scholarly journals Prevention of the collapse of pial collaterals by remote ischemic perconditioning during acute ischemic stroke

2016 ◽  
Vol 37 (8) ◽  
pp. 3001-3014 ◽  
Author(s):  
Junqiang Ma ◽  
Yonglie Ma ◽  
Bin Dong ◽  
Mischa V Bandet ◽  
Ashfaq Shuaib ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Cerebral Artery ◽  
Laser Speckle ◽  
Laser Scanning Microscopy ◽  
Collateral Flow ◽  
Contrast Imaging ◽  
Peripheral Ischemia ◽  
Remote Ischemic Perconditioning

Collateral circulation is a key variable determining prognosis and response to recanalization therapy during acute ischemic stroke. Remote ischemic perconditioning (RIPerC) involves inducing peripheral ischemia (typically in the limbs) during stroke and may reduce perfusion deficits and brain damage due to cerebral ischemia. In this study, we directly investigated pial collateral flow augmentation due to RIPerC during distal middle cerebral artery occlusion (MCAo) in rats. Blood flow through pial collaterals between the anterior cerebral artery (ACA) and the MCA was assessed in male Sprague Dawley rats using in vivo laser speckle contrast imaging (LSCI) and two photon laser scanning microscopy (TPLSM) during distal MCAo. LSCI and TPLSM revealed that RIPerC augmented collateral flow into distal MCA segments. Notably, while control rats exhibited an initial dilation followed by a progressive narrowing of pial arterioles 60 to 150-min post-MCAo (constricting to 80–90% of post-MCAo peak diameter), this constriction was prevented or reversed by RIPerC (such that vessel diameters increased to 105–110% of post-MCAo, pre-RIPerC diameter). RIPerC significantly reduced early ischemic damage measured 6 h after stroke onset. Thus, prevention of collateral collapse via RIPerC is neuroprotective and may facilitate other protective or recanalization therapies by improving blood flow in penumbral tissue.

Capillary Index Score Derived from Computed Tomography Angiography as An Indicator of Collateral Flow after Acute Ischemic Stroke

2019 ◽  
Author(s):  
Shang Kai ◽  
Xiaoxing Zhang ◽  
Yuehua Li
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Cerebral Artery ◽  
Treatment Strategies ◽  
Artery Occlusion ◽  
Index Score ◽  
Collateral Flow ◽  
Imaging Data ◽  
Flow Group ◽  
Cerebral Artery Occlusion

Abstract 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 <2 (pCIS). Agreement between the methods was evaluated using the Kappa test. Logistic regression was performed to explore the relationship between CTA-based CIS and clinical outcomes. Results The two methods had high consistency (Kappa = 0.72), and the diagnostic accuracy of CTA for CIS classification was 87.5%. The decrease in the NIHSS score at discharge was not significantly different between the fCIS and pCIS groups according to CTA (p = 0.156), while the 90-day mRS was higher in the pCIS group (p = 0.04). High CTA-based CIS and low blood glucose at admission were significantly correlated with good outcome. Conclusion CIS calculated using CTA is as reliable as DSA-based CIS for assessing collateral flow in AIS, and is also a good predictor of clinical outcome. This index could be useful for guiding patient selection and treatment strategies for AIS.

scholarly journals Analysis of Thrombi Retrieved from Cerebral Arteries of Patients with Acute Ischemic Stroke.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 263-263
Author(s):  
Victor J. Marder ◽  
Dennis J. Chute ◽  
Sidney Starkman ◽  
Anna M. Abolian ◽  
Chelsea Kidwell ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Carotid Artery ◽  
Middle Cerebral Artery ◽  
Acute Ischemic Stroke ◽  
Cerebral Artery ◽  
Cerebral Arteries ◽  
Clinical Consequence ◽  
Initiation Of Therapy ◽  
Stroke Center

