Effect of cold weather on carotid artery stenosis and occlusion:A retrospective observational study

Objective:To investigate the effect of cold weather on carotid artery stenosis and occlusion.Methods:We conducted a retrospective observational study,in which 145 patients with carotid artery stenosis and occlusion were enrolled[115 men and 30 women;the mean age was 61.08 years(95%CI 59.27-62.88)].Patients were divided into the low-temperature group(n=98)(≤12℃)and the non-low temperature group(n=47)(>12℃).Clinical characteristics,blood pressure,National Institutes of Health Stroke Scale(NIHSS),blood fat,and blood viscositys were compared between the two groups.Correlation between NIHSS and mean daily temperature was analyzed.Results:There was no significant difference in the systolic and diastolic blood pressure between the two groups(P>0.05).The NIHSS score was slightly higher in the non-low temperature group compared to that of the low-temperature group(U=2984,P<0.01).Glycemia,cholesterol level,prothrombin time,fibrinogen,and International Normalized Ratio did not show any significant difference(P>0.05).Correlation analysis showed a very low positive and statistically significant correlation between ambient temperature and NIHSS score(r=0.18,P=0.029).Conclusion:Cold weather does not impact blood pressure,blood cholesterol,and coagulation factors of patients with carotid artery stenosis and occlusion.The neurological deficit is more severe in the non-low ambient temperature group.A potential relationship exists between ambient temperature and the level of neurological impairment.

Imaging characteristics and treatment strategies for carotid artery occlusion caused by skull base fracture:Three case reports

BACKGROUND Traumatic internal carotid artery(ICA)occlusion is a rare complication of skull base fractures,characterized by high mortality and disability rates,and poor prognosis.Therefore,timely discovery and correct management are crucial for saving the lives of such patients and improving their prognosis.This article retrospectively analyzed the imaging and clinical data of three patients,to explore the imaging characteristics and treatment strategies for carotid artery occlusion,combined with severe skull base fractures.CASE SUMMARY This case included three patients,all male,aged 21,63,and 16 years.They underwent plain film skull computed tomography(CT)examination at the onset of their illnesses,which revealed fractures at the bases of their skulls.Ultimately,these cases were definitively diagnosed through CT angiography(CTA)examinations.The first patient did not receive surgical treatment,only anticoagulation therapy,and recovered smoothly with no residual limb dysfunction(Case 1).The other two patients both developed intracranial hypertension and underwent decompressive craniectomy.One of these patients had high intracranial pressure and significant brain swelling postoperatively,leading the family to choose to take him home(Case 2).The other patient also underwent decompressive craniectomy and recovered well postoperatively with only mild limb motor dysfunction(Case 3).We retrieved literature from PubMed on skull base fractures causing ICA occlusion to determine the imaging characteristics and treatment strategies for this type of disease.CONCLUSION For patients with cranial trauma combined with skull base fractures,it is essential to complete a CTA examination as soon as possible,to screen for blunt cerebrovascular injury.

Morphological and functional observations of a novel model of retinal ischemia injury induced by bilateral carotid artery stenosis in mice

AIM:To investigate the features of retinal ischemic injuries in a novel mouse model with bilateral carotid artery stenosis(BCAS).METHODS:BCAS was induced with microcoil implantation in 6-8-week-old C57BL6 mice.Cerebral blood flow was monitored at 2,7,and 28d postoperatively.Retinal morphological changes were evaluated by fundus photography and hematoxylin-eosin staining.Fluorescein fundus angiography(FFA)was performed to detect retinal vascular changes and circulation.The levels of apoptosis,activation of neurogliosis,and expression of hypoxiainducible factor(HIF)-1αin the retina were assessed by Western blotting and immunofluorescence staining,followed by retinal ganglion cell(RGC)density detection.Additionally,electrophysiological examinations including photopic negative response(PhNR)was also performed.RESULTS:The mice demonstrated an initial rapid decrease in cerebral blood flow,followed by a 4-week recovery period after BCAS.The ratio of retinal artery and vein was decreased under fundus photography and FFA.Compared with the sham mice,BCAS mice showed thinner retinal thickness on day 28.Additionally,apoptosis was increased and RGC density was decreased mainly in peripheral retinal region.Neurogliosis was mainly located in the inner retinal layers,with a stable increase in HIF-1αexpression.The dark-adapted electroretinogram showed a notable reduction in the a-,b-,and oscillatory potential(OP)wave amplitudes between days 2 and 7;this gradually recovered over the following 4wk.However,the b-and OPwave amplitudes were still significantly decreased on PhNR examination on day 28.CONCLUSION:BCAS can result in relatively mild retinal ischemia injuries in mice,mainly in the inner layer and peripheral region.Our study provides a novel animal model for investigating retinal ischemic diseases.

