Proximal Anterior Cerebral Artery Research Articles

Rare combo: moyamoya and lupus in men.

Moyamoya syndrome (MMS) is a rare, chronic, progressive cerebrovascular disorder characterized by stenosis at the apices of the intracranial internal carotid arteries, including the proximal anterior cerebral arteries and middle cerebral arteries. Cerebral angiography images are used for detection through measurement. Systemic lupus erythematosus (SLE) is an autoimmune disease that can cause multisystemic involvement. The coexistence of SLE and MMS has been rarely reported in the literature. A 46-year-old male patient with malar rash, Raynaud phenomenon presented to the hospital with a complaint of weakness in the left lower extremity, which began 3days before the date of the visit. In the diffusion magnetic resonance imaging, multiple diffusion restrictions were observed in the right frontal region. The patient underwent MR angiography, revealing stenosis in the terminal and supraclinoid segments of the right internal carotid artery, which made us consider moyamoya disease. This patient, with a malar rash and Raynaud's, a positive antibody profile, was diagnosed as a male with SLE accompanied by MMS.

Surgery Versus Endovascular Treatment for Proximal Anterior Cerebral Artery Aneurysms: A Meta-Analysis

Background: Proximal anterior cerebral artery (PACA) aneurysms account for less than 1% of all intracranial aneurysms. These aneurysms possess a challenge to surgeons due to their small size, wide base, fragile wall, and accompanying vascular anomalies. Surgery and endovascular treatment are both effective treatment options for PACA aneurysms but there is currently no consensus on which is the method of choice. Objective: A systematic review and meta-analysis was conducted to investigate treatment strategies for aneurysms at proximal anterior cerebral artery. Material and Methods: The Cochrane Library, EMBASE, PubMed, and Web of Science databases were systematically searched for studies published between January 01, 2000 and December 01, 2020 that investigated surgery and/or endovascular treatment for patients with PACA. Results and Conclusions: Nineteen retrospective studies involving 358 patients met the inclusion criteria. Among these patients, 150 were treated surgically and 208 were treated using an endovascular technique. Preoperative morbidity was significantly greater in the surgical patients compared with the endovascular treated patients but there was no difference between groups in procedural related morbidity. The rates of favorable clinical outcome at time of discharge and at follow-up were statistically significantly greater in the endovascular group compared with the surgical group. Procedural related mortality was 8.7% for the surgical group and 1% in the endovascular group. In summary, our meta-analysis emphasized the safety and efficiency of endovascular treatment, and concluded that it was superior to surgery in acquiring favorable clinical outcome and reducing the perioperative complications. However, surgery was still the preferred treatment strategy for ruptured PACA aneurysms. Preoperative evaluation seems to be of great vital.

June 2023 Stroke Highlights.

June 2023 Stroke Highlights.

Influence of neurovascular anatomy on perforation site in different mouse strains using the filament perforation model for induction of subarachnoid hemorrhage.

BackgroundFilament perforation is a widely-used method to induce subarachnoid hemorrhage (SAH) in mice. Whereas the perforation site has been assumed to be in the branching of middle cerebral artery (MCA) and anterior cerebral artery (ACA), we recently observed more proximal perforations.MethodsFilament perforation was performed in CD1- (n = 10) and C57Bl/6N-mice (n = 9) ex vivo. The filament was left in place and the perforation site was microscopically assessed. Digital subtraction angiography (DSA) was performed in CD1- (n = 9) and C57Bl/6J-mice (n = 29) and anatomical differences of the internal carotid artery (ICA) were determined.ResultsWhereas in C57Bl/6N-mice perforation occurred in the proximal intracranial ICA in 89% (n = 8), in CD1-mice the perforation site was in the proximal ICA in 50% (n = 5), in the branching between MCA and ACA in 40% (n = 4), and in the proximal ACA in 10% (n = 1). DSA revealed a stronger angulation (p<0.001) of the ICA in CD1-mice (163.5±2.81°) compared to C57Bl/6J-mice (124.5±5.49°). Body weight and ICA-angle showed no significant correlation in C57Bl/6J- (r = -0.06, pweight/angle = 0.757) and CD1-mice (r = -0.468, pweight/angle = 0.242).ConclusionFilament perforation in mice occurs not only at the hitherto presumed branching between MCA and ACA, but seems to depend on mouse strain and anatomy as the proximal intracranial ICA may also be perforated frequently.

