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Background: The presence of reperfusion ventricular arrhythmias (VA) has been shown to correlate with larger infarct size (IS). However it is unclear whether the initial area at risk (AAR), also a determining factor for IS, is responsible for this correlation. We hypothesized that IS would be significantly larger in the presence of VA, while AAR would not differ. Methods: 68 STEMI patients from the MAST study with 24-hour, continuous, 12 lead Holter monitoring initiated prior to primary percutaneous coronary intervention (PCI) resulting in TIMI 3 flow post PCI were included. VA bursts were identified against subject-specific background VA rates using a previously validated statistical outlier method. IS, and infarct endocardial surface area (ESA) were obtained using CMR at mean 4.9 days after admission. Holter and CMR results were determined in core laboratories blinded to all other data. Results: VA bursts were present in 69% (45/65) of patients. No significant differences were found for demographic characteristics, comorbidities, infarct location, number of diseased coronary vessels, or duration of ischemia between groups with and without VA burst. IS was significantly smaller in the group without VA bursts (median 9.3% vs 17.0%; p=0.025). Infarct ESA did not significantly differ between the population with and without VA burst; median 24.3% vs 20.0%; p=0.15. Conclusion: VA bursts are a marker for larger IS independent of AAR, assessed by surrogate markers. These findings support the hypothesis that VA bursts are a marker of reperfusion damage occurring downstream at myocellular level. (c) 2018 Elsevier B.V. All rights reserved.

In an acute stroke setting, transcranial Doppler (TCD) and transcranial color-coded duplex (TCCD) have an important diagnostic utility in the monitoring of an arterial occlusion and microemboli detection. In addition, TCD has proven to be a very useful tool in the detection and progression of cerebral vasospasm in patients with subarachnoid hemorrhage. TCD/TCCD may have an important role in defining collateral blood flow (CF) in stroke patients. It is a noninvasive technique and can be utilized repeatedly allowing for changes in the blood flow dynamics as treatment is delivered. In this review, we outlined the evolving role of TCD/TCCD in defining CF in patients with an acute ischemic stroke, predicting clinical outcome and monitoring the treatment's efficacy of the CF augmentation.

Collateral circulation plays a vital role in sustaining blood flow to the ischaemic areas in acute, subacute or chronic phases after an ischaemic stroke or transient ischaemic attack. Good collateral circulation has shown protective effects towards a favourable functional outcome and a lower risk of recurrence in stroke attributed to different aetiologies or undergoing medical or endovascular treatment. Over the past decade, the importance of collateral circulation has attracted more attention and is becoming a hot spot for research. However, the diversity in imaging methods and criteria to evaluate collateral circulation has hindered comparisons of findings from different cohorts and further studies in exploring the clinical relevance of collateral circulation and possible methods to enhance collateral flow. The statement is aimed to update currently available evidence and provide evidence-based recommendations regarding grading methods for collateral circulation, its significance in patients with stroke and methods under investigation to improve collateral flow.

The Fractional Flow Reserve (FFR) is a clinical index of functional severity validated for isolated stenoses. FFR may be viewed as the ratio of achievable blood flow in a stenotic artery to the the...

International audience; Coarctation of aorta is a congenital anomaly characterized by a narrowing segment between the aortic arch and the descending aorta. This stenosis is responsible for upper body hypertension and the recruitment of a collateral network via the intercostal arteries to improve lower body perfusion. However, hemodynamic perturbations along the aorta have not been completely studied. The objective of this work is to analyze the collateral network of patients with aortic coarctation who required surgical repair. MRI was performed to obtain hemodynamic parameters such as the variation of flow along the descending thoracic aorta and an estimation of the collateral flow. The shape of the aorta was also studied. Both morphological elements and hemodynamic parameters of aortic coarctation may be quite useful to determine consequences of aortic narrowing and the best moment to propose surgical repair or imaging monitoring. We also expect giving more information on the collateral network to develop modelisation of this element.