Imaging characteristics and treatment strategies for carotid artery occlusion caused by skull base fracture

The internal carotid artery occlusion caused by head and neck trauma,also known as traumatic intracranial artery occlusion,is relatively rare clinically.Traumatic skull base fracture is a common complication of traumatic brain injury.Traumatic skull base fracture is one of the causes of traumatic internal carotid artery occlusion.If not detected early and treated in time,the prognosis of patients is poor.This editorial makes a relevant analysis of this disease.

Cerebral perfusion in patients with unilateral internal carotid artery occlusion by dual post-labeling delays arterial spin labeling imaging

BACKGROUND Global and regional cerebral blood flow(CBF)changes in patients with unilateral internal carotid artery occlusion(ICAO)are unclear when the dual post-labeling delays(PLD)arterial spin labeling(ASL)magnetic resonance imaging(MRI)technique is used.Manual delineation of regions of interest for CBF measurement is time-consuming and laborious.AIM To assess global and regional CBF changes in patients with unilateral ICAO with the ASL-MRI perfusion technique.METHODS Twenty hospitalized patients with ICAO and sex-and age-matched controls were included in the study.Regional CBF was measured by Dr.Brain's ASL software.The present study evaluated differences in global,middle cerebral artery(MCA)territory,anterior cerebral artery territory,and Alberta Stroke Program Early Computed Tomography Score(ASPECTS)regions(including the caudate nucleus,lentiform nucleus,insula ribbon,internal capsule,and M1-M6)and brain lobes(including frontal,parietal,temporal,and insular lobes)between ICAO patients and controls at PLD 1.5 s and PLD 2.5 s.RESULTS When comparing CBF between ICAO patients and controls,the global CBF in ICAO patients was lower at both PLD 1.5 s and PLD 2.5 s;the CBF on the occluded side was lower in 15 brain regions at PLD 1.5 s,and it was lower in 9 brain regions at PLD 2.5 s;the CBF in the contralateral hemisphere was lower in the caudate nucleus and internal capsule at PLD 1.5 s and in M6 at PLD 2.5 s.The global CBF in ICAO patients was lower at PLD 1.5 s than at PLD 2.5 s.The ipsilateral CBF at PLD 1.5 s was lower than that at PLD 2.5 s in 15 regions,whereas the contralateral CBF was lower at PLD 1.5 s than at PLD 2.5 s in 12 regions.The ipsilateral CBF was lower than the contralateral CBF in 15 regions at PLD 1.5 s,and in M6 at PLD 2.5 s.CONCLUSION Unilateral ICAO results in hypoperfusion in the global and MCA territories,especially in the ASPECTS area.Dual PLD settings prove more suitable for accurate CBF quantification in ICAO.

Relationship between syndrome elements and anterior communicating artery opening in patients with smptomatic severe carotid artery stenosis/occlusion

Objective To study the relationship between syndrome elements and anterior communicating artery(ACoA)opening in patients with symptomatic severe carotid artery stenosis/occlusion.Methods Thirty-six patients with symptomatic severe carotid stenosis/occlusion were collected,including 26 patients with cerebral infarction and 10 patients with transient ischemic attack(TIA).Syndrome elements at five time points were collected.Computer tomography angiography(CTA)combined with magenic resonance angiograp(MRA)was used to evaluate the primary collateral circulation,and the prognosis and syndrome elements were statistically analyzed according to whether the ACoA was open or not.Results The ACoA was open more in the primary collateral circulation among patients with symptomatic severe carotid stenosis/occlusion.There was a statistically significant difference in national institute of health stroke scale(NIHSS)score improvement and good prognosis[the modified rankin scale(mRS)≤2]between the ACoA open group and the ACoA nonopen group on the 90th day(P<0.05).The proportion of patients with internal wind syndrome,blood stasis syndrome,Qi deficiency syndrome,and Yin deficiency syndrome in the ACoA non-open group was higher than that in the open group.Conclusion In the patients with severe carotid artery stenosis/occlusion,the group with presence of anterior communicating artery had better prognosis.The syndrome elements are more complex in the group without the presence of anterior communicating artery.The proportion of Qi deficiency syndrome was positively correlated with the non-opening of anterior communicating artery.The imaging evaluation of collateral circulation can provide guidance for syndrome differentiation and treatment.

