Ipsilateral External Carotid Research Articles

Intravenous Regeneration-associated Cell Transplantation Enhances Tissue Recovery in Mice with Acute Ischemic Stroke.

Previously, we reported that transplantation of regeneration-associated cells (RACs) via the ipsilateral external carotid artery reduced stroke volume in mice with permanent occlusion of the middle cerebral artery (MCA). However, intracarotid arterial transplantation is invasive and requires skill, and severe complications may occur, such as thromboembolism, infection, and decreased cerebral blood flow. This study aimed to investigate the efficacy of intravenous injection of RACs in reducing stroke volume and increasing anti-inflammatory and angiogenic factors in mice with focal cerebral ischemia. Mice with occluded MCAs received intravenous injections of phosphate-buffered saline (PBS) (control), low-dose RACs, or high-dose RACs. The proximal part of the left MCA was occluded to induce permanent focal ischemia. After 3 days, we administered PBS or low-dose (1 × 104 /50 µL) or high-dose RACs (1 × 105 /50 µL) through the tail vein and assessed the infarct volume on day 7. High-dose RACs significantly decreased infarct volume compared to PBS, whereas low-dose RACs showed no effect. The number of interleukin-10 (IL-10)-positive and vascular endothelial growth factor (VEGF)-positive cells in the peri-infarct area on day 7 was significantly higher in mice treated with low-dose and high-dose RACs than in the PBS control group. Intravenous injection of RACs can reduce ischemic stroke volume; however, a higher dose of RACs is required than the dose used in intraarterial transplantation. By assessing IL-10 and VEGF expression, the study sheds light on the underlying mechanisms of RAC therapy, revealing its potential anti-inflammatory and angiogenic properties in the treatment of cerebral ischemia.

Ultrasonographic Predictors for Post-operative Ischemic Events After Indirect Revascularization Surgeries in Patients with Moyamoya Disease

ObjectiveRecurrent stroke after revascularization surgeries predicts poor outcome in patients with moyamoya disease (MMD). Early identification of patients with stroke risk paves the way for rescue intervention. This study aimed to investigate the role of ultrasound in identifying patients at risk of post-operative ischemic events (PIEs). MethodsThis prospective study enrolled patients with symptomatic MMD who underwent indirect revascularization surgeries. Ultrasound examinations were performed preoperatively and at 3 mo post-operatively to evaluate the hemodynamic changes in extracranial and intracranial arteries on the operated side. PIE was defined as ischemic stroke or transient ischemic attack in the operated hemisphere within 1 y. The areas under receiver operating characteristic curves were compared between models for prediction of PIE. ResultsA total of 56 operated hemispheres from 36 patients (mean age, 23.0 ± 18.5 y) were enrolled in this study, and 27% developed PIE. In multivariate logistic regression models, PIE was associated with lower end-diastolic velocity and flow volume (FV) of the ipsilateral external carotid artery (ECA), and lower FV of ipsilateral superficial temporal artery and occipital artery at 3 mo post-operatively (all p < 0.05). Moreover, the post-operative FV of the ipsilateral ECA was the only one factor that significantly increased the areas under receiver operating characteristic curves from 0.727 to 0.932 when adding to a clinical–angiographic model for prediction of PIE (p = 0.017). This parameter was significantly lower in hemispheres with PIE, both in adult and pediatric patients. ConclusionAfter indirect revascularization, surgeries in patients with symptomatic MMD, FV of ipsilateral ECA at 3 mo helps clinicians to identify patients at risk of PIE.

Outcome of CAS under flow reversal and analysis for the intraprocedural flow of internal carotid artery

ObjectiveCarotid artery stenting (CAS) under flow reversal with dual protection using a proximal balloon and distal filter has been an established procedure for internal carotid artery (ICA) stenosis. This study investigates the effect of external carotid artery (ECA) occlusion on outcomes of CAS and ICA flow under flow reversal. MethodsWe reviewed 231 cases of CAS under flow reversal with ECA occlusion and 32 without. In the last 14 of 32 cases, the flow in the ICA under flow reversal was analyzed by ultrasound. The collateral index, which was defined as the total value of the maximum diameters of the ipsilateral anterior cerebral artery at the A1 segment and the anterior communicating artery, as well as those of the ipsilateral posterior cerebral artery at the P1 segment and the ipsilateral posterior communicating artery, and the maximum diameter of the ipsilateral ECA were correlated with the flow direction in the ICA. ResultsThere was no significant difference in the outcome of CAS between the groups with or without ECA occlusion. Among the 14 cases without ECA occlusion, antegrade flow in the ICA was observed in 6 cases (42.9 %). The group with the antegrade flow in the ICA exhibited a significantly lower collateral index (5.08±0.33 vs 6.71±0.28, p=0.01) and a significantly larger ECA diameter (4.66±0.51 mm vs 3.21±1.24 mm, p=0.01) than the group with the stagnant or retrograde flow in the ICA. ConclusionsThe outcomes of CAS under flow reversal were acceptable even without ECA occlusion. The ECA occlusion may not be necessary for CAS under dual protection; however, distal filter protection should be used even under flow reversal.

