scores was evaluated using Pearson's correlation. Receiver operating characteristic analysis was performed to determine the optimal HIR threshold for the prediction of good DSA collaterals. A total of 98 patients were included; 49% (48/98) had good DSA collaterals and these patients had significantly smaller hypoperfusion volumes (TMax>6s, 89 vs. 125mL; P=0.007) and perfusion mismatch volumes (72 vs. 89mL; P=0.016). HIR was significantly correlated with DSA collaterals (-0.327; 95% confidence interval, -0.494 to -0.138; P=0.01). An HIR cut-off of <0.4 best predicted good DSA collaterals with an odds ratio of 4.3 (95% confidence interval, 1.8-10.1) (sensitivity, 0.792; specificity, 0.560; area under curve, 0.708). The HIR is a robust indicator of angiographic collaterals and might be used as a surrogate of collateral assessment in patients undergoing magnetic resonance imaging. HIR <0.4 best predicted good DSA collaterals.

EDAS Revascularization for Symptomatic Intracranial Atherosclerotic&amp;nbsp;Steno-Occlusive Disease (ERSIAS) Phase-II Trial

Background: Intracranial atherosclerotic disease (ICAD) is one of the most challenging stroke etiologies, with frequent recurrences despite optimized medical management. Encephaloduroarteriosynangiosis (EDAS) is an indirect revascularization method that produces collaterals from the extracranial circulation into cerebral hypoperfused areas. We present the results of a phase-II trial of EDAS in patients with ICAD failing medical management. Methods: ERSIAS was a prospective objective performance criterion (OPC) trial of EDAS plus intensive medical management (IMM) in patients with symptomatic ICAD despite optimized medical management, and poor angiographic collaterals. The primary endpoint was any stroke or death within 30 days postsurgery or stroke in the territory of the qualifying artery beyond 30 days. The primary analysis compared event rates through one year with the OPC of 10·1%, based on a 10% reduction from the 20·1% rate in the IMM arm of SAMMPRIS trial. The event rates through two years were compared with propensity-score-matched (PSM) medically treated patients from the SAMPPRIS and COSS trials. Secondary endpoints included functional neurological outcome and angiographic neovascularization. Findings: Fifty-two patients underwent EDAS-plus-IMM. The median age was 52 years (IQR=38·3-65·8), and 32 were females (61·5%). The primary endpoint rate at one year was 9·6%, lower than the OPC of 10·1% (p=0·07), meeting the p<0·10 threshold for nonfutility and advancement to phase-III. In the sensitivity analysis, the primary endpoint event rate at two years was lower than in PSM control patients, 9·6 % vs. 21·2% (p<0·07). Overall, 86% of EDAS-plus-IMM patients were functionally independent at last follow-up, and 89% demonstrated neovascularization. There were two (3·8%) surgical complications (wound dehiscence) and no intracranial hemorrhages. Interpretation: ERSIAS phase-II provides evidence of safety and strong signals of the efficacy of EDAS-plus-IMM, supporting testing of the technique in a randomized controlled clinical trial. Trial Registration: NCT01819597. Funding Statement: Research reported in this publication was supported by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health (NIH), under award no. K23NS079477. Declaration of Interests: None. Ethics Approval Statement: Protocol ID:IRB#12-000439 UCLA IRB Initial Approval Date: 7/19/2012 Committee: Medical IRB 3

Abstract WP66: Impaired Collaterals Are Associated With Intracranial Thrombus Extension: Evidence From MRI, Catheter Angiography, and Retrieved Thrombus Composition

