Abstract WP152: Collateral Circulation Alters Downstream Hemodynamic Stress Caused by Intracranial Atherosclerotic Stenosis

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Xin Liu ◽  
Yuehua Pu ◽  
Zhongrong Miao ◽  
Yilong Wang ◽  
Liping Liu ◽  
...  
Keyword(s):  
Collateral Circulation ◽  
Recurrent Stroke ◽  
Pressure Sensors ◽  
Fractional Flow ◽  
Median Percentage ◽  
Hemodynamic Stress ◽  
Flow Reserve ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis ◽  
Severe Coronary Artery

Background and purpose: Fractional flow reserve (FFR) has exceled the degree of stenosis and become the new guiding post for identifying functionally severe coronary artery lesions. In the current study, we utilized a similar indicator, fractional flow (FF), to gauge the hemodynamic impact of symptomatic intracranial atherosclerotic stenosis (ICAS), and to clarify its relationships with the severity of stenosis and collateral status. Methods: Patients with symptomatic ICAS (70-99% stenosis) confirmed on digital subtraction angiography (DSA) were consecutively recruited. FF was obtained during DSA examination, defined as the ratio of pressures measured distal to an ICAS lesion (Pd) and within the aorta (Pa), by pressure sensors. Leptomeningeal collaterals was grading from zero (absent) to four (complete compensatory) based on DSA examination. The correlations between FF, anatomical stenosis and collateral status were analyzed. Results: Twenty five patients with a mean age of 55.6years were included. The median percentage of stenosis and median FF were 82.3% and 0.68, respectively. Eleven patients were evaluated as poor collaterals (grade 0-2), and fourteen patients were good collaterals (grade 3-4). Overall, the hemodynamic impact of the lesions aggravated (with a decreased FF) as the percentage of stenosis increased (r= -0.398,P =0.06). However, the collateral status significantly altered such correlation, which was more significant in patients with poor collateral circulation (r=-0.677, P=0.032), but did not exist in patients with good collateral circulation (r=-0.279, P=0.356). Conclusions: An anatomically severe (70-99%) symptomatic ICAS lesion may lay significant hemodynamic stress downstream as assessed by the indicator FF. However, a good collateral circulation may mitigate such hemodynamic impact, which may partly explain the protective effect of good collaterals against recurrent stroke in such patients.

Collateral circulation alters downstream hemodynamic stress caused by intracranial atherosclerotic stenosis

2017 ◽  
Vol 39 (6) ◽  
pp. 498-503 ◽  
Author(s):  
Xin Liu ◽  
David Dornbos ◽  
Yuehua Pu ◽  
Xinyi Leng ◽  
Ligang Song ◽  
...  
Keyword(s):  
Collateral Circulation ◽  
Hemodynamic Stress ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis

Intracranial atherosclerosis: From anatomy to pathophysiology

2017 ◽  
Vol 12 (3) ◽  
pp. 236-245 ◽  
Author(s):  
Yuehua Pu ◽  
Linfang Lan ◽  
Xinyi Leng ◽  
Lawrence KS Wong ◽  
Liping Liu
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Collateral Circulation ◽  
Future Research ◽  
Fractional Flow ◽  
Cerebral Hemodynamic ◽  
Flow Reserve ◽  
Atherosclerotic Stenosis ◽  
Computational Fluid Dynamics Analysis ◽  
Hemodynamic State

Background Intracranial atherosclerotic stenosis is an important etiology subtype of ischemic stroke. Stenosis severity was thought to be the main reference index for clinical treatment and research. However, stenosis could not reflect the ischemia risk completely, instead the hemodynamic state across the lesion, the extent of collateral circulation, and perfusion impairment downstream the stenosis are more important. Aims We write this review aimed to summarize novel angiographic methods applied in the evaluation of functional severity of ICAS, and commented on their limitations and prospects in future research. Summary of review The main methods to estimate cerebral blood flow including fractional flow assessed by signal intensity ratio, computational fluid dynamics analysis or pressure wire, quantitative magnetic resonance angiography. Fractional flow as a series cerebral hemodynamic parameters may reflect the status of collateral circulation and cerebral blood flow. But the accuracy of the methods was not validated. The method to calculate fractional flow reserve in cardiovascular disease cannot duplicate in cerebrovascular disease. Fractional flow measurement by floating a pressure guidewire across the intracranial stenosis was technically feasible and safe. In the future researches, a non-invasive method should be established to identify high-risk intracranial lesions and may help in decision-making. Conclusions The relationship between stenosis and cerebral blood flow was individualized. Cerebral hemodynamic criteria should be used to screen patients to endovascular treatment, which will optimize the diagnosis and treatment strategies for patients with symptomatic intracranial artery stenosis.