Abstract 097: Un‐stumped by Carotid Stump Syndrome: Use of External Carotid Stenting in Preventing Ischemic Stroke

Introduction Recurrent infarcts to the internal carotid artery territory in the setting of a corresponding occlusion raises concern for carotid stump syndrome. Over time, robust anastomoses may develop between the patent ipsilateral external carotid artery and the anterior circulation distal to the site of occlusion. A carotid stump’s disturbance of flow uncommonly can form emboli that travel via retrograde flow from the occluded internal carotid artery to the ipsilateral external carotid artery and its collaterals. Stenosis of the external carotid artery in such patients can be a source of atheroembolism or hypoperfusion. We describe a case of external carotid stenting with carotid stump coil occlusion. Methods We present a case report. Verbal consent to share this information was obtained directly from the patient. Results A 75‐year‐old man with aortic stenosis, atrial arrhythmia, multiple prior bi‐hemispheric strokes, on aspirin and clopidogrel, presented with left facial droop, arm weakness, and slurred speech. Magnetic resonance imaging revealed embolic appearing strokes in the right middle cerebral artery territory (Figure 1A). Cerebral angiography revealed complete occlusion of the right internal carotid artery with perfusion of the right middle cerebral artery by external carotid artery anastomoses, and the external carotid was found to be stenosed proximally. Digital subtraction angiography revealed right external carotid – middle cerebral artery anastomoses via the right sphenopalatine artery, middle meningeal artery, internal maxillary artery, and ophthalmic collaterals (Figure 1B). The patient underwent coiling of the right internal carotid artery stump (Figure 1C) followed by stenting of the right external carotid using a 9 mm x 40 mm Cordis precise Pro stent. Post‐stenting angiogram demonstrated good apposition of the stent to the parent vessel walls and improvement of flow into the right external carotid and intracranial circulation (Figure 1D). The patient was treated with aspirin and ticagrelor for 3 months. Repeat imaging at follow up did not show further embolic episodes, with improvement in the patient’s deficits. After three months, he was continued on aspirin alone. Conclusion In patients with an occluded internal carotid artery and recurrent embolic infarcts ipsilateral to the side of the occlusion, carotid stump syndrome may be considered. In this case, we believe the patient’s carotid occlusion served as a nidus for emboli formation, or that there was atheroembolism from the stenosed external carotid artery despite adherence to dual antiplatelet therapy. By coiling the stump, we addressed a possible source of emboli, and stenting of the proximal external carotid optimized anterograde flow and prevented further atheroembolism. Our case showcases an interventional neuroradiology approach to carotid stump emboli and external carotid artery stenosis.

Abstract 093: Carotid Stump Syndrome: an Insidious Source of Recurrent Ischemic Strokes

Introduction Carotid stump syndrome (CSS) is a paradoxical phenomenon that occurs when there are repeated ischemic events in the carotid vascular territory despite demonstrated occlusion of the ipsilateral internal carotid artery (ICA). It is thought to be caused by turbulent blood flow in the patent stump of the occluded ICA creating microemboli which reach the brain through anastomotic channels and retrograde flow. We present a case of recurrent infarctions in setting of known ipsilateral ICA occlusion, who was diagnosed with carotid stump syndrome. Methods A male veteran in his 60s with a medical history of DVTs on apixaban, PVD, and ischemic stroke with residual right‐sided weakness, presented with worsening right‐sided weakness and difficulty with ambulation. Two months prior to the presentation he was diagnosed with acute infarcts in left frontal, parietal, and temporal lobes due to thromboembolism from left ICA occlusion. On presentation his neurological exam revealed right‐sided hemiparesis. MRI brain showed multiple acute and chronic cortical and subcortical infarcts in the left frontotemporoparietal lobes and lack of flow void in the left distal ICA. To further evaluate the dynamics of blood flow patient underwent a cerebral angiogram which confirmed the diagnosis of complete occlusion of left ICA and demonstrated reconstitution of the intracranial ICA through retrograde filling via the ophthalmic artery and anastomotic branches with the internal maxillary artery (IMax). For secondary prevention he was started on statin and aspirin while his home Apixaban was continued. Surgical and endovascular treatment approaches were discussed but the patient declined any intervention. In his four months follow up clinic visit he had no further concerns of recurrent strokes or new symptoms. Results Carotid stump syndrome is a rare cause of cerebral and retinal ischemia; however, it must be considered in patients with recurrent ischemic strokes and chronic ipsilateral ICA occlusion. Due to the patent proximal, or perhaps in some cases distal, carotid stump, there’s turbulent flow and hence the thrombus formation can occur. Hemodynamic and embolic factors attribute towards the microembolization from the proximal carotid stump through the external carotid artery (ECA), into the facial artery and IMax and their distal branches which anastomose with the ophthalmic artery, causing the emboli to end up in the major branches of the carotid terminus. If a distal stump is symptomatic, then the microemboli can readily end up in the distal ICA branches. In addition to medical management with DAPT or anticoagulation and high intensity statin, our literature review supports endovascular or surgical interventions due to reportedly good outcomes. Interventional approaches may include ECA‐ICA stenting with a covered stent or stent‐assisted coil embolization of the proximal stump. Surgical procedures include an endarterectomy on the ipsilateral ECA or contralateral ICA to increase collateral circulation. ECA‐ICA bypass is another option. Conclusion Carotid stump syndrome is a rare and underrecognized cause of recurrent ischemic strokes, though it is a potentially treatable entity. The therapeutic goals include medical management along with endovascular or surgical treatment whenever possible.

