Common Carotid Artery Blood Flow Research Articles

Impact of Suturing Techniques on Microvascular Anastomosis Maturation.

INTRODUCTION Microvascular anastomosis using interrupted suture is a widely accepted standard technique. Continuous suture is less common due to the presumption that its firmness can negatively affect anastomosis maturation. The purpose of this study was to determine whether the use of continuous suture allows maturation of the microanastomosis site. MATERIAL AND METHODS A rat common carotid artery (CCA) end-to-end microanastomosis model was utilized, with 19 Long-Evans rats in the interrupted sutures group and 13 in the continuous suture group. Immediate blood flow of the operated and contralateral intact CCAs was compared before clamping, at the completion of the anastomosis and after 14 days. Quantitative transit time flowmetry measurement and histological examination were employed. RESULTS Initial blood flow in both intact CCAs was similar across all animals (p = .004). In the interrupted suture group, median anastomosis blood flow was 88.9% of the contralateral CCA blod flow, with a median suture time of 46 minutes. After two weeks, blood flow increased to 96.1%. In the continuous suture group, median anastomosis blood flow was 88.3% of the contralateral CCA blood flow, with a median suture time of 30 minutes. After two weeks, blood flow increased to 100.0%. The reduction in suture time achieved with continuous suture was 34.8% (p < .001). Histological examination confirmed scar maturity. CONCLUSIONS The maturation rates of continuous and interrupted suture microanastomosis were comparable in our study, implying that concerns about the suture restricting maturation may be unwarranted. Additional finding is the potential for a reduction in microanastomosis time when using the continuous suture technique.

Sex-dependent impact of a short rest after lunch on hemodynamics as assessed by Doppler sonography.

Taking a short rest after lunch suppresses increases in blood flow to the digestive organs and maintains blood flow to the brain in the afternoon, possibly providing beneficial effects in preventing post-prandial drowsiness. The present study investigated sex-dependent influences on changes in hemodynamics produced by taking a short rest after lunch. Subjects comprised 20 healthy young adults (10 men, 10 women; mean age 21 ± 1years). Doppler sonography was performed to measure blood flow in the superior mesenteric artery (SMA) and common carotid artery (CCA) before and after lunch every hour on each day, with and without a 15-min rest with eyes closed after lunch. Blood pressure and heart rate (HR) were also measured. For both men and women, peak systolic velocity (PSV) in the SMA was suppressed by taking a rest. PSV in the CCA in men was increased at 0.5h after lunch in the resting condition but was decreased in the non-resting condition (median 109%, interquartile range [IQR] 102-120% vs. median 98%, IQR 90-107%; P = 0.037). No such differences were observed in women. Although post-prandial increases in HR were observed in women, a similar increase was only found for men in the resting condition. An increase in CCA blood flow was observed only in men. The present study suggests that a short rest after lunch could better promote the maintenance of blood flow to the brain in men than in women.

Carotid blood flow in abnormal head posture: a prospective observational study exploring facial asymmetry in strabismus

To investigate whether abnormal head posture (AHP) induces changes in common carotid artery blood flow (CCBF), thereby leading to the development of facial asymmetry in the setting of strabismus and ocular torticollis. This was a prospective observational study of pediatric subjects in an urban ophthalmology clinic who underwent bilateral carotid artery ultrasound examination with spectral Doppler in an upright, straight-head posture and with a head tilt of 30°-45° to the right and left. The primary outcome was change in carotid flow on the side of the head tilt. The secondary outcome was change in blood flow on the contralateral side of the head tilt. Seventeen subjects were enrolled, and 34 carotid arteries were assessed. There was no significant difference between upright, straight-head position and head tilt in ipsilateral (7.8 ± 1.8 mL/s vs 7.5 ± 2.0 mL/s [P = 0.4312]) or contralateral (7.8 ± 1.8 mL/s vs 8.1 ± 2.4 mL/s [P = 0.3401]) CCBF. CCBF does not fluctuate with AHP and thus does not appear to be the etiology for facial asymmetry in strabismus.

A novel needle mouse model of vascular cognitive impairment and dementia.