Pediatric Moyamoya Biomarkers: Narrowing the Knowledge Gap

Moyamoya is a progressive cerebrovascular disorder that leads to stenosis of the arteries in the distal internal carotid, proximal middle cerebral and proximal anterior cerebral arteries of the circle of Willis. Typically a network of collaterals form to bypass the stenosis and maintain cerebral blood flow. As moyamoya progresses it affects the anterior circulation more commonly than posterior circulation, and cerebral blood flow becomes increasingly reliant on external carotid supply. Children with moyamoya are at increased risk for ischemic symptoms including stroke and transient ischemic attacks (TIA). In addition, cognitive decline may occur over time, even in the absence of clinical stroke. Standard of care for stroke prevention in children with symptomatic moyamoya is revascularization surgery. Treatment of children with asymptomatic moyamoya with revascularization surgery however remains more controversial. Therefore, biomarkers are needed to assist with not only diagnosis but also with determining ischemic risk and identifying best surgical candidates. In this review we will discuss the current knowledge as well as gaps in research in relation to pediatric moyamoya biomarkers including neurologic presentation, cognitive, neuroimaging, genetic and biologic biomarkers of disease severity and ischemic risk.

Assessment of Primary Collateral Grades Based on the Integrity of Willis' Circle: Predicting the Prognosis of Acute Intracranial Internal Carotid Artery Occlusion Before Thrombectomy

Endovascular mechanical thrombectomy (EVMT) has shown significant efficacy in improving neurological functions in patients with intracranial internal carotid artery occlusion (IICAO), but its clinical outcomes are variable. We examined the relationship between favorable clinical outcomes after EVMT in IICAO and a set of predictors. In this retrospective study, 189 patients with IICAO treated by EVMT at 3 centers from November 2015 to December 2020 were included and analyzed. Non-contrast computed tomography and computed tomography angiography were evaluated on admission. The morphology of IICAO was categorized into Ia, Ib, L, or T types, depending on the involvement of the posterior communicating artery origin, proximal anterior cerebral artery, and middle cerebral artery. The Willis' circle was categorized as integrated or compromised Willis' circle. In combination with the involvement of the IICAO and the integrity of Willis' circle, we used the primary collateral grade (PCG) to describe the presence of functional Willisian collaterals. Baseline data including demographics, characteristics, vascular risk factors, and initial National Institutes of Health Stroke Scale scores were collected. Hemorrhagic transformation was evaluated using the 24-hour non-contrast computed tomography after EVMT. Favorable outcomes based on modified Rankin scale, were defined as 0-2 at 90days. A total of 189 patients were included (median age, 69years; 126 male [66.7%]). 104 patients [55.0%] showed reperfusion after EVMT, but 72 patients [38.1%] achieved favorable outcomes at 90days. The mortality rate of type Ib was significantly higher than that with type Ia (χ2=14.21, P= 0.001). The outcome with different structure of Willis' circle was not statistically different between the 2 groups. A multivariate logistic regression analysis showed that IICAO T-type (odds ratio, 0.028 [95% confidence interval: 0.323-3.829], P= 0.042) and PCG 2 (odds ratio 9.427[95% confidence interval:1.863-47.698], P= 0.007) were predictors of favorable outcomes. Evaluation of PCG by determining the type of IICAO and the integrity of Willis' circle may serve as a valuable indicator for the prognosis and as an essential reference for screening patients before EVMT.

Comparison of Endovascular Therapy for Ruptured Cerebral Aneurysm during Spasm and Nonspasm Period.

