Regional dynamic cerebral autoregulation across anterior and posterior circulatory territories:A detailed exploration and its clinical implications

Cerebral autoregulation(CA)is the mechanism that maintains stable cerebral blood flow(CBF)despite fluctuations in systemic blood pressure,crucial for brain homeostasis.Recent evidence highlights distinct regional variations in CA between the anterior(carotid)and posterior(vertebrobasilar)circulations.Noninvasive neuromonitoring techniques,such as transcranial Doppler,transfer function analysis,and near-infrared spectroscopy,facilitate the dynamic assessment of CBF and autoregulation.Studies indicate a robust autoregulatory capacity in the anterior circulation,characterized by rapid adjustments in vascular resistance.On the contrary,the posterior circulation,mainly supplied by the vertebral arteries,may have a lower autoregulatory capacity.in acute brain injuries such as intracerebral and subarachnoid hemorrhage,and traumatic brain injuries,dynamic CA can be significantly altered in the posterior circulation.Proposed physiological mechanisms of impaired CA in the posterior circulation include:(1)Decreased sympathetic innervation of the vasculature impairing compensatory vasoreactivity;(2)Endothelial dysfunction;(3)Increased cerebral metabolic rate of oxygen consumption within the visual cortex causing CBFmetabolism(i.e.,neurovascular)uncoupling;and(4)Impaired blood-brain barrier integrity leading to impaired astrocytic mediated release of vasoactive substances(e.g.nitric oxide,potassium,and calcium ions).Furthermore,more research is needed on the effects of collateral circulation,as well as the circle of Willis variants,such as the fetal-type posterior cerebral artery,on dynamic CA.Improving our understanding of these mechanisms is crucial to improving the diagnosis,prognosis,and management of various cerebrovascular disorders.

Clinical Analysis of Embryonic Posterior Cerebral Artery

Objective:To understand the clinical characteristics of patients with embryonic posterior cerebral artery and its correlation with abnormal vascular development.Methods:The clinical data of 396 patients with embryonic posterior cerebral artery confirmed by magnetic resonance angiography(MRA)and computed tomography angiography(CTA)were analyzed.Results:Two-hundred patients had clinical manifestations of posterior circulation ischemia,including recurrent dizziness,vertigo,and tinnitus;45 had headaches,97 had limb weakness,and 16 patients had syncope or impaired consciousness.Seventy-six patients with circulatory infarction were admitted to the hospital.There were 251 patients with history of hypertension,74 with diabetes,113 with hyperlipidemia,13 with dominant vertebral artery,10 with intracranial aneurysm,and 19 with absence of A1 segment of the anterior cerebral artery(considering developmental variation).Conclusion:Embryonic posterior cerebral artery develops abnormally during the embryonic period,often accompanied by abnormal vascular access.Due to abnormal hemodynamics,the incidence of posterior circulation ischemia,aneurysm,and infarction increases in such patients.

Safety of different acupuncture manipulations for posterior circulation ischemia with vertigo

Acupuncture at Fengchi（GB20） in the posterior neck improves vertigo.However,subarachnoid hemorrhage and spinal epidural hematoma have been reported to occur after acupuncture in the posterior neck.Therefore,in the present study,we assessed the safety of acupuncture at Fengchi.Laboratory tests and adverse event reports were used to evaluate the safety of different acupuncture manipulations for the treatment of posterior circulation ischemia with vertigo.A total of 136 patients were randomly assigned to four groups.Verum acupuncture was conducted with different needle insertion directions（contralateral paropia or prominentia laryngea） and different needle twisting frequencies（60 or 120 times/minute） at Fengchi and matching acupoints（for example,Zhongwan [CV12],Qihai [CV6],Zusanli [ST36],and Fenglong [ST40]）.The patients received 14 treatments over 3–4 weeks.Routine blood analysis,hepatic and renal function tests,urine and feces tests and electrocardiography were performed before the first treatment session and after the final session.Adverse events were recorded after every session.Of the 136 patients,120 completed the study.There were no significant differences between pretreatment and posttreatment test results in any of the groups.Only five patients suffered from minor adverse events（needling pain,slight hematoma and transient chest tightness）.No serious adverse events were found.Our results indicate that a 14-session course of needling at Fengchi is relatively safe for treating posterior circulation ischemia with vertigo.

Effect of medical care linkage-continuous management mode in patients with posterior circulation cerebral infarction undergoing endovascular interventional therapy

BACKGROUND Acute cerebral infarction is a severe type of ischemic stroke that can be divided into anterior circulation cerebral infarction and posterior circulation cerebral infarction(PCCI).PCCI affects the structure of the posterior circulation brain,because posterior part of the brain,which has more complex anatomical structures and more prone to posterior circulation vascular variation.Therefore,improving the prognosis of PCCI patients is necessary.AIM To explore the effect of medical care linkage-continuous management mode(MCLMM)on endovascular interventional therapy(EIT)for PCCI.METHODS Sixty-nine patients with PCCI who received EIT and conventional nursing intervention were selected as the control group,and 78 patients with PCCI who received EIT and MCLMM intervention were selected as the observation group.The incidence of postoperative complications,compliance and disease selfmanagement behavior after six months of intervention,modified Rankin scale(mRS)and Barthel index(BI)scores in the acute phase and after one year of intervention,and recurrence within one year were compared between the two groups.RESULTS The total incidence rate of postoperative complications in the observation group(7.69%)was lower than that in the control group(18.84%)(P<0.05).The scores for medical compliance behavior(regular medication,appropriate diet,and rehabilitation cooperation rates)and disease self-management behavior(self-will,disease knowledge,and self-care ability)in the observation group were higher than those in the control group(P<0.05).After one year of intervention,in the observation group,the mRS score was significantly lower,and the BI score was significantly higher than those in the control group(P<0.05).The recurrence rate within one year in the observation group(3.85%)was significantly lower than that in the control group(13.04%)(P<0.05).CONCLUSION MCLMM can reduce the incidence of complications after EIT for PCCI,improve patient compliance behavior and disease self-management ability,and promote the recovery of neurological function.

