Steno-occlusive Carotid Artery Disease Research Articles

Bilateral Ortak Karotis Arter Ligasyonu Sonrası Kraniyofacioservikal Resirkülasyon Sırasında Trigeminal Ağ ve Karotiko-vertebrobaziler Vaskülatürü Arasındaki Sihirli İlişki: Ön Çalışma

Aim: Steno-occlusive carotid artery disease causes increased intraluminal pressure, retrograde blood flow, intraluminal enlargement, vessel wall thinning, convolution, vascular remodelling, angiogenesis, and aneurysm formation. We investigated whether there is a relationship between trigeminal ganglion (TGG) ischemia and luminal surface area values of external/internal carotid arteries (ECA/ICA) after common carotid artery ligation (BCCAL). 
 Material and Methods: This study was conducted in 20 hybrid male rabbits as control (GA;n=5), SHAM (GB;n=5), and study group (GC,n=10). Following anterior mid-cervical incision, permanent BCCAL was performed for only GC and animals sacrificed under general anaesthesia after three months. Degenerated neuron (DN) density of TGGs and ECAs/ICAs' luminal surface values were estimated by Cavalieri and Stereological methods. Lumen enlargement, wall thinning, elongation, convolution, and dolichoectasia were detected in the carotid artery vasculature. 
 Results: The mean DN density of TGG was 12±4 in GA, 53±11 in GB, and 960±112 in GC. The mean number of ECA branches was calculated as 4±1/GA, 7±2/GB, and 11±3/GC. Total surface values of ECA/ICA (as mm2): 4.8±1.2/GA; 3.9±0.8/GB and 3.6±0.4/GC. 
 Conclusion: The low density of DN in TGG could have a beneficial effect on neovascularization, collateral development, a renormalization of carotid circulation, and prevention of ischemic damage supplied by ECA/ICA of study group.

Bilateral Arteria Carotis Communis Ligasyonu Sonrası Arteria Basilaris’te Gözüken Morfohistopatolojik Değişikliklere Cinsiyetin Etkisi: Deneysel Çalışma

Aim: Steno-occlusive carotid artery disease causes increased pressure, retrograde blood flow, luminal enlargement, vascular wallthinning, elongation, convolutions, vascular re-modelization, and aneurysm formation in basilar arteries. We investigated if gender affectsthe severity of histomorphologic alterations of basilar arteries after bilateral common carotid artery ligation.Material and Methods: This study was conducted on 7 male and 7 female rabbits. Two of both male and female rabbits were used as acontrol group and the remaining were used as the study group. Permanent ligation of the common carotid arteries from just proximal ofbifurcation was performed to replicate steno-occlusive carotid artery disease. Basilar artery volumes were measured by stereologicalmethods after the sacrifice of the animals at the end of the 3rd week. Results were compared Mann-Witney U test between groups.Results: Luminal enlargement, wall thinning, elongation, convolutions, and doligoectatic configurations were detected in the majority ofbasilar arteries. The mean basilar arterial volume values were estimated as male rabbits were 3.65 ± 0.35 mm3 in control and 4.96 ± 0.99mm3 in the study group. The mean basilar arterial volume values were estimated as female rabbits were 3.97 ± 0.40 mm3 in control and6.32 ± 1.13 mm3 in the study group. The severity of basilar enlargement was significantly higher in the female rabbits compared with themale rabbits (p < 0.01).Conclusion: Bilateral common carotid artery ligation causes more severe luminal enlargement, wall thinning, elongation, convolution, andaneurysm formation in female rabbits than males.Keywords: Bilateral common carotid artery ligation (BCCAL), basilar artery (BA), stereological method

Stellate ganglion ischemia on the prevention of pulmonary vasospasm during bilateral carotid artery ligation: The first experimental study.

Fatal pulmonary edema and hemorrhage are significant complications of endovascular treatment in steno-occlusive carotid artery disease; a rational mechanism has not been adequately examined in the literature so far. We investigated if cervical sympathetic ganglia ischemia prevents pulmonary vasospasm on the prognosis of bilateral common carotid artery ligation (BCCAL). Twenty-three adult New Zealand rabbits (4.2 ± 0.3 kg) were randomly divided into three groups: the control group (G1, n = 5), the sham group (G2, n = 6), and the BCCAL group (G3, n = 12). Common carotid arteries were dissected bilaterally in G2/G3, and permanent BCCAL was applied to only in G3. All animals were followed for 3 weeks and decapitated under general anesthesia. Histopathological changes in stellate ganglia and severity of pulmonary vasospasm-related lung edema and hemorrhage were investigated. Results were analyzed by the Kruskal-Wallis test. Two animals of G3 dead within three weeks and the remainder were sacrificed three weeks later. Subpleural petechial foci and an endotracheal bloody fluid collection were grossly observed in the lungs. Histopathologically, pulmonary artery vasospasm, perivascular and subintimal edema, interalveolar hemorrhage, and alveolar wall destructions were observed with less ischemic-degenerated neuron density-determined stellate ganglia animals. Neurodegeneration of stellate ganglia may have a beneficial effect on the prevention of lung injury during steno-occlusive carotid artery disease.