Objective Cerebral vasospasm complicates the treatment of aneurysmal subarachnoid hemorrhage, and the optimal timing of surgery for ruptured intracranial aneurysm diagnosed during the cerebral vasospasm period has been a matter of debate. This study aimed to clarify the differences in endovascular treatment outcomes between the timing of intervention during spasm and nonspasm. Methods and Materials We retrospectively reviewed 68 consecutive patients with ruptured cerebral aneurysms who underwent coil embolization between January 2016 and March 2021. Clinical presentations, radiographic findings, and outcomes were retrospectively reviewed and compared between patients who were treated at the time of spasm and nonspasm. Information regarding the following clinical characteristics was collected: age, sex, World Federation of Neurosurgical Societies (WFNS) grade on admission, aneurysm morphology, treatment result, and outcome. We defined from day 4 to day 14 as the timing of spasm, and vasospasm as more than 30% narrowing of the proximal anterior cerebral artery, middle cerebral artery, and internal carotid artery segment during the second examination compared with the first. The chi-squared test or Fisher's exact test were performed to evaluate the covariates for binary categorical dependent variables as appropriate, and nonnormal variables were compared using the Mann-Whitney U test. Results Ten patients (14.7%) underwent coil embolization at the time of vasospasm. Age, sex, WFNS grade, and aneurysm morphology were not different between the spasm and nonspasm groups. Additionally, there were no significant between-group differences in volume embolization ratio, procedure-related complications, occurrence of delayed cerebral ischemia, and outcome at discharge. Conclusion There were no significant between-group differences in treatment results and outcomes between the spasm and nonspasm groups. Endovascular treatment at the time of vasospasm could be the optimal treatment method for ruptured cerebral aneurysms.

Surgical techniques and indications for treatment of adult moyamoya disease

Moyamoya disease (MMD) is a chronic, progressive cerebrovascular disease involving the occlusion or stenosis of the terminal portion of the internal carotid artery (ICA) and the proximal anterior and middle cerebral arteries. Adults with MMD have been shown to progressively accumulate neurological and cognitive deficits without treatment, with a mortality rate double that of pediatric patients with MMD. Surgical intervention is the mainstay of treatment to prevent disease progression and improve clinical outcomes. Several different types of bypasses can be utilized for revascularization in MMD, including indirect, direct, and combined forms of extracranial-to-intracranial (EC-IC) bypass. Overall, the choice of appropriate technique requires consideration of the age of the patient, preoperative hemodynamics, neurologic status, and territories most at risk and in need of revascularization. Here, we will review the indications and surgical techniques for the treatment of adult MMD. Step-by-step instructions for performing several bypass variants with technical pearls are discussed.

Delayed Rupture of an Anterior Communicating Artery Pseudoaneurysm Caused by Distal Occlusion Thrombectomy Using a Stent Retriever: A Case Report and Mechanism of Injury

We report a case of delayed rupture of an anterior communicating artery (Acom) pseudoaneurysm following mechanical thrombectomy (MT) of a distal artery occlusion using a stent retriever. An elderly patient with right hemiparesis showed left proximal internal cerebral artery and middle cerebral artery occlusions. During MT, a fragmented thrombus moved to the anterior cerebral artery (ACA). A stent retriever was deployed to the occluded ACA, and the Acom and proximal ACA segment were significantly straightened. Additionally, we attempted a blind exchange mini-pinning (BEMP) technique, but a subarachnoid hemorrhage (SAH) occurred. Bleeding was almost entirely absorbed 9 days after the procedure, but the SAH recurred at 20 days, and computed tomography angiography revealed a new pseudoaneurysm formation in the Acom. We suggest that the proposed mechanism of pseudoaneurysm formation was likely due to the dislocation and avulsion of the Acom perforators when the ipsilateral ACA was pushed and pulled during MT.

A clinical investigation of the anatomy of the proximal anterior cerebral artery and its association with anterior communicating artery aneurysm

