Can intracranial time-of-flight-MR angiography predict extracranial carotid artery stenosis?

Objectives Extracranial stenosis of the internal carotid artery (ICA) is an important cause of ischemic stroke and transient ischemic attack (TIA). It can be diagnosed using contrast-enhanced CT or MR angiography (MRA) as well as Doppler ultrasound. In this study, we assessed the diagnostic value of intracranial time-of-flight (TOF) MRA to predict extracranial ICA stenosis (ICAS). Methods We retrospectively analyzed consecutive patients with acute ischemic stroke or TIA and middle- (50–69%) or high-grade (70–99%) unilateral extracranial ICAS according to NASCET criteria assessed by ultrasound between January 2016 and August 2018. The control group consisted of patients without extracranial ICAS. Intraluminal signal intensities (SI) of the intracranial ICA on the side of the extracranial stenosis were compared to the contralesional side on TOF-MRA source images. SI ratios (SIR) of contralesional:lesional side were compared between groups. Results In total, 151 patients were included in the main analysis. Contralesional:lesional SIR in the intracranial C4-segment was significantly higher in patients with ipsilateral extracranial ICA stenosis (n = 51, median 74 years, 57% male) compared to the control group (n = 100, median 68 years, 48% male). Mean SIR was 1.463 vs. 1.035 (p < 0.001) for right-sided stenosis and 1.362 vs. 1.000 (p < 0.001) for left-sided stenosis. Receiver-operating characteristic curve demonstrated a cut-off value of 1.086 for right-sided [sensitivity/specificity 75%/81%; area under the curve (AUC) 0.81] and 1.104 for left-sided stenosis (sensitivity/specificity 70%/84%; AUC 0.80) in C4 as a good predictor for high-grade extracranial ICAS. Conclusions SIR on TOF-MRA can be a marker of extracranial ICAS.

Cerebral venous steal equation for intracranial segmental perfusion pressure predicts and quantifies reversible intracranial to extracranial flow diversion

Cerebral perfusion is determined by segmental perfusion pressure for the intracranial compartment (SPP), which is lower than cerebral perfusion pressure (CPP) because of extracranial stenosis. We used the Thevenin model of Starling resistors to represent the intra-extra-cranial compartments, with outflow pressures ICP and Pe, to express SPP = Pd–ICP = FFR*CPP–Ge(1 − FFR)(ICP–Pe). Here Pd is intracranial inflow pressure in the circle of Willis, ICP—intracranial pressure; FFR = Pd/Pa is fractional flow reserve (Pd scaled to the systemic pressure Pa), Ge—relative extracranial conductance. The second term (cerebral venous steal) decreases SPP when FFR < 1 and ICP > Pe. We verified the SPP equation in a bench of fluid flow through the collapsible tubes. We estimated Pd, measuring pressure in the intra-extracranial collateral (supraorbital artery) in a volunteer. To manipulate extracranial outflow pressure Pe, we inflated the infraorbital cuff, which led to the Pd increase and directional Doppler flow signal reversal in the supraorbital artery. SPP equation accounts for the hemodynamic effect of inflow stenosis and intra-extracranial flow diversion, and is a more precise perfusion pressure target than CPP for the intracranial compartment. Manipulation of intra-extracranial pressure gradient ICP–Pe can augment intracranial inflow pressure (Pd) and reverse intra-extracranial steal.

Apolipoproteins A1 and B and their ratio in acute ischemic stroke patients with intracranial and extracranial arterial stenosis: an Egyptian study

