Cerebral microembolism in acute spontaneous internal carotid artery dissection

Dissective tandem stroke: an endovascular approach

Ischemic stroke due to internal carotid artery occlusion is a potential devastating condition. More frequently the occlusions are embolic in nature, but sometimes they are caused by arterial dissection and their treatment is a challenge. We describe an illustrative case where a young patient with middle cerebral artery stroke caused by carotid artery dissection was submitted to endovascular treatment of mechanical thrombectomy and stenting, giving an excellent outcome. We believe that tandem approach is a treatment of choice in these cases.

Cervical arterial dissection and traumatic myelopathy following yoga: surgical case report

INTRODUCTION

Cervical spondylosis can predispose patients to central canal stenosis. In this setting, myelopathy through further flattening of the cord from extrinsic compression can be precipitated by relatively minor traumas. Arterial dissection is similarly considered a result of high velocity or momentum during trauma, commonly associated with fractures, cervical hyperflexion, or direct blunt force to the neck. Overall, precautions for both arterial dissection and myelopathy are rarely considered in low-velocity, static activities such as yoga.

CASE PRESENTATION

The authors report the case of a 63-year-old man who suffered concurrent cervical myelopathy from multilevel spondylopathy, right vertebral artery dissection, and left cervical carotid artery dissection following a yoga session. Symptomatology consisted of acute onset neck pain, upper extremity sensory paresthesia, worsening gait and balance, and impaired dexterity for several weeks. Cervical MRI was obtained given myelopathic symptoms and revealed spondylosis with compression and T2 signal change at C3-C4. CT angiography of the neck revealed aforementioned dissections without flow limiting stenosis or occlusion. A therapeutic heparin infusion was started preoperatively until the patient underwent C3-C4 anterior cervical discectomy and fusion. Aspirin and Plavix were then started without incidence and the patient had significant but gradual improvement in myelopathic symptoms at 6-week follow-up.

DISCUSSION

The static yet intensive poses associated with yoga present a rare etiology for arterial dissection and myelopathy, but patients with persistent and progressive symptoms should be screened with the appropriate imaging modality. Cervical decompression should be expedited before initiating an antiplatelet medication.

Micro-Embolic Signals and Dissection: Association or Causation for Stroke? A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

Although the mechanism of stroke in cervical artery dissection (CAD) has been hypothesized to be embolization rather than hemodynamic compromise, there are a limited number of studies supporting this hypothesis. Detection of micro-embolic signals (MESs) using transcranial Doppler (TCD) helps in understanding the mechanism in these patients. A systematic review and meta-analysis were performed to estimate the prevalence of MES and its association with stroke outcomes in patients with acute stroke/TIA secondary to dissection.

METHODS

A comprehensive literature search was conducted for studies before January 26, 2021, in PubMed, Embase, Google Scholar, Cochrane Library, and ClinicalTrials.gov. Studies were identified that used TCD to detect MES in stroke/TIA patients secondary to CAD. Pooled prevalence was calculated. Entire statistical analysis was conducted in R version 3.6.2.

RESULTS

Eleven studies involving 112 patients (50 MES+, 62 MES-) were included in our meta-analysis. The pooled prevalence of MES among acute stroke/TIA patients secondary to dissection was 46.0% (95% CI 26.0-67.0%). The presence of MES was associated with an increased risk of early ischemic recurrence in patients with CAD. We could not estimate the functional outcome and mortality associated with the presence of MES due to the scarcity of data.

CONCLUSIONS

Our meta-analysis showed 46% prevalence of MES in the studies which looked at acute stroke/TIA secondary to CAD using TCD. This finding supports the assumption that embolism may be a major cause of stroke in patients with dissection although this could be determined only in a small population.

Systematic review of the effectiveness of carotid surgery and endovascular carotid stenting versus best medical treatment in managing symptomatic acute carotid artery dissection

Cervical artery dissection (CeAD) with an intramural haematoma can lead to stroke risk, especially in young patients. We performed comprehensive searches of the Cochrane Stroke Group Trials Register, the CENTRAL, MEDLINE and EMBASE to review the effectiveness of surgical and endovascular interventions versus best medical treatment alone for symptomatic CeAD. Furthermore, we aim to elaborate on the phenotypic individual disease manifestations of spontaneous Cervical Artery Dissection (sCAD) and how they translate into stroke and risk of dissection recurrence. Primary outcomes were ipsilateral stroke and disability. Secondary outcomes were death, any stroke, or transient ischaemic attack, residual stenosis >50%, recurrence of CeAD, expanding pseudo-aneurysm or major bleeding. Our search yielded no randomised controlled trials and/or controlled clinical trials (CCTs) comparing either carotid surgery or endovascular therapy with optimal medical management; thus there was no evidence to support the use of any specific method for management of extracranial CeAD in patients who fail antithrombotic therapy. However, despite the absence of controlled studies to compare surgery or endovascular therapy in patients who fail antithrombotic therapy, carotid surgery in young patients can be justified as a personalized precision approach given the high morbidity and mortality in this age group.