PurposeAneurysms of the anterior communicating artery (ACoA) account for ∼22–25% of deaths attributed to subarachnoid haemorrhage secondary to ruptured aneurysms. The variant anatomy of the vessels surrounding the ACoA may alter hemodynamic forces which may have a bearing on the development of the ACoA aneurysm. The present study aimed to describe the anatomy of the proximal anterior cerebral artery and to describe ACoA aneurysm morphometry and projection. Methods100 CT angiograms of patients with ACoA aneurysm were analysed. Out of the 100 CT angiograms, aneurysm morphology was analysed on 75 CT reconstructed angiograms. The recorded parameters were statistically correlated with demographic characteristics. ResultsThe average length and diameter of the A1 segment of the anterior cerebral artery (ACA) was 13.36 ± 2.70 mm and 1.66 ± 0.47 mm on the right, respectively; and 12.43 ± 2.90 mm and 1.77 ± 0.53 mm on the left, respectively. The average length and diameter of the A2 segment of the ACA was 24.72 ± 6.12 mm and 1.59 ± 0.42 mm on the right, respectively; and 25.07 ± 5.88 mm and 1.60 ± 0.41 mm on the left, respectively. The aneurysm morphometry was described as mean dome length (5.80 ± 2.41 mm), mean dome diameter (4.43 ± 2.15 mm) and the mean neck diameter (3.02 ± 1.72 mm). The projection of the dome was classified as anterior (40%), posterior (6%), inferior (18%) and superior (36%). ConclusionVariant anatomy of the vessels surrounding the ACoA were found in 53% of patients with ACoA aneurysm. Therefore, this study concurs with the literature that variant anatomy may be considered a risk factor for the development of ACoA aneurysms. Furthermore, knowledge of the anatomical parameters of the vessels surrounding the ACoA may be significant to the endovascular surgeon during pre-operative planning.

Morphological and Hemodynamic Risk Factors for the Rupture of Proximal Anterior Cerebral Artery Aneurysms (A1 Segment).

ObjectiveThe treatment of unruptured small intracranial aneurysms remains controversial. A distinguishing characteristic of A1 segment aneurysms is that they tend to rupture when they are small, which may be related to their distinctive morphology and hemodynamics. Our study sought to investigate the rupture risk factors of A1 segment aneurysms by analyzing the clinical risk factors, morphology, and hemodynamic characteristics of A1 segment aneurysms.MethodsWe retrospectively enrolled 49 (23 ruptured, 26 unruptured) consecutive patients presenting to our institute with A1 segment aneurysms between January 2010 and March 2020. Independent risk factors associated with the rupture of A1 segment aneurysms were analyzed by multivariate regression analysis in the ruptured group and unruptured group.ResultsClinical risk factors, including age, sex, hypertension, smoking history, and SAH family history revealed no difference between the ruptured and unruptured groups. The ruptured group presented a significantly larger size (Size, P = 0.007), aspect ratio (AR, P = 0.002), size ratio (SR, P = 0.001), bottleneck index (BN, P = 0.016), dome-to-neck ratio (DN, P = 0.001), and oscillatory shear index (OSI) (P = 0.001) than the unruptured group. The normalized wall shear stress (NWSS) of the ruptured aneurysms was lower than the unruptured group (P = 0.001). In the multivariate regression analysis, only SR (OR = 3.672, P = 0.003) and NWSS (OR = 0.474, P = 0.01) were independent risk factors in the A1 segment aneurysm rupture.ConclusionA higher SR and lower NWSS revealed a close connection with the rupture of A1 segment aneurysms in our study, thus providing a reference for clinical decision-making in treating A1 segment unruptured aneurysms.

Outcomes after reperfusion therapies in patients with ACA stroke: A multicenter cohort study from the EVATRISP collaboration

BackgroundPatients with stroke secondary to occlusions of the anterior cerebral artery (ACA) often have poor outcomes. The optimal acute therapeutic intervention for these patients remains unknown. MethodsPatients with isolated ACA-stroke were identified from 10 centers participating in the EndoVascular treatment And ThRombolysis in Ischemic Stroke Patients (EVATRISP) prospective registry. Patients treated with endovascular thrombectomy (EVT) were compared to those treated with intravenous thrombolysis (IVT). Odds ratios with 95% confidence intervals (OR; 95%CI) were calculated using multivariate regression analysis. ResultsIncluded were 92 patients with ACA-stroke. Of the 92 ACA patients, 55 (60%) were treated with IVT only and 37 (40%) with EVT (±bridging IVT). ACA patients treated with EVT had more often wake-up stroke (24% vs. 6%, p = 0.044) and proximal ACA occlusions (43% vs. 24%, p = 0.047) and tended to have higher stroke severity on admission [NIHSS: 10.0 vs 7.0, p = 0.054). However, odds for favorable outcome, mortality or symptomatic intracranial hemorrhage did not differ significantly between both groups. Exploration of the effect of clot location inside the ACA showed that in patients with A1 or A2/A3 ACA occlusions the chances of favorable outcome were not influenced by treatment allocation to IVT or EVT. DiscussionTreatment with either IVT or EVT could be safe with similar effect in patients with ACA-strokes and these effects may be independent of clot location within the occluded ACA.

