Objective duplex ultrasound evaluation of the extracranial circulation in multiple sclerosis patients undergoing venoplasty of internal jugular vein stenoses: a pilot study

Pathogenesis and Management in Cerebrovenous Outflow Disorders

In keeping with its status as one of the major causes of disability and mortality worldwide, brain damage induced by cerebral arterial disease has been the subject of several decades of scientific investigation, which has resulted in a vastly improved understanding of its pathogenesis. Brain injury mediated by venous etiologies, however, such as cerebral, jugular, and vertebral venous outflow disturbance, have been largely ignored by clinicians. Unfortunately, this inattention is not proportional to the severity of cerebral venous diseases, as the impact they exact on the quality of life of affected patients may be no less than that of arterial diseases. This is evident in disease sequelae such as cerebral venous thrombosis (CVT)-mediated visual impairment, epilepsy, and intracranial hypertension; and the long-term unbearable head noise, tinnitus, headache, dizziness, sleeping disorder, and even severe intracranial hypertension induced by non-thrombotic cerebral venous sinus (CVS) stenosis and/or internal jugular venous (IJV) stenosis. In addition, the vertebral venous system (VVS), a large volume, valveless vascular network that stretches from the brain to the pelvis, provides a conduit for diffuse transmission of tumors, infections, or emboli, with potentially devastating clinical consequences. Moreover, the lack of specific features and focal neurologic signs seen with arterial etiologies render cerebral venous disease prone to both to misdiagnoses and missed diagnoses. It is therefore imperative that awareness be raised, and that as comprehensive an understanding as possible of these issues be cultivated. In this review, we attempt to facilitate these goals by systematically summarizing recent advances in the diagnosis and treatment of these entities, including CVT, CVS stenosis, and IJV stenosis, with the aim of providing a valid, practical reference for clinicians.

Cervical spondylotic internal jugular venous compression syndrome

Aims

This study aimed to identify the clinical profiles of cervical spondylosis‐related internal jugular vein stenosis (IJVS) comprehensively.

Methods

A total of 46 patients, who were diagnosed as IJVS induced by cervical spondylotic compression were recruited. The clinical manifestations and imaging features of IJVS were presented particularly in this study.

Results

Vascular stenosis was present in 69 out of the 92 internal jugular veins, in which, 50.7% (35/69) of the stenotic vessels were compressed by the transverse process of C1, and 44.9% (31/69) by the transverse process of C1 combined with the styloid process. The transverse process of C1 compression was more common in unilateral IJVS (69.6% vs 41.3%, P = 0.027) while the transverse process of C1 combined with the styloid process compression had a higher propensity to occur in bilateral IJVS (52.2% vs 30.4%, P = 0.087). A representative case underwent the resection of the elongated left lateral mass of C1 and styloid process. His symptoms were ameliorated obviously at 6‐month follow‐up.

Conclusions

This study proposes cervical spondylotic internal jugular venous compression syndrome as a brand‐new cervical spondylotic subtype. A better understanding of this disease entity can be of great relevance to clinicians in making a proper diagnosis.

Neck vein obstruction: Diagnosis and the role of chronic persistent Chlamydophila pneumoniae infection

Background

The objective of this review is to describe the diagnosis of neck vein obstruction and the possible role of chronic persistent Chlamydophila pneumoniae infection in producing the syndrome of chronic cerebrospinal venous obstruction.

Method

The normal patterns of flow in the neck veins are described and guidelines for interpretation of the quantitative duplex ultrasound examination of the extracranial neck veins are developed.

Result

An infective cause of neck vein obstruction is proposed and from a literature search of the role of the obligate intracellular bacterium Chlamydophila pneumoniae in vascular and chronic diseases, a diagnostic protocol for confirming chronic persistent Chlamydophila pneumoniae infection, which includes the quantitative duplex ultrasound examination and specific blood tests are suggested.

Conclusion

Further research to validate this diagnostic protocol is required.