Bilateral common carotid artery (CCA) stenosis (BCAS) is a useful model to mimic vascular cognitive impairment and dementia (VCID). However, current BCAS models have the disadvantages of high cost and incompatibility with MRI scanning due to metal implantation. We have established a new low-cost VCID model that better mimics human VCID and is compatible with live-animal MRI. The right and the left CCAs were temporarily ligated to 32 and 34 gauge needles with three ligations, respectively. After needle removal, CCA blood flow, cerebral blood flow, white matter injury (WMI) and cognitive function were measured. In male mice, needle removal led to ∼49.8% and ∼28.2% blood flow recovery in the right and left CCA, respectively. This model caused persistent and long-term cerebral hypoperfusion in both hemispheres (more severe in the left hemisphere), and WMI and cognitive dysfunction in about 90% of mice, which is more reliable compared to other models. Importantly, these pathological changes and cognitive impairments lasted for up to 24 weeks after surgery. The survival rate over 24 weeks was 81.6%. Female mice showed similar cognitive dysfunction, but a higher survival rate (91.6%) and relatively milder white matter injury. A novel, low-cost VCID model compatible with live-animal MRI with long-term outcomes was established.Significance StatementBCAS is an animal model mimicking carotid artery stenosis to study VCID. However, current BCAS models cost high cost and is incompatibility with MRI scanning due to metal implantation. We established a new asymmetric BCAS model by ligating the common carotid artery to various needle gauges followed by an immediate needle removal. Needle removal led to moderate stenosis in the right CCA and severe stenosis in the left CCA. This needle model replicates the hallmarks of VCID well in about 90% of mice, which is more reliable compared to other models, has ultra-low cost, and is compatible with MRI scanning in live animals. It will provide a new valuable tool and offer new insights for VCID research.

Correlation of Common Carotid Artery Blood Flow Parameters With Transthoracic Echocardiographic Cardiac Output for Assessing Fluid Responsiveness After Passive Leg Raising (PLR) Test in Critically Ill Patients.

Introduction The passive leg raising (PLR) test is a simple, non-invasive method of knowing fluid responsiveness by acting as an internal-fluid challenge. The PLR test coupled with a non-invasive assessment of stroke volume would be the ideal method to assess fluid responsiveness. This study aimed to determine the correlation between transthoracic echocardiographic cardiac output (TTE-CO)and common carotid artery blood flow(CCABF) parameters in determining fluid responsiveness with the PLR test. Methods We performed a prospective observational study on 40 critically ill patients. Patients were evaluated with a 7-13 MHz linear transducer probe for CCABFparameters calculated using time-averaged mean velocity (TAmean) and with a 1-5 MHz cardiac probe equipped with tissue doppler imaging (TDI) for TTE-CO calculated using left ventricular outflow tract velocity time integral (LVOT VTI) with an apical five-chamber view. Two separate PLR tests (five minutes apart) were done within 48 hours of ICU admission. The first PLR test was to assess the effects on TTE-CO. The second PLR test was performed to assess the effects on CCABF parameters. Patients were designated as fluid responders (FR) if changes in TTE-CO (Δ TTE-CO) ≥ 10 %. Results A positive PLR test was observed in 33% of patients. A strong correlation was present between absolute values of TTE-CO calculated using LVOT VTI and the absolute values of CCABF calculated using TAmean (r=0.60, p<0.05). However, a weak correlation was found between Δ TTE-CO and changes in CCABF (Δ CCABF) during the PLR test (r=0.05, p<0.74). A positive PLR test response could not be detected by Δ CCABF (area under the curve (AUC): 0.59 ± 0.09). Conclusions We found a moderate correlation between TTE-CO and CCABF at baseline. However,Δ TTE-COhad a very poor correlation with Δ CCABF, during the PLR test. Considering this, CCABF parameters may not be recommended as a means to detect fluid responsiveness with PLR tests in critically ill patients.

Involvement of α- and β-Adrenergic Receptors in Skeletal Muscle Blood Flow Changes During Hyper-/Hypocapnia in Anesthetized Rabbits.

This study investigated the involvement of α1- and β2-adrenergic receptors in skeletal muscle blood flow changes during variations in ETCO2. Forty Japanese White rabbits anesthetized with isoflurane were randomly allocated to 1 of 5 groups: phentolamine, metaproterenol, phenylephrine, butoxamine, and atropine. Heart rate (HR), systolic blood pressure (SBP), common carotid artery blood flow (CCBF), masseter muscle tissue blood flow (MBF), and quadriceps muscle tissue blood flow (QBF) were recorded and analyzed at 3 periods: (1) baseline, (2) during hypercapnia (phentolamine and metaproterenol groups) or hypocapnia (phenylephrine, butoxamine, and atropine groups), and (3) during or after receiving vasoactive agents. MBF and QBF decreased during hypercapnia. The decrease in MBF was smaller than that in QBF. SBP and CCBF increased, while HR decreased. Both MBF and QBF recovered to their baseline levels after phentolamine administration. MBF became greater than its baseline level, while QBF did not fully recover after metaproterenol administration. MBF and QBF increased during hypocapnia. The increase rate in MBF was larger than that in QBF. HR, SBP, and CCBF did not change. Both MBF and QBF decreased to ∼90% to 95% of their baseline levels after phenylephrine or butoxamine administration. Atropine showed no effects on MBF and QBF. These results suggest the skeletal muscle blood flow changes observed during hypercapnia and hypocapnia may mainly involve α1-adrenergic but not β2-adrenergic receptor activity.