Cerebral autoregulation and blood flow distribution in the precerebral arteries for determining indications of extra-intracranial bypass in patients with carotid artery occlusion

Background. Prevention of ischemic stroke in patients with carotid artery occlusion is conventionally associated with performing cerebral revascularization. However, determining the indications for it is still an actual problem. The informative value of noninvasive assessment of cerebral autoregulation and blood flow distribution in the precerebral arteries in patients with carotid artery stenosis is shown. At the same time, in patients with carotid artery occlusion, these indicators have been studied to a lesser extent.Aim. To evaluate the informative value of cerebral autoregulation and blood flow distribution in the precerebral arte ries for determination the indications of extra‑intracranial bypass in patients with carotid occlusion.Materials and methods. 54 patients (aged from 41 to 83 y. o.) with carotid artery occlusion were studied. Blood flow velocity in intracranial arteries was determined with transcranial Doppler (system Multi‑Dop X), whereas flow velocity index in precerebral arteries – with duplex scanning (system Vivid Е). Cerebral autoregulation was assessed based on phase shift between spontaneous oscillations of blood flow velocity in basal cerebral arteries and systemic blood pressure within the range of Mayer’s waves (80–120 mHz).Results. The state of cerebral autoregulation was imparied on both sides in 90 % patients with the symptomatic carotid occlusion (0.3 ± 0.3 rad ipsilateral, 0.7 ± 0.6 rad contralateral). The state of cerebral autoregulation was not impaired in 79 % patients with asymptomatic carotid occlusion (1.0 ± 0.3 rad ipsilateral, 1.1 ± 0.4 rad contralateral). The flow velocity index in the contralateral internal carotid artery (306 ± 109 ml / min) and the ipsilateral vertebral (139 ± 69 ml / min) and external carotid (175 ± 72 ml / min) arteries was increased.Conclusions. Noninvasive preoperative assessment of cerebral autoregulation and blood flow distribution in the precerebral arteries makes to evaluate the state of the cerebrovascular reserve to quantify and can be used to determining indications for cerebral revascularization in patients with carotid occlusion.

Abstract Number ‐ 66: Symptomatic Chronic Internal Carotid Artery Occlusion Managed With Bilateral Common Carotid Angioplasty: A Case Report