There are several ways to identify donor artery patency and success of surgery after an anastomosis of the superficial temporal artery (STA) to the middle cerebral artery (MCA). The purpose of this study was to evaluate the ratio of bilateral STA mean flow rate (MFR) with the use of color Doppler ultrasonography (CDUS) after bypass surgery and to confirm the possibility of this value as a predictor of the extent of collateral flow.Eleven consecutive patients who had undergone STA-MCA anastomosis were included. In every case, bilateral STA MFR, mean velocity, and cross-sectional diameter were measured preoperatively and postoperatively at 1 week, 1 month, and 2 months via CDUS. We measured the bilateral STA MFR ratio changes to compensate for systemic hemodynamic variables.One month after surgery, 9 of the 11 patients who underwent STA-MCA anastomosis had good patency on DSA. In patients with good patency, there was a significant increase in the baseline STA MFR ratio compared with those at 1 week, 1 month, and 2 months postoperatively (2.88, 3.07, and 4.38, respectively, P0.05). The mean STA cross-sectional diameter ratio also was significantly increased postoperatively in the good patency group (1.35, 1.41, and 1.49, respectively, P = 0.044). In addition, the mean STA mean velocity ratio was increased postoperatively in the good patency group (1.48, 1.40, and 1.67, respectively, P = 0.042).We conclude that using CDUS to measure both STA MFR ratio is a potential method to predict the extent of collateral flow through an STA-MCA anastomosis.

SummaryPurpose Patients with complex congenital heart disease may need to be converted to a Fontan circulation with systemic venous return surgically connected to the pulmonary circulation. These patients frequently form aortopulmonary collaterals (APC), that is arterial inflows to the pulmonary artery vascular tree. The aim of this study was to develop a method to calculate the effect of APC on the pulmonary flow distribution based on magnetic resonance imaging (MRI) measurements and computational fluid dynamics simulations in order to enable prediction of interventional outcomes in Fontan patients. Methods Patient-specific models of 11 patients were constructed in a 3D-design software based on MRI segmentations. APC flow was quantified as the difference between pulmonary venous flow and pulmonary artery flow, measured by MRI. A method was developed to include the modulating effect of the APC flow by calculating the patient-specific relative pulmonary vascular resistance. Simulations, including interventions with a Y-graft replacement and a stent dilatation, were validated against MRI results. Results The bias between simulated and MRI-measured fraction of blood to the left lung was 2·9 ± 5·3%. Including the effects of the APC flow in the simulation (n = 6) reduced simulation error from 9·8 ± 7·0% to 5·2 ± 6·3%. Preliminary findings in two patients show that the effect of surgical and catheter interventions could be predicted using the demonstrated methods. Conclusions The work demonstrates a novel method to include APC flow in predictive simulations of Fontan hemodynamics. APC flow was found to have a significant contribution to the pulmonary flow distribution in Fontan patients.

Meandering flow void around the splenium, which can be recognized on conventional T2-weighted images, implicates collateral flow in the splenial artery in patients with moyamoya disease. In this report, curves of flow voids around the splenium (SFVs) were evaluated in patients with moyamoya disease, and their diagnostic value and pathophysiology were verified.A total of 65 consecutive patients with moyamoya disease were included in this analysis. The number of SFV curves was counted on each side. The numbers of SFV curves in patients with moyamoya disease was compared with those in the control group. The clinical features of patients with large numbers of flow voids were analyzed.The mean number of SFVs was significantly higher in the moyamoya disease group than in the control group or the atherosclerotic disease group. The cut-off SFV count for a diagnosis of moyamoya disease should be set to 2.25 in consideration of receiver operating characteristic curve analysis. A multivariate logistic analysis of SFV data in moyamoya disease revealed significant differences between the high SFV count group (≥2.25) and the low SFV count group (2.25) in age, flow voids in the basal ganglia, and magnetic resonance angiography score of the internal carotid artery and anterior cerebral artery.Based on this study, number of SFV curves on conventional T2-weighted imaging could be a useful measurement for confirming a diagnosis of moyamoya disease. Increased number of SFV curves was associated with age and progress of disease.