Noninvasive fractional flow in intracranial atherosclerotic stenosis: Reproducibility, limitations, and perspectives

2017 ◽  
Vol 381 ◽  
pp. 150-152 ◽  
Author(s):  
Xinyi Leng ◽  
Linfang Lan ◽  
Vincent H.L. Ip ◽  
Haipeng Liu ◽  
Jill Abrigo ◽  
...  
Keyword(s):  
Fractional Flow ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis

Fractional flow reserve — The influence of the collateral circulation

2009 ◽  
Vol 132 (3) ◽  
pp. e109-e110 ◽  
Author(s):  
Narbeh Melikian ◽  
Thomas Cuisset ◽  
Michalis Hamilos ◽  
Bernard De Bruyne
Keyword(s):  
Fractional Flow Reserve ◽  
Collateral Circulation ◽  
Fractional Flow ◽  
Flow Reserve

Abstract WP169: Symptomatic Intracranial Atherosclerotic Stenosis: The Associations Between Cerebral Hemodynamics and the Stroke Mechanisms

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Xueyan Feng ◽  
Ka Lung Chan ◽  
Jill Abrigo ◽  
Linda Lan ◽  
Yuming Xu ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cerebral Perfusion ◽  
Recurrent Stroke ◽  
Pressure Ratio ◽  
Teaching Hospitals ◽  
Parent Artery ◽  
Anterior Circulation ◽  
Arterial Embolism ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis

Background: Intracranial atherosclerotic stenosis (ICAS) may cause ischemic stroke by various mechanisms; artery-to-artery (AA) embolism and hypoperfusion often co-exist and bear a high risk of recurrent stroke despite optimal medical treatment. Little is known regarding how ICAS lesions cause ischemic strokes via different mechanisms, while the hemodynamic features of ICAS lesions may play an important role. Methods: Patients with acute ischemic stroke attributed to 50-99% ICAS in the anterior circulation confirmed in CT angiography (CTA) were recruited from two teaching hospitals. We classified probable stroke mechanisms as parent artery atherosclerosis occluding penetrating artery (PAO), AA embolism, hypoperfusion, and mixed mechanisms, based on infarct topography and ICAS lesion features. Computational fluid dynamics (CFD) models were built based on CTA to simulate blood flow across culprit ICAS lesions. We calculated translesional pressure ratio (PR), the ratio of pressures distal and proximal to the lesion; and translesional wall shear stress ratio (WSSR), the ratio of WSS at the stenosis throat and at proximal normal vessel segment. We defined PR ≤ median as low PR, indicating larger pressure gradient across the lesion, hence restricted downstream perfusion; and WSSR ≥ 4 th quartile as high WSSR, indicating higher WSS upon the lesion. We associated PR and WSSR with probable stroke mechanisms. Results: Among 99 patients, 44 had AA embolism as a probable stroke mechanism, 13 with AA embolism alone and 31 with coexisting hypoperfusion; 18 and 37 respectively had isolated PAO and isolated hypoperfusion as the probable stroke mechanisms. High WSSR was independently associated with AA embolism (adjusted OR 4.86; p = 0.008). The significant, positive relationship between high WSSR and higher risk of AA embolism remained in those with a low PR (adjusted OR 4.01; p = 0.044), but not in those with a normal PR (p = 0.621). Conclusions: High WSS upon ICAS lesions may increase plaque vulnerability, but it may only cause distal arterial embolism when there is impaired cerebral perfusion. Therefore, in secondary prevention of ischemic stroke in ICAS via AA embolism, impaired cerebral perfusion may be an important therapeutic target.

Clinical significance of the circle of Willis in intracranial atherosclerotic stenosis

2014 ◽  
Vol 8 (3) ◽  
pp. 251-255 ◽  
Author(s):  
Kang Min Kim ◽  
Hyun-Seung Kang ◽  
Woong Jae Lee ◽  
Young Dae Cho ◽  
Jeong Eun Kim ◽  
...  
Keyword(s):  
Endovascular Treatment ◽  
Primary Endpoint ◽  
Recurrent Stroke ◽  
Arterial Occlusion ◽  
Circle Of Willis ◽  
Asymptomatic Group ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis ◽  
Antiplatelet Medication ◽  
Stroke Group

