Vertebral Artery Diameter and Flow: Nature or Nurture

Efficacy and safety of a new torque-controlled angiographic catheter in cerebral angiography: A multicenter, randomized, open-label trial

Objective

We aimed to examine the effectiveness and safety of a novel torque-controlled catheter for cerebral angiography.

Methods

A total of 417 patients who underwent routine transfemoral cerebral angiography were enrolled in a randomized controlled study to compare the new torque-controlled and control group catheters. Device success was assessed on parameters such as the assessment of the common carotid artery, device rotation force, and success rate with the crossover group after the failed procedure. Four neurointerventionalists investigated the degree of satisfaction of using the new device. Superiority and non-inferiority tests of satisfaction scores were estimated for the new torque-controlled and the control group catheters.

Results

The new torque-controlled catheter showed improved performance in terms of technical device success (92.79 vs. 98.09 %, P = 0.010), crossover after technical device failure (0 vs. 86.67 %, P = 0.004), and common carotid artery access (92.79 vs. 98.56 %, P = 0.004). The flexibility and rotational force of the new torque-controlled catheter were higher than those of the control group catheters (75.48 vs. 100 %, P < 0.001). No marked adverse cerebrovascular accidents or vessel damage occurred in either group during the procedure. The differences between the two groups in terms of the device rotational force and operator satisfaction were 1.836 (1.765-1.907) and 2.092 (2.000-2.183), respectively. The new torque-controlled catheter showed superior device rotational force satisfaction, operator satisfaction, and manufacturer satisfaction, with statistical significance.

Conclusion

The new torque-controlled catheter was effective, safe, and convenient compared to the control group catheters for diagnostic cerebrovascular angiography.

Morphological Features of the Vertebrobasilar System Predict Ischemic Stroke Risk in Spontaneous Vertebral Artery Dissection

The vertebral artery's morphological characteristics are crucial in spontaneous vertebral artery dissection (sVAD). We aimed to investigate morphologic features related to ischemic stroke (IS) and develop a novel prediction model. Out of 126 patients, 93 were finally analyzed. We constructed 3D models and morphological analyses. Patients were randomly classified into training and validation cohorts (3:1 ratio). Variables selected by LASSO - including five morphological features and five clinical characteristics - were used to develop prediction model in the training cohort. The model exhibited a high area under the curve (AUC) of 0.944 (95%CI, 0.862-0.984), with internal validation confirming its consistency (AUC = 0.818, 95%CI, 0.597-0.948). Decision curve analysis (DCA) indicated clinical usefulness. Morphological features significantly contribute to risk stratification in sVAD patients. Our novel developed model, combining interdisciplinary parameters, is clinically useful for predicting IS risk. Further validation and in-depth research into the hemodynamics related to sVAD are necessary.

Vertebral artery hypoplasia and hemodynamic impairment in transient global amnesia: a case control study

Introduction

The aetiology of transient global amnesia (TGA) is still a matter of debate. Besides ischemia of the mesial temporal lobe including the hippocampus, migraine-like mechanisms, epileptic seizures affecting mnestic structures, or venous congestion in the (para) hippocampal area due to jugular vein insufficiency have been discussed. We assessed the diameters of the intracranial arteries of TGA patients compared to controls to identify differences that support the hypothesis of reduced hippocampal perfusion as a pivotal factor in the pathophysiology of TGA.

Methods

We reviewed magnetic resonance imaging time of flight angiographies (TOF-MRA) that were acquired during in-patient treatment of 206 patients with acute TGA.

Results

The diameters of the vertebral artery (VA) in the V4 segment, the proximal basilar artery, and the internal carotid arteries were measured manually. We compared the findings with TOF-MRA images of an age and sex matched control group of neurological patients without known cerebrovascular pathology. In TGA patients the diameter of the right VA was significantly (p < 0.01) smaller compared to controls (2.09 mm vs. 2.35 mm). There were no significant differences in the diameters of the other vessels. Only the fetal variant of the posterior cerebral artery was slightly more common in TGA.

Discussion

The smaller diameter (hypoplasia) of the right VA supports the hypothesis of a contribution of hemodynamic factors to the pathophysiology of TGA. The fact that hypoplasia represents a congenital condition might be the explanation why previous studies failed to find an increased rate of the classical (acquired) vascular risk factors.

