Ultrasound shear wave elastography imaging of common carotid arteries in patients with Spontaneous Coronary Artery Dissection (SCAD)

Background Shear wave elastography (SWE) is emerging as a valuable clinical tool for a variety of conditions. The aim of this pilot study was to assess the potential of SWE imaging of the common carotid arteries (CCA) in patients with spontaneous coronary artery dissection (SCAD), a rare but potentially life-threatening condition, hypothesized to be linked to changes in vessel wall elasticity. Methods Ultrasound shear wave elastography (SWE) estimates of artery wall elasticity were obtained from the left and right CCAs of 89 confirmed SCAD patients and 38 non-dissection controls. SWE images obtained over multiple cardiac cycles were analysed by a blinded observer to estimate elasticity in the form of a Young’s Modulus (YM) value, across regions of interest (ROI) located within the anterior and posterior CCA walls. Results YM estimates ranged from 17 to 133 kPa in SCAD patients compared to 34 to 87 kPa in non-dissection controls. The mean YM of 55 [standard deviation (SD): 21] kPa in SCAD patients was not significantly different to the mean of 57 [SD: 12] kPa in controls, p = 0.32. The difference between groups was 2 kPa [95% Confidence Interval − 11, 4]. Conclusions SWE imaging of CCAs in SCAD patients is feasible although the clinical benefit is limited by relatively high variability of YM values which may have contributed to our finding of no significant difference between SCAD patients and non-dissection controls.

Significant Stenosis of the Brachiocephalic Trunk and Moderate Stenosis of the Left Circumflex Artery in Computed Tomography Angiography Images

Atherosclerosis, as a civilization disease, is a serious epidemiological problem. Significant carotid disease and significant coronary artery disease result in acute consequences, such as ischemic stroke and myocardial infarction, which are the major causes of cardiovascular mortality. Typically, atherosclerosis of the aortic arch branches involves the bulbs of the common carotid arteries and the proximal segments of the internal carotid arteries, and can be effectively assessed by ultrasonography. Computed tomography angiography enables the identification of patients with less typical clinical manifestations of atherosclerosis, e.g., brachiocephalic trunk stenosis with symptoms of the steal syndrome and moderate stenosis in the coronary arteries. We present examples of computed tomography angiography images of this type of changes.

The content of ATP Synthase in Cerebral Ischemia of Varying Severity Comparative Analysis

Objective. Evaluation of changes in the content of ATP synthase in the parietal cortex and hippocampus of the brain of rats with ischemia of varying severity in a comparative aspect. Methods. The experiments were performed on 88 male outbred white rats weighing 260 ± 20 g. Brain ischemia was modeled under conditions of intravenous thiopental anesthesia (40-50 mg / kg). Total cerebral ischemia was modeled by decapitation of animals. The brain sampling was carried out 1 hour and 24 hours after decapitation - to study tissue respiration of mitochondria, as well as 1 hour later to determine the content of ATP synthase. Subtotal cerebral ischemia was modeled by simultaneous ligation of both common carotid arteries. The material was taken after 1 hour to determine the content of ATP synthase. Stepwise subtotal cerebral ischemia was performed by sequential ligation of both common carotid arteries with an interval of 7 days. The sampling was carried out 1 hour after ligation of the second common carotid artery in each of the subgroups. Partial cerebral ischemia was modeled by ligation of one common carotid artery on the right. The sampling was carried out 1 hour after the operation. Determination of the content of ATP synthase was carried out by immunohistochemical method using monoclonal antibodies. For this purpose, after decapitation, the brain was quickly removed from the rats, pieces of the cerebral cortex were fixed in zinc-ethanol-formaldehyde at + 4 ° C (overnight), then embeddedвinвparaffin. Results. In the group of stepwise subtotal cerebral ischemia, the smallest decrease in the content of ATP synthase was observed in the 1st subgroup with an interval between dressings of 7 days, while the greatest decrease in the content of the enzyme was noted in the 3rd subgroup with the minimum interval between the dressings of the common carotid artery (1 day). Modeling of more severe types of ischemic damage led to pronounced morphological changes in neurons in the parietal cortex and hippocampus of the rat brain - a decrease in their size, deformation of the perikarya, an increase in the degree of neuronal chromatophilia with their simultaneous wrinkling and subsequent death. These disorders were most pronounced in the 3rd subgroup of stepwise subtotal cerebral ischemia with the shortest interval between dressings, which was 1 day, and in the group of total cerebral ischemia. Conclusion. Thus, the most pronounced decrease in the content of ATP synthase was observed in the groups of total cerebral ischemia, subtotal cerebral ischemia and in the 3rd subgroup of stepwise subtotal cerebral ischemia, with a minimal time interval between the ligation of the common carotid artery. In stepwise subtotal cerebral ischemia with an interval between ligation of the common carotid artery of 7 days, the suppression of the ATP synthase content was not so significant.