Carotid artery stenting versus carotid endarterectomy in the treatment of symptomatic and asymptomatic carotid stenosis: a systematic review and meta-analysis

Purpose: To evaluate the short-term and intermediate-to long-term efficacy and safety of carotid artery stenting(CAS) compared with carotid endarterectomy(CEA). Materials and Methods: The published literature was electronically searched for randomized controlled trials(RCTs) between CAS and CEA for the treatment of carotid stenosis performed from January 2000 to January 2017. The short-term and intermediate-to long-term outcomes were evaluated. Results: We identified 10 RCTs including 7,183 participants with symptomatic or asymptomatic carotid stenosis. Our meta-analysis found different results between the patients with and those without symptoms. In patients with symptomatic carotid stenosis, the total stroke incidence in the CAS group was significantly higher than that in the CEA group within the 30-day periprocedural period(p<0.001); however, the myocardial infarction incidence in the CAS group was significantly lower than that in the CEA group(p<0.05). There was no significant difference between the two groups in the mortality within 30 days post-procedure, but the intermediate-to long-term incidence of stroke or death in the CAS group was higher than that of the CEA group(p<0.05). In contrast, for asymptomatic patients, there were no significant differences between the CAS and CEA groups in the short-and intermediate-to long-term outcomes. Conclusion: For patients with symptomatic carotid stenosis, CEA is associated with an increased risk of myocardial infarction, whereas CAS is correlated with an increased risk of procedurally related strokes. However, for patients with asymptomatic carotid stenosis, no significant difference was found in the efficacy or safety between CAS and CEA.

Intravascular ultrasonography assisted carotid artery stenting for treatment of carotid stenosis: Two case reports

BACKGROUND Digital subtraction angiography(DSA),the gold standard of cerebrovascular disease diagnosis,is limited in its diagnostic ability to evaluate arterial diameter.Intravascular ultrasonography(IVUS)has advantages in assessing stenosis and plaque nature and improves the evaluation and effectiveness of carotid artery sten-ting(CAS).CASE SUMMARY Case 1:A 65-year-old man presented with a five-year history of bilateral lower limb weakness due to stroke.Physical examination showed decreased strength(5-/5)in both lower limbs.Carotid artery ultrasound,magnetic resonance angiography,and computed tomography angiography(CTA)showed a right proximal internal carotid artery(ICA)stenosis(70%-99%),acute cerebral infarction,and severe right ICA stenosis,respectively.We performed IVUS-assisted CAS to measure the stenosis and detected a low-risk plaque at the site of stenosis prior to stent implantation.Post-stent balloon dilatation was performed and postoperative IVUS demonstrated successful expansion and adherence.CTA six months postoperatively showed no significant increase in in-stent stenosis.Case 2:A 36-year-old man was admitted with a right common carotid artery(CCA)dissection detected by ultrasound.Physical examination showed no positive neurological signs.Carotid ultrasound and CTA showed lumen dilation in the proximal CCA with an intima-like structure and bulging in the proximal segment of the right CCA with strip-like low-density shadow(dissection or carotid web).IVUS-assisted DSA confirmed right CCA dissection.CAS was performed and intraoperative IVUS suggested a large residual false lumen.Post-stent balloon dilatation was performed reducing the false lumen.DSA three months postoperatively indicated good stent expansion with mild stenosis.CONCLUSION IVUS aids decision-making during CAS by accurately assessing carotid artery wall lesions and plaque nature preoperatively,dissection and stenosis morphology intraoperatively,and visualizing and confirming CAS postoperatively.

