scholarly journals Neurovascular Coupling Varies with Level of Global Cerebral Ischemia in a Rat Model

2012 ◽  
Vol 33 (1) ◽  
pp. 97-105 ◽  
Author(s):  
Wesley B Baker ◽  
Zhenghui Sun ◽  
Teruyuki Hiraki ◽  
Mary E Putt ◽  
Turgut Durduran ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Ischemia ◽  
Carotid Artery ◽  
Electrical Response ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Laser Speckle ◽  
Global Cerebral Ischemia ◽  
Functional Responses ◽  
Bilateral Carotid

In this study, cerebral blood flow, oxygenation, metabolic, and electrical functional responses to forepaw stimulation were monitored in rats at different levels of global cerebral ischemia from mild to severe. Laser speckle contrast imaging and optical imaging of intrinsic signals were used to measure changes in blood flow and oxygenation, respectively, along with a compartmental model to calculate changes in oxygen metabolism from these measured changes. To characterize the electrical response to functional stimulation, we measured somatosensory evoked potentials (SEPs). Global graded ischemia was induced through unilateral carotid artery occlusion, bilateral carotid artery occlusion, bilateral carotid and right subclavian artery (SCA) occlusion, or carotid and SCA occlusion with negative lower body pressure. We found that the amplitude of the functional metabolic response remained tightly coupled to the amplitude of the SEP at all levels of ischemia observed. However, as the level of ischemia became more severe, the flow response was more strongly attenuated than the electrical response, suggesting that global ischemia was associated with an uncoupling between the functional flow and electrical responses.

Assessing the Effects of Antihypertensive Medication on Cerebral Blood Flow: Demonstration in Internal Carotid Artery Occlusion

DICP ◽  
1991 ◽  
Vol 25 (12) ◽  
pp. 1299-1301 ◽  
Author(s):  
Susan C. Fagan ◽  
James R. Ewing ◽  
Steven R. Levine ◽  
Gretchen E. Tietjen ◽  
Nabih M. Ramadan ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Antihypertensive Medication ◽  
Internal Carotid ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Internal Carotid Artery Occlusion ◽  
Bilateral Carotid

Dynamic cerebral blood flow (CBF) studies using acetazolamide or hypercapnia as a vasodilatory challenge have attempted to evaluate intracranial hemodynamics. We report two patients with asymptomatic internal carotid artery occlusion in whom the vasodilatory stimulus was a single oral dose of antihypertensive medication (prazosin hydrochloride or enalapril maléate). In both patients, changes in regional CBF occurred that were larger than those seen in nine normal controls. One patient experienced an improvement in regional CBF with a reduction in probe pair asymmetry. In the other patient, who had bilateral carotid artery disease, a decrease in regional CBF in all 16 probes (mean decrease 12 percent) and an accentuation of the predose asymmetry were observed. Both patients remained asymptomatic throughout the study. Assessing these effects on cerebral circulation may help identify patients at risk for iatrogenic focal cerebral ischemia and provide information regarding the functional status of the cerebral vasculature.

scholarly journals Acute Functional Recovery of Cerebral Blood Flow after Forebrain Ischemia in Rat

2008 ◽  
Vol 28 (7) ◽  
pp. 1275-1284 ◽  
Author(s):  
Chao Zhou ◽  
Tomokazu Shimazu ◽  
Turgut Durduran ◽  
Janos Luckl ◽  
Daniel Y Kimberg ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Ischemia ◽  
Statistical Parametric Mapping ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Laser Speckle ◽  
Activation Area ◽  
Blood Flow Response ◽  
Flow Response

After complete cerebral ischemia, the postischemic blood flow response to functional activation is severely attenuated for several hours. However, little is known about the spatial and temporal extent of the blood flow response in the acute postischemic period after incomplete cerebral ischemia. To investigate the relative cerebral blood flow (rCBF) response in the somatosensory cortex of rat to controlled vibrissae stimulation after transient incomplete ischemia (15-min bilateral common carotid artery occlusion + hypotension), we employed laser speckle imaging combined with statistical parametric mapping. We found that the ischemic insult had a significant impact on the baseline blood flow ( P <0.005) and the activation area in response to functional stimulation was significantly reduced after ischemia ( P < 0.005). The maximum rCBF response in the activation area determined from the statistical analysis did not change significantly up to 3 h after ischemia ( P > 0.1). However, the time when rCBF response reached its maximum was significantly delayed ( P < 0.0001) from 2.4 ± 0.2 secs before ischemia to 3.6 ± 0.1 secs at 20 mins into reperfusion ( P < 0.001); the delay was reduced gradually to 2.9 ± 0.2 secs after 3 h, which was still significantly greater than that observed before the insult ( P = 0.04).

scholarly journals Study on the correlation between the circle of Willis structure and collateral circulation in bilateral carotid artery occlusion

2021 ◽  
Author(s):  
Yang Liu ◽  
Lei Zhu ◽  
Bei Hou ◽  
Tuoyi Wang ◽  
Dechao Xu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Carotid Artery ◽  
Cerebral Artery ◽  
Collateral Circulation ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Complete Type ◽  
Bilateral Carotid ◽  
Flow Compensation