Abstract 1122‐000005: Plasminogen Activator Inhibitor‐1 5G/5G Polymorphism – Do We Know All About It?

Introduction : The etiology of ischemic stroke is heterogeneous, and it has been proposed that different stroke subtypes might have different genetic architecture 1,2. The plasminogen activator inhibitor‐1 (PAI‐1) has been of particular interest due to its role in thrombotic diseases. Several polymorphisms have been found for this gene, with some having protective effect while others increase the risk of ischemic and hemorrhagic strokes 3,4. The protective role appears to be due to the role of PAI‐1 in fibrinolytic cascade and that PAI‐1 also inhibit plasmin‐dependent metalloproteinases activation. We hereby, present a case of ischemic stroke in young adult and its association with our gene of interest. Methods : Case: We present a case of 43‐year‐old woman with past medical history significant for Acetylcholine Receptor (AChR) antibody positive Myasthenia Gravis diagnosed in 1993 status post thymectomy (1994), currently on prednisone and intravenous immunoglobulin every two weeks (failed cyclosporine and mycophenolate mofetil). She had two events in 2018 where she reported episodic right sided numbness and weakness that lasted for few hours. Stroke workup was done, and she was found to have focal moderate to severe stenosis of the left middle cerebral artery (MCA) on CT angiography (figure 1) with very subtle left hypoperfusion in the MCA on the brain single‐photon emission computerized tomography scan. She underwent catheter angiogram (figure 1) showing severe stenosis involving the mid and distal M1 segment of the left MCA and nondominant proximal A1 segment left anterior cerebral artery (ACA). There were robust leptomeningeal collaterals from the left anterior and left posterior cerebral arteries. She also reported history of two miscarriages in the first trimester. Hypercoagulable workup was done and all of those were negative including: SLE profile, Lupus anticoagulant, ANA comprehensive panel, Cryoglobulin, Anticardiolipin antibody, Antithrombin III, Antithrombin antigen, protein C, protein S, Factor VIII activity, Factor V Leiden. She also had rheumatoid arthritis factor, Homocysteine, sedimentation rate, and C‐reactive protein done which were unremarkable. Genetic workup showed that she is PAI‐1 5G/5G homozygous. She has been stable since 2018 without new focal neurological events and is on Aspirin monotherapy and Statin. Results : The genetics for stroke disease are very complicated and yet to be discovered fully. The association between PA‐1 5G/5G and intracranial stenosis has not been reported previously. New genetic associations will need to be increasingly considered as we assess our cerebrovascular diseases and stroke patients Conclusions : • With the current knowledge, ischemic stroke have polygenic basis but no single common “stroke gene” has been identified yet. • Here we present a case suggesting that PAI‐1 5G/5G genotype is may be associated with an independent risk of intracranial atherosclerosis.

Clinical and neuroimaging analysis of carotid infarction in the acute ischemic stroke

Background. The assessment of clinical manifestations in patients with acute pre-circular infarction is important for verification of the lesion, the choice of the treatment program, prediction of the stroke consequences. The purpose is to investigate the clinical, neurological, and neuroimaging features of lacunar and non-lacunar carotid infarctions in acute ischemic stroke and to assess their short-term consequences. Materials and methods. There was performed a clinical and radiological analysis of carotid infarction in 540 patients with acute ischemic stroke, which were divided into two groups: 155 patients were verified for infarcts in the cortex and white matter of the brain in the vasculature of the anterior and middle cerebral artery; in 385 patients, infarct foci were found in the area of the deep hemispheres of the brain (subcortical-capsular infarcts). Results. Clinical neuroimaging analysis of patients with ischemic stroke in the vasculature of the cortical branches of the anterior and middle cerebral arteries of the anterior circulatory basin showed that acute cerebral circulatory disorders caused the development of small cortical infarctions in 89 (57.4 %) patients and 65 (41 %) — lacunar infarction, in one patient (0.7 %) with occlusion of the proximal anterior cerebral artery — total infarction. The neurological clinical picture of infarcts of varying localization, which was determined by the location and size of the lesion, was described. Conclusions. The obtained results showed that the consequences of anterior circular infarctions depended on the localization of the lesion of the arterial area, the caliber of the infarction of the dependent artery, the size of the infarct locus. For the most part, these factors determined the background severity of neurological deficit after the development of acute ischemic stroke.