Introduction: Retrograde collateral flow is critical to maintain tissue perfusion despite large vessel occlusion. However, the premorbid factors associated with good collateral flow remain unclear, with substantial discrepancies in the literature. Methods: Patients from the registries of 6 French stroke centres with the following criteria were included: (1) acute stroke with isolated M1 occlusion ( i.e , without tandem occlusion) referred for thrombectomy between May 2015 and March 2017; and (2) baseline brain MRI, including diffusion weighted imaging, MR-angiography and dynamic susceptibility-contrast perfusion-weighted imaging (PWI). A collateral flow map derived from PWI source data was automatically generated, replicating Kim et al’s previously validated method (Ann. Neurol., 2014). Collateral flow was dichotomized into good and poor. The association between good collateral flow and baseline clinical, biological and radiological variables was studied. Results: One hundred and sixteen patients were included, of which 66 (57%) had good collaterals. As expected, the latter patients had lower admission NIHSS (median: 15 vs . 18, P=0.005) and lower baseline DWI lesion volume (median: 7ml vs . 32ml, Pvs . distal) were similar in both groups (123min vs . 118min, P=0.75; 70% vs. 68%, P=0.85, respectively). There was no significant (P>0.05) difference in gender, age, history of hypertension or diabetes, current smoking, baseline blood glucose and use of statins or antiplatelets between the good and poor collaterals groups. Conclusions: Despite the expected association between PWI-derived collateral flow and baseline clinical and radiological stroke severity in our sample of acute M1 occlusions, there was no association with premorbid factors previously found associated in some -but not all- studies. Our findings suggest that collateral flow is predominantly explained by genetic factors.

Introduction: White matter hyperintensity volume (WMHv), a quantitative neuroimaging biomarker of cerebral small vessel disease (CSVD), is associated worse outcomes after ischemic stroke. In this study, we hypothesized that worse outcomes in CSVD patients were due to poor collateral flow during acute ischemia. Methods: 47 patients with acute ischemic stroke (AIS) were prospectively enrolled in this study. Serial MRIs were performed at 3 hours and 30 days after stroke onset. 3-hour FLAIR images were used to determine WMHv, after manually delineating lesions with MIPAV. An index of collateral flow (delayed perfusion to the penumbra) was determined by subtracting core volume (volume of tissue with ADC2. Patient’s NIHSS was scored at 3 hours and 30 days after stroke onset and the difference was calculated (ΔNIHSS). Log-transformed WMHv was correlated to ΔNIHSS and the collateral flow index, using Pearson correlation. Results: Mean age = 63.9 years (SD 13.5); 37% female; median 3-hour NIHSS = 13 (IQR 6.5-20); median change in NIHSS between 3h and 30d = 4 (IQR: 0-7); median core volume = 13cm3 (IQR 4.3-35.6); median WMHv = 1.257cm3 (IQR 641-3595). WMHv was associated with reduced improvement in ΔNIHSS (R=-0.42, ρ=0.005). Furthermore, WMHv demonstrated a trend for association with poor collateral flow (R=-0.28, ρ=0.062). In this dataset, we will explore the relationship between WMHv and other tissue-based metrics of collateral flow, including the hypoperfusion intensity ratio (HIR) and the cerebral blood volume ratio (rCBV). Conclusions: Our study confirms that patients with CSVD have worse outcomes after AIS. The data also raise the possibility that these worse outcomes in CSVD patients may be mediated by compromised collateral flow in the setting of acute ischemia.

Background: Sphenopalatine ganglion (SPG) stimulation enhances collateral flow, stabilizes blood-brain barrier, and showed evidence of benefit in patients with confirmed cortical involvement (CCI) when started 8-24h after onset in the ImpACT-24B randomized trial. To characterize SPG stimulation benefit magnitude, we derived number needed to treat (NNT) values based on shifts over all levels of 3 month global disability. Methods: From the distribution of the 7-level modified Rankin Scale (mRS) at 3m in SPG- and sham-stimulation CCI patients, NNT to benefit (NNTB) and NNT to harm (NNTH) values were derived by automated (algorithmic min-max) and expert generation of joint outcome distribution tables. For dichotomized mRS outcomes, net NNT values were derived directly from absolute risk differences. Results: Among 520 patients with confirmed cortical infarction ineligible for thrombolysis, 244 were treated with SPG and 276 with sham stimulation. NNT values for dichotomized and shift mRS outcomes are shown in the Table. Of the 6 possible binary cutpoints on the mRS, 4 showed more favorable outcome with SPG stimulation. The dichotomized endpoint with the greatest group difference was ambulatory and capable of bodily self-care (mRS 0-3), 62.3% vs 51.1%, NNTB 8.9. Across all 6 individual possible dichotomizations of the mRS, the NNTB ranged from 8.9 to -166.7. For shifts by 1 or more levels across all 6 transitions of the mRS, the biologically most plausible NNTB was 5.7 (IQR 5.6-6.5), NNTH 34.5 (IQR 30.3-40.0), and net NNTB 6.8 (IQR 6.5-7.7), These values correlated closely with the automatically derived net NNTB of 5.9. Conclusions: The findings of this pivotal trial indicate that, out of every 1000 CCI patients treated with SPG stimulation, 146 patients will have a less disabled 3-month outcome, including 76 more who will be functionally independent. SPG stimulation can substantially improve the outcome of thrombolysis-ineligible acute ischemic stroke patients.