Introduction Several guidelines have addressed symptomatic or asymptomatic carotid artery stenosis treatment with intensive medical management and surgical management based on the severity of stenosis [1]. In acute occlusions, endovascular treatment (EVT) and carotid endarterectomy (CEA) with or without prior thrombolytics provide the best recanalization and functional outcomes when compared to intravenous or intra‐arterial thrombolysis alone. There is, however, less robust evidence on management of symptomatic chronic internal carotid artery (ICA) occlusion occurring in tandem with significant contralateral ICA stenosis [2]. In chronic ICA occlusion (ICAO), EVT and carotid endarterectomy (CEA) are technically unfeasible, but indirect procedures have been arising as safe and effective alternatives, notably CEA or stenting of contralateral stenotic ICA [3] and CEA or stenting of ipsilateral external carotid artery (ECA) [4]. We hereby report a case of symptomatic chronic ICAO that was managed with staggered angioplasty and stenting of bilateral common carotid artery (CCA) bifurcations. Methods We hereby present a case report. Results A 62‐year‐old male with atrial fibrillation and hypertension woke up with sudden dysarthria and right upper extremity and facial weakness. NIHSS at presentation was 4. Last seen normal 9 hours prior. Non‐contrast head computerized tomography (CT) did not show acute intracranial abnormality, CT angiogram of head and neck showed severe right ICA stenosis and complete occlusion of the left ICA at cervical, petrous and cavernous segments, with distal reconstitution at the supraclinoid segment with left proximal middle cerebral artery (MCA) thrombus. CT perfusion showed a core infarct volume of 8cc in left MCA territory, mismatch volume of 78cc and ratio of 10.8. Risks of acute neuro‐intervention were deemed to outweigh benefits. Given favorable perfusion imaging, and in concordance with the EXTEND trial [5], tPA was administered. The patient remained stable without hemorrhagic complications with residual deficits of mild right upper extremity weakness and mild expressive aphasia. MRI confirmed left ICA territory ischemic infarcts. Patient underwent stenting of the asymptomatic right ICA at the CCA bifurcation first, followed by left CCA stent after one month with impressive improvement in subsequent perfusion imaging. Conclusions Our case encourages consideration of well‐timed angioplasty and stenting in cases of chronic bilateral carotid artery disease especially when the asymptomatic side is also significantly stenotic

Volumetric Flow Assessment in Extracranial Arteries in Patients with 70-99% Internal Carotid Artery Stenosis.

Background: Cerebral blood flow (CBF) can be related to the risk of occurrence of neurological symptoms. Well-developed collateral circulation is a good prognostic factor in patients with cerebrovascular disease. Understanding the mechanisms of collateral circulation may be important in the diagnosis, treatment, and monitoring in this group of patients. The aim of this study covered the assessment of CBF in patients with 70–99% Internal carotid artery (ICA) stenosis, focusing on the circulation pathways and flow volume in extracranial arteries. Materials and methods: 53 patients with 70–99% ICA stenosis (mean age 73.4 ± 7 years old; 17 female, mean age 73.9 ± 7.5 years old; 36 male, mean age 73.2 ± 6.8 years old) were included in the study. In all patients a Doppler ultrasound (DUS) examination, measuring blood flow volume in the internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA), was performed. The cerebral blood flow (CBF) was compared to the previously reported CBF values in the healthy population > 65 years old. Results: Among the study groups three subgroups with flow differences were identified: patients with elevated CBF (significant volumetric flow compensation—26/53, 49%), patients with CBF similar to (mild compensation—17/53, 32%), and patients with CBF lower than (no compensation—10/53, 19%) the healthy, equally aged population. The percentage of patients with significant volumetric flow compensation was the highest in age groups 65–69 years old (62.5%) and >80 years old (60%). In the oldest age group (>80 years old) no patients without flow compensation (0%) were observed. The level of compensation depends on the number of the arteries with compensatory increased flow. In patients with significant volumetric flow compensation, the compensatory increased flow was observed, on average, in 3.31 arteries, in the mild compensation group—in 2.18 arteries, and in the no compensation group only in 1 artery. ICA plays the most important role in the volumetric flow compensation—the increase in the flow volume, in comparison to the reference values, was between 116.7 mL/min and 251.9 mL/min (in the ECA 57.6 mL/min–110.4 mL/min; in the VA 73.9 mL/min–104.9 mL/min). The relative flow increase was highest in the VA: 215–246%, then in the ECA: 163–206%, and finally in the ICA: 148.6–192%. The increased flow was most commonly observed in the VA—57 arteries, in second place in the ECA—42 arteries, and ICA—31 arteries. In patients with unilateral ICA stenosis, the volumetric flow increase was stated more frequently in the ipsilateral ECAs then in the contralateral ones (23 vs. 14). In the VA the opposite tendency was observed (29 contralateral vs. 23 ipsilateral). The ability of volumetric flow compensation decreased significantly with increasing age. Conclusions: Understanding the mechanisms of collateral circulation and their assessment in Doppler ultrasonography may provide a novel and easily accessible tool of identifying and monitoring patients with cerebrovascular disease.

CT angiography for diagnosis of carotid near-occlusion: a digital subtraction angiography validation study.