Abstract To obtain insights into the pathogenesis of ischemic stroke, we analyzed thromboemboli and other occlusive material retrieved acutely from the cerebral arteries of patients. The experimental design was an observational study in 25 consecutive patients with acute ischemic stroke treated by endovascular mechanical thromboembolectomy. Patients with acute occlusion of a proximal cerebral artery, a disabling neurologic deficit, and either initiation of therapy within 8 hours of onset or initiation of therapy beyond 8 hours if imaging demonstrated substantial residual penumbral tissue at risk were treated at a tertiary Comprehensive Stroke Center (the UCLA Stroke Center). Thrombus was removed by an endovascular mechanical embolectomy device (Merci® Retriever System, Concentric Medical, Mountain View, CA) after placement by angiographic catheter into the occluded intracranial carotid artery, middle cerebral artery or vertebral-basilar artery under fluoroscopic guidance. Our results show that the large majority (20 of 25) of extracted thrombi have similar histologic architecture, a complex of layered, sometimes serpentine, lengths of fibrin:platelet deposits interspersed with linear streaks of nucleated cells. This histology was prevalent with both cardioembolic and atherosclerotic etiologies, indicating the same pathogenetic influences of blood flow and shear in thrombus formation. This histologic pattern among thrombi was present in both the internal carotid artery (ICA) and the middle cerebral artery (MCA). Clots composed uniformly of erythrocytes were uncommon (3 of 25) and were observed only with incomplete extractions, suggesting that sampling was of the proximal thrombus tail where post-occlusion thrombosis had occurred under conditions of stagnant flow. Calcifications or cholesterol were not present. Thrombus size, not histology, predicted the site of arterial occlusion, with no thrombus larger than 3 mm width causing stroke limited to the MCA and no thrombus larger than 5 mm width removed from the ICA. Fungus-containing thrombus was extracted from one patient who had mycotic valvular disease, and an unusual complication occurred in another case, namely, scraping of a small atheroma and attached intima from the MCA, albeit without clinical consequence. We conclude that thromboemboli that cause acute ischemic stroke are of similar, complex structure, regardless of macroscopic dimensions, and are similarly influenced by blood flow, whether the primary etiology is cardioembolic or atherosclerotic. Embolus size is the critical aspect that determines its ultimate destination, those of more than 5 mm width appearing to bypass the cerebral vessels entirely. The mixed fibrin:platelet pattern present in the preponderance of thromboemboli provides foundation for the success of both antiplatelet and anticoagulant treatment strategies in stroke prevention.

Abstract WP48: Relationship of Cerebral Blood Flow by Pseudo-continuous Arterial Spin Labeling and Stenosis in Middle Cerebral Artery Territory in Patients Evaluated for Acute Ischemic Stroke

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Eric Lai ◽  
Raja Rizal Azman Raja Aman ◽  
Hui Zhang ◽  
Pui-Wai Chiu ◽  
Queenie Chan ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Ischemic Stroke ◽  
Middle Cerebral Artery ◽  
Acute Ischemic Stroke ◽  
Cerebral Artery ◽  
Arterial Spin Labeling ◽  
Spin Labeling ◽  
Arterial Stenosis ◽  
Vascular Territory

Purpose: Correlation of arterial stenosis with cortical and subcortical cerebral blood flow (CBF) in the middle cerebral artery (MCA) territory. Methods: 126 patients with acute cerebrovascular symptoms from March to June 2015 underwent MRI and MR Angiography (MRA) in a University hospital using a 3.0 Tesla scanner. Sequences included T1W, T2W, FLAIR, DWI, MRA, Pseudocontinuous Arterial Spin Labeling (pcASL, post-labeling delay 1.525 s). 13 patients (corrupted pcASL data) were excluded, with 113 patients (mean age: 67.74±14.19) evaluated (61 acute ischemic stroke, 52 patients transient ischemic attack). Institutionally developed software was used to determine CBF. MCA stenosis was graded into 4 categories by a neuroradiologist: 0 (no stenosis), 1 (mild <50%), 2 (moderate 50-70%) and 3 (severe >70%). Mean and standard deviation of MCA categories (leptomeningeal and perforating) CBF and corresponding degree of MCA stenosis were measured. Spearman correlation coefficients between CBF of cortical and subcortical regions and degree of MCA stenoses were calculated using SPSS (version 23.0). Results: The table showed the descriptive statistics. There was significant correlation between CBF of cortical region of MCA vascular territory and degree of stenosis of MCA in both left (r s = -0.296, p =0.001) and right (r s = -0.306, p =0.001) side. In the contrary, there was no correlation between subcortical CBF of MCA vascular territory and degree of stenosis of MCA in both sides. Conclusion: pcASL is a feasible non-invasive method to measure CBF in clinical setting. In MCA territory, the cortical blood flow correlated (fairly) with large vessel stenosis but not subcortical flow. We conclude that cortical CBF correlated with large artery stenosis, though being attenuated by collateral blood supply. No such relationship in subcortical CBF might be due to differential grey and white matter CBF flow, variable MCA stenotic location, and perforators originating from other territories.