Background Apolipoprotein A1 and B and their ratio are considered a better biomarker for cardiovascular diseases than a lipid profile, but this previous finding is not proved to cerebrovascular ischemic diseases. The aim of this study is to assess the relation between apolipoprotien A1 and B and their ratio to intra- and extracranial carotid atherosclerosis in patients with ischemic acute stroke. Methods 90 Egyptian patients with acute ischemic stroke are included in the study, and they have been classified into 3 groups: group 1 includes 30 patients with intracranial stenosis, group 2 includes 30 patients with extracranial arterial stenosis, and group 3 includes 30 patients with non-arterial stenosis. Patients were subjected to clinical assessment, routine laboratory measures, and Color-Coded Duplex Sonography for extracranial and intracranial arteries. The measurement of serum levels of apolipoproteins A1 and B was done using enzyme-linked immuno-sorbent assay (ELISA). Results A statistically significant difference was found between patient groups as regards the frequency of abnormal serum LDL-cholesterol (p = 0.04), being elevated in patients with extracranial stenosis (p = 0.01). There was a significant difference between patients groups as regards the frequency of abnormal serum HDL-cholesterol (p = 0.02), being lower in patients with extracranial stenosis. High Apo B/A1 ratio was an independent risk factor for intracranial arterial stenosis (p = 0.045). An abnormal elevation of serum LDL cholesterol was an independent risk factor of extracranial arterial stenosis (p = 0.021). Conclusion Apo B/A1 ratio is an independent risk factor for intracranial arterial stenosis, while serum LDL cholesterol is an independent risk factor for extracranial arterial stenosis. Apo B/A1 ratio and serum LDL cholesterol are reliable serum biomarkers for cranial arterial stenosis in acute ischemic stroke patients.

Use of dual layered stents in endovascular treatment of extracranial stenosis of the internal carotid artery: one year results of a patient-based meta-analysis of 4 clinical studies

Background Small sized clinical studies evaluating one year outcomes of CAS performed with two available DLS, Roadsaver® (RS) and CGuard® (CG), have been published. Purpose To evaluate one year safety and efficacy of dual layered mesh covered carotid stent systems (DLS) for carotid artery stenting (CAS). Methods We performed an individual patient-level meta-analysis including studies enrolling more than 100 CAS with DLS. Primary endpoint was the death and stroke rate; secondary endpoints were restenosis and in-stent thrombosis rates at one year. Results Patients were divided in two groups according to DLS (RS N=250; CG N=306). At one year, 11 patients died (1.97%), 7 patients in the group RS (2.8%) and 4 patients in the CG one (1.31%), 10 strokes occurred, 4 in the group RS (1.6%) and 6 in the CG one (1.96%). Overall death and stroke rate was 3.77% (N=21), 11 events in the group RS (4.4%) and 10 in the CG group (3.27%). Symptomatic status was the only predictor of death and or stroke. At one year restenosis occurred in 12 patients (2.1%), 10 in the group RS (4%) and 2 in the CG one (0.65%) (p=0.007). In stent thrombosis occurred in 1 patient (0.18%) of the group CG (0.32%). RS use was the only independent restenosis predictor. Conclusions This study suggests that DLS use for CAS is associated to a low one year death and stroke rate and specific DLS stent use could affect restenosis rate. Funding Acknowledgement Type of funding source: None

Patients with isolated vertigo attack preceding stroke have different clinic characteristics: a retrospective study

Background Isolated vertigo attack history preceding the acute stroke were frequently accompanying with other focal neurological symptoms. To clarify the different clinical characteristics between isolated vertigo attack and vertigo symptom accompanying hemiplegia preceding stroke, we performed this 4-year retrospective study. Methods Medical records of 1283 patients hospitalized with vertigo symptom had been screened. Patients were divided into two groups: isolated vertigo attack history preceding the stroke defined as IVA group, vertigo symptom accompanying hemiplegia attack defined as VAH group. Clinic characteristics including ABCD2 score, infarction volume and location, relative risk factors and the following medical intervention were compared between the group. Results Patients featured with VAH had higher extracranial stenosis (21.2% vs. 9.0%, P < 0.01) and ABCD2 score (3.7 ± 1.9 vs. 2.3 ± 1.5, P = 0.03), patient with IVA showed a higher diabetic prevalence (40.9% vs. 29.7%, P = 0.02). The frequency of vertigo events tended to be more commonly in patient with VAH (median 3.1 vs. 5.5, p < 0.03). The total cerebral infarction volume in IVA group tended to be larger than VAH with a median of 4.56 cm3 versus 2.32 cm3 (p = 0.02). Additionally, less patients with IVA sought medical intervention when vertigo symptom occurred. Conclusions Clinical characteristics including ABCD2 score, total cerebral infarction volume and the location were different between AVH and IVH group. In addition, less patients in IVH cohort sought medical intervention when vertigo symptom occurred.