Abstract WP436: Reduced Blood Flow in the Pial Collaterals and Penetrating Arterioles During Chronic Hypoperfusion in Type 2 Diabetic Mice

Introduction: The degree of cortical hypoperfusion following carotid steno-occlusion depends on the dynamic compensation from the collateral circulation. The presence of collaterals is associated with a reduced risk of stroke and transient ischemic attack (TIA) in patients with steno-occlusive carotid artery disease. Although metabolic syndrome negatively impacts collateral status among patients with ischemic stroke, it is unclear whether type 2 diabetes (T2DM) specifically affects leptomeningeal collateral flow regulation and the adaptation of collateral vessels at the circle of Willis during hypoperfusion. Methods: Spatial and temporal changes of the leptomeningeal collateral flow and the flow dynamics of the penetrating arterioles in the distal MCA and ACA branches over two weeks following unilateral common carotid artery occlusion (CCAO) were determined by optical coherent tomography in db/+ and db/db mice, a mouse model for obesity and type 2 diabetes. The temporal adaptation of the circle of Willis (CW) following CCAO was assessed by measuring CW vessel diameters. Results: Following unilateral CCAO, db/db mice exhibited diminished leptomeningeal collateral flow compensation compared to db /+ mice, which coincided with a reduced dilation of distal ACA branches, leading to reduced flow not only in pial vessels, but also in penetrating arterioles bordering the distal MCA and ACA. However, no apparent cell death was detected in either strain of mice during the first week after CCAO. db/db mice also experienced a more severe early reduction in the vessel diameters of several ipsilateral main feeding arteries in the CW, in addition to a delayed post-CCAO adaptive response by one to two weeks compared to db/+ mice. Conclusions: T2DM is an additional risk factor for hemodynamic compromise during cerebral hypoperfusion, which may increase the severity and the risk of stroke or TIA.

Inverse Association Between Basilar Artery Volume and Neuron Density in the Stellate Ganglion Following Bilateral Common Carotid Artery Ligation: An Experimental Study.

This study examined the relationship between neuron density in the stellate ganglion and the severity of basilar artery (BA) enlargement after bilateral common carotid artery ligation. Rabbits (n= 24) were randomly divided into 3 groups: unoperated control group (n= 4), experimental group subjected to bilateral common carotid artery ligation (n= 15), and sham-operated control group (n= 5). Histologic examination of the BAs and stellate ganglia was performed 2 months later. Permanent bilateral common carotid artery ligation was induced by ligation of common carotid arteries at prebifurcation levels as a model for steno-occlusive carotid artery disease. Mean BA volume and neuron density in stellate ganglia for all animals were 4200 μm3 ± 240 and 8325 μm3 ± 210. In sham-operated animals, the mean values were 4360 μm3 ± 340 and 8250 mm3 ± 250. For the experimental group, mean volume and density in animals with slight dilatation of the BA (n= 6) were 4948 μm3 ± 680 and 10,321 mm3 ± 120, whereas in animals with severe dilatation (n= 9), the values were 6728 μm3 ± 440 and 6300 mm3 ± 730. An inverse association was observed between degree of BA enlargement and stellate ganglia neuronal density. High neuron density in stellate ganglia may protect against steno-occlusive carotid artery disease by preventing BA dilatation and aneurysm formation in the posterior circulatory arteries.

Impaired Collateral Flow Compensation During Chronic Cerebral Hypoperfusion in the Type 2 Diabetic Mice.

The presence of collaterals is associated with a reduced risk of stroke and transient ischemic attack in patients with steno-occlusive carotid artery disease. Although metabolic syndrome negatively impacts collateral status, it is unclear whether and to what extent type 2 diabetes mellitus affects cerebral collateral flow regulation during hypoperfusion. We examined the spatial and temporal changes of the leptomeningeal collateral flow and the flow dynamics of the penetrating arterioles in the distal middle cerebral artery and anterior cerebral artery branches over 2 weeks after unilateral common carotid artery occlusion (CCAO) using optical coherent tomography in db/+ and db/db mice. We also assessed the temporal adaptation of the circle of Willis after CCAO by measuring circle of Willis vessel diameters. After unilateral CCAO, db/db mice exhibited diminished leptomeningeal collateral flow compensation compared with db/+ mice, which coincided with a reduced dilation of distal anterior cerebral artery branches, leading to reduced flow not only in pial vessels but also in penetrating arterioles bordering the distal middle cerebral artery and anterior cerebral artery. However, no apparent cell death was detected in either strain of mice during the first week after CCAO. db/db mice also experienced a more severe early reduction in the vessel diameters of several ipsilateral main feeding arteries in the circle of Willis, in addition to a delayed post-CCAO adaptive response by 1 to 2 weeks, compared with db/+ mice. Type 2 diabetes mellitus is an additional risk factor for hemodynamic compromise during cerebral hypoperfusion, which may increase the severity and the risk of stroke or transient ischemic attack.