scholarly journals Occult blood flow patterns distal to an occluded artery in acute ischemic stroke

2021 ◽  
pp. 0271678X2110449
Author(s):  
Nerea Arrarte Terreros ◽  
Bettine G van Willigen ◽  
Wera S Niekolaas ◽  
Manon L Tolhuisen ◽  
Josje Brouwer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Arterial Occlusion ◽  
Flow Patterns ◽  
Study Patient ◽  
Patient Specific ◽  
Collateral Flow ◽  
Large Variability ◽  
Blood Flow Patterns

Residual blood flow distal to an arterial occlusion in patients with acute ischemic stroke (AIS) is associated with favorable patient outcome. Both collateral flow and thrombus permeability may contribute to such residual flow. We propose a method for discriminating between these two mechanisms, based on determining the direction of flow in multiple branches distal to the occluding thrombus using dynamic Computed Tomography Angiography (dynamic CTA). We analyzed dynamic CTA data of 30 AIS patients and present patient-specific cases that identify typical blood flow patterns and velocities. We distinguished patterns with anterograde (N = 10), retrograde (N = 9), and both flow directions (N = 11), with a large variability in velocities for each flow pattern. The observed flow patterns reflect the interplay between permeability and collaterals. The presented method characterizes distal flow and provides a tool to study patient-specific distal tissue perfusion.

Optimized mouse model of embolic MCAO: From cerebral blood flow to neurological outcomes

2020 ◽  
pp. 0271678X2091762 ◽  
Author(s):  
Rongrong Wang ◽  
Hailian Wang ◽  
Yaan Liu ◽  
Di Chen ◽  
Yangfan Wang ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Ischemic Stroke ◽  
Mouse Model ◽  
Infarct Volume ◽  
Laser Speckle ◽  
Core Area ◽  
Contrast Imaging ◽  
Vessel Occlusion ◽  
Doppler Flowmetry

The embolic middle cerebral artery occlusion (eMCAO) model mimics ischemic stroke due to large vessel occlusion in humans and is amenable to thrombolytic therapy with rtPA. However, two major obstacles, the difficulty of the eMCAO surgery and unpredictable occurrence of clot autolysis, had impeded its application in mice. In this study, we modified catheters to produce suitable fibrin-rich embolus and optimized the eMCAO model using cerebral blood flow (CBF) monitored by both laser Doppler flowmetry (LDF) and 2D laser speckle contrast imaging (LSCI) to confirm occlusion of MCA. The results showed that longer embolus resulted in higher mortality. There was a compensatory increase in MCA territory perfusion after eMCAO associated with decreased infarct volume; however, this was only partly dependent on recanalization as clot autolysis was only observed in ∼30% of mice. Cortical CBF monitoring with LSCI showed that the size of peri-core area at 3 h displayed the best correlation with infarct volume that is attributed to compensatory collateral blood flow. The peri-core area best predicted functional outcome after eMCAO. In summary, we developed a reliable eMCAO mouse model that better mimics embolic ischemic stroke in humans, which will increase the potential for successful translation of stroke neuroprotective therapies.

Abstract TP127: Impact of Smoking on Collateral Blood Flow in Patients With Acute Ischemic Stroke With Large Cerebral Artery Embolic Occlusion

Stroke ◽  
2019 ◽  
Vol 50 (Suppl_1) ◽  
Author(s):  
George K Vilanilam ◽  
Mohammed K Badi ◽  
Emily G McCoy ◽  
Caitlin E D'Souza ◽  
Tara L Becker ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Cerebral Artery ◽  
Collateral Blood Flow

scholarly journals Augmenting Collateral Blood Flow during Ischemic Stroke via Transient Aortic Occlusion

2013 ◽  
Vol 34 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Ian R Winship ◽  
Glenn A Armitage ◽  
Gomathi Ramakrishnan ◽  
Bin Dong ◽  
Kathryn G Todd ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Collateral Circulation ◽  
Aortic Occlusion ◽  
Collateral Flow ◽  
Collateral Blood Flow ◽  
Flow Through ◽  
Transient Aortic Occlusion