Transcranial Doppler as a Predictor of Ischemic Events in Vertebral Artery Dissection

BACKGROUND AND PURPOSE

Transcranial Doppler (TCD) helps identify patients with carotid dissections at risk of ischemic events (IEs). There is paucity of data identifying independent predictors of IE in vertebral arterial dissection (VAD). We sought to investigate the clinical and ultrasound predictors of IE.

METHODS

Patients with VAD admitted between June 2017 and February 2020 were evaluated clinically and with TCD; sonographic curves, microembolic signals (MES), and the breath-holding index (BHI) test were applied. Covariates found on univariate screen (P < .25) were included in a multivariable linear regression to identify independent predictors of IEs.

RESULTS

Of 88 patients with 100 VAD, 75 (85.2%) were females with a mean age 37.9 ± 7.5 years. All patients received antiplatelet treatment. TCD monitoring lasted an average of 21 ± 2.1 minutes. TCD was abnormal in 23 cases (26.1%); 21 patients had abnormal sonographic curves in the vertebral/basilar arteries, while in 4 cases, MES were present and in 5 (4.5%), BHI was abnormal. None of the patients with a normal TCD had an IE. Six strokes occurred during follow up. On univariate analysis, male sex, diabetes, dyslipidemia, a previous myocardial infarct, migraine, time of consultation to the ER, bilateral VAD, MES, BHI abnormalities, post stenotic flow in the basilar artery (PFB), and basilar/vertebral velocities were significantly associated with the risk of IEs. In the multivariate analysis, only the presence of PFB was a significant predictor of IE (OR: 68.6, 95% CI 5-937, <.001).

CONCLUSIONS

TCD in VAD predicts patients at high risk of IE.

Relationship of spontaneous microembolic signals to risk stratification, recurrence, severity, and mortality of ischemic stroke: a prospective study

Introduction

The presence of microembolic signals (MES) during the acute phase of stroke is poorly understood, and its role and clinical application in relation to risk stratification and prognosis in patients remain uncertain. We assessed the prevalence of spontaneous MES in acute stroke and their relationship with risk stratification, stroke recurrence, morbidity, and mortality.

Patients and methods

This was a prospective cohort study conducted in the Stroke Unit. The MES presence was evaluated by transcranial Doppler (TCD) in patients with ischemic stroke within 48 h. The outcomes (risk stratification, morbidity, mortality, and recurrence of a stroke) were followed up for 6 months. The relationship between risk stratification and MES was obtained by odds ratios and that between MES and stroke recurrence, morbidity, and mortality using multiple logistic regression; considering statistical significance at P < 0.05.

Results

Of the 111 patients studied, 70 were men (63.1%) and 90 were white (81.1%), with a median age of 68 years. The MES frequency was 7%. There was a significant relationship between MES and symptomatic carotid disease (OR = 22.7; 95% CI 4.1–125.7; P < 0.001), a shorter time to monitoring (OR = 12.4; 95% CI  1.4–105.4; P = 0.02), and stroke recurrence (OR = 16.83; 95% CI 2.01–141; P = .009).

Discussion

It was observed that the stroke recurrence adjusted for prior stroke was higher and earlier among patients with MES detection. In conclusion, MES demonstrated a significant correlation with symptomatic carotid disease and a shorter DELAY until monitoring, and could be a predictor for the early recurrence of stroke in the long term.

Recanalization after Extracranial Dissection: Effect of Antiplatelet Compared with Anticoagulant Therapy

BACKGROUND

Cervical arterial dissection is a leading cause of stroke in young patients, yet optimal management remains controversial. Existing studies focusing on recurrent stroke were underpowered to demonstrate differences between antithrombotic strategies. Vessel recanalization is a more prevalent outcome and is potentially clinically important. We aimed to assess recanalization rates with anticoagulation compared with antiplatelet therapy.

METHODS

We studied a single-center retrospective cohort of patients with extracranial carotid or vertebral artery dissection. Subjects with baseline and follow-up imaging between 1999 and 2013 were included. Stenosis was measured using North American Symptomatic Carotid Endarterectomy Trial methodology. Univariate and multivariable analyses were performed to determine factors associated with recanalization, defined as ≥50% relative improvement in stenosis from baseline to follow-up imaging. Secondary analyses assessed absolute and relative stenosis change and limited the cohort to >50% stenosis at diagnosis.

RESULTS

We identified 75 patients with 84 dissections, mean age 47 years, 43% female, 39% non-white. Patients treated with anticoagulation had worse stenosis at baseline (median 99% versus 50%, P = .02). Comparing anticoagulation with antiplatelet therapy in the first month, there were no differences in the rates of ≥50% relative improvement in stenosis (50% versus 48%, P = .84) nor in absolute (median 16% versus 7%, P = .34) or relative (median 48% versus 43%, P = .92) change in stenosis from baseline to follow-up. In multivariable analysis, anticoagulation was not associated with recanalization (odds ratio [OR] 1.41, 95% confidence interval [CI]: .5-4.1, P = .52), whereas hypertension was negatively associated (OR .26, 95% CI: .09-.72, P = .009).