The association between vertebral artery hypoplasia and fetal-type variants of the posterior cerebral artery with imaging findings among patients with posterior circulation stroke: A single-center cross-sectional study

Background and Aim

The present study investigated the correlation between vertebral artery hypoplasia and fetal-type variations of posterior cerebral arteries with stroke patterns and imaging findings in individuals with posterior circulation ischemic stroke.

Methods

In this cross-sectional study, patients with symptoms of acute ischemic stroke in the posterior circulation system referred to Ghaem Hospital in Mashhad between 2016 and 2022 were investigated. Demographic data, including age, gender, systemic diseases, history of previous stroke or transient ischemic attacks, and clinical manifestations of patients, were recorded using questionnaires and checklists from patient files. The results of imaging studies, including magnetic resonance imaging and computed tomography angiography, were also recorded. The obtained data were analyzed by SPSS statistical software.

Results

Among 974 patients suffering from posterior circulation ischemic stroke, 155 patients with an average age of 60.44 ± 13.95 years were included in the study, out of which 97 patients (62.6%) were male. Unilateral vertebral artery hypoplasia on the right, left, and bilateral hypoplasia was present in 67 (43.2%), 35 (22.6%), and 5 (3.2%) patients, respectively. There were complete unilateral fetal origin on the right in 38 (24.5%), complete unilateral on the left in 12 (7.7%), partial unilateral on the right in 12 (7.7%), partial unilateral on the left in 6 (3.9%), complete bilateral in 14 (9%), and partial bilateral in 8 (5.2%) patients. There was no significant relationship between vertebral artery hypoplasia and PCA fetal-type variants with different ischemia locations and infarct patterns (p > 0.05). Also, there was no significant relationship between the age and gender of patients with ischemia location and infarct pattern (p > 0.05).

Conclusion

Despite previous evidence showing a relation between vertebral artery hypoplasia and PCA fetal-type variants as risk factors for PC stroke, the present study did not establish a significant correlation between these factors and the location of ischemia and infarct patterns.

Orthostatic hemodynamics in the vertebral artery and blood pressure in patients with orthostatic dizziness/vertigo

OBJECTIVES

Orthostatic dizziness/vertigo (ODV) is a common symptom and is believed to occur due to the cerebral hypoperfusion caused by orthostatic hypotension (OH). However, the detailed mechanism underlying ODV onset is poorly understood. The vertebral artery (VA) mainly supplies blood to the central vestibular system; therefore, the orthostatic decrease of VA blood flow could possibly lead to ODV. This study investigated the orthostatic blood pressure and VA hemodynamics in ODV patients to elucidate the hemodynamic mechanism underlying ODV onset. Furthermore, the influence of orthostatic hypotension (OH) on VA hemodynamics was examined because OH is probably the most common cause of ODV.

METHODS

This study included 181 patients with ODV and 73 control patients without ODV. All subjects underwent an active standing test to measure the extracranial Doppler (ECD) sonography spectrum of the VA and blood pressure (BP). VA blood flow velocity and BP were simultaneously measured for each patient in the supine static position and then in the upright standing positions following 3 min of standing. We investigated the orthostatic change in the average of flow velocity in bilateral VAs (VAFV) and BP for ODV patients compared with the control patients.

RESULT

VAFV in ODV patients was significantly reduced when standing up compared with the control patients. In the ODV patients, there was no difference in orthostatic decrease in VAFV between patients those with OH and without OH. However, the VAFV in the standing position was significantly lower in patients with OH than without OH. In cases with OH, the ODV patients exhibited a greater decrease in VAFV compared with the control patients, but this was not statistically significant. In the absence of OH, a significantly greater orthostatic decrease in VAFV was observed in ODV patients compared with the controls.

CONCLUSION

Our findings suggest that the orthostatic decrease of VA blood flow is deeply involved in the hemodynamic mechanism underlying ODV onset and is possibly associated with OH and other etiologies.

The Relationship Between Posterior Communicating Artery Formation and Vertebral Artery Flow Parameters

Objectives:

It is important to know the range of normal vertebral artery (VA) flow volume. Diminished VA flow volume is associated with vertebrobasilar insufficiency. The study aim was to investigate the relationship between the posterior communicating artery (PCoA) calibration and the VA flow parameters, in patients with no underlying cerebrovascular disease, below 50 years of age.