Recanalization of extracranial internal carotid artery occlusion A 12-year retrospective study

This study aimed to summarize therapy experience of carotid endarterectomy, carotid endarterec- tomy combined with Fogarty catheter embolectomy, and hybrid surgery for the treatment of extrac- ranial internal carotid artery occlusion. The study included 65 patients with extracranial internal ca- rotid artery occlusion who underwent carotid endarterectomy, carotid endarterectomy combined with Fogarty catheter embotectomy, or hybrid surgery in the Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China between January 2006 and December 2012. Prior to surgery, all patients underwent perfusion CT or xenon CT to evaluate the occlusion. The procedure for each patient was chosen according to digital subtraction angiography data. The carotid artery was successfully recanalized in 46 of 51 patients who underwent carotid endarterectomy, 9 of 10 patients who underwent carotid endarterectomy combined with Fogarty catheter embolectomy, and 3 of 4 patients who underwent hybrid surgery. In patients with symptomatic carotid artery occlusion, the carotid artery can be recanalized by choosing a treatment procedure based on imaging ex- amination findings.

An Integrated Analysis of Risk Factors of Cognitive Impairment in Patients with Severe Carotid Artery Stenosis

Objective To investigate cognitive dysfunction in patients with carotid artery stenosis(CAS) and potential risk factors related to cognitive-especially memory-dysfunction. Methods Forty-seven patients with carotid artery stenosis were recruited into our study cohort. The Mini-Mental State Examination(MMSE) and the Montreal Cognitive Assessment(MoCA) were adopted to assess cognitive function, the Wechsler Memory Scale(WMS) to assess memory function, high-resolution MRI and enhanced ultrasound to evaluate carotid plaques, and computed tomography perfusion(CTP) imaging to evaluate intracranial blood perfusion. Single-factor analysis and multiple-factor regression analysis were used to analyze potential risk factors of cognitive impairment. Results Mini-Mental State Examination test results showed that 22 patients had cognitive impairment, and MoCA test results showed that 10 patients had cognitive impairment. Analysis of various risk factors indicated that the average memory quotient of female patients was higher than that of males(P = 0.024). The cognitive and memory performance of those with an educational background above high school were significantly better than those of participants with high school or lower(P = 0.045). Patients with abnormal intracranial perfusion performed worse on the MMSE test(P = 0.024), and their WMS scores were significantly lower(P = 0.007). The MMSE scores and the memory quotients were significantly lower in patients with a history of cerebral infarction(MMSE, P = 0.047, memory quotient score, P = 0.018). Conclusion A history of cerebral infarction and abnormal cerebral perfusion are associated with decline in overall cognitive function and memory in patients with carotid stenosis. Being female and having an educational background above high school may be protective factors in the development of cognitive dysfunction.

Bilateral cerebral infarction in diabetic ketoacidosis and bilateral internal carotid artery occlusion:A case report and review of literature

BACKGROUND Diabetic ketoacidosis(DKA)is a serious complication of type 1 diabetes mellitus(T1DM).Very rarely does DKA lead to cerebral edema,and it is even rarer for it to result in cerebral infarction.Bilateral internal carotid artery occlusion(BICAO)is also rare and can cause fatal stroke.Moreover,case reports about acute cerebral infarction throughout both internal carotid arteries with simultaneous BICAO are very scarce.In this study,we present a patient with BICAO,T1DM,hypertension,and hyperlipidemia,who had a catastrophic bilateral cerebral infarction after a DKA episode.We briefly introduce BICAO and the mechanisms by which DKA results in cerebral infarction.CASE SUMMARY A 41-year-old woman presented with ischemic stroke that took place 3 mo prior over the left corona radiata,bilateral frontal lobe,and parietal lobe with right hemiplegia and Broca’s aphasia.She had a history of hypertension for 5 years,hyperlipidemia for 4 years,hyperthyroidism for 3 years,and T1DM for 31 years.The first brain magnetic resonance imaging not only revealed the aforementioned ischemic lesions but also bilateral internal carotid artery occlusion.She was admitted to our ward for rehabilitation due to prior stroke sequalae.DKA took place on hospital day 2.On hospital day 6,she had a new massive infarction over the bilateral anterior cerebral artery and middle cerebral artery territory.After weeks of aggressive treatment,she remained in a coma and on mechanical ventilation due to respiratory failure.After discussion with her family,compassionate extubation was performed on hospital day 29 and she died.CONCLUSION DKA can lead to cerebral infarction due to several mechanisms.In people with existing BICAO and several stroke risk factors such as hypertension, T1DM,hyperlipidemia, DKA has the potential to cause more serious ischemic strokes.