CONCLUSIONS

Anticoagulation was not associated with greater likelihood of recanalization compared with antiplatelet medication therapy.

Critical Care Management of Acute Ischemic Stroke

OPINION STATEMENT

Ischemic stroke accounts for approximately 85% of all strokes. Although severe strokes constitute a minority of cases, they are associated with a majority of the subsequent disability and death. Reperfusion therapy with intravenous tissue plasminogen activator (tPA) and/or endovascular thrombectomy is a mainstay of acute stroke management. Intensive care management of stroke is focused on reducing complications of reperfusion, such as hemorrhagic transformation, and minimizing secondary brain injury, including brain edema and progressive stroke. Additionally, severe stroke patients frequently need ventilatory or hemodynamic support provided in an intensive care unit (ICU) setting. Here, we discuss the current medical and surgical ICU management aspects of acute ischemic stroke and identify areas where ongoing studies may reveal new treatments to improve neurological recovery.

3D T1-weighted black blood sequence at 3.0 Tesla for the diagnosis of cervical artery dissection

OBJECTIVE

We aimed to investigate the value of three-dimensional (3D) T1 volumetric isotropic turbo spin echo acquisition (VISTA) in the diagnosis of cervical artery dissection (CAD).

METHODS

We prospectively included patients who were suspected as having a CAD within 1 month of onset. For T1 VISTA, the diagnosis of the dissection was based on the presence of intramural high-signal, intimal flap, double lumen and aneurysmal dilation. The final diagnosis of dissection was based on the clinical history, physical examination, and all of the imaging tests.

RESULTS

A total of 46 patients were included in this study. The final diagnosis of CAD was made for 21 patients. Diagnosis of dissection was made for 20 of the 21 patients after assessing T1 VISTA. A definitive diagnosis of dissection was not made for 5 patients (including 3 patients with digital subtraction angiography) before the T1 VISTA examination. The sensitivity and specificity for T1 VISTA were 95.2% (95% CI, 76.2% to 99.9%) and 100% (95% CI, 86.3% to 100%), respectively. The agreement between the two researchers for T1 VISTA for diagnosis of CAD was very good (k=0.91). For patients without acute artery occlusion, all of them had a definite conclusion with or without dissection by T1 VISTA (n=29). However, for 17 patients with acute artery occlusion, the possibility of dissection could not be excluded for 6 of them by T1 VISTA (p=0.001).

CONCLUSIONS

3D T1 VISTA at 3.0 Tesla was useful in the diagnosis of acute CAD. However, for some patients with total occlusion of the artery without typical imaging features of dissection, the unequivocal distinction between intramural haematoma and intraluminal thrombus may be not adequate by T1 VISTA alone. Future studies should investigate whether a follow-up scan, a contrast-enhanced imaging or an optimal VISTA technique could be useful.

Antiplatelet Therapy vs. Anticoagulation in Cervical Artery Dissection: Rationale and Design of the Cervical Artery Dissection in Stroke Study (CADISS)

Rationale

Cervical artery dissection is an important cause of stroke in the young. It can present with local symptoms or stroke/transient ischaemic attacks. Following presentation there is a risk of stroke, particularly in the first month following presentation. The mechanism of stroke is believed to be thromboembolic in the majority of cases. Many clinicians anticoagulate patients with cervical dissection for 3–6 months. This is not evidence based and is supported by a paucity of data and no data from randomised control trials.

Aims

CADISS is a prospective multicentre randomised-con-trolled trial in acute (within 7 days of onset) carotid and vertebral artery dissection. Intracerebral artery dissection is excluded.

Design

Patients are randomised to antiplatelet therapy (aspirin, dipyridamole or clopidogrel alone or in dual combination) or anticoagulation therapy [heparin followed by warfarin aiming for an International Normalised Ratio (INR) in the range 2–3] for at least 3 months. Treatment is open-label.

Study outcome

The primary end-point is ipsilateral stroke or death within 3 months from randomisation. Secondary end-points include any TIA or stroke, major bleeding and presence of residual stenosis at 3 months (> 50%). All neuroimaging and serious adverse events will be adjudicated blinded to treatment. An initial feasibility phase of 250 subjects will allow us to determine whether there are sufficient clinical end-points to provide the power to determine a treatment effect and adequate numbers of patients can be recruited. The feasibility phase will be continued into a fully powered definitive treatment trial. Initial power calculations based on limited natural history data suggest a sample size of approximately 3000. Sample size calculations will be refined once the frequency of outcome events during the feasibility phase is known.