Background Pial arterioles can provide a variable degree of collateral flow to ischemic vascular territories during acute ischemic stroke. This study sought to identify predictive factors of the degree of pial collateral recruitment in acute ischemic stroke. Methods Clinical information and arteriograms from 62 consecutive patients with stroke due to either middle cerebral artery (MCA) M1 segment or internal carotid artery (ICA) terminus occlusion within 6 h following symptom onset were retrospectively reviewed. Pial collaterals were defined based on the extent of reconstitution of the MCA territory. Patients with slow antegrade flow distal to the occlusion site were excluded and no anesthetics were used prior or during angiography. Results were analyzed using multivariate nominal logistic regression. Results Better pial collateral recruitment was associated with proximal MCA versus ICA terminus occlusion ( p = 0.005; odds ratio (OR) = 9.3; 95% confidence interval (CI), 2.16–53.3), lower presenting National Institutes of Health Stroke Scale Score (NIHSSS) ( p = 0.023; OR = 6.51; 95% CI, 1.49–41.7), and lower diastolic blood pressure ( p = 0.0411; OR = 5.05; 95% CI, 1.20–29.2). Age, gender, symptom duration, diabetes, laterality, systolic blood pressure, glucose level, hematocrit, platelet level, and white blood cell count at presentation were not found to have a statistically significant association with pial collateral recruitment. Conclusions Extent of pial collateral recruitment is strongly associated with the occlusion site (MCA M1 segment versus ICA terminus) and less strongly associated with presenting NIHSSS and diastolic blood pressure.

Transverse colectomy refers to the removal of the portion of the colon between the hepatic flexure and the splenic flexure – the transverse colon. Primary blood supply to the transverse colon is from the middle colic vessels with collateral flow from the ileocolic, right, and left colic vessel through marginal artery. Transverse colectomy is commonly performed for tumors and/or polyps of transverse colon. If the lesion is located in close proximity to either flexures, then it is advisable to perform an extended right or extended left colectomy. Laparoscopic transverse colectomy is technically challenging as it involves mobilization of hepatic as well as splenic flexure, careful identification and sealing of middle colic vessels while preserving blood supply to the rest of the colon, and meticulous retromesenteric dissection. In this chapter, we discuss various important steps involved in laparoscopic transverse colectomy.

The anesthesiologist is a key member of the neurophysiological monitoring team. In addition to providing management to insure patient safety and comfort, the anesthesiologist participates in patient positioning, physiological management, and the conduct of an anesthetic using agents compatible with monitoring of the neural structures at risk. The anesthesiologist is also key to assisting in a search for the etiology of factors leading to changes in the monitoring. These include technical, physiological, pharmacological, positional, and surgical issues. In addition, when monitoring changes signal possible increased neural risk, the anesthesiologist may participate in management strategies to help mitigate injury, such as minimizing oxygen consumption, enhancing collateral blood flow, and increasing oxygen supply.

Background We previously found that the structural defects of the coronary collateral microcirculation reserve ( CCMR ) prevent these preformed collateral vessels from continuously delivering the native collateral blood and supporting the ischemic myocardium in rats. Here, we tested whether these native collaterals can be remodeled by artificially increasing pigment epithelium–derived factor ( PEDF ) expression and demonstrated the mechanism for this stimulation. Methods and Results We performed intramyocardial gene delivery ( PEDF ‐lentivirus, 2×10 7 TU) along the left anterior descending coronary artery to artificially increase the expression of PEDF in the tissue of the region for 2 weeks. By blocking the left anterior descending coronary artery, we examined the effects of PEDF on native collateral blood flow and CCMR . The results of positron emission tomography perfusion imaging showed that PEDF increased the native collateral blood flow and significantly inhibited its decline during acute myocardial infarction. In addition, the number of CCMR vessels decreased and the size increased. Similar results were obtained from in vitro experiments. We tested whether PEDF induces CCMR remodeling in a fluid shear stress–like manner by detecting proteins and signaling pathways that are closely related to fluid shear stress. The nitric oxide pathway and the Notch‐1 pathway participated in the process of CCMR remodeling induced by PEDF . Conclusions PEDF treatment activates the nitric oxide pathway, and the Notch‐1 pathway enabled CCMR remodeling. Increasing the native collateral blood flow can promote the ventricular remodeling process and improve prognosis after acute myocardial infarction.