Color M-Mode Ultrasound to Assess Carotid Arteries: A Feasibility Study

Introduction: The gradual process of atherosclerosis involves both structural and functional changes that can accumulate over years and contribute to cardiovascular risk. We propose the use of color M-mode ultrasound to evaluate the distensibility of the carotid artery as a quantitative measurement of dynamic function that could evaluate age-related vascular change when considering atherosclerotic cardiovascular disease evaluation and risk. The aim of the study was to assess the feasibility of color M-mode ultrasound to evaluate age-related changes in the carotid arteries. Methods: Color M-mode ultrasound of the distal common carotid artery (CCA) with concurrent electrocardiogram tracing was performed on 62 adults (19 men and 43 women) in 3 age groups: young adult (20-44 years; n = 22), middle age (45-64 years; n = 20), and senior (≥65 years; n = 20). Color M-mode ultrasound images of the CCA were processed offline using ImageJ to quantify total, red, green, and blue (RGB) pixels in systole and diastole. The CCA distensibility was calculated by using the following equation: distensibility coefficient (DC) = (systolic − diastolic diameter)/(diastolic diameter × pulse pressure). The difference in ultrasound parameters among the 3 age groups was analyzed by one-way analysis of variance (ANOVA). Intraobserver and interobserver reliability of offline imaging processing was tested using intraclass correlation coefficient (ICC). Results: We observed a significant difference in CCA distensibility among the 3 age groups ( P &lt; .05). The interobserver reproducibility and intraobserver repeatability in performing offline image processing were excellent (ICC &gt;0.85). Conclusion: These findings suggest that color M-mode ultrasound is feasible in evaluating changes in CCA distensibility and systolic pixel values representing CCA blood flow significantly decreased in seniors.

Leg Fidgeting Improves Executive Function following Prolonged Sitting with a Typical Western Meal: A Randomized, Controlled Cross-Over Trial.

Prolonged uninterrupted sitting and a typical Western meal, high in fat and refined sugar, can additively impair cognitive and cerebrovascular functions. However, it is unknown whether interrupting these behaviours, with a simple desk-based activity, can attenuate the impairment. The aim of this study was to determine whether regular leg fidgeting can off-set the detrimental effects of prolonged sitting following the consumption of a typical Western meal, on executive and cerebrovascular function. Using a randomized cross-over design, 13 healthy males consumed a Western meal and completed 180-min of prolonged sitting with leg fidgeting of 1 min on/4 min off (intervention [INT]) and without (control [CON]). Cognitive function was assessed pre and post sitting using the Trail Maker Test (TMT) parts A and B. Common carotid artery (CCA) blood flow, as an index of brain flow, was measured pre and post, and cerebral (FP1) perfusion was measured continuously. For TMT B the CON trial significantly increased (worsened) completion time (mean difference [MD] = 5.2 s, d = 0.38), the number of errors (MD = 3.33, d = 0.68) and cognitive fatigue (MD = 0.73, d = 0.92). Compared to CON, the INT trial significantly improved completion time (MD = 2.3 s, d = 0.97), and prevented declines in cognitive fatigue and a reduction in the number of errors. No significant changes in cerebral perfusion or CCA blood flow were found. Leg fidgeting for 1-min on/4-min off following a meal high in fats and refined sugars attenuated the impairment in executive function. This attenuation in executive function may not be caused by alterations in CCA blood flow or cerebral perfusion.

Carotid Artery Blood Flow Changes Associated with Head Positioning in Patients Undergoing Thyroidectomy.

Background and Aims:There are possibilities of insufficiency in blood flow through carotid arteries during head positioning in thyroid surgeries under general anesthesia which is usually compensated by collateral circulation in normal conditions. This compensation may be hampered in patients with congenital abnormalities or diseases such as atherosclerosis. We aimed to elucidate the changes in common carotid artery blood flow related to head positioning during thyroid surgery by Doppler examination.Methods:In this observational prospective study, Doppler examination of both common carotid arteries including arterial diameter, peak systolic velocity, average velocity, and blood flow volume of forty patients who had undergone elective thyroidectomy under endotracheal anesthesia was done. Three sets of data (baseline, after induction, and after surgery) were collected and analyzed.Results:There was a significant reduction in the diameter (P = 0.002) and the blood flow (P = 0.0001) in both carotid arteries and an increase in peak and mean velocity which was more pronounced immediately after head positioning and persisted till the end of the procedure. There was no correlation between the hemodynamic parameters with the carotid artery diameter, blood flow, and velocity.Conclusions:The head-and-neck positioning during thyroidectomy surgery reduces the blood flow through the carotid arteries which continued till the end of the procedure.