Evolving Treatments for Acute Ischemic Stroke

The purpose of this article is to review advances in stroke treatment in the hyperacute period. With recent evolutions of technology in the fields of imaging, thrombectomy devices, and emergency room workflow management, as well as improvement in statistical methods and study design, there have been ground breaking changes in the treatment of acute ischemic stroke. We describe how stroke presents as a clinical syndrome and how imaging as the most important biomarker will help differentiate between stroke subtypes and treatment eligibility. The evolution of hyperacute treatment has led to the current standard of care: intravenous thrombolysis with tissue-type plasminogen activator and endovascular treatment for proximal vessel occlusion in the anterior cerebral circulation. All patients with acute ischemic stroke are in need of hyperacute secondary prevention because the risk of recurrence is highest closest to the index event. The dominant themes of modern stroke care are the use of neurovascular imaging and speed of diagnosis and treatment.

Use of Heparin in Acute Ischemic Stroke: Is There Still a Role?

Heparin has long been a contested therapy in acute ischemic stroke (AIS). In current practice, heparin is considered on a case-by-case basis, but there is no consensus as to the appropriate timing of anticoagulation or for which ischemic stroke subtypes heparin may be beneficial. To provide better clarity on this issue, we review current research focusing on the use of heparin in AIS in each stroke subtype and subsequently make recommendations to provide readers with a systematic approach to managing complex stroke patients for which acute anticoagulation may be valuable. We conclude that there are certain subpopulations of ischemic stroke patients that may derive benefit from heparin when given acutely, including patients with symptomatic large artery stenosis >70 %, non-occlusive intraluminal thrombus, and in patients with high-risk cardiac conditions including left ventricular thrombus, left ventricular assist devices, and mechanical heart valves.

Diagnosis and treatment of cervical artery dissection

Cervical artery dissection (CAD) is a major cause of stroke in the young. A mural hematoma is detected in most CAD patients. The intramural blood accumulation should not be considered a reason to withhold intravenous thrombolysis in patients with CAD-related stroke. Because intravenous-thrombolyzed CAD patients might not recover as well as other stroke patients, acute endovascular treatment is an alternative. Regarding the choice of antithrombotic agents, this article discusses the findings of 4 meta-analyses across observational data, the current status of 3 randomized controlled trials, and arguments and counterarguments favoring anticoagulants over antiplatelets. Furthermore, the role of stenting and surgery is addressed.

Vertebral artery dissection with compelling evidence on duplex ultrasound presenting only with neck pain

Vertebral artery dissection (VAD) is among the most common identifiable etiologies of stroke in young adults and poses a diagnostic challenge due to nonspecific symptoms and substantial variability of imaging results. Here, we present a case of unspecific neck pain as isolated symptom of VAD with unusually compelling evidence on duplex ultrasound. This observation has clinical relevance as the absence of any neurological symptoms in our patient highlights the necessity of considering cervical artery dissection in patients presenting with unspecific symptoms such as neck pain, even if isolated. Furthermore, our image of intramural hematoma on duplex ultrasound has been captured in an unusual, clear and distinct fashion and might therefore be a useful reference image in the clinical assessment of patients with a suspicion of cervical artery dissection.

Intracranial and extracranial arterial dissection presenting with ischemic stroke: Lesion location and stroke mechanism

Background and purpose Although cervicocranial artery dissections (CADs) are common causes of ischemic stroke in young individuals, anatomical locations and mechanisms of ischemic strokes are still unclear. We evaluate the prevalence, location, and pathogenic mechanisms of ischemic stroke caused by CADs.

METHODS

We reviewed CAD patients who presented with acute (<7days) ischemic events and who had undergone diffusion weighted magnetic resonance imaging (MRI) and appropriate vascular imagings (MR angiography, computed tomography angiography, digital subtraction angiography, and high-resolution MRI). Stroke mechanisms were categorized as artery-to-artery (AA) embolism, local branch occlusion, in situ thrombotic occlusion and hemodynamic impairment.

RESULTS

One hundred and thirty-five patients with cerebral infarcts (n=125) or transient ischemic attacks (n=10) were included. The locations of 159 dissected vessels were: 77 vertebral, 29 internal carotid, 24 middle cerebral, 12 basilar, eight posterior inferior cerebellar, five anterior cerebral, and four posterior cerebral arteries. Among stroke mechanisms, A-A embolism (n=70, 55.5%) was the most common followed by local branch occlusions (n=40, 31.7%) and in situ thrombotic occlusions (n=8, 6.3%). Intracranial CADs were more common (89 vs. 44), less often associated with trauma (21.3% vs. 40.9%, p=0.018) and A-A embolism (32.9% vs. 97.6%, p<0.001), and more often treated with intravenous thrombolysis (15.7% vs. 2.3%. p=0.021) than extracranial CADs.