Background Acute complete occlusion of a coronary artery results in progressive ischemia, moving from the endocardium to the epicardium (“wavefront”). Dependent on time-to-reperfusion and collateral flow, myocardial infarction (MI) will manifest, with transmural MI portending poor prognosis. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging can detect MI with high diagnostic accuracy. Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy in patients with STEMI Purpose We sought to visualize time-dependent necrosis in a ST-segment elevation myocardial infarction (STEMI) population by LGE-CMR. Methods STEMI patients with: single-vessel disease, complete occlusion with Thrombolysis in Myocardial Infarction (TIMI) score 0, absence of collateral flow (Rentrop score 0) and symptom onset Results 164 patients (54±11 years, 80% male) were included. Receiver-operating-characteristic (ROC)-curve (area under the curve [AUC] = 0.81) indicating transmural necrosis revealed the best diagnostic cut-off for a symptom-to-balloon time of 121 minutes, i.e. patients with >121 minutes demonstrated increased IS, transmurality index, transmurality grade (all p-values Conclusions In myocardial infarction with no residual antegrade, and no collateral flow, immediate reperfusion is vital. A symptom-to-balloon time of >121 minutes causes a high grade of transmural necrosis. In the present, pure STEMI population, time to reperfusion to salvage myocardium was less than suggested by current guidelines.

A three-compartment heart – a severe congenital defect, can develop after genetic mutation or teratogenic influence on fetus at early stages of embryogenesis. According to the literary data, the survival of such patients without surgery is 6–7 %. This publication demonstrates clinical case of the patient who has single ventricle of the heart and lived up to 56 without surgery.

Background The capillary index score (CIS) determined from DSA is used to evaluate cerebral collateral flow in acute ischemic stroke (AIS) caused by cerebral artery occlusion. Our aim was to determine the reliability of CIS calculated from MIP-CTA images as an alternative to DSA-based CIS, as CTA is less invasive and less expensive. Methods Clinical and imaging data of 40 patients with AIS caused by cerebral artery occlusion within 6 h from symptom onset were collected. CIS was calculated from CTA and DSA images. Patients were classified into the favorable collateral flow group if CIS was ≥2 (fCIS), and into the poor collateral flow group if CIS was

Background We occasionally noticed that native collateral blood flow showed a recessive trend in the early stages of acute myocardial infarction in rats, which greatly interferes with the accurate assessment of native collateral circulation levels. Here, we sought to recognize the coronary collateral circulation system in depth, especially the microcirculation part, on this basis. Methods and Results In this study, we detected native collateral flow with positron emission tomography perfusion imaging in rats and found that the native flow is relatively abundant when it is initially recruited. However, this flow is extremely unstable in the early stage of acute myocardial infarction and quickly fails. We used tracers to mark the collateral in an ischemic area and a massive preformed collateral network was labeled. The ultrastructures of these collateral microvessels are flawed, which contributes to extensive leakage and consequent interstitial edema in the ischemic region. Conclusions An unrecognized short‐lived native coronary collateral microcirculation reserve is widely distributed in rat hearts. Recession of collateral blood flow transported by coronary collateral microcirculation reserve contributes to instability of native collateral blood flow in the early stage of acute myocardial infarction. The immature structure determines that these microvessels are short‐lived and provide conditions for the development of early interstitial edema in acute myocardial infarction.

In selected patients with severe heterogenous emphysema lung volume reduction can be performed by using endobronchial valves. So far, only unilateral procedures have been published. Here is described a patient where a right-sided closure of the right upper lobe resulted in an increase of FEV1sec of more than 50%, and some years later the procedure was repeated on the left side with further considerable improvement. A tracheal bronchus to the apical segment of the right upper lobe made measuring the collateral flow at bronchoscopy impossible, but clearly visible fissures were used as a substitute. In conclusion, valve treatment in suitable patients can give substantial improvement in lung function and quality of life and can be repeated on the other side if warranted some years later.