Effect of increased positive end-expiratory pressure on intracranial pressure and cerebral oxygenation: impact of respiratory mechanics and hypovolemia

BackgroundTo evaluate the impact of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) in animals with different respiratory mechanics, baseline ICP and volume status.MethodsA total of 50 male adult Bama miniature pigs were involved in four different protocols (n = 20, 12, 12, and 6, respectively). Under the monitoring of ICP, brain tissue oxygen tension and hemodynamical parameters, PEEP was applied in increments of 5 cm H2O from 5 to 25 cm H2O. Measurements were taken in pigs with normal ICP and normovolemia (Series I), or with intracranial hypertension (via inflating intracranial balloon catheter) and normovolemia (Series II), or with intracranial hypertension and hypovolemia (via exsanguination) (Series III). Pigs randomized to the control group received only hydrochloride instillation while the intervention group received additional chest wall strapping. Common carotid arterial blood flow before and after exsanguination at each PEEP level was measured in pigs with intracranial hypertension and chest wall strapping (Series IV).ResultsICP was elevated by increased PEEP in both normal ICP and intracranial hypertension conditions in animals with normal blood volume, while resulted in decreased ICP with PEEP increments in animals with hypovolemia. Increasing PEEP resulted in a decrease in brain tissue oxygen tension in both normovolemic and hypovolemic conditions. The impacts of PEEP on hemodynamical parameters, ICP and brain tissue oxygen tension became more evident with increased chest wall elastance. Compare to normovolemic condition, common carotid arterial blood flow was further lowered when PEEP was raised in the condition of hypovolemia.ConclusionsThe impacts of PEEP on ICP and cerebral oxygenation are determined by both volume status and respiratory mechanics. Potential conditions that may increase chest wall elastance should also be ruled out to avoid the deleterious effects of PEEP.

Neurological Deficit and Corrective Effect of Omega-3 Polyunsaturated Fatty Acids in Cerebral Ischemia in Rats: A case-control study

Objectives: It was to assess vasoprotective effects of ω-3 polyunsaturated fatty acids in cerebral ischemia. Materials and methods: The experiments were carried out on 42 male outbred white rats weighing 260 ± 20 g. modeling of cerebral ischemia was carried out under conditions of intravenous thiopental anesthesia (40-50 mg / kg). The studies used models of subtotal, partial and stepwise subtotal cerebral ischemia. The table shows the experimental groups and the number of animals in them. Subtotal cerebral ischemia (SCI) was modeled by simultaneous ligation of both common carotid arteries (CCA). Partial cerebral ischemia (PCI) was modeled by ligating one CCA on the right. Stepwise subtotal CI (SSCI) was performed by sequential ligation of both CCA with an interval of 1 day (subgroup 1), 3 days (subgroup 2), or 7 days (subgroup 3). To study the effects of omega-3 polyunsaturated fatty acids (ω-3 PUFA), animals with CI were injected intragastrically with the drug "Omegamed" (SCI+ω-3 PUFA) at a dose of 5 g / kg body weight for a week. The control group consisted of sham-operated rats of the same sex and weight. Neurological deficits were assessed in the "muscle strength", "swimming test" and "open field" tests after 5-6 hours of the ischemic period. The study was carried out 6 hours after the simulation of the CI. Quantitative continuous data were obtained, which were processed using the licensed computer program Statistica 10.0 for Windows (StatSoft, Inc., USA). Since the experiment used small samples that had an abnormal distribution, the analysis was carried out by methods of nonparametric statistics. Data are presented as Me (LQ; UQ), where Me is the median, LQ is the value of the lower quartile; UQ is the upper quartile value. Differences between groups were considered significant at p &lt;0.05 (Regression Model). Results: With a stepwise bilateral ligation of both common carotid arteries with an interval of 1 day, neurological disorders were most pronounced, which indicates an aggravation of neurological deficit with a reduction in the time between CCA dressings. In rats with SCI, the changes were more pronounced than with PCI, but less than with SCI. The least pronounced changes were noted in the 3rd subgroup (the interval between CCA dressings was 7 days). Studies have shown the dependence of the severity of brain damage in SSCI on the interval between the cessation of blood flow in both CCA. At a 7-day interval between CCA dressings, compensatory mechanisms were activated, which prevented the development of morphological changes and neurological deficits. When CCA was ligated with an interval of 1 day, the degree of neurological deficit was maximal, which indicates insufficient implementation of compensatory mechanisms. Compared with the control group, the rats of the "SCI+ω3-PUFA" group retained neurological deficit, the muscle strength indicator was 86% less (p&lt;0.05), the swimming duration - by 63% (p&lt;0.05), the number of crossed squares - by 55% (p&lt;0.05), the number of washes - by 62% (p&lt;0.05), the number of racks - by 62.5% (p&lt;0.05) and the number of bowel movements - by 60% (p&lt;0.05). However, in comparison with the SCI group, the neurological deficit was less pronounced. There was an increase in muscle strength by 67% (p&lt;0.05), swimming duration by 37.5% (p&lt;0.05) and the number of squares crossed in the open field test by 31% (p&lt;0.05), which indicates the presence of a corrective action in the ω-3 polyunsaturated fatty acids preparation. Conclusion: The introduction of the preparation of ω-3 polyunsaturated fatty acids has a corrective effect in conditions of subtotal cerebral ischemia, contributing to a lesser severity of manifestations of neurological deficit (an increase in muscle strength, duration of swimming and the number of squares crossed in the open field test).