CONCLUSIONS

In our cohort, intracranial CADs are more common than extracranial CADs, and the vertebral artery is the most frequently involved site. Although A-A embolism is the main stroke mechanism, local branch occlusion is another important stroke mechanism.

Antiplatelet treatment compared with anticoagulation treatment for cervical artery dissection (CADISS): a randomised trial

BACKGROUND

Extracranial carotid and vertebral artery dissection is an important cause of stroke, especially in young people. In some observational studies it has been associated with a high risk of recurrent stroke. Both antiplatelet drugs and anticoagulant drugs are used to reduce risk of stroke but whether one treatment strategy is more effective than the other is unknown. We compared their efficacy in the Cervical Artery Dissection in Stroke Study (CADISS), with the additional aim of establishing the true risk of recurrent stroke.

METHODS

We did this randomised trial at hospitals with specialised stroke or neurology services (39 in the UK and seven in Australia). We included patients with extracranial carotid and vertebral dissection with onset of symptoms within the past 7 days. Patients were randomly assigned (1:1) by an automated telephone randomisation service to receive antiplatelet drugs or anticoagulant drugs (specific treatment decided by the local clinician) for 3 months. Patients and clinicians were not masked to allocation, but investigators assessing endpoints were. The primary endpoint was ipsilateral stroke or death in the intention-to-treat population. The trial was registered with EUDract (2006-002827-18) and ISRN (CTN44555237).

FINDINGS

We enrolled 250 participants (118 carotid, 132 vertebral). Mean time to randomisation was 3·65 days (SD 1·91). The major presenting symptoms were stroke or transient ischaemic attack (n=224) and local symptoms (headache, neck pain, or Horner's syndrome; n=26). 126 participants were assigned to antiplatelet treatment versus 124 to anticoagulant treatment. Overall, four (2%) of 250 patients had stroke recurrence (all ipsilateral). Stroke or death occurred in three (2%) of 126 patients versus one (1%) of 124 (odds ratio [OR] 0·335, 95% CI 0·006-4·233; p=0·63). There were no deaths, but one major bleeding (subarachnoid haemorrhage) in the anticoagulant group. Central review of imaging failed to confirm dissection in 52 patients. Preplanned per-protocol analysis excluding these patients showed stroke or death in three (3%) of 101 patients in the antiplatelet group versus one (1%) of 96 patients in the anticoagulant group (OR 0·346, 95% CI 0·006-4·390; p=0·66).

INTERPRETATION

We found no difference in efficacy of antiplatelet and anticoagulant drugs at preventing stroke and death in patients with symptomatic carotid and vertebral artery dissection but stroke was rare in both groups, and much rarer than reported in some observational studies. Diagnosis of dissection was not confirmed after review in many cases, suggesting that radiographic criteria are not always correctly applied in routine clinical practice.

FUNDING

Stroke Association.

Traumatic Dissection of Four Brain-Supplying Arteries without Neurologic Deficit

Study Design Case report and review of the literature. Objectives Case report of a traumatic dissection of all major brain-supplying arteries resulting from a horseback-riding accident. Overview of the literature on diagnostic and therapeutic recommendations. Methods Case presentation. For the discussion, handpicked articles and PubMed database research with the keywords "dissection," "vertebral artery," "spine trauma," "computed tomography," "magnetic resonance imaging," and "angiography" were used. Results Despite high-energy induced acute lesion of all four cervical arteries, this 45-year-old patient did not demonstrate signs of microemboli nor suffer from stroke. Conclusion In case of high-energy trauma of the head and/or the neck, emergency physicians must consider traumatic cervical artery dissection (TCAD). Thus, emergency care algorithms should routinely include computed tomography angiography and magnetic resonance imaging. Although the incidence of TCAD-induced stroke is low, antiplatelet therapy is recommended in the presence of TCAD.

Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.

Current optimal assessment and management of carotid and vertebral spontaneous and traumatic dissection

Dissection of the internal carotid or vertebral artery has been recognized as a cause of stroke in young patients. It is disproportionate in its representation as a cause of stroke in this age group. Intimal tears, intramural hematomas, and dissection aneurysms may be the result of trauma or may occur spontaneously. Spontaneous dissection may be the result of inherent arterial weakness or in association with other predisposing factors. Clinical diagnosis is often difficult, but increased awareness and a range of modern investigations such as computerized tomography or magnetic resonance imaging may aid in diagnosis. Management options include antiplatelet therapy, anticoagulation, thrombolysis, and surgical or endovascular procedures. Prognosis is variable, and dissection may be asymptomatic but may lead to profound neurological deficit and death.

Timing and mechanism of ischemic stroke due to extracranial blunt traumatic cerebrovascular injury

OBJECT

Extracranial cerebrovascular injury is believed to be an important cause of neurological injury in patients who have suffered blunt trauma. The authors sought to determine the timing and mechanisms of ischemic stroke in patients who suffered traumatic cerebrovascular injury (TCVI).