075 Association between intracranial stenosis and extracranial stenosis seen in stroke patients

IntroductionThe association between intracranial stenosis (ICS) and extracranial stenosis (ECS) using CT angiography (CTA) and the occurrence of ischaemic stroke and TIA has not yet been fully investigated.This study aimed to investigate if there is a clinically significant relationship between ICS and ECS with stroke and its risk factors, including diabetes, hypertension, hypercholesterolemia, atrial fibrillation (AF) and ischaemic heart disease (IHD).MethodsFour hundred and fifteen consecutive patients that presented to Calvary Public Hospital, Bruce were retrospectively analysed, with 158 excluded for incomplete CTA and MRA results. ICS and ECS severity was based on grading used in the WASID and SAMPRISS trials, while the Fazekas scale was used to grade periventricular white matter disease. CTA findings were used to base the presence and absence of stenosis.ResultsICS and/or ECS was present in 80% with ischaemic stroke, 78% with TIAs but comparatively only in 56% of those diagnosed as ‘mimics’ (p<0.05). Univariate analysis demonstrated an association between presence of ICS and AF, hypertension, IHD and diabetes (82%, 73%, 84%, 78%; p<0.001) respectively, while for ECS only with AF, hypertension and IHD (77%, 67%, 81%; p<0.001) respectively. Diabetes was independently associated as single biggest risk factor for ICS. Most steno-occlusive lesions were bilateral for ICS and ECS at 80% and 61%, respectively. There also seems to be an association between the presence of ECS and the presence of ICS, with ECS particularly demonstrating predictive value for ICS (ECS PPV for ICS=0.85, chi-square p-value<0.001).ConclusionThese findings suggest a significant association between the presence of ICS and ECS with the occurrence of ischaemic stroke and TIAs as well as with well-known stroke risk factors. This also indicates that perhaps the underlying pathophysiology for steno-occlusive lesions plays a role in ischaemic stroke and warrants further investigating.

Digital Subtraction Angiographic Pattern of Extracranial and Intracranial Atherosclerotic Arterial Stenosis among Ischemic Stroke Patients

Background: Stroke is the second leading cause of death in adult population throughout the world and is the most common cause of severe adult physical disability. Atherosclerotic stenosis is one of the predominant cause of ischemic stroke. The aim of this study was to evaluate the type, number and severity of intracranial and extracranial atherosclerotic stenosis and its association with different risk factors. Methods: This prospective observational study was conducted in the Department of Neurology, BSMMU, Dhaka, from July 2017 to August 2018. Only patients having significant (≥50%) symptomatic stenosis were included in this study. Results: In total 42 cases, 25 patients had extracranial stenosis, 13 patients had intracranial stenosis and 4 patients had both intracranial and extracranial stenosis. Overall 17 (40.47%) patients have intracranial involvement and 29 (69.04%) patients had extracranial involvement. The most commonly involved intracranial stenotic segment was MCA, present in 8 (32%) out of 25 intracranial segments followed by ICA 7 (28%) and intracranial vertebral artery 4(16%). Most commonly involved extracranial stenotic segment was ICA, present in 37 (77.08%) out of 48 extracranial segments. Diabetes was found to be the most common risk factor of intracranial stenosis (p value 0.022) while hypercholesterolemia was the major risk factor for severe (≥70%) stenosis. Conclusion: Extracranial arterial stenosis is more common than intracranial arterial stenosis. Anterior circulation stenosis is more common than posterior circulation stenosis. Intracranial stenosis is more prevalent in diabetic patients. Hypercholesterolemiaismore commonly seen in severe (e”70%) stenosis. Bangladesh Journal of Neuroscience 2017; Vol. 33 (2): 89-95