Type 4 persistent primitive olfactory artery associated with contralateral accessory middle cerebral artery arising from the fenestrated segment of the distal anterior cerebral artery

Persistent primitive olfactory artery (PPOA) is a rare variation of the proximal anterior cerebral artery (ACA) that generally follows an extreme anteroinferior course and takes a hairpin turn before continuing to the A2 segment of the ACA (type 1). There are four other types of extremely rare variations. The type 4 variation continues to the accessory middle cerebral artery (MCA) instead of the ACA. Only a few cases have been reported. We herein report a case of type 4 PPOA in which the contralateral side of the accessory MCA arose from the fenestrated segment of the distal ACA. No similar cases were found in the relevant English-language literature. For the identification of these variations on MR angiography, volume-rendering images were superior to maximum-intensity-projection images.

Transcranial Doppler Ultrasound Pre and Post Middle Cerebral Artery Stent Placement

This report describes a 42 year old male with a 5 year history of transient ischemic attacks (TIAs), migraines, previous strokes, and symptoms referable to a left middle cerebral artery (MCA) territory event. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) revealed severe stenoses in the proximal left MCA and proximal left anterior cerebral artery (ACA). Transcranial Doppler ultrasound/Transcranial Doppler imaging (TCD/TCI) and cerebral angiogram confirmed the stenoses with a mean flow velocity (MFV) at the proximal left MCA, with a velocity of 230 cm/s. A Wingspan Stent System stent was placed in the proximal left MCA. Cerebral angiogram and serial TCD examinations performed post stent placement showed a patent left MCA without stenosis and a MFV of 55 cm/s. The left ACA was occluded following proximal left MCA stent placement. This case highlights the usefulness of TCD in the assessment of the MCA and other basal cerebral arteries.

Clinical prognosis of isolated anterior cerebral artery territory infarction: a retrospective study

BackgroundIsolated anterior cerebral artery territory (ACA) infarction is a rare phenomenon, and is known to have distinctive clinical features. Little is known regarding the clinical prognosis of isolated ACA territory infarction with associated factors, and its impact on dwelling and job status. We investigated the short- and long-term outcomes of anterior cerebral artery (ACA) territory infarction, and the associated factors involved in the development of the distinctive symptoms.MethodsThis retrospective study in a prospective cohort of acute ischaemic stroke patients included consecutively enrolled patients with isolated ACA territory infarction. We investigated the functional status using the modified Rankin scale (mRS) score at discharge, three months’ post-discharge, and one-year post-discharge. We also investigated the occlusion site of the ACA (proximal vs. distal); presence of distinctive symptoms of ACA territory infarction including behaviour changes, indifference, aphasia, and urinary incontinence; and the effect of these symptoms on dwelling and job status one year after discharge.ResultsBetween April 2014 and March 2019, 47 patients with isolated ACA territory infarction were included. Twenty-nine patients (61.7 %) had good outcomes (mRS ≤ 2) at discharge; however, the mRS score increased at three months (40; 85.1 %, p < 0.001) and one year (41; 87.2 %) post-discharge. Occlusion of the ACA proximal segment was independently associated with the development of distinctive symptoms (adjusted odds ratio, 17.68; 95 % confidence interval: 2.55–122.56, p < 0.05). Twenty-one (48.8 %) patients with good outcomes at one year experienced a change in dwelling status and job loss; 20 (95.2 %) of them had distinctive ACA territory symptoms with proximal ACA occlusion.ConclusionsShort- and long-term outcomes of isolated ACA territory infarction were favourable. However, proximal segment occlusion was associated with the development of distinctive symptoms, possibly related to future dwelling and job status.

Middle cerebral artery pressure laterality in patients with symptomatic ICA stenosis.