Cerebrovascular Anatomy and Pathophysiology

The cerebrospinal vasculature originates at the aortic arch. The right brachiocephalic artery divides into the right common carotid artery and the right subclavian artery. The left common carotid and left subclavian arteries arise directly from the aortic arch. The 2 common carotid arteries bifurcate into the internal and external carotid arteries. The anterior circulation of the brain includes the distal branches from the internal carotid artery, including the anterior cerebral artery and the middle cerebral artery. The vertebral arteries arise from the subclavians and join at the pontomedullary junction, forming the basilar artery. The vertebrobasilar system and distal branches are commonly known as the posterior circulation of the brain.

Retrograde Carotid Stenting Using Newly Released Venous Stent for Cerebral Malperfusion in Type A Aortic Dissection

Stanford Type A aortic dissections (TAAD) should be considered for repair, given the involvement of branch vessels which can result in malperfusion, specifically cerebral malperfusion secondary to dissection of the innominate and carotid arteries. This is a case report with a focus on four patients presenting with both acute and chronic symptomatic TAAD, with extension into the innominate and common carotid arteries. In all four cases, the decision to intervene utilizing a hybrid endovascular approach was made to increase perfusion to the brain and alleviate symptoms. Through the use of retrograde carotid stenting utilizing both the VICI venous stent (Boston Scientific, Marlborough, MA) and Abre self-expanding Nitinol stent (Medtronic, Minneapolis, MN) we obtained good results, specifically absence of symptoms and return to normal function of the patients.

Potentiation of the protective effect of hypercapnic hypoxia in combination with pharmacological neuroprotective agents