EVALUATION OF NEUROLOGICAL DEFICIENCY IN RATS WITH CEREBRAL ISCHEMIA AND ADMINISTRATION OMEGA-3 POLYUNSATURATED FATTY ACIDS

Objectives. It was to assess the degree of neurological deficit in rats with cerebral ischemia and administration of omega-3 polyunsaturated fatty acids. Methods. The experiments were carried out on 42 male outbred white rats weighing 260 ± 20 g. Modeling of cerebral ischemia was carried out under conditions of intravenous thiopental anesthesia (40-50 mg / kg). The studies used models of subtotal, partial and stepwise subtotal cerebral ischemia. The table shows the experimental groups and the number of animals in them. Subtotal cerebral ischemia (SCI) was modeled by simultaneous ligation of both common carotid arteries (CCA). Partial cerebral ischemia (PCI) was modeled by ligating one CCA on the right. Stepwise subtotal CI (SSCI) was performed by sequential ligation of both CCA with an interval of 1 day (subgroup 1), 3 days (subgroup 2), or 7 days (subgroup 3). To study the effects of omega-3 polyunsaturated fatty acids (ω-3 PUFA), animals with CI were injected intragastrically with the drug "Omegamed" (SCI+ω-3 PUFA) at a dose of 5 g / kg body weight for a week. The control group consisted of sham-operated rats of the same sex and weight. Neurological deficits were assessed in the "muscle strength", "swimming test" and "open field" tests after 5-6 hours of the ischemic period. Results. With a stepwise bilateral ligation of both common carotid arteries with an interval of 1 day, neurological disorders were most pronounced, which indicates an aggravation of neurological deficit with a reduction in the time between CCA dressings. In rats with SCI, the changes were more pronounced than with PCI, but less than with SCI. The least pronounced changes were noted in the 3rd subgroup (the interval between CCA dressings was 7 days). Studies have shown the dependence of the severity of brain damage in SSCI on the interval between the cessation of blood flow in both CCA. At a 7-day interval between CCA dressings, compensatory mechanisms were activated, which prevented the development of morphological changes and neurological deficits. When CCA was ligated with an interval of 1 day, the degree of neurological deficit was maximal, which indicates insufficient implementation of compensatory mechanisms. Compared with the control group, the rats of the "SCI+ω3-PUFA" group retained neurological deficit, the muscle strength indicator was 86% less (p&lt;0.05), the swimming duration - by 63% (p&lt;0.05), the number of crossed squares - by 55% (p&lt;0.05), the number of washes - by 62% (p&lt;0.05), the number of racks - by 62.5% (p&lt;0.05) and the number of bowel movements - by 60% (p&lt;0.05). However, in comparison with the SCI group, the neurological deficit was less pronounced. There was an increase in muscle strength by 67% (p&lt;0.05), swimming duration by 37.5% (p&lt;0.05) and the number of squares crossed in the open field test by 31% (p&lt;0.05), which indicates the presence of a corrective action in the ω3-PUFA preparation. Conclusion. The introduction of the preparation of ω-3 polyunsaturated fatty acids has a corrective effect in conditions of subtotal cerebral ischemia, contributing to a lesser severity of manifestations of neurological deficit (an increase in muscle strength, duration of swimming and the number of squares crossed in the open field test). Key words: cerebral ischemia, rats, neurological deficiency, omega-3 polyunsaturated fatty acids.