METHODS

This is a prospective study of all patients with TCVI who were admitted to a Level I trauma center during a 28-month period. All patients who suffered blunt trauma and had risk factors for TCVI underwent screening CT angiography (CTA) of the head and neck on admission. All patients with either an ischemic stroke or CTA suggesting TCVI underwent confirmatory digital subtraction angiography (DSA). Patients with DSA-confirmed TCVI were treated with 325 mg aspirin daily; all patients were observed during their hospitalization for the occurrence of new ischemic stroke. In addition, a subset of patients with TCVI underwent transcranial Doppler ultrasonography monitoring for microembolic signals.

RESULTS

A total of 112 patients had CTA findings suggestive of TCVI; 68 cases were confirmed by DSA. Overall, 7 patients had an ischemic stroke in the territory of the affected artery prior to or during admission. Four of the patients had their event prior to diagnosis with CTA and 2 occurred prior to DSA. In 1 patient the ischemic stroke was found to be due to an extracranial atherosclerotic carotid plaque, and this patient was excluded from further analysis. All patients with ischemic stroke had brain CT findings consistent with an embolic mechanism. Two (8.7%) of 23 monitored patients with TCVI had microembolic signals on transcranial Doppler ultrasonography.

CONCLUSIONS

Most ischemic strokes due to TCVI are embolic in nature and occur prior to screening CTA and initiation of treatment with aspirin.

[Detection of micro-embolic signals: a review of the literature]

BACKGROUND

The detection of micro-embolic signals (MES), by transcranial Doppler sonography might be useful for risk stratification in patients with symptomatic and asymptomatic carotid or cerebral artery stenosis, dissections, aortic atheroma, interventional procedures, and right to left cardiac shunts.

AIM

Review of the technique and clinical situations of MES detection.

METHODS

PubMed search from 1990 to 2012.

RESULTS

MES were found in 0,19, 48% versus 0,3, and 12% of patients with symptomatic and asymptomatic inferior than 30, 30 to 69, and 70 to 99% carotid stenosis, respectively. MES were related to the risk of recurrent stroke or transient ischemic attack (TIA). In the ACES study, the absolute annual risk of stroke or TIA after 2 years was 7% with vs 3% without MES. In patients with intracranial stenosis, the risk of stroke recurrence was 48% with vs 7% without MES at 13.6 months follow-up. MES were reported in 25% of the symptomatic versus none of the asymptomatic patients with intracranial stenosis.

CONCLUSION

Detection of MES is feasible and reproducible for multicenter studies, using rigourous methodology and long lasting recordings. It may contribute to risk stratification, especially in patients with extra- or intracranial stenosis.

Cervical carotid artery dissection: current review of diagnosis and treatment

Carotid artery dissection is a cause of stroke, especially in young and middle-aged patients. A dissection occurs when there is an intimal tear or rupture of the vasa vasorum, leading to an intramural hematoma, which is thought to result from trauma or can occur spontaneously, and is likely multifactorial, involving environmental and intrinsic factors. The clinical diagnosis of carotid artery dissection can be challenging, with common presentations including pain, partial Horner syndrome, cranial nerve palsies, or cerebral ischemia. With the use of noninvasive imaging, including magnetic resonance and computed tomography angiography, the diagnosis of carotid dissection has increased in frequency. Treatment options include thrombolysis, antiplatelet or anticoagulation therapy, endovascular or surgical interventions. The choice of appropriate therapy remains controversial as most carotid dissections heal on their own and there are no randomized trials to compare treatment options.

Mechanism of Ischemic Infarct in Spontaneous Cervical Artery Dissection

Background and Purpose—

It is unclear whether strokes in patients with spontaneous cervical artery dissection (CAD) are due to secondary thromboembolism or to a reduction in cerebral blood flow from the primary cervical lesion. The aim of this study was to identify the most likely mechanism of stroke using cervical and cerebral imaging parameters in patients with CAD.

Methods—

The study was approved by the local Ethics Committee. Informed consent was waived. We retrospectively evaluated the cerebrovascular ultrasound, cervical MR angiography, and stroke brain MRI in consecutive patients with CAD. An embolic mechanism was considered in the case of direct visualization of an intracranial embolism as a susceptibility vessel sign on T2* or in the case of pial artery territory infarction on diffusion-weighted imaging. A hemodynamic mechanism was considered in the case of watershed infarction and in the case of an association of watershed infarction and pial artery territory infarction when ≥2 of the following were present: severe stenotic or occlusive CAD, reduced intracranial velocity on cerebrovascular ultrasound or signal on MR angiography, or hyperintense vessel sign on fluid-attenuated inversion recovery. The remaining patients were considered to have a mixed mechanism.

Results—

Of 172 consecutive patients with CAD, 100 (58%) had acute stroke on diffusion-weighted imaging. Stroke was attributed to a thromboembolic mechanism in 85 of 100 patients, a hemodynamic mechanism in 12 of 100 patients, and a mixed mechanism in 3 of 100 patients.