An internal carotid artery (ICA) stenosis can potentially decrease the perfusion pressure to the brain. In this study, computational fluid dynamics (CFD) was used to study if there was a hemispheric pressure laterality between the contra- and ipsilateral middle cerebral artery (MCA) in patients with a symptomatic ICA stenosis. We further investigated if this MCA pressure laterality (ΔPMCA) was related to the hemispheric flow laterality (ΔQ) in the anterior circulation, i.e., ICA, proximal MCA and the proximal anterior cerebral artery (ACA). Twenty-eight patients (73±6 years, range 59–80 years, 21 men) with symptomatic ICA stenosis were included. Flow rates were measured using 4D flow MRI data (PC-VIPR) and vessel geometries were obtained from computed tomography angiography. The ΔPMCA was calculated from CFD, where patient-specific flow rates were applied at all input- and output boundaries. The ΔPMCA between the contra- and ipsilateral side was 6.4±8.3 mmHg (p<0.001) (median 3.9 mmHg, range -1.3 to 31.9 mmHg). There was a linear correlation between the ΔPMCA and ΔQICA (r = 0.85, p<0.001) and ΔQACA (r = 0.71, p<0.001), respectively. The correlation to ΔQMCA was weaker (r = 0.47, p = 0.011). In conclusion, the MCA pressure laterality obtained with CFD, is a promising physiological biomarker that can grade the hemodynamic disturbance in patients with a symptomatic ICA stenosis.

Comparison of Single and Dual Monitoring during Carotid Endarterectomy

We compared the rate of selective shunt and pattern of monitoring change between single and dual monitoring in patients undergoing carotid endarterectomy (CEA). A total of 121 patients underwent 128 consecutive CEA procedures. Excluding five procedures using internal shunts in a premeditated manner, we classified patients according to the monitoring: Group A (n = 72), patients with single somatosensory evoked potential (SSEP) monitoring; and Group B (n = 51), patients with dual SSEP and motor evoked potential (MEP). Among the 123 CEAs, an internal shunt was inserted in 12 procedures (9.8%) due to significant changes in monitoring (Group A 5.6%, Group B 15.7%, p = 0.07). The rate of shunt use was significantly higher in patients with the absence of contralateral proximal anterior cerebral artery (A1) on magnetic resonance angiography (MRA) than in patients with other types of MRA (p <0.001). Significant monitor changes were seen in 16 (12.5%) in both groups. In four of nine patients in Group B, SSEP and MEP changes were synchronized, and in the remaining five patients, a time lag was evident between SSEP and MEP changes. In conclusion, the rate of internal shunt use tended to be more frequent in patients with dual monitoring than in patients with single SSEP monitoring, but the difference was not significant. Contralateral A1 absence may predict the need for a shunt and care should be taken to monitor changes throughout the entire CEA procedure. Use of dual monitoring can capture ischemic changes due to the complementary relationship, and may reduce the rate of false-negative monitor changes during CEA.

Reader response: Optimizing in-hospital triage for large vessel occlusion using a novel clinical scale (GAI2AA).

In their development of the GAI2AA scale,1 Ohta et al. identified a history of atrial fibrillation (AF) or AF on ECG as independent predictors of an anterior circulation large vessel occlusion (LVO) in patients presenting within 4.5 hours of symptom onset. Using a different case definition—all patients who had an occlusion of the common carotid, internal carotid, proximal middle cerebral, anterior or posterior cerebral arteries, or the vertebrobasilar system—and a different patient population—patients admitted to the University of Kentucky Medical Center vs 3 Japanese stroke centers—we also found that a history of AF was associated with an LVO (36.2% vs 18.5%, p < 0.001),2 although the frequency was less than reported by Ohta et al. (65% vs 24%, p < 0.001). In our cohort, the C-statistic for LVO based on a history of AF alone (0.579; 95% CI 0.540–0.617) reflected no more than moderate discriminative capacity and did not improve the accuracy of the Cincinnati Prehospital Stroke Severity scale, Los Angeles Motor Scale, Rapid Arterial Occlusion Evaluation score, or the Field Assessment Stroke Triage for Emergency Destination scale. Nonetheless, simply obtaining a history of AF can alert emergency responders that a patient with an acute focal neurologic deficit may have an LVO.