Primary balloon angioplasty for chronic occlusion of intracranial internal carotid artery: A case report

Chronic occlusion of large intracranial arteries is the main cause of ischemic stroke in China.Patients with symptomatic intracranial artery occlusion and hemodynamic impairment are at high risk of recurrent stroke.Chronic occlusion of the intracranial segment of the internal carotid artery is a common type of intracranial artery occlusion.Medical management is regarded as the standard treatment for this disease.With the development of endovascular treatment,some patients with chronic cerebral artery occlusion have achieved satisfactory results with endovascular therapy.We reported a patient with symptomatic chronic occlusion of the ophthalmic segment of the internal carotid artery.Simple balloon angioplasty was performed,and the occluded ophthalmic segment of the internal carotid artery was successfully recanalized without perioperative complications.At 4 months followup,the internal carotid artery remained patent and perfusion of the right cerebral hemisphere improved dramatically.In addition,we briefly reviewed the relevant literature.

Evaluation of the Protégé^(TM) stent in the treatment of carotid artery stenosis with adjunctive use of a filter Embolic Protection Device (PROCAR)-one-month follow-up data on 77 patients

Objective The trial was designed to evaluate the safety and performance of the ev3 Protégé TM stent in the treatment of de novo or re-stenotic common and/or internal carotid artery stenoses with adjunctive use of a CE-marked filter embolic protection device.Methods This study was a prospective multi-center, single-arm trial. Between June and October 2003, 77 patients were enrolled in 8 investigational centers throughout Europe. The primary endpoint was the incidence of Major Neurological Events (MANE) through one month. Other endpoints were the ability to properly place the stent, and primary patency and MANE after six months. Eligible for the study were patients with a de novo or restenotic target lesion located in the common and/or internal carotid artery (>70% stenosis for asymptomatic and >50% stenosis for symptomatic patients). The ev3 Spider (Embolic Protection Filter was used in 75 of 77 cases. Results In 76 out of the 77 patients (99%), the stent could be successfully implanted with a residual stenosis ≤30% as criterion. Of the 74 patients that had a carotid ultrasound at one month follow-up, none had a re-stenosis of the target lesion. There were three MANEs during or immediately after the procedure (3.9%), two were major and one was a minor stroke. There were eight severe complications (9.1%); six of these happened during or immediately after the procedure and were related to the procedure, none was related to the device. They are resolved without sequelae. No deaths have occurred.Conclusions The Protégé stent is safe and performs well in the treatment of carotid artery stenosis. The technical success rate for placement of the Protégé stent as assessed by the residual stenosis post implant was very high and all stents were successfully deployed. The incidence of MANE was comparable with that in other recent carotid stent studies and still lower than standard CEA.

EVALUATION OF THE BRAIN TOLERANCE TO CAROTID ARTERY OCCLUSION

Objective: To establish an objective criterion for assessing brain tolerance to carotid artery occlusion. Methods Endovascular trial balloon occlusion of carotid artery (TBO) in combination with single-photon emission computed tomography (SPECT), transcranial Doppler ultrasonography (TCD) and carotid artery stump pressure (SP) measurement was performed routinely for those patients who might have carotid artery manipulated or permanently occluded. Results Out of the 10 cases, one failed the TBO, though an angiographically adequate collateral circulation was observed. The patient’s SP and relative symmetry (rS) of SPECT imaging were 51mmHg and 86%. The remaining cases showed negative TBOs. After carotid occlusions, their mean velocity of ipsilateral middle cerebral artery decreased (16. 3 ± 6. 9 )%. The mean rS was (98. 0 ± 2. 4)% (92. 7% -101. 3% ). The mean SP was (64. 5 ± 13. 0)mmHg [(72. 3±11. 3)% of baseline, range 32-83mmHg. For one subject, the ICA was occluded spontaneously in the test. A reversal internal carotid artery (ICA ) flow was noted in 3 patients with balloon inflated in the common carotid artery (CCA ). When the CCA was occluded, the system blood pressure and heart rate increased apparently. However, this phenomenon did not occur when the ballon was inflated in the ICA. Conclusion With this TBO technique, clinically silent areas of decreased perfusion might be detected. We suggest it be a routine examination prior to carotid manipulations.