Conclusions—

Stroke in patients with CAD is most frequently associated with both direct and indirect signs of artery-to-artery embolization on imaging, a finding that should help design future therapeutic trials.

Microembolic Signals in Acute Posterior Circulation Cerebral Ischemia

Background and Purpose—

The clinical significance of microembolic signals (MES) in the posterior circulation remains unclear. The aim of this study was to investigate the sources and consequences of MES in acute posterior circulation cerebral ischemia.

Methods—

We evaluated a total of 140 consecutive patients (93 males, mean age 62.9 years) who had acute posterior circulation cerebral ischemia. The MES monitoring was conducted at the basilar artery through the suboccipital window for a 30-minute period.

Results—

MES were detected in 18 (12.9%) of the 140 patients. Clinical characteristics and laboratory data did not differ between the MES-positive and MES-negative groups. Intracranial vertebrobasilar artery (VBA) stenosis was independently associated with the presence of MES (odds ratio, 9.85; 95% confidence interval, 1.22–79.48; P =0.032), whereas the patients with vertebral artery stenosis that was limited to the extracranial portion did not show an association. Microembolic signals occurred significantly more frequently in patients with severe degree of VBA stenosis compared to those with nonsignificant stenosis (odds ratio, 9.88; 95% confidence interval, 1.23–79.07; P =0.031). In a subgroup analysis of the 79 patients who had lesions on diffusion-weighted images and relevant VBA stenosis, the MES-positive group showed more frequent embolic infarction ( P =0.010) and multiple lesion patterns ( P =0.007) than single perforating infarctions.

Conclusions—

In acute posterior circulation cerebral ischemia, intracranial and severe VBA stenosis is associated with MES and may be its root causes. The presence of MES in VBA stenosis suggests that multiple and embolic type infarctions are the mechanisms of stroke.

A novel treatment for embolising carotid dissection

INTRODUCTION

A rare but significant cause for stroke is sub-intimal carotid dissection and this mechanism accounts for approximately 2.5% of all strokes.(1) Dissection of the carotid artery is often caused by trauma to the face or neck.(2) Under 45 years old, it is the second leading cause of stroke.(3) Neurological symptoms can be lacking or subtle, therefore the condition may be overlooked but the pathological processed is believed to be attributed to thromboembolism.(4) Microemboli in the middle cerebral artery, are known as a risk factor for ischaemic stroke following a transient ischaemic attack (TIA) and can be detected by transcranial Doppler examination (TCD).(5) The established treatment regime is antiplatelet therapy, anticoagulation or both along with supportive therapy.(6) Current evidence suggests managing microemboli in both crescendo TIA's and post carotid endarterectomy improves outcome.(7) We have found the use of Tirofiban, a potent intravenous antiplatelet agent currently licensed for use in acute coronary syndrome, effective in the treatment of microemboli in this manner.(7)

CASE PRESENTATION

We report a case of symptomatic carotid artery dissection post radical neck dissection, causing TCD detected microemboli and successfully treated with Tirofiban.

CONCLUSION

We believe further study into the use of Tirofiban in the treatment of microemboli after carotid dissection is indicated.

Microembolus detection by transcranial Doppler sonography: review of the literature

Transcranial Doppler can detect microembolic signals which are characterized by unidirectional high intensity increase, short duration, random occurrence, and a “whistling” sound. Microembolic signals have been detected in a number of clinical settings: carotid artery stenosis, aortic arch plaques, atrial fibrillation, myocardial infarction, prosthetic heart valves, patent foramen ovale, valvular stenosis, during invasive procedures (angiography, percutaneous transluminal angioplasty), surgery (carotid, cardiopulmonary bypass, orthopedic), and in certain systemic diseases. Microembolic signals are frequent in large artery disease, less commonly detected in cardioembolic stroke, and infrequent in lacunar stroke. This article provides an overview about the current state of technical and clinical aspects of microembolus detection.

Cerebrovascular dissections: a review. Part II: blunt cerebrovascular injury

Traumatic cerebrovascular injury (TCVI) is present in approximately 1% of all blunt force trauma patients and is associated with injuries such as head and cervical spine injuries and thoracic trauma. Increased recognition of patients with TCVI in the past quarter century has been because of aggressive screening protocols and noninvasive imaging with computed tomography angiography. Extracranial carotid and vertebral artery injuries demonstrate a spectrum of severity, from intimal disruption to traumatic aneurysm formation or vessel occlusion. The most common intracranial arterial injuries are carotid-cavernous fistulae and traumatic aneurysms. Data on the long-term natural history of TCVI are limited, and management of patients with TCVI is controversial. Although antithrombotic medical therapy is associated with improved neurological outcomes, the optimal medication regimen is not yet established. Endovascular techniques have become more popular than surgery for the treatment of TCVI; endovascular options include stenting of dissections, intra-arterial thrombolysis for acute ischemic stroke caused by trauma, and embolization of traumatic aneurysms.