Characterization of vessels distal from occluded site is important when considering endovascular revascularization therapy (EVT) for acute ischemic stroke. The goal of this study was to assess the clinical value of intra-arterial contrasted high-resolution cone-beam computed tomography from the ascending aorta (Ao-CBCT) for visualization of the vessels distal from occluded site. Acute ischemic stroke patients with large vessel occlusion who were to undergo EVT were evaluated. In EVT, digital subtraction angiography (DSA) and Ao-CBCT were performed with local anesthesia. Ao-CBCT images were acquired in a 20-second rotational scan. Contrast medium was injected (1 mL/s for a total of 30 seconds using a 4-Fr catheter and an imaging delay of 10 seconds) from the ascending aorta. We assessed the image quality of Ao-CBCT and compared the visualization of the vessels distal from occluded site among magnetic resonance angiography (MRA), DSA and Ao-CBCT. We analyzed 14 patients (mean age, 66 years; three female patients). Stroke subtypes were cardiogenic (n = 6), atherothrombotic (n = 5) and others/unknown (n = 3). Occluded sites were middle cerebral artery (MCA) M1 (n = 8), MCA M2 (n = 2), internal carotid artery (ICA) (n = 2), MCA M4 (n = 1) and basilar artery (BA) (n = 1). All obtained Ao-CBCT images successfully characterized the vessels distal from occluded site, and 11 images (79%) were excellent. In all cases, Ao-CBCT images could depict distal vessels with more detail when compared with MRA and DSA. Ao-CBCT is an efficient method to obtain detailed information regarding vessels distal from occluded site when compared with conventional examination methods.

Leptomeningeal collateral vessels, linking the 3 major arterial territories over the surface of the brain, have been recognized for >140 years.1 More widespread use of advanced clinical imaging in the past decade has led to increasing recognition of the key importance of collaterals in ischemic stroke outcome.2 However, recent studies from several groups indicate that failure of initially good collateral supply is a key feature of patients with delayed infarct expansion.3,4 This clinically challenging problem typically occurs in the first 1 to 2 days after hospital admission in patients with initially mild stroke symptoms. Rethrombosis of reperfused vessels was previously thought to be the likely cause of delayed infarct expansion in most patients. However, this theory is not supported by more recent evidence from imaging studies. Despite the important recent observations, there is limited understanding of the dynamic control of the collateral circulation, in particular, the cause of collateral blood flow failure. In this article, we will discuss recent observations from our experimental stroke model, indicating a dramatic increase in intracranial pressure (ICP) occurring around 24 hours after onset of even small stroke.5,6 We have also shown a significant linear reduction of collateral blood flow in response to progressive ICP elevation.7 We believe that a similar transient ICP elevation occurring during the first 1 to 2 days post stroke is a likely mechanism to explain delayed infarct expansion in patients with minor stroke. Perhaps surprisingly, we can find no published data on ICP at 24 hours in patients with minor stroke. The preclinical findings suggest that gathering such data should be a priority. ### Human Stroke There is a strong association between the extent of leptomeningeal collaterals and clinical stroke outcome. Initial studies using digital subtraction angiography permitted direct visualization of collateral vessels and …

Basilar artery thrombosis is typically associated with devastating outcomes. EVT has proven to be highly effective in the anterior circulation yet outcomes and ways of selecting patients for EVT for basilar artery occlusion remain unclear. Mainly limited by relatively small number of patients as well as different center-specific practices, we evaluated clinical and radiographic variables associated with EVT outcomes. Methods: A single-center retrospective cohort of acute ischemic stroke patients with any LVO between January 2014 and January 2018 were reviewed which underwent EVT. Patients with basilar artery occlusion were identified based on presenting CTA/MRA (n=35). We stratified patients into good outcomes (37.1 % vs 62.9 % p=0.133) and good collaterals vs poor collaterals while adjusting for clot length, posterior circulation collateral score, reperfusion status. Results: A total of (n=334) patients were identified to have an LVO. Out of these (n=35) had basilar artery occlusions. (n=30) had emergent EVT while (n=5) were initially treated with medical management and taken for EVT as a rescue therapy. After stratifying for good vs poor outcomes, multivariate analysis showed that poor collateral score is associated with poor outcome (mRS=3-6) (OR 0.98 p=0.60 CI 0.67-0.97). Clot length greater than 10 mm is associated with poor outcome at 90 days (HR 0.325 p=0.045 CI 0.56-0.833). Conclusion: Basilar artery occlusions carry a worse prognosis in cases with poor collateral scores, clot length >10mm and longer time to reperfusion from symptoms onset.