Abstract Background and purpose Bilateral carotid artery occlusion (CAO) is a rare condition and the collateral circulation is more complicated than in unilateral CAO. The circle of Willis (CoW) is the most important collateral circulation compensation pathway in CAO. However, the specific role of CoW in the collateral circulation compensation pathway of CAO has not been fully elucidated. The purpose of this study is to investigate the role of CoW in the collateral circulation compensation pathway of CAO. Materials and methods Clinical, imaging, and hemodynamic data of 30 patients with bilateral CAO were collected to analyze the collateral blood flow compensation pathway and its characteristics, and to examine the correlation between the structure of the CoW and the collateral circulation of bilateral CAO. Results This paper summarized 30 patients with bilateral CAO. There were 0 cases of the CoW complete type, 18 cases of the partially complete type (60%), and 12 cases of the incomplete type (40%). For the partially complete type cases, there were 14 complete anterior circulation cases (46.7%). The collateral circulation collateral circulation pathway included 14 cases with anterior communicating artery(ACoA), 7 cases with posterior cerebral artery (PCA)-middle cerebral artery (MCA) leptomeningeal anastomosis (LMA), 5 cases with ophthalmic artery(OA), 3 cases with lateral posterior communicating artery(PCoA), 1 case with internal carotid artery (ICA) stealing, 1 case with new Moyamoya vessels, and 4 cases of other types. There were four cases (13.3%) with complete posterior circulation, including four cases with bilateral PCoA, three cases with PCA-MCA LMA, and two cases with OA. There were 12 cases (40%) with incomplete CoW, including 8 cases with PCA-MCA LMA, 3 cases with lateral PCoA, 1 case with anterior cerebral artery (ACA)-MCA LMA, 4 cases with OA, and 1 other case. Conclusion The collateral circulation pathway differs among patients with different CoW structure types. When the CoW is partially complete, it mainly provides blood flow compensation to the ischemic area through primary collateral circulation. When the CoW is incomplete, it mainly provides blood flow compensation to the ischemic area through secondary collateral circulation.

scholarly journals Adaptation of the cerebrocortical circulation to carotid artery occlusion involves blood flow redistribution between cortical regions and is independent of eNOS

2016 ◽  
Vol 311 (4) ◽  
pp. H972-H980 ◽  
Author(s):  
Andreas Polycarpou ◽  
László Hricisák ◽  
András Iring ◽  
Daniel Safar ◽  
Éva Ruisanchez ◽  
...  
Keyword(s):  
Blood Flow ◽  
Carotid Artery ◽  
Blood Supply ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Laser Speckle ◽  
Collateral Vessels ◽  
The Right

Cerebral circulation is secured by feed-forward and feed-back control pathways to maintain and eventually reestablish the optimal oxygen and nutrient supply of neurons in case of disturbances of the cardiovascular system. Using the high temporal and spatial resolution of laser-speckle imaging we aimed to analyze the pattern of cerebrocortical blood flow (CoBF) changes after unilateral (left) carotid artery occlusion (CAO) in anesthetized mice to evaluate the contribution of macrovascular (circle of Willis) vs. pial collateral vessels as well as that of endothelial nitric oxide synthase (eNOS) to the cerebrovascular adaptation to CAO. In wild-type mice CoBF reduction in the left temporal cortex started immediately after CAO, reaching its maximum (−26%) at 5–10 s. Thereafter, CoBF recovered close to the preocclusion level within 30 s indicating the activation of feed-back pathway(s). Interestingly, the frontoparietal cerebrocortical regions also showed CoBF reduction in the left (−17–19%) but not in the right hemisphere, although these brain areas receive their blood supply from the common azygos anterior cerebral artery in mice. In eNOS-deficient animals the acute CoBF reduction after CAO was unaltered, and the recovery was even accelerated compared with controls. These results indicate that 1) the Willis circle alone is not sufficient to provide an immediate compensation for the loss of one carotid artery, 2) pial collaterals attenuate the ischemia of the temporal cortex ipsilateral to CAO at the expense of the blood supply of the frontoparietal region, and 3) eNOS, surprisingly, does not play an important role in this CoBF redistribution.

scholarly journals Capillary Flow and Diameter Changes during Reperfusion after Global Cerebral Ischemia Studied by Intravital Video Microscopy

2004 ◽  
Vol 24 (4) ◽  
pp. 383-391 ◽  
Author(s):  
Erik F. Hauck ◽  
Sebastian Apostel ◽  
Julie F. Hoffmann ◽  
Axel Heimann ◽  
Oliver Kempski
Keyword(s):  
Cerebral Ischemia ◽  
Capillary Flow ◽  
Fluorescein Isothiocyanate ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Global Cerebral Ischemia ◽  
Sham Operation ◽  
Cranial Window ◽  
Bilateral Carotid ◽  
Flow Velocities

The reaction of cerebral capillaries to ischemia is unclear. Based on Hossmann's observation of postischemic “delayed hypoperfusion,” we hypothesized that capillary flow is decreased during reperfusion because of increased precapillary flow resistance. To test this hypothesis, we measured cerebral capillary erythrocyte velocity and diameter changes by intravital microscopy in gerbils. A cranial window was prepared over the frontoparietal cortex in 26 gerbils anesthetized with halothane. The animals underwent either a sham operation or fifteen minutes of bilateral carotid artery occlusion causing global cerebral ischemia. Capillary flow velocities were measured by frame-to-frame tracking of fluorescein isothiocyanate labeled erythrocytes in 1800 capillaries after 1-hour reperfusion. Capillary flow velocities were decreased compared to control (0.25 ± 0.27mm/s vs. 0.76 ± 0.45 mm/s; P < 0.001). Precapillary arteriole diameters in reperfused animals were reduced to 76.3 ± 6.9% compared to baseline ( P < 0.05). Capillary diameters in reperfused animals (2.87 ± 0.97 μm) were reduced ( P < 0.001) compared to control (4.08 ± 1.19 μm). Similar reductions of precapillary (24%) and capillary vessel diameters (30%) and absolute capillary flow heterogeneity indicate that delayed (capillary) hypoperfusion occurs as a consequence of increased precapillary arteriole tone during reperfusion.

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