Vasoprotective Effects of Omega-3 Polyunsaturated Fatty Acids in Cerebral Ischemia

Objective: It was to assess vasoprotective effects of ω-3 polyunsaturated fatty acids in cerebral ischemia. Methods: The experiments were carried out on 42 male outbred white rats weighing 260 ± 20 g. Modeling of cerebral ischemia was carried out under conditions of intravenous thiopental anesthesia (40-50 mg/kg). The studies used models of subtotal, partial and stepwise subtotal cerebral ischemia. The table shows the experimental groups and the number of animals in them. Subtotal cerebral ischemia (SCI) was modeled by simultaneous ligation of both common carotid arteries (CCA). Partial cerebral ischemia (PCI) was modeled by ligating one CCA on the right. Stepwise subtotal CI (SSCI) was performed by sequential ligation of both CCA with an interval of 1 day (subgroup 1), 3 days (subgroup 2), or 7 days (subgroup 3). To study the effects of omega-3 polyunsaturated fatty acids (ω-3 PUFA), animals with CI were injected intragastrically with the drug “Omegamed” (SCI+ω-3 PUFA) at a dose of 5g/kg body weight for a week. The control group consisted of sham-operated rats of the same sex and weight. Neurological deficits were assessed in the “muscle strength”, “swimming test” and “open field” tests after 5-6 hours of the ischemic period. Results: With a stepwise bilateral ligation of both common carotid arteries with an interval of 1 day, neurological disorders were most pronounced, which indicates an aggravation of neurological deficit with a reduction in the time between CCA dressings. In rats with SCI, the changes were more pronounced than with PCI, but less than with SCI. The least pronounced changes were noted in the 3rd subgroup (the interval between CCA dressings was 7 days). Studies have shown the dependence of the severity of brain damage in SSCI on the interval between the cessation of blood flow in both CCA. At a 7-day interval between CCA dressings, compensatory mechanisms were activated, which prevented the development of morphological changes and neurological deficits. When CCA was ligated with an interval of 1 day, the degree of neurological deficit was maximal, which indicates insufficient implementation of compensatory mechanisms. Compared with the control group, the rats of the “SCI+ω3-PUFA” group retained neurological deficit, the muscle strength indicator was 86% less (p&lt;0.05), the swimming duration - by 63% (p&lt;0.05), the number of crossed squares - by 55% (p&lt;0.05), the number of washes - by 62% (p&lt;0.05), the number of racks - by 62.5% (p&lt;0.05) and the number of bowel movements - by 60% (p&lt;0.05). However, in comparison with the SCI group, the neurological deficit was less pronounced. There was an increase in muscle strength by 67% (p&lt;0.05), swimming duration by 37.5% (p&lt;0.05) and the number of squares crossed in the open field test by 31% (p&lt;0.05), which indicates the presence of a corrective action in the ω-3 polyunsaturated fatty acids preparation. Conclusion The introduction of the preparation of ω-3 polyunsaturated fatty acids has a corrective effect in conditions of subtotal cerebral ischemia, contributing to a lesser severity of manifestations of neurological deficit (an increase in muscle strength, duration of swimming and the number of squares crossed in the open field test).

Hemodynamic Responses in Carotid Bifurcation Induced by Enhanced External Counterpulsation Stimulation in Healthy Controls and Patients With Neurological Disorders.

Enhanced external counterpulsation is a Food and Drug Administration–approved, non-invasive, assisted circulation therapy for ischemic cardiovascular and cerebrovascular diseases. Previous studies have confirmed that EECP stimulation induces largely different cerebral hemodynamic responses in patients with ischemic stroke and healthy controls. However, the underlying mechanisms remain uncertain. We hypothesize that different blood redistributions at the carotid bifurcation may play a key role. Ten subjects were enrolled in this study, namely, five patients with neurological disorders and five young healthy volunteers as controls. Magnetic resonance angiography (MRA) was performed on the carotid artery. All the subjects received a single session of EECP treatment, with external cuff pressures ranging from 20 to 40 kPa. Vascular ultrasound measurements were taken in the common carotid artery (CCA), external carotid artery (ECA) and internal carotid artery (ICA). Three-dimensional patient-specific numerical models were developed to calculate the WSS-derived hemodynamic factors. The results indicated that EECP increased CCA and ECA blood flow in both groups. The ICA blood flow in the patient group exhibited a mean increase of 6.67% during EECP treatment compared with the pre-EECP condition; a mean decrease of 9.2% was observed in the healthy control group. EECP increased the averaged wall shear stress (AWSS) throughout the carotid bifurcation in the patient group; the ICA AWSS of the healthy group decreased during EECP. In both groups, the oscillatory shear index (OSI) in the ICA increased proportionally with external cuff pressure. In addition, the relative resident time (RRT) was constant or slightly decreased in the CCA and ECA in both groups but increased in the ICA. We suggest that the benefits of EECP to patients with neurological disorders may partly result from blood flow promotion in the ICA and increase in WSS at the carotid bifurcation. In the healthy subjects, the ICA blood flow remained constant during EECP, although the CCA blood flow increased significantly. A relatively low external cuff pressure (20 kPa) is recommended as the optimal treatment pressure for better hemodynamic effects. This study may play an important role in the translation of physiological benefits of EECP treatment in populations with or without neurological disorders.