IntroductionThe effectiveness of a scoring system based on the circle of Willis for evaluations of collateral circulation was studied in patients with intracranial atherosclerotic stenosis.MethodsEighty-three patients who underwent medical or endovascular treatment for symptomatic and severe intracranial atherosclerotic stenosis were enrolled in the study. Clinical profiles, status of the circle of Willis (poor and good integrity group), and clinical outcomes were analyzed. Primary endpoints were: (1) symptomatic ischemic or hemorrhagic stroke within 30 days; and (2) recurrent transient ischemic attack or ischemic stroke beyond 30 days.ResultsThe estimated rates of the primary endpoint at 1 and 2 years after treatment were 8.5% and 11.4% in the medical group and 7.0% and 9.7% in the endovascular group, respectively. A primary endpoint event after medical treatment was only identified in patients with poor integrity of the circle of Willis (p=0.059). In patients with poor integrity of the circle of Willis, previous antiplatelet medication before initial presentation (p=0.026) and hypertension (p=0.006) were more prevalent. During the follow-up period, complete arterial occlusion was identified in 9 patients. The circle of Willis score of the patients with complete arterial occlusion was 1.33±1.52 in the fatal stroke group (n=3) and 3.20±1.64 in the asymptomatic group (n=6, p=0.099).ConclusionsIf patients have poor integrity of the circle of Willis, the risk of recurrent stroke may be increased. Such patients appear to be good candidates for endovascular treatment.

Abstract 122: Stroke Patterns And Causative Mechanisms Of Ischemia In Patients With Symptomatic Intracranial Atherosclerotic Stenosis

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Elena Lopez-Cancio ◽  
Maria G Matheus ◽  
Jose Romano ◽  
David S Liebeskind ◽  
Shyam Prabhakaran ◽  
...  
Keyword(s):  
Recurrent Stroke ◽  
Posterior Circulation ◽  
Embolic Stroke ◽  
Severe Stenosis ◽  
Anterior Circulation ◽  
Treatment Assignment ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis ◽  
Artery Embolism ◽  
Circulation Patterns

Background/objectives: Putative mechanisms of stroke in intracranial atherosclerotic stenosis (ICAS) include hypoperfusion, artery-to-artery embolism or perforator occlusion, each of which may be characterized by different stroke patterns on neuroimaging. Our aims are to determine: 1) the different stroke patterns in patients with ICAS; 2) the correlation of angiographic factors (collaterals, degree and location of stenosis) with stroke patterns; and 3) if the patterns of recurrent stroke in the same territory are similar to qualifying strokes. Methods: From the WASID dataset, we selected patients with a stroke at baseline who had conventional angiographic information on collaterals (n=136), and patients with a recurrent stroke in the territory during follow-up (n= 47). We categorized stroke patterns as follows: for anterior circulation-subcortical (SC), cortical (C), territorial (T), borderzone (BZ) and multiple (M); for posterior circulation,-subcortical (SC), cortical (C), cerebellar (CB) and multiple (M). We defined an embolic mechanism if C, T, CB or multiple were present. The association between stroke patterns and collateral grade assessment (ASITN/SIR), location and degree of stenosis, and treatment assignment (warfarin vs aspirin) was analyzed using Chi-Square and McNemar’s tests. Results: Anterior circulation patterns (n=72) at baseline were: 14(19%) SC, 5(7%) T, 2(29%) C, 12(17%) BZ and 20(28%) M. All isolated BZ stroke patterns were located in internal borderzone region. BZ pattern was equally distributed among patients with no collaterals (5/40=12%) vs. patients with collaterals (7/32=22%) (p= 0.29) and among patients with moderate (8/43=19%) vs. severe stenosis (4/29=14%) (p=0.59). Posterior circulation patterns (n= 64) at baseline were: 25(39%) SC, 5(8%) C, 10(16%) CB and 24(38%)M. Embolic stroke pattern at baseline was the most frequent (85/136=62.5%). Among patients with a recurrent stroke in the territory (n=47), embolic pattern was also the most frequent (32/47, 68%). The probability of having a recurrent embolic stroke pattern was related to stenosis degree (81% in severe vs 50% in moderate stenosis, p= 0.03), collateral grade (83% with collaterals vs 53% no collaterals, p= 0.09), and previous embolic stroke pattern (74 % who had baseline embolic stroke vs 25% who had baseline non-embolic stroke,p= 0.01). Having a recurrent embolic stroke pattern was not influenced by treatment assignment (67% treated with warfarin vs 69% treated with aspirin, p=0.85). Conclusions: Artery-to-artery embolism seems to be the most frequent mechanism of stroke in ICAS patients and was not modified by antithrombotic treatment. Isolated BZ infarcts were less frequent, and were not related to poor collaterals or more severe stenosis.

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