Correlating cognitive impairment with carotid atherosclerosis and carotid artery stenosis in patients with acute cerebral infarction

BACKGROUND：Studies have demonstrated that carotid atherosclerosis and carotid artery stenosis are closely associated with cognitive impairment in patients with and without clinically evident cerebrovascular disease. OBJECTIVE： To investigate the correlation between the degree of pathological changes in carotid atherosclerosis, carotid artery stenosis, and cognitive impairment in patients with acute cerebral infarction through the use of color Doppler imaging. DESIGN, TIME AND SETTING： The present concurrent, non-randomized, controlled experiment was performed at the Departments of Neurology and Ultrasound, Affiliated Hospital of North Sichuan Medical College between November 2006 and August 2007. PARTICIPANTS： Fifty-five patients with cerebral infarction, consisting of 35 males and 20 females, aged 50–82 years, were admitted to the hospital between November 2006 and August 2007 and recruited for this study. An additional 30 subjects consisting of 18 males and 12 females, aged 47–78 years, that concurrently received a health examination at the same hospital, were also included as normal controls. METHODS： Intima-media thickness （IMT）, plaque shape, size, and echo intensity of all subjects were detected by color Doppler flow imaging. Assessment criteria： IMT 〉 1.0 mm was considered to be intimal thickening, and IMT 〉 1.2 mm was determined to be formed atherosclerotic plaques. In the position of the largest plaque, the degree of carotid artery stenosis was determined by the following formula： （1-cross-sectional area of residual vascular luminal area/vascular cross-sectional area） × 100%. Less than 30% exhibited mild stenosis, 30%-40% moderate stenosis, and 〉 50% severe stenosis. MAIN OUTCOME MEASURES： IMT and the degree of carotid artery stenosis were evaluated by color Doppler flow imaging. The Mini-Mental State Examination （MMSE）, as well as the clinical memory scale, was compared between patients with cerebral infarction and normal controls. RESULTS： In the cerebral infarction group, IMT was increased, the degree of carotid artery stenosis was aggravated, and the MMSE and MQ scores of clinical memory scale were decreased. In particular, orientation of time and place, attention, calculation, and short-time memory were decreased. There were statistically significant differences in MMSE and MQ of clinical memory scale between patients with cerebral infarction and normal controls （P 〈 0.01）. The scores from the two scales were significantly lower in patients with cerebral infarction with carotid plaque subgroup compared to the cerebral infarction with no carotid plaque subgroup （P 〈 0.01）. The scores from the two scales were also significantly lower in patients with IMT 〉 1.0 mm, as well as moderate and severe carotid artery stenosis, compared to patients with IMT ≤ 1.0 mm, and normal and mild stenosis group （P 〈 0.05）. CONCLUSION： More severe atherosclerotic and carotid artery stenosis leads to more obvious cognitive impairment.

Effect of the Wall Thickness of the Vessel on FFRCT of Carotid Artery Stenosis

Fractional flow reserve(FFR)computed from computed tomography angiography(CTA),i.e.,FFRCT has been used in the clinic as a noninvasive parameter for functional assessment of coronary artery stenosis.It has also been suggested to be used in the assessment of carotid artery stenosis.The wall thickness of the vessel is an important parameter when establishing a fluid-structure coupling model of carotid stenosis.This work studies the effect of the vessel wall thickness on hemodynamic parameters such as FFRCT in carotid stenosis.Models of carotid stenosis are established based on CTA image data using computer-aided design software.It is assumed that the vessel wall is a linear elastic and isotropic material,and the blood an incompressible Newtonian fluid.Under the pulsating flow condition,ANSYS Transient Structural and CFX are used to simulate the blood flow of fluid-structure coupling in the carotid stenosis model in order to obtain hemodynamic parameters and the corresponding FFRCT.The results show that when the elastic modulus of the vessel wall is fixed,FFRCT will decrease with the increase of the wall thickness.Similarly,FFRCT will decrease with the increase of the elastic modulus when the wall thickness is fixed.The difference in hemodynamic parameters such as FFRCT,however,is relatively small if the stiffness of the two models are close.The results demonstrate that the effect of the vessel wall thickness,especially for a model with small elastic modulus,should be taken into account in using FFRCT for functional assessment of carotid stenosis.Moreover,under the linear elasticity and isotropic material assumptions,the stiffness coefficient may replace the elastic modulus and wall thickness as a parameter reflecting material property of the vessel wall in the carotid stenosis model.