Carotid near-occlusion (CNO) is a variant of severe stenosis where there is a distal luminal collapse of the internal carotid artery (ICA) beyond a tight stenosis. This study aimed to validate new visual extracranial diagnostic CT angiography (CTA) criteria, for the diagnosis of CNO. The new criteria include distal ICA diameter smaller than contralateral ICA and distal ICA diameter less than or equal to the ipsilateral external carotid artery (ECA). We also assessed the previously described CTA criteria: stenosis ≤ 1.3mm, ipsilateral distal ICA ≤ 3.5mm, ipsilateral distal ICA/contralateral distal ICA ratio ≤ 0.87, ipsilateral distal ICA/ipsilateral ECA ≤ 1.27. Fifty-eight patients with ICA stenosis (including the near-occlusion variant) or occlusion on digital subtraction angiography (DSA) were included. These patients had DSA and CTA studies completed within 30days of each other. DSA was considered the reference test. Two neuroradiologists blinded to the DSA results assessed the CTA images and evaluated the new and previously published CNO diagnostic criteria. Twenty-eight CNO were identified with DSA. The "distal ICA diameter less than or equal to the ipsilateral ECA" criterion had 79% sensitivity and 83% specificity with excellent interobserver agreement (kappa = 0.80), while three or more of the previously published criteria reached 82% sensitivity and 90% specificity, with a good interobserver agreement (kappa = 0.64). CT angiography may be useful for CNO diagnosis. The new visual diagnostic criteria provide acceptable results of sensitivity and specificity with an excellent interobserver agreement. However, false-negative and positive results persist.

Non-Invasive Evaluation of Cerebral Hemodynamic Changes After Surgery in Adult Patients With Moyamoya Using 2D Phase-Contrast and Intravoxel Incoherent Motion MRI.

ObjectiveTo explore the feasibility of 2D phase-contrast MRI (PC-MRI) and intravoxel incoherent motion (IVIM) MRI to assess cerebrovascular hemodynamic changes after surgery in adult patients with moyamoya disease (MMD).MethodsIn total, 33 patients with MMD who underwent 2D PC-MRI and IVIM examinations before and after surgery were enrolled. Postsurgical changes in peak and average velocities, average flow, forward volume, and the area of superficial temporal (STA), internal carotid (ICA), external carotid (ECA), and vertebral (VA) arteries were evaluated. The microvascular perfusion status was compared between the hemorrhage and non-hemorrhage groups.ResultsThe peak velocity, average flow, forward volume, area of both the ipsilateral STA and ECA, and average velocity of the ipsilateral STA were increased (p < 0.05). The average flow and forward volume of both the ipsilateral ICA and VA and the area of the ipsilateral VA were increased (p < 0.05). The peak velocity, average velocity, average flow and forward volume of the contralateral STA, and the area of the contralateral ICA and ECA were also increased (p < 0.05), whereas the area of the contralateral VA was decreased (p < 0.05). The rf value of the ipsilateral anterior cerebral artery (ACA) supply area was increased (p < 0.05) and more obvious in the non-hemorrhage group (p < 0.05).ConclusionTwo-dimensional PC-MRI and IVIM may have the potential to non-invasively evaluate cerebrovascular hemodynamic changes after surgery in patients with MMD. An improvement in the microvascular perfusion status is more obvious in patients with ischemic MMD than in patients with hemorrhagic MMD.

External carotid artery stenting in patients with ipsilateral internal carotid artery occlusion: Peri-operative and 12-month follow-up.

This study aimed to evaluate the safety and clinical efficacy of external carotid artery (ECA) stenting in patients with ipsilateral internal carotid artery (ICA) occlusion. In patients with ICA occlusion, severe ipsilateral ECA stenosis may exacerbate pre-existing cerebral ischemia and cognitive impairment. It remains unclear whether ECA stenting to normalize ECA collaterals to the cerebralis alleviates cerebral ischemia and improves cognitive function. From January 2008 to June 2019, we retrospectively collected clinical data of 36 consecutive patients with ipsilateral ICA occlusion who had undergone ECA stenting (mean age, 66.7 ± 8.3 years; males, n = 26 [72.2%]). Neurocognitive test results, including Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MOCA) tests, symptom assessment, and adverse events were recorded. ECA stenting was successful in all 36 patients. Intra-operatively, six (16.7%) patients experienced hemodynamic depression during balloon dilation and recovered completely within 2 days. Within a 12-month follow-up period, two patients experienced a transient ischemic attack, one patient had a contralateral minor stroke, and 33 patients remained asymptomatic. No other adverse events occurred in the peri-operative or follow-up periods. Compared with baseline, significant MMSE (25.3 ± 1.3 vs. 23.6 ± 1.7; p < .05) and MOCA (24.1 ± 1.3 vs. 22.8 ± 1.7; p < .05) test score improvements were observed 3 months post-operatively and were maintained throughout follow-up. ECA stenting may improve cerebral ischemia and cognitive function in patients with severe ECA stenosis and ipsilateral ICA occlusion; however, further research is required to support our findings.