The role of sympathectomy on the regulation of basilar artery volume changes in stenoocclusive carotid artery modeling after bilateral common carotid artery ligation: an animal model

Stenoocclusive carotid artery disease causes important histomorphologic changes in all craniocervical vasculatures, such as luminal enlargement, vascular wall thinning, elongation, convolutions, and aneurysm formation in the posterior circulation. Although increased pressure, retrograde blood flow, and biochemical factors are described in the pathogenesis of vascular remodelisation, the vasoregulatory role of the autonomic nervous system has not been investigated thus far. We investigated the relationship between the sympathetic nervous system and the severity of histomorphologic alterations of basilar arteries after bilateral common carotid artery ligation (BCCAL). This study was conducted on 21 rabbits. The rabbits were randomly divided into three groups: baseline group (n = 5), sympathectomy non-applied group (SHAM; n = 8), and sympathectomy applied group (n = 8) before bilateral common carotid artery ligation. Permanent ligation of the prebifurcations of the common carotid arteries was performed to replicate stenoocclusive caroid artery disease. Basilar artery volumes were measured after ligation. Volumes of the basilar arteries were estimated by stereologic methods and compared between groups. Luminal enlargement, wall thinning, elongation, convolutions, and doligoectatic configurations were detected in the majority of basilar arteries. The mean basilar arterial volume was 4.27 ± 0.22mm3 in the baseline group; 5.28 ± 0.67mm(3) in the SHAM group, and 8.84 ± 0.78mm3 in the study group. The severity of basilar enlargement was significantly higher in the study group compared with the SHAM (p < 0.005) and baseline groups (p < 0.001). Sympathectomy causes basilar artery enlargment, which is beneficial for maintaining cerebral blood flow; however, it also causes wall thinning, elongation, convolution, and aneurysm formation, which may be hazardous in stenoocclusive carotid artery disease. Sympathectomy can prevent new vessel formation and hyperthyrophic changes at the posterior circulation. Neovascularisation is not detected adequately in sympathectomised animals.

Commentary: Steno-Occlusive Carotid Artery Disease in the Setting of Acute Ischemic Stroke: To Stent or Not to Stent?

Commentary: Steno-Occlusive Carotid Artery Disease in the Setting of Acute Ischemic Stroke: To Stent or Not to Stent?

Endovascular Revascularization of Symptomatic Acute Extracranial Internal Carotid Artery Occlusion

See related article, pages 2426–2430. Acute extracranial internal carotid artery (ICA) occlusion resulting in ischemic stroke is different from other forms of acute occlusion of the cerebral blood vessels. The occluded segment of the ICA consists of predominantly atherosclerotic plaque and a superimposed thrombus. The occluded segments in other cerebral blood vessels, such as the middle cerebral artery, usually consist of an occlusive embolus in a normal vessel.1 Therefore, the pathophysiologic processes involved in the occlusion of the extracranial ICA are similar to processes observed in acute occlusion of the coronary arteries. In acute myocardial infarction, primary stent placement has provided the best treatment outcomes.2 The present report provides early evidence to expand this approach to other …

Extent of spontaneous cross-flow via the anterior communicating artery in steno-occlusive carotid artery disease

Purpose: Our purpose was to evaluate the agreement of transcranial color-coded duplex sonography (TCCS) measurements and intra-arterial digital subtraction angiography (DSA) findings in determining the extent of spontaneous cross-flow via the anterior communicating artery (AcoA) in patients with internal carotid artery (ICA) stenosis.Methods: Thirty adult patients with suspected uni- or bilateral high-grade carotid artery stenosis were prospectively examined by DSA and angle-corrected TCCS. The extent of cross-flow was determined considering retrograde flow in the ipsilateral anterior cerebral artery (ACA) and sideto-side differences of the A1-segments of the ACA and middle cerebral arteries (MCAs) by both techniques. Cross-flow was angiographically categorized by means of a four-step scale. DSA findings were correlated with side-to-side differences in mean blood flow velocity as well as flow direction measured by TCCS.Results: Twenty-seven of 30 patients had a uni- or bilateral ICA stenosis of >49%. Excellent agreement between TCCS and DSA was evaluated for the detection of lack (grades 0 and 1) or presence (grades 2 and 3) of reversed flow in the ACA (sensitivity 100%, specificity 93%, positive predictive value 94%). Post hoc analysis of the mean velocities in the ACA and MCA revealed a side-to-side difference of 25 cm/s as a cutting point allowing for definition of a corresponding four-grade scale for ultrasound. However, full agreement, i.e.same grade of cross-flow detected by both techniques, was only found in 17(57%) of 30 cases.Conclusions: Non-invasive TCCS is reliable for detecting reversed flow in the ACA in patients with ICA stenosis. However, there is only a moderate agreement between angiography and TCCS in quantifying the extent of spontaneous anterior cross-flow because different information on the intracranial hemodynamics may be obtained.