Extracranial and intracranial sonographic findings in vertebral artery diseases

Low Vertebrobasilar Velocity Is Associated with a Higher Risk of Posterior Circulation Ischemic Lesions

Background: Transcranial color-coded sonography (TCCS) is used as a real-time tool to evaluate patients suspected of having vertebrobasilar insufficiency (VBI). However, the sonographic criteria for VBI remain inconclusive. The purpose of this study was to analyze the velocity in the vertebrobasilar system, which links the risk for posterior circulation infarction (POCI) and total ischemic stroke (TIS) in patients with VBI. Methods: Patients’ data were retrospectively reviewed if they were suspected of having VBI within a 2-year period. Baseline characteristics, brain images, and a series of sonography data were recorded and analyzed. We compared vertebrobasilar (VB) velocities in different age groups and in patients with infarctions. Results: A total of 875 patients were enrolled, with 112 and 427 candidates in the POCI and TIS groups, respectively. The mean velocity (MV)s of BA and bilateral VAs were all negatively correlated with age (all p < 0.001). The adjusted odds ratio was 2.55 (1.58−4.13, p < 0.001) in POCI and 1.75 (1.15−2.67, p = 0.009) in TIS if the mean velocity of the VB arteries was below 15 cm/s. Conclusions: Low VB velocity detected in TCCS was more commonly associated with ageing-related changes and a higher risk of both POCI and TIS. Recognition and aggressive treatment for these patients are necessary.

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.

[Subclavian artery stenosis combined with vertebral artery stenosis may lead to compensatory blood flow changes in the contralateral vertebral artery]

OBJECTIVE

To investigate the severity of blood steal and the hemodynamic profiles in patients with subclavian artery stenosis combined with vertebral artery stenosis.

METHODS

A retrospective analysis was performed of transcranial Doppler (TCD) data from patients with subclavian artery stenosis (SAS) and concomitant unilateral/bilateral vertebral artery stenosis (VAS, &gt;50%) or occlusion in our institution between February, 2014 and July, 2018.Thirty-seven patients with SAS combined with VAS (SAS+VAS) were reviewed for types of blood steal, peak systolic velocities of blood flow in affected subclavian artery and the contralateral vertebral artery, and the findings of hyperemia testing.These data were also reviewed for 39 SAS patients without VAS (control group) for comparison of blood steal and hemodynamic profiles.

RESULTS

In SAS+VAS group, 5 patients showed no blood steal; blood steal in stage Ⅰ was found in 22 patients, stage Ⅱ in 7, and stage Ⅲ in 3, as compared to the numbers of 17, 12 and 10 in the control group, respectively (H=9.431, P=0.002).The peak systolic velocity of the contralateral vertebral artery was 43.91±17.43 cm/s in SAS+VAS group, significantly lower than that in the control group (53.56±17.45 cm/s; t= 629.5, P=0.006).Hyperemia testing showed a significant difference in the negative rate between SAS+VAS group and the control group[35.1%(13/37) vs 7.7%(3/39);χ²=8.603, P=0.003).

CONCLUSIONS

SAS combined with VAS may lead to reduced compensatory blood flow in the contralateral vertebral artery to lessen the severity of subclavian steal syndrome.

Extracranial and Intracranial Ultrasonographic Findings in Posterior Circulation Infarction

OBJECTIVES

Patients with posterior circulation infarction are at higher risk of early recurrent stroke, especially those with vertebrobasilar stenosis or hypoplasia. The clinical presentations of this condition vary over a broad range, making diagnosis and treatment a challenge. Hemodynamic changes and stenosis detected by ultrasonography (US) are sensitive and important indicators for further evaluation. In this study, we correlated extracranial and intracranial US characteristics with brain magnetic resonance imaging (MRI) in patients with posterior circulation infarction.

METHODS

Inpatients with acute ischemic stroke who received both MRI and US were enrolled. Baseline characters, underlying disorders, the ischemic territory, and vascular stenosis on MRI were recorded. Series of US data, including flow volume, diameter, mean velocity, and pulsatility index, were analyzed. Patients with new infarction over the medulla, pons, midbrain, or cerebellum were enrolled as the posterior circulation infarction group. Patients with pure anterior circulation infarction were also enrolled.