Cerebral Autoregulation and Blood Flow Redistribution in the Precerebral Arteries in Patients with Carotid Artery Occlusion

Abstract Background: State of cerebral autoregulation and changed blood flow in the precerebral arteries can serve as selection criteria in favor of extra-intracranial bypass surgery and as a prediction factor in patients with carotid artery occlusion. However, information capacity of quantitative values of this functional state of the brain circulation has not been studied well enough. Objective: The objective is to assess the state of cerebral autoregulation and blood flow redistribution in the precerebral arteries in patients with carotid artery occlusion. Material and Methods: The study involved 24 patients aged 41 to 80 with carotid artery occlusion. Eight of them were asymptomatic. We measured blood flow velocity in intracranial arteries by using transcranial Doppler (MultiDop X) and flow velocity index in precerebral arteries - by using duplex scanning (Vivid e). Cerebral autoregulation was evaluated with cross-spectral analysis of spontaneous oscillations of blood pressure (CNAP, Austria) and blood flow velocity within the range of Mayer’s waves (80-120 mHz). Results: In most symptomatic patients the cerebral autoregulation decreased on both sides (0.3±0.3 rad ipsilaterally and 0.6±0.4 rad contralaterally). There was no cerebral autoregulation impairment in all asymptomatic patients (1.1±0.5 rad ipsilateral and 1.3±0.5 rad contralateral). We noticed an increased blood flow index in the contralateral internal carotid artery (312±113 ml/min) and ipsilateral vertebral and external carotid arteries (126±64 ml/min and 158±72 ml/min, respectively). Conclusion: A comprehensive analysis of cerebral autoregulation and blood flow in the precerebral arteries helps to identify the extent of cerebral hemodynamics compensation in carotid artery occlusion, which can classify patients in need of revascularization surgery. Keywords Blood flow index; Carotid artery occlusion; Cerebral autoregulation; Cerebrovascular reserve; Extra-intracranial bypass surgery

Detection and Differentiation of Dural Arteriovenous Fistulas in the Transverse Sinus/Sigmoid Sinus and Cavernous Sinus Using Carotid Ultrasound: Importance of Evaluation of the Occipital Artery.

Dural arteriovenous fistula (DAVFs) in the transverse sinus (TS)/sigmoid sinus (SS) and cavernous sinus (CS) are observed frequently in the clinic. This study aimed to detect DAVFs with ultrasound and compare carotid ultrasound findings between these conditions. We retrospectively reviewed 26 patients with either a TS/SS DAVF or a CS DAVF who were admitted to our hospital for evaluation of DAVFs from 2014 to 2018. The shunt site decision was made by neuroendovascular experts, whereas carotid ultrasound examinations were performed by ultrasound specialists. The flow velocity of the ipsilateral external carotid artery was reviewed in all 26 patients, whereas that of the occipital artery (OA) was examined in 20 patients. Blood flow velocities were compared between the TS/SS DAVF and CS DAVF groups. The study included 18 patients with a TS/SS DAVF (11 women and 7 men; mean age ± SD, 65.3 ± 18.6 years) and 8 patients with a CS DAVF (7 women and 1 man; mean age, 70.4 ± 9.3 years). Evaluations of feeder arteries on cerebral angiography showed that all patients had dural branches from the internal carotid and middle meningeal arteries as feeders of CS DAVFs, whereas the OA was the major feeder source of all TS/SS DAVF cases. The end-diastolic velocity (EDV) of the external carotid artery was significantly higher in patients with a TS/SS DAVF compared with those with a CS DAVF (P = .004). The EDV of the OA was significantly elevated in TS/SS DAVF cases compared with CS DAVF cases (P < .001). Duplex ultrasound parameters are significantly different between patients with TS/SS and CS DAVFs. An increased EDV of the OA can predict the presence of a TS/SS DAVF.

External carotid artery stenting in symptomatic internal carotid artery occlusion

We report the case of a patient with an anterior ischemic stroke due to tandem occlusion of the left M2 segment and ipsilateral internal carotid artery (ICA), with concomitant severe stenosis of the ipsilateral external carotid artery (ECA) and contralateral ICA, and moderate stenosis of the left vertebral artery (VA); as thrombectomy was not possible, stenting of the right ICA was performed. Two days after significant recovery, the patient showed neurological deterioration when in upright position, and brain magnetic resonance imaging confirmed decreased cerebral blood flow on the left hemisphere. Stenting of the left ECA and balloon angioplasty of the ipsilateral VA were performed in order to increase collateral flow, with an almost complete resolution of symptoms. This case highlights the importance of assessing the collateralization pattern when an ICA occlusion is present, and the potential need to revascularize an ipsilateral stenotic ECA.

Revascularization for Cerebral Ischemia, Step-by-Step Demonstration of Bonnet Bypass: 3-Dimensional Operative Video.