Collateral circulation provides an alternative route for blood flow to reach ischemic tissue during a stroke. Blood flow through the cerebral collaterals is a critical predictor of clinical prognosis after stroke and response to recanalization, but data on collateral dynamics and collateral therapeutics are lacking. Here, we investigate the efficacy of a novel approach to collateral blood flow augmentation to increase collateral circulation by optically recording blood flow in leptomeningeal collaterals in a clinically relevant model of ischemic stroke. Using high-resolution laser speckle contrast imaging (LSCI) during thromboembolic middle cerebral artery occlusion (MCAo), we demonstrate that transiently diverting blood flow from peripheral circulation towards the brain via intra-aortic catheter and balloon induces persistent increases in blood flow through anastomoses between the anterior and middle cerebral arteries. Increased collateral flow restores blood flow in the distal middle cerebral artery segments to baseline levels during aortic occlusion and persists for over 1 hour after removal of the aortic balloon. Given the importance of collateral circulation in predicting stroke outcome and response to treatment, and the potential of collateral flow augmentation as an adjuvant or stand-alone therapy for acute ischemic stroke, this data provide support for further development and translation of collateral therapeutics including transient aortic occlusion.

scholarly journals Laser Speckle Contrast Imaging of Collateral Blood Flow during Acute Ischemic Stroke

2010 ◽  
Vol 30 (8) ◽  
pp. 1432-1436 ◽  
Author(s):  
Glenn A Armitage ◽  
Kathryn G Todd ◽  
Ashfaq Shuaib ◽  
Ian R Winship
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Cerebral Arteries ◽  
Artery Occlusion ◽  
Laser Speckle ◽  
Collateral Blood Flow ◽  
Contrast Imaging ◽  
Vessel Occlusion ◽  
Laser Speckle Contrast Imaging ◽  
Speckle Contrast

Collateral vasculature may provide an alternative route for blood flow to reach the ischemic tissue and partially maintain oxygen and nutrient support during ischemic stroke. However, much about the dynamics of stroke-induced collateralization remains unknown. In this study, we used laser speckle contrast imaging to map dynamic changes in collateral blood flow after middle cerebral artery occlusion in rats. We identified extensive anastomatic connections between the anterior and middle cerebral arteries that develop after vessel occlusion and persist for 24 hours. Augmenting blood flow through these persistent yet dynamic anastomatic connections may be an important but relatively unexplored avenue in stroke therapy.

scholarly journals Which Acute Ischemic Stroke Patients Are Fast Progressors?

Stroke ◽  
2021 ◽  
Vol 52 (5) ◽  
pp. 1847-1850
Author(s):  
Johanna M. Ospel ◽  
Michael D. Hill ◽  
Manon Kappelhof ◽  
Andrew M. Demchuk ◽  
Bijoy K. Menon ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Cerebral Artery ◽  
Posterior Cerebral Artery ◽  
Vascular Anatomy ◽  
Collateral Flow ◽  
Stroke Patients ◽  
Escape Trial ◽  
Imaging Characteristics

Background and Purpose: Fast infarct progression in acute ischemic stroke has a severe impact on patient prognosis and benefit of endovascular thrombectomy. In this post hoc analysis of the ESCAPE trial (Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke), we identified acute ischemic stroke patients with rapid infarct growth and investigated their baseline clinical and imaging characteristics. Methods: Control arm patients were included if they had follow-up imaging at 2-8 hours without substantial recanalization, and if their baseline Alberta Stroke Program Early CT Score was ≥9. Fast infarct progression was defined as Alberta Stroke Program Early CT Score decay ≥3 points from baseline to 2- to 8-hour follow-up imaging. Clinical and imaging baseline characteristics were compared between fast progressors and other patients, and occlusion site and collateral flow patterns were assessed in detail. Results: Fast infarct progression occurred in 15 of 43 included patients (34.9%). Fast progressors had worse collaterals (poor in 3/15 [20%] versus 0/28 patients, P =0.021) and more carotid-T or -L occlusions (8/15 [53.4%] versus 3/28[10.7%], P =0.021). In 8 out of 15 (53.3%), occlusion site and circle of Willis configuration prevented collateral flow via the anterior or posterior cerebral artery. Conclusions: Most patients with fast infarct progression had terminal carotid occlusions and impaired collateral flow via the anterior or posterior cerebral artery, indicating that occlusion location and intracranial vascular anatomy are relevant for infarct progression.

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