Angioplasty and stenting for severe vertebral artery orifice stenosis: effects on cerebellar function remodeling verified by blood oxygen level-dependent functional magnetic resonance imaging

Vertebral artery orifice stenting may improve blood supply of the posterior circulation of the brain to regions such as the cerebellum and brainstem. However, previous studies have mainly focused on recovery of cerebral blood flow and perfusion in the posterior circulation after interventional therapy. This study examined the effects of functional recovery of local brain tissue on cerebellar function remodeling using blood oxygen level-dependent functional magnetic reso- nance imaging before and after interventional therapy. A total of 40 Chinese patients with severe unilateral vertebral artery orifice stenosis were enrolled in this study. Patients were equally and randomly assigned to intervention and control groups. The control group received drug treat- ment only. The intervention group received vertebral artery orifice angioplasty and stenting ＋ identical drug treatment to the control group. At 13 days after treatment, the Dizziness Handicap Inventory score was compared between the intervention and control groups. Cerebellar function remodeling was observed between the two groups using blood oxygen level-dependent functional magnetic resonance imaging. The improvement in dizziness handicap and cerebellar function was more obvious in the intervention group than in the control group. Interventional therapy for severe vertebral artery orifice stenosis may effectively promote cerebellar function remodeling and exert neuroprotective effects.

Pipeline versus Tubridge in the treatment of unruptured posterior circulation aneurysms

Background To compare the safety and efficacy of pipeline embolization device(PED)and Tubridge flow diverter(TFD)for unruptured posterior circulation aneurysms.Methods Posterior aneurysm patients treated with PED or TFD between January,2019,and December,2021,were retrospectively reviewed.Patients’demographics,aneurysm characteristics,treatment details,complications,and follow-up information were collected.The procedural-related complications and angiographic and clinical outcome were compared.Results A total of 107 patients were involved;PED was applied for 55 patients and TFD for 52 patients.A total of 9(8.4%)procedural-related complications occurred,including 4(7.3%)in PED group and 5(9.6%)in TFD group.During a mean of 10.3-month angiographic follow-up for 81 patients,complete occlusion was achieved in 35(85.4%)patients in PED group and 30(75.0%)in TFD group.The occlusion rate of PED group is slightly higher than that of TFD group.A mean of 25.0-month clinical follow-up for 107 patients showed that favorable clinical outcome was achieved in 53(96.4%)patients in PED group and 50(96.2%)patients in TFD group,respectively.No statistical difference was found in terms of procedural-related complications(p=0.737),occlusion rate(p=0.241),and favorable clinical outcome(0.954)between groups.Conclusions The current study found no difference in complication,occlusion,and clinical outcome between PED and TFD for unruptured PCAs.

Variability of the Circle of Willis in North American Caucasian and Middle East Arabic Cohorts

The cerebral arterial circle (circle of Willis) plays an important role in the redistribution of the blood flow between the anterior and posterior territories and maintains the plasticity of the cerebral blood circulation. The anatomical variability of the vascular circle often alters the cerebral hemodynamics and determines the outcomes of acute and chronic cerebrovascular disease. The heritability and prevalence of certain variants of the circle of Willis in different ethnic and racial groups are frequently disputed by authors. Our cross-sectional retrospective study aims to compare the patterns of the cerebral arterial circle in 64 Caucasian cadavers with 64 Arabic living individuals, by methods of anatomic dissection and magnetic resonance angiography, respectively. The typical structure of the circle of Willis was revealed in 8.3% of the Caucasian study group, and in 22.2% of the Arabic one. The anterior part of the circle of Willis was incomplete in 6 out of 64 of the Caucasian specimens, where the anterior communicating artery was hypoplastic (6.3%) or absent (3.1%). The posterior part of the circle of Willis had hypoplastic or absent posterior communicating artery on one side in 20, and on both sides in 12 out of 64 Caucasian specimens. In the Arabic cohort, the posterior part of the circle of Willis was incomplete in 17 out of 64 specimens, with absence of the posterior communicating artery unilaterally (in 11 cases) or bilaterally (in 6 cases). The present study reveals that the configuration of the cerebral arterial circle and distribution of the blood flow between the anterior and posterior territories have certain differences in the Caucasian study group versus the Arabic one.

Cardioembolic occlusion of the internal carotid artery presented with infarction in the posterior cerebral artery territory

Posterior circulation stroke may rarely be associated with occlusive disease in the anterior circulation, such as in the context of a direct （fetal） origin of the posterior cerebral artery （PCA） from the internal carotid artery （ICA）, or in the presence of a persistent trigeminal artery （PTA） or persistent hypoglossal artery （PHA）. Usually, they happened as infarction involving both ipsilateral carotid and posterior cerebral artery territories with carotid atherosclerosis etiology.3 Here, we reported a rare case with cadioembolic occlusion of the ICA presented with infarction mainly in the PCA territory.

Relationship between heart rate variability and posterior circulation cerebral infarction and its value in prognosis prediction

Objective To investigate the characteristic of heart rate variability(HRV)changes in patients with posteriorcirculation cerebral infarction and its value in prognosis prediction.Methods Fifty-four cases continuously diagnosed with acute posterior circulation cerebral infarction from March 2015 to November 2015 in the Department