Introduction: Poor leptomeningeal collateral flow is related to worse neurological outcome in acute ischemic stroke. The increased release of stress hormones during the first hours of acute stroke leads to inhibition of insulin secretion and increase insulin resistance, thus inducing stress hyperglycemia, which is often evident on blood glucose levels at admission. While admission hyperglycemia, independent of diabetes mellitus (DM) is associated with poor clinical outcome in ischemic stroke, studies on its effect on collateral circulation after acute cerebral embolism are largely inconclusive. Methods: We identified a consecutive series of patients aged 18 years and older from 2008 to 2018 with acute embolic large vessel stroke confirmed on CT angiography (CTA) using an institutional database. Individual CTAs were over-read, and collateral scores of the affected hemisphere were calculated using a modification of the Tan scale (0-4), by two trained readers. We reviewed the electronic medical records for presenting NIHSS, admission glucose and HbA1C levels, and prior history of DM. Spearman’s ρ, odds ratios (OR), and their 95% confidence intervals (CI) were analyzed. All tests were considered significant when P Results: Of the 405 patients identified through the database (mean age 70 years [range, 55-85], 45% [183/405] women), 35% (142/405) had a prior history of DM. Mean admission glucose was 134±51 mg/dL, and median NIHSS at presentation was 17. Blood glucose level at admission was negatively correlated with collateral scores (ρ= -0.23, P=0.008). Specifically, glucose levels above 120 mg/dL were significantly associated (OR 1.68 CI 1.13-2.5) with poor collateral scores (≤1). However, collateral scores exhibited no statistically significant relationship with HbA1c (ρ=-0.08, P=0.15) or prior history of DM (P=0.73). Conclusions: Patients with higher admission glucose levels have poor collateral scores, while HbA1c and prior DM do not have a similar effect on collateral flow. Our results suggest that poor collateral flow may explain adverse outcomes associated with hyperglycemia in acute ischemic stroke. Determining if there is a benefit of aggressive glycemic control within the first few hours of embolic stroke warrants further study.

Background and Purpose: Red cell distribution width (RDW) has been recognized as a prognostic marker in cardiovascular diseases and stroke. Increased RDW is predictive of poor outcome and mortality in acute ischemic stroke patients. However, the underlying mechanisms are not fully understood. We aimed to explore the association between RDW, collateral flow, infarct volume growth, final infarct volume (FIV), and clinical outcomes in acute stroke patients with large artery atherosclerosis. Methods: This is a single-center retrospective cohort study based on a prospective registry of consecutive acute ischemic stroke patients within 6 hours of onset. Acute ischemic stroke identified with anterior circulation large artery atherosclerosis (LAA) with complete baseline and follow-up imaging (Non-contrast CT, CT Angiography, Perfusion CT) as well as clinical profiles were enrolled. Collaterals was assessed using the volume ratio between delay time (DT) >3s and DT>6s lesions. Baseline infarct core volume was defined by relative cerebral blood flow Results: A total number of 100 patients were included in this study. Multivariate adjusted general linear models revealed that increased RDW was associated with poorer collaterals (multivariate adjusted coefficient -0.11, 95% CI -0.20 — -0.02, p=0.02) and increased infarct volume growth (multivariate adjusted coefficient 0.06, 95% CI 0.03 — 0.08, p Conclusion: For patients with LAA stroke, high RDW was associated with poorer collateral flow and increased infarct volume growth, which may explain the predictive value of RDW and poor functional outcomes in acute stroke.