Background: Clot propagation after initial occlusion may increase target thrombus burden and its pathophysiologic basis has not been extensively studied in acute human ischemic stroke. We investigated whether clot characteristics on MRI, catheter angiography, and thrombus histopathology indicated that impaired collaterals may be associated with extension of acute intracranial occlusions via stasis clotting in slow flow arterial segments. Methods: Analysis of consecutive AIS-LVO endovascular thrombectomy patients at 2 academic medical centers with: 1) pretreatment MRI, and 2) retrieved thrombi. GRE MR susceptibility vessel sign presence and extent of ASITN collateral scores were rated by blinded assessors. Extracted clots were fixed in formalin, stained by hematoxylin and eosin, and RBC, WBC and fibrin percent composition quantified by a neuropathologist blinded to clinical details. We evaluated the correlation of collateral grade with clot size by susceptibility vessel sign (SVS) and clot composition by RBC%. Non-parametric values were computed via Spearman correlation. Results: Among the 48 patients, mean age was 71.4 (SD 17.7), 56.3% female, and mean presenting NIHSS was 15.5 (SD 7.41). A susceptibility vessel sign was present in 65%, with mean SVS length 15.6 mm (SD 8.3). Collateral scores were mean 2.3 (SD 1.2). The number of passes per procedure was mean 1.98 (SD 1.30) The presence of a susceptibility vessel sign correlated with higher RBC% in retrieved thrombi (r s =0.36 p=0.011). Worse collateral grades correlated with longer SVS length (r s =-0.50 p=0.004) and greater SVS width (r s =-0.54 p=0.002). Worse collateral grade also trended toward correlation with higher RBC% in retrieved clots (r s =-0.19 p=0.18). Conclusion: Impaired angiographic collaterals are associated with longer RBC-rich thrombi on susceptibility imaging and trend toward association with higher RBC% in retrieved thrombi. These findings support that, in LVO acute ischemic stroke, clot propagation after initial occlusion occurs by stasis clotting accelerated by impaired collaterals.

Lipoprotein (a) interactions with cholesterol-containing lipids on angiographic coronary collateralization in type 2 diabetic patients with chronic total occlusion

BackgroundWe investigated whether or to what extent the interaction of lipoprotein (a) [Lp(a)] with cholesterol-containing lipids was associated with angiographic coronary collateralization in type 2 diabetic patients with chronic total occlusion.MethodsSerum levels of Lp(a), total cholesterol, low-density lipoprotein–cholesterol (LDL-C), high-density lipoprotein–cholesterol (HDL-C), and triglyceride were determined and non-HDL-C was calculated in 706 type 2 diabetic and 578 non-diabetic patients with stable coronary artery disease and angiographic total occlusion of at least one major coronary artery. The degree of collaterals supplying the distal aspect of a total occlusion from the contra-lateral vessel was graded as poor (Rentrop score of 0 or 1) or good coronary collateralization (Rentrop score of 2 or 3).ResultsFor diabetic and non-diabetic patients, Lp(a), total cholesterol, LDL-C, and non-HDL-C levels were higher in patients with poor coronary collateralization than in those with good collateralization, whereas HDL-C and triglyceride levels were similar. After adjustment for potential confounding factors, tertiles of Lp(a), total cholesterol, LDL-C and non-HDL-C remained independent determinants for poor collateralization. A significant interaction between Lp(a) and total cholesterol, LDL-C or non-HDL-C was observed in diabetic patients (all P interaction < 0.001) but not in non-diabetics. At high tertile of total cholesterol (≥ 5.35 mmol/L), LDL-C (≥ 3.36 mmol/L) and non-HDL-C (≥ 4.38 mmol/L), diabetic patients with high tertile of Lp(a) (≥ 30.23 mg/dL) had an increased risk of poor collateralization compared with those with low tertile of Lp(a) (< 12.66 mg/dL) (adjusted OR = 4.300, 3.970 and 4.386, respectively, all P < 0.001).ConclusionsIncreased Lp(a) confers greater risk for poor coronary collateralization when total cholesterol, LDL-C or non-HDL-C are elevated especially for patients with type 2 diabetes.

A case report of dipyridamole stress-induced ST depression progressing to ST-elevation myocardial infarction despite intravenous aminophylline: steal, spasm, or something else?

BackgroundDipyridamole stress is commonly used for myocardial perfusion imaging and is generally safe. Myocardial ischaemia can occasionally occur and is classically thought to be due to coronary steal as a result of redistribution of flow away from collateral dependent myocardium. Although ischaemia more commonly presents as electrocardiographic (ECG) ST depression and angina, ST-elevation myocardial infarction may occur as a very rare complication.Case summaryWe report a case of a patient who developed chest pain and ST depression during dipyridamole infusion. The pain persisted despite intravenous aminophylline with new inferior ST elevation soon after. Coronary angiography showed subtotal right coronary artery occlusion with no collateral supply. The symptoms and ECG changes resolved after percutaneous coronary intervention.DiscussionCoronary steal may not fully account for our patient’s presentation given the failure of aminophylline and absent angiographic collaterals. Vasospasm may be triggered by dipyridamole and can directly cause ischaemia or provoke rupture of an unstable plaque. Augmentation of cardiac energetics during vasodilator stress may also play a role.