Materials and Methods:

The study population consisted of 102 cases below 50 years of age. The basilar artery (BA), internal carotid artery (ICA), and the PCoA calibrations were measured with magnetic resonance angiography. The VA flow parameters (maximum systolic velocity, end-diastolic velocity, mean velocity, VA flow volume, and VA calibration) were measured with duplex sonography.

Results:

There was no statistically significant difference between these two imaging groups, in terms of VA Vmax, VA flow volumes, VA calibrations, and BA calibrations. However, the mean right ICA and mean left ICA calibrations were significantly higher in group 2 than group 1 ( P < .01). There was no significant correlation between mean PCoA calibration and mean Vmax, mean calibration, and the total flow volume of vertebral arteries.

Conclusion:

The findings indicate that the VA flow rate may be relatively maintained, regardless of PCoA measurements in this study.

An Ultrasound Evaluation of the Vertebral Artery in Patients With Vertebral Artery Hypoplasia

Purpose

The aim of the current study was to assess and compare Doppler ultrasound findings, especially the resistivity index (RI), among and between patients with vertebral artery hypoplasia (VAH) and normal populations.

Material and methods

Fifteen consecutive patients with VAH (mean age 54 ± 21 years) and 15 sex-matched controls without VAH (mean age 54 ± 22 years) were selected for the study. The vertebral arteries (VA) were examined with Doppler ultrasound. We also explored each group for sex and age differences (young: age ≤ 50, old: age >50).

Results

The mean RI (MRI), right RI (RRI), left RI (LRI), non-dominant-side RI, and dominant-side RI were significantly higher in the Case Group than the Control Group. In the Case Group, the affected-side RI (A.RI) was significantly higher than the normal side, while the normal side peak systolic velocity was significantly higher than the affected side. The MRI and A.RI were significantly higher in older patients. We also found a significant negative correlation between the mean diameter (MD) and MRI. MRI and A.RI both correlated positively with age in the Case Group, while left peak systolic velocity decreased significantly with age in the Control Group [p-values < 0.05].

Conclusion

The dominant VA had a higher RI in the Case Group than the Control Group. It can therefore be inferred that the dominant VA in patients with VAH does not work completely normally, thus making these patients even more susceptible to vertebrobasilar insufficiency and possible strokes.

Are the Morphological Indices of the Vertebrobasilar System Heritable? A Twin Study Based on 3D Reconstructed Models

Background and Objectives: The asymmetrical vertebral artery (VA) flow and diameter are common findings, which can result in an asymmetrical blood flow in the basilar artery (BA), leading to bending of the artery over time. This study investigated whether the variation of the different vertebrobasilar morphological indices that influence flow characteristics might be inherited. Materials and Methods: We analyzed 200 cerebral magnetic resonance imaging (MRI) scans of healthy Caucasian twins (100 pairs) who underwent time-of-flight MRI. From the scans, we reconstructed the 3D mesh of the posterior circulation from the start of the V4 segment to the basilar tip and subsequently analyzed the morphology of the vertebrobasilar system. The phenotypic covariances of the different morphological parameters were decomposed into heritability (A), shared (C), and unshared (E) environmental effects. Results: 39% of the twins had left dominant VA, while 32.5% had right dominant. In addition, 28.5% were classified as equal. The vertebral artery V4 segment diameter, curvature, and tortuosity were mainly influenced by shared (C) and unshared (E) environmental factors. A moderate heritability was found for the BA length (A: 63%; 95% CI: 45.7–75.2%; E: 37%; 95% CI: 24.8–54.3%) and volume (A: 60.1%; 95% CI: 42.4–73.2%; E: 39.9%; 95% CI: 26.8–57.6%), while the torsion of both arteries showed no heritability and were only influenced by the unshared environment. Conclusions: The length and volume of the BA show a moderate genetical influence. However, most of the measured morphological indices were influenced by shared and unshared factors, which highlight the role of the ever-changing hemodynamic influences shaping the geometry of the vertebrobasilar system.

Evaluation of hemodynamic characteristics in posterior circulation infarction patients with vertebral artery dominance by color doppler flow imaging and transcranial doppler sonography

PURPOSE

The aim of this study was to investigate the hemodynamic characteristics of posterior circulation infarction (PCI) patients with the vertebral artery dominance (VAD) using Color Doppler flow imaging (CDFI) and Transcranial Doppler sonography (TCD) and to explore the pathogenesis of PCI caused by VAD.