Цель исследования - изучение возможности потенцирования нейропротекторного эффекта гиперкапнической гипоксии при помощи комбинации с фармакологическими активаторами основных механизмов, увеличивающих толерантность головного мозга к ишемии/гипоксии. Методика. Исследования проводились на 140 крысах-самцах Wistar, которые подвергались курсам респираторных воздействий гиперкапнической гипоксии (PO2 - 90 мм рт. ст.; PCO2 - 50 мм рт. ст.) в течении 5 сут по 30 мин ежедневно. После завершения курса тренировок крысам вводили фармакологические препараты (активатор аденозиновых рецепторов, блокатор карбоангидразы, активатор опиоидных рецепторов, блокатор ангиотензин-превращающего фермента) и через 24 ч производилась билатеральная окклюзия общих сонных артерий, а через 72 ч производился подсчет поврежденных/уцелевших клеток в СА1 регионе гиппокампа. Результаты. Морфологическая оценка выживаемости нейронов показала, что применение эналаприла усиливало нейропротекторный эффект гиперкапнической гипоксии, применение АТФ и даларгина не показало значимого прироста эффективности, а блокатор карбоангидразы ацетазоламид полностью устранял нейропротекторный эффект респираторных тренировок. Заключение. Выраженным потенцирующим эффектом на нейропротекцию, обусловленную респираторными тренировками с гиперкапнической гипоксией, обладает ее комбинация с ингибитором АПФ (эналаприлом). Aim. We studied the possibility of potentiating the neuroprotective effect of hypercapnic hypoxia using a combination with pharmacological activators of major mechanisms that increase the brain tolerance to ischemia/hypoxia. Methods. Studies were carried out on 140 male Wistar rats conditioned with respiratory hypercapnic hypoxia (PO2 - 90 mm Hg; PCO2 - 50 mm Hg) for 5 days, 30 min daily. After this exposure, the rats were injected with a drug (adenosine receptor activator (ATP), carbonic anhydrase blocker (acetazolamide), opioid receptor activator (dalargin), angiotensin converting enzyme (ACE) blocker (enalapril). 24 hrs later, the common carotid arteries were occluded bilaterally. 72 hrs after drug injection, the damaged/surviving cells in the CA1 region of the hippocampus were counted. Results. Morphological evaluation of neuronal survival showed that enalapril enhanced the neuroprotective effect of hypercapnic hypoxia. ATP and dalargin did not significantly increase this effect, and acetazolamide completely eliminated this neuroprotective effect. Conclusion. Thus, the neuroprotective effect of hypercapnic hypoxia conditioning was potentiated by its combination with an ACE inhibitor.

Edema-Swelling as a Standard Dose-Dependent Response of the Dentate Gyrus of the Hippocampal Formation to Acute Ischemia

The aim of research was to study structural changes and give a morphometric characteristic of the edemaswelling manifestations of the dentate gyrus (DG) of the hippocampal formation in sexually mature white rats after common carotid artery occlusion (OCCA) of different duration and ligation (LCCA) of the common carotid arteries.Material and methods. Acute ischemia was simulated in white adult Wistar rats by 20-, 30-, and 40-min occlusion and ligation of the common carotid arteries. Histological (staining with hematoxylin-eosin, according to Nissl), immunohistochemical (NSE, MAP-2, GFAP) and morphometric research techniques were used for morphological investigations. Morphometric analysis of the edema-swelling manifestations was carried out on samples stained with hematoxylin-eosin using plugins of the ImageJ 1.53 program (Find Maxima, Find Foci). Statistical hypotheses (nonparametric tests) were tested using Statistica 8.0 software.Results. After reperfusion, pronounced involution of large zones of edema-swelling occurred in the DG of the hippocampal formation in white rats of the groups I, II, III after 7–14 days, and in rats of the group IV (ligation) the edema-swelling manifestations persisted for 30 days. Similar dynamics was recorded for the molecular and polymorphic layer of the DG, but the values of the integral variable chosen to assess the edema-swelling manifestations (the total intensity of the peak pixels) were different. The largest relative area of the brightest peaks was detected after bilateral ОССА (groups II and III) and LCCA (group IV), the smallest – after unilateral ОССА (group I). It is significant that after mild ischemia (20- and 30-min ОССА), the parameter increased only in 1 and 3 days, and then decreased. After more severe ischemia (40-min ОССА), similar manifestations of overhydration were observed in 1–7 days. With LССА, a high level of DG overhydration was noted throughout the observation period, as evidenced by the high relative area of all the brightest peaks. Statistically significant differences were found when comparing all groups for all periods, between groups in 14 and 30 days, between periods in groups I, II, and III (ANOVA Kruskal–Wallis test; Mann–Whitney U-test).Conclusion. After ОССА and LССА the restoration of the structures of the sensory input of the hippocampus (DG) occurs together with long-term preservation of signs of hyperhydration of the neuropil, perineuronal and perivascular spaces (legs of astrocytes). The extreme degree of these manifestations after LССА evidences a disruption of the drainage-detoxification function of astrocytes. In ОССА, long-term preservation of the edema-swelling manifestations is recommended to be considered as a condition for the implementation of the mechanisms of sanogenesis and restoration of the DG nervous tissue.