Abstract 151: Physiologic Predictors of Collateral Circulation and Infarct Growth in Setting of Anesthesia During Thrombectomy: Detailed Analysis of the GOLIATH Trial

Introduction: Collateral circulation plays a pivotal role in acute ischemic stroke due to large vessel occlusion and may be affected by multiple variables during sedation for endovascular therapy (EVT). Identification of potentially modifiable physiologic predictors of collateral circulation will help to refine the most optimal anesthetic strategy in clinical practice and future trials. Methods: We conducted detailed analyses of the GOLIATH database to identify 1) predictors of collateral circulation grade and 2) infarct growth at 24h. Angiographic collaterals immediately prior EVT were graded by two investigators, followed by consensus adjudication. We also modified the ASITN collateral scale by dividing grade 2 in two separate categories: 2- (persistent filling defect in &gt;50% of the ischemic territory) and 2+ (&lt;50% of the territory) and sought to determine its impact on clinical outcome and 24h infarct growth. Multivariable analysis was used to identify predictors of collaterals and infarct growth. Results: Collaterals were evaluable in 62% (80/128) of analyzed patients, including grades 1 (n=9), 2- (n=19), 2+ (n=31), 3 (n=21). Ordinal analysis demonstrated nominal, but non-significant association between modified ASITN scale and infarct growth (figure 1). There was no correlation between collaterals and outcome. Among all analyzed variables [Age, NIHSS, ASPECTS, HTN, DM, time to groin, end tidal CO2 levels, general anesthesia, Propofol dose, Phenylephrine dose, mean arterial pressure (MAP) drop &lt; 70 mmhg ], the most significant predictor of infarct growth at 24h was Phenylephrine dose (beta 6.13; p=0.026), and the most significant predictor of collateral grade was MAP &lt; 70 mmhg (OR 0.34; p = 0.044). Conclusions: ASITN grade 2-/+ may be useful as distinct categories for collateral grading. Higher phenylephrine dose is a strong predictor of infarct growth, while lower MAP strongly correlates with worse angiographic collaterals during sedation for EVT.

Abstract 84: Collaterals Drive Reperfusion in Stratis

Background: Collateral circulation to the ischemic territory is a pivotal factor in outcomes after acute ischemic stroke. Extent of angiographic collaterals prior to endovascular therapy has been linked with reperfusion in previous trials, yet the mechanism remains unclear. We analyzed whether downstream collateral grade influences the pace and degree of ultimate reperfusion. Methods: The angiography dataset collated by the STRATIS Core Lab was analyzed to relate the grade of collateral circulation (ASITN) with adjudicated procedural time metrics to exact time of first TICI ≥ 2A and with the final eTICI score, delineating reperfusion into 7 distinct categories. Results: Collateral grade on routine angiography injections was available in 574/984 (58%) of STRATIS subjects (age 67.5 ± 15.1, 47% women, baseline NIHSS 16.8 ± 5.5). Collaterals included 203/574 (35.4%) with ASITN 3-4, 291/574 (50.7%) ASITN 2 and 80/574 (13.9%) ASITN 0-1. TICI ≥ 2A was achieved at 32.4 ± 23.5 minutes from angiography start and 26.4 ± 18.6 minutes from visualization of the arterial occlusion. The eTICI included 78 TICI 3 (13.6%), 140 TICI 2C (24.4%), 226 TICI o2B (39.3%), 68 TICI m2B (11.8%), 44 TICI 2A (7.7%), 4 TICI 1 (0.7%) and 14 TICI 0 (2.4%). More robust collateral grade was strongly associated with lower NIHSS (15.9 ± 5.4 (ASITN 3-4); 16.7 ± 5.5 (ASITN 2); 19.6 ± 5.1 (ASITN 0-1); p&lt;0.001). Intervals from angiography start, visualization of the arterial occlusion and first device pass to TICI ≥ 2A were all shorter in ASITN 3-4 versus 0-2, with time from first device pass to TICI ≥ 2A reaching statistical significance (p=0.034). Better collaterals were also strongly linked with more extensive reperfusion (Figure). Collaterals and reperfusion were linked at all occlusion sites (ICA, M1, M2, BA). Conclusions: Collaterals on routinely available angiography prior to thrombectomy in STRATIS were strikingly tied to both the speed and degree of final reperfusion, across every site of arterial occlusion.