Backgrounds: Penumbral perfusion dynamically changes with alterations of collateral flow and systemic blood pressure. We investigated the association between acute changes of systolic blood pressures and infarct growth within penumbral area. Method: We included ischemic stroke patients 15 mL, and mismatch ratio >1.8. Perfusion quantification, 3D voxel-registration and image segmentation were done by Olea 3.0 and Analyze 12.0. Penumbra was defined as Tmax >6s lesion without infarct. Infarct growth within penumbra was defined by the infarct volume at a follow-up image. Hypoperfusion intensity ratio (HIR) was defined by the proportion of Tmax >10s within penumbra. Blood pressure change integral (BPCI) was defined by an integration of SBP initial - SBP trajectory over 24 h (Figure A). BP dropmax was defined by a maximum decrease of SBP between successive measurements. Results: Among 25 patients included (age, 71.3±13.5; male, 56%), median baseline NIHSS score was 13 (interquartile range [IQR], 8-18). Median volume of initial infarct within Tmax >6s was 16 mL (IQR, 6-58), penumbra was 80 mL (IQR, 29-138), HIR was 46% (IQR, 31-63), and infarct growth within penumbra was 26% (IQR, 11-48). Median BPCI was 157.4 mmHg·h (IQR, -76.8-566.2) and BP dropmax was 34 mmHg (IQR, 25-43). Median infarct growth was linearly associated with BPCI (β=0.022; p -value=0.03; Figure B), BP dropmax (β=0.77; p -value=0.048; Figure C), and HIR (β=0.69; p -valuedropmax increased infarct growth rate (Figure D). Conclusions: Acute decline of systemic blood pressure may aggravates penumbral perfusion and thus increase infarct growth within penumbral tissue in emergent large vessel occlusion patients without recanalization.

Introduction: Good collateral flow is associated with improved outcomes in acute embolic stroke. There is compelling data linking smoking to all types of stroke, with current smokers at a higher risk than former or never smokers. Smoking has, however, been shown to promote collaterals in coronary vascular bed in humans. It is unknown if there is a similar effect in cerebral collateral flow. We aimed to investigate if cigarette smoking was positively associated with collateral blood flow in a homogenous cohort of patients with acute large vessel occlusive embolic stroke. Methods: We identified all patients aged ≥18 with acute ischemic stroke showing embolic occlusion of ICA terminus/M1 MCA on admission CT angiography (CTA), between 2008 to 2018, through an institutional database. Patients with chronic occlusions and stenotic lesions were excluded. Individual CTAs were independently reviewed by two trained investigators to calculate collateral scores of the affected hemisphere using the modified Tan scale (0-4) as a reference. Details of cigarette smoking history were obtained from the electronic medical records. Patients were grouped into smokers (former and current smokers) and never smokers. Odds ratios (OR) and their 95% confidence intervals (CI) were estimated, and all tests were considered significant when P Results: Of the 612 patients identified through the database, 429/612 patients (mean age 71±16 years, 45% [194/429] women) satisfied the inclusion criteria. 64.8% (278/429) had a positive history of smoking with an average of 47±12 pack-years. There was a significant association between good collateral scores (≥2) with smoking history (OR 1.74 CI 1.17-2.61, P=0.006). This trend remained significant even after comparing raw collateral scores (0-4) ( P=0.006, Spearman’s ρ=0.22). However, number of pack-years and collateral scores exhibited no statistically significant relationship (P=0.6). Conclusions: Our study shows that patients who have ever smoked have higher intracranial collateral vessel scores in the event of an acute embolic stroke. Increased impedance and reduced cerebral blood flow resulting from cigarette smoking may stimulate collateral recruitment in cerebral pial circulation, similar to the effect in coronary bed.

Background: Neuroprotection for acute ischemic stroke remains an elusive goal. Intracranial collaterals may favor neuroprotective drugs delivery at the acute stage of ischemic stroke. A recent phase 2 study showed that cyclosporine A (CsA) reduced ischemic damage in patients with a proximal occlusion who experienced effective recanalization. Collateral flow may improve this benefit. Materials & Methods: Collateral supply was assessed using dynamic susceptibility contrast MRI in 47 patients among the 110 patients from the original study and were graded in two groups: good collaterals and poor collaterals. Patients with good collaterals had significantly smaller initial infarct in both CsA group (p = 0.003) and controls (p = 0.016). Similarly, the final lesion volume was significantly lower in patients with good collaterals in both groups. Results: In patients with either good or poor collaterals CsA showed no additional benefit on ischemic lesion progression and final infarct size at day 30. Conclusion: We failed to demonstrate any significant additional benefit of CsA in patients with good collateral circulation.