Open or closed: Changes in ductus arteriosus flow patterns at birth using 4D flow MRI in newborn piglets.

The ductus arteriosus (DA) functionally closes during the transition from fetal to postnatal life because of lung aeration and corresponding cardiovascular changes. The thorough and explicit measurement and visualization of the right and left heart output during this transition has not been previously accomplished. We combined 4D flow MRI (dynamic volumetric blood flow measurements) and T2 relaxometry (oxygen delivery quantification) in surgically instrumented newborn piglets to assess the DA. This was performed in Large White‐Landrace‐Duroc piglets (n = 34) spanning four age groups: term‐9 days, term‐3, term+1, and term+5. Subject's DA status was classified using 4D flow: closed DA, forward DA flow, reversed DA flow, and bidirectional DA flow. Over all states, vessel diameters and flows normalized to body weight increased with age (for example in the ascending aorta flow—term‐9: 126.6 ± 45.4; term+5: 260.2 ± 80.0 ml/min per kg; p = 0.0005; ascending aorta diameter—term‐9: 5.2 ± 0.8; term+5: 7.7 ± 0.4 mm; p = 0.0004). In subjects with reversed DA blood flow there was lower common carotid artery blood flow (forward: 37.5 ± 9.0; reversed: 20.0 ± 7.4 ml/min per kg; p = 0.032). Linear regression revealed that as net DA flow decreases, common carotid artery flow decreases (R2 = 0.32, p = 0.004), and left (R2 = 0.33, p = 0.003) and right (R2 = 0.34, p = 0.003) pulmonary artery flow increases. Bidirectional DA blood flow changed oxygen saturation as determined by MRI between the ascending and descending aorta (ascending aorta: 90.1% ± 8.4%; descending aorta: 75.6% ± 14.2%; p < 0.05). Expanded use of these techniques in preterm animal models will aid in providing new understandings of normal versus abnormal DA transition, as well as to test the effectiveness of related clinical interventions.

The effect of norepinephrine on common carotid artery blood flow in septic shock patients

This study was designed to evaluate the hemodynamic effect of norepinephrine (NE) on the peak systolic velocity (PSV), diameter, and blood flow of the common carotid artery (CCA) using the point-of-care ultrasound (POCUS) in patients with septic shock. The study involved patients above 18 years old with septic shock. Arterial monitoring, carotid ultrasonography, and transthoracic echocardiography were performed before NE administration (T0). When the mean arterial pressure exceeded 65 mmHg after NE administration (T1), the measurement was repeated. Twenty-four patients (median age 67 [interquartile range: 54–77] years; 42% female) with septic shock were examined in this study. Before (T0) and after (T1) NE administration, the PSV (mean, standard deviation [SD]) changed from 85.3 (21.1) cm/s to 83.5 (23.5) cm/s (p = 0.417); this change was not significant. However, the diameter and blood flow of the CCA increased significantly from 0.6 (0.09) cm and 0.75 (0.27) L/min to 0.66 (0.09) cm and 0.85 (0.27) L/min, respectively (p < 0.001). The diameter of the left ventricular outflow tract (LVOT) remained unchanged, but the velocity time integral of the LVOT increased significantly from 21.7 (4.39) cm to 23.6 (5.14) cm. There was no significant correlation between changes in blood flow of the CCA and changes in cardiac output (coefficient −0.365, p = 0.079). In conclusion, NE increased the diameter and blood flow of the CCA significantly, without changing the PSV in patients with septic shock.

The association between carotid blood flow and resting-state brain activity in patients with cerebrovascular diseases

Cerebral hypoperfusion impairs brain activity and leads to cognitive impairment. Left and right common carotid arteries (CCA) are the major source of cerebral blood supply. It remains unclear whether blood flow in both CCA contributes equally to brain activity. Here, CCA blood flow was evaluated using ultrasonography in 23 patients with cerebrovascular diseases. Resting-state brain activity and cognitive status were also assessed using magnetoencephalography and a cognitive subscale of the Functional Independence Measure, respectively, to explore the relationships between blood flow, functional brain activity, and cognitive status. Our findings indicated that there was an association between blood flow and resting-state brain activity, and between resting-state brain activity and cognitive status. However, blood flow was not significantly associated with cognitive status directly. Furthermore, blood velocity in the right CCA correlated with resting-state brain activity, but not with the resistance index. In contrast, the resistance index in the left CCA correlated with resting-state brain activity, but not with blood velocity. Our findings suggest that hypoperfusion is important in the right CCA, whereas cerebral microcirculation is important in the left CCA for brain activity. Hence, this asymmetry should be considered when designing appropriate therapeutic strategies.