The rostral epidural rete mirabile of the llama as a place of retrograde transport of various substances – anatomical basics

The aim of this study was to analyse the structure of the rostral epidural rete mirabile in the llama. Some specimens were prepared by injecting stained chemically cured acrylic into the bilateral common carotid arteries. After about 1 month received vascular corrosion casts on the bone scaffold. Some specimens made using red and blue latex introduced into the bilateral common carotid arteries and the bilateral external jugular vein. The rostral epidural rete mirabile is a well-developed, bilateral structure composed of numerous arteries, which are multiply anastomosed with each other. The cranial section of the rete is asymmetrical. Its lateral part is much better developed, because there are rostral branches to the rostral epidural rete mirabile at this point. The arterial vessels are not accompanied by homonymous veins. However, the arteries of the rostral epidural rete mirabile are accompanied by venous vessels of the cavernous sinus. That rete plays an important role in selective brain cooling, the conservation of body water, and retrograde transport of neurotransmitters. CO, GnRH, beta-endorphin, progesterone, testosterone, oxytocin, LHRH and dopamine diffuse from the venous blood of the cavernous sinus to the arterial blood of the rostral epidural rete mirabile.

Effect of Chronic Khat Chewing on Intima-Media Thickness of Common Carotid Arteries in Yemeni volunteers

Objective: To assess the changes occurring in both common carotid arteries (CCAs) intima-media thickness (IMT) in Yemeni chronic khat chewers using B-mode ultrasonography. Methods: This cross-sectional study was conducted among 195 participants (103 regular khat chewers and 92 non-khat chewers) conveniently selected at the Radiology Department of the University of Science and Technology Hospital (USTH) in Sana’a from August 2017 to August 2018. Data about gender, age, BMI, chewing khat and the period of chewing were collected from participants using a structured questionnaire. B-mode ultrasonography of bilateral CCAs was then performed to measure the IMT. Data were analyzed using suitable statistical tests, and P-values <0.05 were considered statistically significant. Results: The majority of participants with CCA-IMT were males (91.8%) and aged 27 years or younger (59.0%), with a mean age of 27.9 ± 6.8 years. Khat chewers constituted more than half of patients with CCA-IMT. There was no statistically significant difference in the mean values of RT CCA-IMT and LT CCA-IMT between khat chewers and non-khat chewers. The CCA-MIT was significantly higher among male khat chewers compared to male non-chewers (P = 0.004). However, there was no statistically significant difference between khat chewers and non-chewers with respect to the age of 20 years or older (P = 0.301) and BMI of 18.5 kg/m2 or higher (P = 0.888). Age showed a significant positive correlation with RT CCA-IMT (r = 0.380; P < 0.001) and LT CCA-IMT (r = 0.458; P < 0.001) in Khat chewers. In contrast, age showed a significant positive correlation with LT CCA-IMT only in non-khat chewers (r = 0.236; P = 0.024). On the other hand, BMI showed a significant positive correlation with LT CCA-IMT (r = 0.254; P = 0.010) among khat chewers, but no significant correlation was found in CCA-IMT of both sides among non-khat chewers. Among khat chewers, there was a significant positive correlation with RT CCA-IMT (r = 0.273; P = 0.005) and LT CCA-IMT(r = 0.194; P = 0.049). Conclusion: Khat chewing does not lead to a significant difference in CCA-IMT among Yemeni chewers compared to non-chewers. However, the period of chewing may slightly affect the CCA-IMT among khat chewers. Age has a significant positive correlation with CCA-IMT in khat chewers and LT CCA-MIT in non-khat chewers, which could help to determine the contribution of different predisposing factors to atherosclerosis. A significant positive correlation can be found between BMI and LT CCA-MIT among khat chewers. Keywords: Khat Chewing, Intima media thickness, Carotid, Yemen