Relationship between cerebral arterial inflow and venous outflow during dynamic supine exercise

The regulation of cerebral venous outflow during exercise has not been studied systematically. To identify relations between cerebral arterial inflow and venous outflow, we assessed the blood flow (BF) of the cerebral arteries (internal carotid artery: ICA and vertebral artery: VA) and veins (internal jugular vein: IJV and vertebral vein: VV) during dynamic exercise using ultrasonography. Nine subjects performed a cycling exercise in supine position at a light and moderate workload. Similar to the ICA BF, the IJV BF increased from baseline during light exercise (P < 0.05). However, the IJV BF decreased below baseline levels during moderate exercise, whereas the ICA BF returned near resting levels. In contrast, BF of the VA and VV increased with the workload (P < 0.05). The change in the ICA or VA BF from baseline to exercise was significantly correlated with the change in the IJV (r = 0.73, P = 0.001) or VV BF (r = 0.52, P = 0.028), respectively. These findings suggest that dynamic supine exercise modifies the cerebral venous outflow, and there is coupling between regulations of arterial inflow and venous outflow in both anterior and posterior cerebral circulation. However, it remains unclear whether changes in cerebral venous outflow influence on the regulation of cerebral arterial inflow during exercise.

A prolonged antibiotic protocol to treat persistent Chlamydophila pneumoniae infection improves the extracranial venous circulation in multiple sclerosis

Objective Chronic cerebrospinal venous insufficiency (CCSVI) is a condition associated with multiple sclerosis (MS). One mechanism that has been proposed is that the venous obstructions found in MS are due to a chronic persistent venulitis caused by the intra-cellular bacterial parasite, Chlamydophila pneumoniae (Cpn). The objective of the current study is to determine the effect of a combined antibiotic protocol (CAP) on the venous flow in MS patients as measured by a quantitative duplex ultrasound examination (QDUS). Method A non-randomised before-after cohort study was conducted to investigate differences in blood flow volumes pre and 6-months post antibiotic treatment for Cpn infection. Flow volume data were measured by QDUS across affected and unaffected sides from multiple veins segments, including internal jugular vein (IJV) segments J2 and J3, and vertebral vein (VV), as well as global arterial blood flow (GABF). Results 91 patients were included in the study. 64 (70%) were found to have positive Cpn serology. There was a statistically significant post-treatment difference seen for the affected side of Cpn infected patients (mean difference = 56 mL/min, p = 0.02). There was a non-significant increase seen for the affected side of uninfected patients (mean difference = 23 mL/min, p = 0.2). The difference in these effects (34 mL/min) was not statistically significant ( p = 0.3). The mean flow rate decreased in the unaffected side for both infected (-27 mL/min, p = 0.5) and uninfected patients (-69 mL/min, p = 0.01). There was a statistically significant post-treatment increase in GABF for the infected patients (mean difference = 90 mL/min, p = 0.02) and a difference of 76 mL/min for non-infected patients ( p = 0.01). Conclusion A CAP appears to improve the extra-cranial circulation in patients diagnosed with MS. This effect is statistically significant in patients with positive Cpn serology, although patients with negative Cpn serology also show some benefit, betraying a lack of specificity of this effect.

Lack of correlation between extracranial venous abnormalities and multiple sclerosis: a quantitative MRI study

OBJECTIVE:

We aimed to evaluate the presence of venous stenosis and blood flow abnormalities in the neck vessels of patients with multiple sclerosis (MS), in respect to a group of age- and sex-matched healthy controls (HC), and their possible relations with clinical variables using a semi-automated quantitative MRI method.

METHODS:

45 patients with relapsing remitting MS and 40 HC were enrolled in this study. Flow rates and cross-sectional areas of arterial and venous neck vessels were assessed by phase-contrast MRI at two different neck levels (C2-C3 and C6-C7), and differences between groups were evaluated with an unpaired t-test. Correlation between blood flow variables and clinical parameters was analyzed with Spearman's test.

RESULTS:

A significant internal jugular vein (IJV) stenosis was found in 23/45 (51.1%) patients with MS and 18/40 (45.0%) HC. No differences were observed between patients with MS and HC for any of the flow measures obtained. No correlations were found between MRI measures and any of the tested clinical variables.