RESULTS

A total of 210 patients with anterior circulation infarction (mean age ± SD, 66.24 ± 12.88 years) and 143 with posterior circulation infarction (mean age, 65.82 ± 11.39 years) were enrolled. Significant higher frequencies of vertebral artery hypoplasia and decreased intracranial vertebrobasilar velocity in the posterior circulation infarction group (44.75% and 64.33%, respectively) were documented (P < .0001; P = .035). Ischemic lesion distributions were correlated with vertebral artery hypoplasia (55.56 %) and low vertebral and basilar artery velocities (44.44% and 25.53%), as documented by US. A low vertebrobasilar velocity was highly correlated with MRI-documented vascular stenosis (53.06%).

CONCLUSIONS

Vertebral artery hypoplasia and a low velocity in the intracranial vertebrobasilar system on US might change the treatment of patients with posterior circulation infarction for primary and secondary prevention.

Asymptomatic Extracranial Vertebral Artery Disease in Patients with Internal Carotid Artery Stenosis

BACKGROUND

Extracranial vertebral artery disease is seen in patients with internal carotid artery stenosis, although the clinical significance is not well understood.

OBJECTIVE

To determine the prevalence and natural history of extracranial vertebral artery disease in patients with recently symptomatic internal carotid artery stenosis.

METHODS

We analyzed data collected for patients with recently symptomatic internal carotid artery stenosis in the Stent-Protected Angioplasty vs Carotid Endarterectomy trial. We used Cox proportional hazards analysis to compare the relative risk of various endpoints (any stroke, ipsilateral stroke, and death) between the 3 categories of extracranial vertebral artery disease (normal/hypoplastic, moderate/severe stenosis, occlusion) adjusting for age, gender, severity of internal carotid artery stenosis at baseline (<70% and ≥70%), allocated procedure (carotid angioplasty and stent placement or carotid endarterectomy) and hypertension.

RESULTS

Moderate to severe stenosis and occlusion of 1 of both extracranial vertebral arteries were diagnosed in 152 (12.9%) and 57 (4.8%) of 1181 subjects, respectively. Comparing subjects with normal or hypoplastic vertebral artery, there was nonsignificant 30%, 40%, and 50% higher risk of any stroke (hazard ratio [HR] 1.3, 95% confidence interval [CI] 0.7-2.3), ipsilateral stroke (HR 1.4, 95% CI 0.7-2.5), and death (HR 1.5, 95% CI 0.7-3.1) among subjects with moderate to severe vertebral artery stenosis after adjusting for potential confounders.

CONCLUSIONS

There may be an increased risk of stroke and death in patients with symptomatic internal carotid artery stenosis with concurrent asymptomatic extracranial vertebral artery stenosis.

Validity of Carotid Duplex Sonography in Screening for Intracranial Dural Arteriovenous Fistula among Patients with Pulsatile Tinnitus

Pulsatile tinnitus may result from intracranial dural arteriovenous fistula (DAVF), which requires early diagnosis and management. This study validated the role of carotid duplex sonography in screening for DAVF in patients with pulsatile tinnitus. The criteria used for DAVF screening were low resistance index of the external carotid artery or occipital artery (OA). Patients then underwent head magnetic resonance imaging to confirm the diagnosis. Of the 155 patients with pulsatile tinnitus who were prospectively screened, 25 (16.1%) had a low resistance index in either the external carotid artery or occipital artery. All were proven to have DAVF. The diagnostic sensitivity, specificity, positive predictive value and negative predictive value were 96%, 100%, 100% and 98%, respectively. Thus, carotid duplex sonography focusing on low resistance indexes of the external carotid and occipital arteries may be a valuable tool in screening for DAVF in patients with pulsatile tinnitus.

Beyond the Bifurcation: There Is More to Cerebrovascular Ultrasound Than Internal Carotid Artery Stenosis!

Carotid ultrasonography (US) is most commonly performed to identify potential areas of flow-limiting stenosis in the internal carotid artery. Identification of stenosis and unstable plaque is important because these entities are leading predictors of stroke, the fourth most common cause of death in the United States. However, US can detect other important but less common vascular pathologies if proper techniques and nuances of these entities are understood.In this article, we discuss the US appearance of abnormalities involving the carotid, vertebral, subclavian, and innominate arteries as well as the key clinical components of each diagnosis. These include congenital variants, dissection, stenosis, and vasculopathy. In addition, correlation of US findings with both magnetic resonance imaging and computed tomography more comprehensively demonstrates the complementary nature of these imaging modalities.