MATERIALS AND METHODS

A total of 186 consecutive PCI patients were enrolled. All the patients underwent magnetic resonance (MR) examination and the clinical data were collected. According to the brain magnetic resonance angiography (MRA), the patients were divided into VAD and non-VAD groups. CDFI and TCD were performed to identify the hemodynamic parameters of the vertebral artery (VA) and basilar artery (BA).

RESULTS

The male population was significantly more frequent in the VAD group (71.3%) as compared to the non-VAD group (53.1%). The significant difference in hemodynamic parameters was observed between VAD and non-VAD groups. Resistance index (RI) of extracranial and intracranial VA was different as well. There were also differences in the VA side-to-side diameter difference-value, peak velocity (Vp), mean velocity (Vm) and pulsatility index (PI) with varying degrees of BA curvature.

CONCLUSIONS

VA and BA hemodynamic changes caused by VAD may be an important risk factor in the process of occurrence of PCI. The combination of CDFI and TCD can help to detect the hemodynamic changes in the intracranial and extracranial segments of VA and BA. This can have important clinical value in understanding the pathogenesis of PCI.

Vertebral artery hypoplasia: an innocent lamb or a disguise?

BACKGROUND

The role of vertebral artery hypoplasia (VAH) in stroke pathophysiology is still debated. In this study, we correlated extra- and intra-cranial vertebral artery ultrasound findings with brain CT/MRI and clinical outcome.

MATERIALS AND METHODS

We recruited all consecutive first-ever stroke patients with a documented acute ischemic brain lesion and a complete extra-intracranial ultrasound evaluation. Those with previous stroke, or with anterior and posterior strokes were excluded. The prevalence of VAH diagnosed by ultrasound was recorded both in anterior circulation and posterior circulation infarctions. In the latter group, we compared the risk profile, topographic and neuroradiological lesion features, etiology and clinical outcome based on the presence of VAH.

RESULTS

The study included 750 patients [436 males (58%); mean age 65 years; age range 18-90] with first-ever acute ischemic stroke: 193 (25.7%) with a posterior circulation infarction, 557 (74.3%) with an anterior circulation infarction. VAH was more often detected in the former group (33.7 vs. 14.1%; p < 0.0001). Patients with posterior circulation stroke and VAH had a significantly higher frequency of basilar artery stenosis [OR 2.07 (1.00-4.26); p < 0.05], stenosis of the contralateral vertebral artery [64 vs. 36%; OR 3.22 (1.24-8.37); p < 0.05], and fetal-type variant of the posterior cerebral artery [25 vs. 13%; OR 2.17 (1.00-4.68); p < 0.05].

CONCLUSIONS

According to our study, VAH identifies patients at higher risk of posterior circulation stroke, and higher frequency of contralateral vertebral artery stenosis and basilar artery stenosis.

Investigation of circle of Willis variants and hemodynamic parameters in twins using transcranial color-coded Doppler sonography

Morphological and hemodynamic variations of the circle of Willis (CW) may have an important impact on cerebrovascular events. However, the environmental and genetic influence remains unclear. For this reason we studied the variations and hemodynamic parameters of the CW in twins using transcranial color-coded sonography (TCCS). Sixty-four twins, 19 monozygotic (MZ) and 13 dizygotic (DZ) pairs from the Italian Twin Registry (average age 45.0 ± 13.7 years) underwent TCCS and risk factor assessment. We examined CW morphology and recorded peak systolic velocity (PSV), end-diastolic velocity (EDV) and pulsatility index (PI). Raw heritability was determined for hemodynamic parameters, whereas concordance and discordance rates were calculated for CW morphological variants. A normal CW anatomy was observed in the majority of MZ and DZ twins (76.5% and 92.3%, respectively). The most frequent variant was a missing anterior cerebral artery (ACA). There was no significant difference in the prevalence of most CW variants depending on the zigosity. Concordance rates were low regarding the presence of variant CW anatomy both in MZ and DZ groups (0.14 and 0.00, respectively). Women had a significantly higher PI in vertebral arteries (VA) and in the right ACA (p = 0.01, p = 0.02 and p < 0.01, respectively). An inverse correlation was observed between hemodynamic parameters and age. Morphological variants of the CW do not seem to be heritable; they are most likely determined by environmental factors. In contrast, hemodynamic parameters of the CW are moderately heritable and this might have implications in the management and prevention of cerebrovascular diseases.