CONCLUSION:

No differences in the IJV area emerged at quantitative MRI evaluation, suggesting that stenosis of the extracranial veins is unrelated to MS. Furthermore, no flow differences in the neck vessels were found between patients with MS and HC in any of the tested flow measures, with no correlation with clinical variables. Our results confirm that the hypothesis of the presence of extracranial venous abnormalities in MS, both in terms of stenosis or flow measures, is not suitable.

ADVANCES IN KNOWLEDGE:

Neck venous drainage abnormalities have been claimed to be associated with MS. Conversely, our quantitative MRI analysis seems to exclude that extracranial venous alterations are related to the disease.

Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse

Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS) was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA). However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a) automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b) the use of just a single CSA value in a pulsatile vessel is inaccurate; (c) time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave) and with the outflow (jugular venous pulse) in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders.

Impact of CCSVI on cerebral haemodynamics: a mathematical study using MRI angiographic and flow data

Background

The presence of abnormal anatomy and flow in neck veins has been recently linked to neurological diseases. The precise impact of extra-cranial abnormalities such as stenoses remains unexplored.

Methods

Pressure and velocity fields in the full cardiovascular system are computed by means of a global mathematical model that accounts for the relationship between pulsating cerebral blood flow and intracranial pressure.

Results

Our model predicts that extra-cranial strictures cause increased pressure in the cerebral venous system. Specifically, there is a predicted pressure increase of about 10% in patients with a 90% stenoses. Pressure increases are related to significant flow redistribution with flow reduction of up to 70% in stenosed vessels and consequent flow increase in collateral pathways.

Conclusions

Extra-cranial venous strictures can lead to pressure increases in intra-cranial veins of up to 1.3 mmHg, despite the shielding role of the Starling resistor. The long-term clinical implications of the predicted pressure changes are unclear.

Transvascular autonomic modulation: a modified balloon angioplasty technique for the treatment of autonomic dysfunction in multiple sclerosis patients

PURPOSE

To describe the use of transvascular autonomic modulation (TVAM) to improve cardiovascular autonomic nervous system (ANS) dysfunction in multiple sclerosis (MS) patients, comparing the safety and efficacy of this modified technique with traditional balloon angioplasty.

METHODS

Twenty-one MS patients (11 men; mean age 48.7±13.0 years) who presented with symptoms of cardiovascular ANS dysfunction underwent TVAM. These patients were compared with age/sex-matched MS patients (10 men; 49.3±11.1 years) in the same stages of the disease who presented with chronic cerebrospinal venous insufficiency (CCSVI) and who underwent venous balloon angioplasty. TVAM involved the coupling of balloon angioplasty of the internal jugular veins with the application of external manual compression and dilation of the azygos and renal veins; unlike traditional angioplasty for CCSVI, which treats only abnormal veins (≥50% stenosis or static valve), all targeted vessels were treated with TVAM regardless of the presence of an abnormality. The effect of TVAM on ANS function was indicated by determining heart rate variability based on the electrocardiographic R-R interval lengths using vector analysis to derive the mean circular resultant (MCR) and the expiration/inspiration (E/I) ratio, the Valsalva ratio, and the 30:15 postural ratio at 24 hours after intervention.

RESULTS

Left renal vein compression was common among the TVAM patients and resulted in ≥50% luminal compromise in 10 of 21 patients. Azygos vein abnormalities (a static valve) were identified in 5 patients. Overall, 18 patients met the diagnostic criteria for CCSVI with at least one lesion >50%, but only 10 lesions were considered treatable by traditional balloon angioplasty. After intervention, the R-R interval values, including the 30:15 postural ratio (p=0.01), the MCR (p=0.1), and E/I ratio (p=0.1), were higher for the TVAM patients compared to the control group. The safety profile of the TVAM procedure was similar to that of traditional balloon angioplasty.

CONCLUSION

The combination of balloon angioplasty of anatomically normal veins coupled with external compression during dilation of these veins can improve indicators of ANS dysfunction. The safety and efficacy of TVAM in MS patients observed in this pilot study is encouraging, paving the way for the treatment of dysautonomia in pathological states other than MS. Further studies should investigate TVAM in a larger MS cohort.