The comparative analyses of the auditory evoked potentials and color Doppler sonography findings in patients diagnosed with vertebrobasilar insufficiency

Auditory evoked potentials (AEP) represent an electrophysiological method used in the diagnostics of pathological changes of the brainstem. Patients with vertebrobasilar insufficiency (VBI) show changes in the AEP-caused ischemia of the brain structures that generate their responses. The aim of the study was to determine the diagnostic significance and correlation among the findings of AEP in patients with VBI established by color Doppler sonography. The cross-sectional and prospective research included 48 inpatients and outpatients treated at the Clinic of Neurology, Clinical Center Nis. Ultrasound Doppler of blood vessels in the neck included an examination of the carotid blood vessels, the outcome and all sonographically available parts of the vertebral artery (VA) with particular emphasis on the intravertebral segment (V2). The morphological and hemodynamic characteristics of VA in this segment were monitored, and it was important to test the systolic velocity in two adjacent intervertebral spaces. Auditory evoked potentials were used to monitor the amplitudes, absolute latencies of waves I, II, III, IV, and V, as well as interwave latencies (IWLs) I-III, III-V, and I-V. There is statistically significant difference in the more frequent pathological finding of AEP in patients with higher degree of the reduced flow of VA established by color Doppler (P < 0.05) compared to patients with less reduction in the flow. Pathological findings of AEP are well correlated with pathological findings of VBI in color Doppler, and it may be applied as an additional and useful marker in diagnosis of VBI.

Transcranial Doppler investigation of hemodynamic alterations associated with blunt cervical vascular injuries in trauma patients

OBJECTIVES

Blunt cervical vascular injuries, often missed with current screening methods, have substantial morbidity and mortality, and there is a need for improved screening. Elucidation of cerebral hemodynamic alterations may facilitate serial bedside monitoring and improved management. Thus, the objective of this study was to define cerebral flow alterations associated with single blunt cervical vascular injuries using transcranial Doppler sonography and subsequent Doppler waveform analyses in a trauma population.

METHODS

In this prospective pilot study, patients with suspected blunt cervical vascular injuries had diagnoses by computed tomographic angiography and were examined using transcranial Doppler sonography to define cerebral hemodynamics. Multiple vessel injuries were excluded for this analysis, as the focus was to identify hemodynamic alterations from isolated injuries. The inverse damping factor characterized altered extracranial flow patterns; middle cerebral artery flow velocities, the pulsatility index, and their asymmetries characterized altered intracranial flow patterns.

RESULTS

Twenty-three trauma patients were evaluated: 4 with single internal carotid artery injuries, 5 with single vertebral artery injuries, and 14 without blunt cervical vascular injuries. All internal carotid artery injuries showed a reduced inverse damping factor in the internal carotid artery and dampened ipsilateral mean flow and peak systolic velocities in the middle cerebral artery. Vertebral artery injuries produced asymmetry of a similar magnitude in the middle cerebral artery mean flow velocity with end-diastolic velocity alterations.

CONCLUSIONS

These data indicate that extracranial and intracranial hemodynamic alterations occur with internal carotid artery and vertebral artery blunt cervical vascular injuries and can be quantified in the acute injury phase by transcranial Doppler indices. Further study is required to elucidate cerebral flow changes resulting from a single blunt cervical vascular injury, which may guide future management to preserve cerebral perfusion after trauma.

Vascular dementia: Diagnostic criteria and supplementary exams. Recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology. Part I

Vascular dementia (VaD) is the most prevalent form of secondary dementia and the second most common of all dementias. The present paper aims to define guidelines on the basic principles for treating patients with suspected VaD (and vascular cognitive impairment - no dementia) using an evidence-based, systematized approach. The knowledge used to define these guidelines was retrieved from searches of several databases (Medline, Scielo, Lilacs) containing scientific articles, systematic reviews, meta-analyses, largely published within the last 15 years or earlier when pertinent. Information retrieved and selected for relevance was used to analyze diagnostic criteria and to propose a diagnostic system encompassing diagnostic criteria, anamnesis, as well as supplementary and clinical exams (neuroimaging and laboratory). Wherever possible, instruments were selected that had versions previously adapted and validated for use in Brazil that take into account both schooling and age. This task led to proposed protocols for supplementary exams based on degree of priority, for application in clinical practice and research settings.

Subclavian Steal Syndrome

Duplex sonography of extracranial arteries is one of the best tools for identifying stenoses and other diseases of the carotid, vertebral, and subclavian arteries. Abnormal Doppler waveforms in vertebral arteries could be evidence of subclavian steal syndrome. The difference of 15 to 20 mm Hg or more in systolic bilateral brachial arterial blood pressure measurements provides important clinical information in patients with subclavian steal syndrome. Complementary to duplex sonographic scanning, radiologists use computerized tomography angiography, magnetic resonance angiography, and digital subtraction angiography for preoperative planning.