The superficial temporal artery (STA) to the middle cerebral artery (MCA) bypass is the most common bypass type for revascularization to treat cerebral ischemia. If the ipsilateral STA is not available for anastomosis, various options for bypass conduits can be exercised. When the entire ipsilateral external carotid and its branches are not available, the contralateral STA may be used as a donor artery through an interposition graft. This technique is known as a "bonnet bypass." In this video, we demonstrate the utilization of a bonnet bypass in a 48-yr-old man with protein S deficiency, and right carotid artery occlusion with recurrent strokes and transient ischemic attacks (TIA). After exhausting nonsurgical options by treating with 2 antiplatelet drugs and supportive lifestyle changes, the patient continued to experience TIAs and watershed strokes in the right hemisphere. Angiography showed that the right anterior artery and the MCA were filled through the Circle of Willis, but the ipsilateral STA and entire external and common carotid arteries were not patent for potential use as a bypass donor. Since the ipsilateral bypass options were not available, we elected to perform a bypass from the contralateral STA trunk to the ipsilateral M2 with a saphenous vein interposition graft, for a so-called bonnet bypass. The patient did well after surgery and has remained symptom-free for 19 mo post bypass. The surgical technique and each step in performing this bonnet bypass are demonstrated in this 3-dimensional video. The patient consented to the publication of his operative video.

Four collateral circulation pathways were observed after common carotid artery occlusion

BackgroundCommon carotid artery (CCA) occlusion (CCAO) is a rare condition. Owing to collateral circulation, ipsilateral internal carotid artery (ICA) and external carotid artery (ECA) are often patent.MethodsThis study included 16 patients with unilateral CCAO and patent ipsilateral ICA and ECA. The pathways which supplied ICA were investigated by digital subtraction angiography (DSA), transcranial Doppler (TCD), magnetic resonance angiography (MRA) and computed tomography angiography (CTA).ResultsIn all 16 patients, TCD found antegrade blood flow in ipsilateral ICA, which was supplied by retrograde blood flow in ipsilateral ECA through carotid bifurcation. We call this phenomenon “ICA steal”. DSA and CTA discovered four pathways of ICA steal, including 1) ipsilateral vertebral artery – occipital artery – ECA – ICA, 2) ipsilateral thyrocervical trunk or costocervical trunk – ascending cervical artery or deep cervical artery – occipital artery – ECA – ICA, 3) contralateral ECA – contralateral superior thyroid artery – ipsilateral superior thyroid artery – ipsilateral ECA – ICA, and 4) ipsilateral thyrocervical trunk – inferior thyroid artery – superior thyroid artery – ECA – ICA.ConclusionsICA is possible to be patent and supplied by several collateral circulation pathways after CCAO.

The effect of muscle metaboreflex on the distribution of blood flow in cerebral arteries during isometric exercise.

The present study examined the effect of muscle metaboreflex on blood flow in different cerebral arteries. Eleven healthy participants performed isometric, one-leg knee extension at 30% maximal voluntary contraction for 2min. Activated muscle metaboreflex was isolated for 2min by post-exercise muscle ischemia (PEMI). The contralateral internal carotid (ICA), vertebral (VA), and ipsilateral external carotid arteries (ECA) blood flows were evaluated using Doppler ultrasound. The ICA blood flow increased at the beginning of exercise (P = 0.004) but returned to the baseline level at the end of exercise (P = 0.055). In contrast, the VA blood flow increased and it was maintained until the end of the exercise (P = 0.011), while the ECA blood flow gradually increased throughout the exercise (P = 0.001). These findings indicate that isometric exercise causes a heterogeneous cerebral blood flow response in different cerebral arteries. During PEMI, the conductance of the VA as well as that of the ICA was significantly lower compared with the baseline value (P = 0.020 and P = 0.032, at PEMI90), while the conductance of the ECA was not different from the baseline (P = 0.587), suggesting that the posterior and anterior cerebral vasculature were similarly affected during exercise by activation of muscle metaboreceptors, but not in the non-cerebral artery. Since ECA branches from ICA, the balance in the different influence of muscle metaboreflex on ECA (vasodilation via exercise-induced hypertension) and ICA (vasoconstriction) may contribute to the decrease in ICA blood flow at the end of isometric exercise.

Wall Shear Stress in the Feeding Native Conduit Arteries of Superficial Arteriovenous Malformations of the Lower Face is a Reliable Marker of Disease Progression.