Common carotid artery blood flow volume in extremely preterm infants.

The aim of this study was to determine carotid blood flow volume, a surrogate for cerebral blood flow, using Doppler ultrasound in extremely preterm infants. In infants <29weeks, right common carotid artery flow volume (RCCAF) was calculated from vessel diameter and intensity-weighted mean velocity measured using Doppler ultrasound on days 1 and 3. In addition, left ventricular output (LVO), ductus arteriosus characteristics and invasive mean arterial blood pressure (MABP) were obtained. Sixty infants with mean gestation of 25.8weeks were studied. The median RCCAF increased from 12 (IQR 9-15) mL/kg/min on day 1, to 14 (IQR 12-18) mL/kg/min on day 3 (p=0.007). RCCAF was positively correlated with invasive MABP on days 1 and 3. RCCAF significantly correlated with LVO in infants with closing or closed ductus arteriosus on day 1. Using multiple regression analysis, RCCAF was significantly associated with invasive MABP on day 1 and to inotropic treatment on day 3. Doppler ultrasound can be used to measure RCCAF in extremely preterm infants receiving intensive care. RCCAF increased during the first three days and was positively related to invasive MABP on day 1. Values were lower than previously described in more mature infants. ISRCTN 83507686.

Remifentanil infusion during desflurane anesthesia reduces tissue blood flow while maintaining blood pressure and tissue oxygen tension in the masseter muscle and mandibular bone marrow.

The aim of this study was to compare changes in tissue blood flow and tissue oxygen tension in the masseter muscle and mandibular bone marrow induced by remifentanil under desflurane or sevoflurane anesthesia. Eleven male tracheotomized Japan White rabbits were anesthetized with desflurane or sevoflurane under mechanical ventilation. The order of the inhalation of desflurane or sevoflurane was randomized. Desflurane or sevoflurane was administered at 1.0 minimum alveolar concentration and remifentanil was infused at 0.4 µg/kg/min. Observed variables included heart rate (HR), blood pressure (BP), common carotid artery blood flow (CCBF), mandibular bone marrow tissue blood flow (BBF), masseter muscle tissue blood flow (MBF), mandibular bone marrow tissue oxygen tension (PbO2), and masseter muscle tissue oxygen tension (PmO2). Two way repeated measures ANOVA showed no interaction between volatile anesthetics and remifentanil infusion except for MBF. There were significant differences in HR, SBP, DBP, MAP and CCBF between desflurane and sevoflurane groups. There were also significant differences in HR, SBP, DBP, MAP, CCBF, BBF and PbO2 before, during and after remifentanil infusion. Desflurane reduced tissue blood flow in the masseter muscle and mandibular bone marrow while better maintained HR and BP than sevoflurane. Under remifentanil infusion, although both anesthetics reduced tissue blood flow, tissue oxygen tension was maintained in masseter muscle and mandibular bone marrow.

Role of the Carotid Body in an Ovine Model of Renovascular Hypertension.

The carotid body is implicated as an important mediator and potential treatment target for hypertension. The mechanisms driving increased carotid body tonicity in hypertension are incompletely understood. Using a large preclinical animal model, which is crucial for translation, we hypothesized that carotid sinus nerve denervation would chronically decrease blood pressure in a renovascular ovine model of hypertension in which hypertonicity of the carotid body is associated with reduced common carotid artery blood flow. Adult ewes underwent either unilateral renal artery clipping or sham surgery. Two weeks later, flow probes were placed around the contralateral renal and common carotid arteries. Hypertension was accompanied by a significant reduction in common carotid blood flow but no change in renal blood flow. Carotid sinus nerve denervation significantly reduced blood pressure compared with sham. In both hypertensive and normotensive animals, carotid body stimulation using potassium cyanide caused dose-dependent increases in mean arterial pressure and common carotid conductance but a reduction in renal vascular conductance. These responses were not different between the animal groups. Taken together, our findings indicate that (1) the carotid body is activated in renovascular hypertension, and this is associated with reduced blood flow (decreased vascular conductance) in the common carotid artery and (2) the carotid body can differentially regulate blood flow to the common carotid and renal arteries. We suggest that in the ovine renovascular model, carotid body hypertonicity may be a product of reduced common carotid artery blood flow and plays an amplifying role with the kidney in the development of hypertension.