Endovascular Therapy of Internal Carotid Artery Tandem Occlusions and Literature Review

Acute large vessel occlusion is a common cause of acute ischemic stroke (AIS), with high rates of disability and lethality. The incidence of tandem occlusion of the internal carotid artery accounts for about 20% of patients with large vessel occlusion of the anterior circulation in acute ischemic stroke. The low rate of recanalization by intravenous thrombolysis in AIS due to internal carotid artery tandem occlusion, the poor establishment of collateral circulation within a short time, and the complex pathogenesis often suggest a poor prognosis for patients. Mechanical thrombectomy (MT) is beneficial for the opening of intracranial large vessel occlusion with internal carotid artery tandem occlusion, there are many problems regarding the emergency management of carotid artery occlusion or stenosis after mechanical thrombectomy, and there are currently no standardized treatment recommendations;The sequential approach to the management of carotid tandem occlusion, the timing of carotid stenting, and the use of antiplatelet agents remain controversial. The current state of research on carotid tandem occlusion is analyzed in the literature to promote clinical understanding of endovascular treatment for patients with acute ischemic stroke due to carotid tandem occlusion.

Efficacy of Different Types of Self-expandable Stents in Carotid Artery Stenting for Carotid Bifurcation Stenosis

Both open and closed loop self-expandable stents were used in carotid artery stenting（CAS） for carotid bifurcation stenosis. We sought to compare the efficacy of two types of stents in CAS. The data of 212 patients treated with CAS（42 and 170 cases implanted with closed and open loop stents, respectively） for carotid bifurcation stenosis and distal filtration protection devices were retrospectively analyzed. Between closed and open loop stents, there were no significant differences in hospitalization duration, NIHSS score before and after the treatment, stenosis at 12 th month, and cumulative incidence of primary endpoint events within 30 days or from the 31 st day to the 12 th month; while there were significant differences in hemodynamic changes and rate of difficulty in recycling distal filtration protection devices. Use of open vs. closed loop stents for carotid bifurcation stenosis seems to be associated with similar incidence of complications, except for greater rate of hemodynamic changes and lower rate of difficulty in recycling the distal filtration protection devices.

PREDICTION OF THE BRAIN TOLERANCE TO CAROTID ARTERY OCCLUSION USING NONINVASIVE METHODS

Objective To predict the tolerance of the brain to carotid occlusion using noninvasive methods.Methods The peak(pV) and mean blood flow velocity(mV) of middle cerebral artery (MCA) and anterior cerebralartery (ACA) and pulsatility index (PI) were measured pre-and postoperatively with transcranial Dopplerultrasound diagnosis system(TCD) associated with the regional cerebral oxygen (rSO2) and somatosensory evokedpotentials (SSEPs) evaluation in 15 patients during manual compression, temporary occlusion and permanentocclusion Ol the carotid artery (CAO). Results There was no neurological delcit appearing during CAO in allthe cases. The mV of ipsilateral MCA and ACA reduced (31.79±13.59)% (12.58% ~56.16%) and reversed to 27.69±23.15cm/s and the rSO2 decreased (5.29±1.96)% (2%~9%). There was a linear correlation between percentchange in mV of ipsilateral MCA and rSO2 fall (P=0.0001). No more than 50% attenuation of SSEPs occurred inall the cases. The difference of PI in all recording time was not signilicant in our study. The pV was correlatedwith mV (P=0.0001). No variables were different significantly between compression and occlusion. Conclusion Afall in velocity by more than 70%, in rSO2 by more than 10% or in SSEPs amplitude by more than 50% iscompelling evidence for intolerance to CAO.

CAS and CEA in the Treatment of Severe Internal Carotid Artery Stenosis

Objective:To explore the clinical value of carotid artery stent implantation(CAS)and carotid endarterectomy(CEA)in the treatment of patients with severe internal carotid artery stenosis.Methods:88 patients with severe carotid artery stenosis who underwent CAS and CEA in the First People's Hospital of Changde City(hereafter referred as "our hospital")from January 2018 to December 2020 were selected as the research objects and divided into CAS group(n=43)and CEA group(n=45).To understand the clinical application value and feasibility of the two surgical schemes by comparing the general situation,cerebral blood flow,MMSE scale,MOCA scale score and serum miR-145,IGF1R levels of the two surgical schemes.Conclusions:CAS and CEA in the treatment of patients with severe internal carotid artery stenosis,have good curative effect,can effectively improve the patient's cerebral blood flow,regulate serum miR-145,IGF 1R levels,promote the recovery of cognitive function,but relatively speaking,the incidence of stroke and hypotension after CAS is higher,and the incidence of hypertension after CEA is higher.