To assess the prognostic value of the wall shear stress (WSS) measured in the feeding native arteries upstream from facial superficial arteriovenous malformations (sAVMs). Reliable prognostic criteria are needed to distinguish progressive from stable sAVMs and thus support the indication for an aggressive or a conservative management to avoid severe facial disfigurement. We prospectively included 25 patients with untreated facial sAVMs, 15 patients with surgically resected sAVMs and 15 controls. All had undergone Doppler ultrasound examination (DUS) with measurements of inner diameters, blood flow velocities, computation of blood flow and WSS of the feeding arteries. Based on the absence or presence of progression in clinical and imaging examinations 6 months after, we discriminated untreated patients as stable or progressive. WSS in the ipsilateral external carotid artery was higher in progressive compared to stable sAVMs (15.8 ± 3.3dynes/cm² vs. 9.6 ± 2.0dynes/cm², mean±SD, p < 0.0001) with a cut-off of 11.5dynes/cm² (sensitivity: 92 %, specificity: 92 %, AUC: 0.955, [95 %CI: 0.789-0.998], p = 0.0001). WSS in the ipsilateral facial artery was also higher in progressive compared to stable sAVMs (50.7 ± 14.5dynes/cm² vs. 25.2 ± 7.1dynes/cm², p < 0.0001) with a cut-off of 34.0dynes/cm² (sensitivity: 100 %, specificity: 92 %, AUC: 0.974, [95 %CI: 0.819-1.000], p = 0.0001). The hemodynamic data of operated patients were not different from those of the control group. WSS measured in the feeding arteries of an sAVM may be a simple reliable criterion to distinguish stable from progressive sAVMs. This value should be considered to guide the therapeutic strategy as well as the long-term follow-up of patients with facial sAVMs.

Identification of plaque location using intraoperative indocyanine green during carotid endarterectomy for patient with near occlusion.

Microscope-integrated near-infrared indocyanine green (ICG) videoangiography (VA) is an effective method of intraoperative blood-flow assessment and identification of plaque location during carotid endarterectomy (CEA). However, the validity of ICG-VA during CEA for patient with near occlusion has not been elucidated. Thirty-four CEA procedures were performed between June 2009 and December 2017 for patient with near occlusion, which are more than 95% stenosis. The lesions were classified into three groups according to the diameter of distal ICA compared with ipsilateral external carotid artery (ECA), as normal diameter (>100%), moderate diameter reduction (50-100%), severe diameter reduction (<50%). Five mg of ICG was injected intravenously before arteriotomy, and ICG-VA was taken to identify the distal end of the plaque. Depiction of the distal end and its accuracy were retrospectively reviewed. There were 18 cases with normal diameter group, 14 cases with moderate diameter reduction group, and 2 cases with severe diameter reduction group. All but one case in the severe diameter reduction group showed apparent distal end signal which were confirmed by arteriotomy afterward. The present study clearly denotes that ICG-VA can visualize the carotid plaque distal end during the CEA, even with the patient with near occlusion. However, it should be noted that there may be a difficulty in visualization of the distal plaque end for patient with severely collapsed distal ICA.

Doppler ultrasound appearance of neck tumors.

Aim: The purpose of this study was the evaluation of the sonographic appearance of neck tumors and determining the features useful in differential diagnosis. Material and method: The studied group consisted of 57 patients: 16 patients with carotid body tumors, 9 patients with neurogenic tumors, 8 patients with venous anomalies, 12 patients with neck cysts, 6 patients with lipomas, 5 patients with extracranial carotid artery aneurysms and 1 with a laryngocele. Results: All carotid paragangliomas were located within the carotid bifurcation and demonstrated rich low-resistance vascular flow, with higher maximum velocity and lower flow resistance parameters registered in the ipsilateral external carotid artery. In 7 out of 9 cases, neurogenic tumors were homogeneous, and in the remaining 2 cases – heterogeneous. Four schwannomas were hypervascular or showed moderate vascularity, and the rest of neurogenic tumors were hypovascular or avascular, with symmetrical maximum velocity and resistance values of carotid blood flow. Apart from one branchial cleft cyst with multiple fine internal acoustic reflexes, all other neck cysts were anechoic and avascular, and presented with posterior acoustic enhancement. The laryngocele presented as a well-demarcated, hypoechoic, homogeneous lesion located in the immediate proximity of the larynx, without signs of internal vascular flow. Lipomas were well-demarcated, homogeneous, hypoechoic tumors with regular margins, without signs of internal vascular flow. Venous malformations presented as irregular, hypoechoic spaces with venous blood flow, easily compressed by the probe. Extracranial carotid artery aneurysms were hypoechoic, well-defined spaces, which presented with slow internal, turbulent flow on Doppler study, and showed continuity with the carotid artery. Conclusions: Doppler ultrasound allows to visualize features characteristic for certain neck tumors. Solid or cystic structure, echogenicity, localization, as well as internal flow signals and vascularity pattern create a combination of ultrasound findings helpful in the differential diagnosis of lesions such as paragangliomas, venous malformations, neurogenic tumors, aneurysms, cysts and laryngoceles.