Evidence-based review of primary and secondary ischemic stroke prevention in adults: a neurosurgical perspective

In this paper, the authors' aim is to provide an evidence-based review of primary and secondary ischemic stroke prevention guidelines covering most of the common risk factors and stroke etiologies for the practicing neurosurgeon. The key to stroke prevention is in the identification and treatment of the major risk factors for stroke. These include hypertension, heart disease, diabetes mellitus, dyslipidemia, and tobacco smoking. An updated approach to secondary prevention of stroke in the setting of intracranial and extracranial large vessel atherosclerosis and cardioembolism is provided along with a brief overview of pertinent clinical trials. Novel pharmacological options for prevention of cardioembolic strokes, such as new alternatives to warfarin, are addressed with recommendations for interruption of therapy for elective surgical procedures. In addition, the authors have reviewed the anticoagulation guidelines and the risk of thromboembolic complications of such therapies in the perioperative period, which is an invaluable piece of information for neurosurgeons. Less common etiologies such as arterial dissections and patent foramen ovale are also briefly discussed. Finally, the authors have outlined the quality measures in the Medicare Physician Quality Reporting System and essential guidelines for Primary Stroke Center certification, which have implications for day-to-day neurosurgical practice.

Cerebrovascular Dissections—A Review Part I: Spontaneous Dissections

Spontaneous cerebrovascular dissections are subintimal or subadventitial cervical carotid and vertebral artery wall injuries and are the cause of as many as 2% of all ischemic strokes. Spontaneous dissections are the leading cause of stroke in patients younger than 45 years of age, accounting for almost one fourth of strokes in this population. A history of some degree of trivial trauma is present in nearly one fourth of cases. Subsequent mortality or neurological morbidity is usually the result of distal ischemia produced by emboli released from the injury site, although local mass effect produced by arterial dilation or aneurysm formation also can occur. The gold standard for diagnosis remains digital subtraction angiography. Computed tomography angiography, magnetic resonance angiography, and ultrasonography are complementary means o evaluation, particularly for injury screening or treatment follow-up. The annual rate of stroke after injury is approximately 1% or less per year. The currently accepted method of therapy remains antithrombotic medication, either in the form of anticoagulation or antiplatelet agents; however, no class I medical evidence exists to guide therapy. Other options for treatment include thrombolysis and endovascular therapy, although the efficacy and indications for these methods remain unclear.

Guidelines for the prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from the american heart association/american stroke association

The aim of this updated statement is to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for noncardioembolic stroke. Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral hemorrhage; and special approaches to the implementation of guidelines and their use in high-risk populations.

Antithrombotic drugs for carotid artery dissection

BACKGROUND

Extracranial internal carotid artery dissection (eICAD) is a leading cause of stroke in younger patients.

OBJECTIVES

1. To determine whether, in patients with eICAD, treatment with anticoagulants, antiplatelet agents or control was associated with a better functional outcome. 2. To compare, among patients treated with either anticoagulants or antiplatelet agents, the risk of ischaemic strokes and major bleeding episodes.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched 3 October 2009). In addition, we performed comprehensive searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2009), MEDLINE (January 1966 to November 2009) and EMBASE (January 1980 to November 2009), checked all relevant papers for additional eligible studies and contacted authors and researchers in the field.

SELECTION CRITERIA

Randomised controlled trials, controlled clinical trials and non-randomised studies (if they reported on outcome stratified by antithrombotic treatment and included at least four patients) of anticoagulants or antiplatelet agents for the treatment of extracranial internal carotid artery dissection. Two review authors independently extracted data.

DATA COLLECTION AND ANALYSIS

Primary outcomes were death (all causes) and death or disability. Secondary outcomes were ischaemic stroke, symptomatic intracranial haemorrhage, and major extracranial haemorrhage during the reported follow-up period. The first choice treatment was taken for analyses.

MAIN RESULTS

We did not find any completed randomised trials. Comparing antiplatelets with anticoagulants across 36 observational studies (1285 patients), there were no significant differences in the odds of death (Peto odds ratio (Peto OR) 2.02, 95% CI 0.62 to 6.60), or the occurrence of ischaemic stroke (OR 0.63, 95% CI 0.21 to 1.86) (34 studies, 1262 patients). For the outcome of death or disability, there was a non-significant trend in favour of anticoagulants (OR 1.77, 95% CI 0.98 to 3.22; P = 0.06) (26 studies, 463 patients). Symptomatic intracranial haemorrhages (5/627; 0.8%) and major extracranial haemorrhages (7/425; 1.6%) occurred only in the anticoagulation group; however, for both these outcomes, the estimates were imprecise and indicated no significant difference between the two treatment modalities.

AUTHORS' CONCLUSIONS

There were no randomised trials comparing either anticoagulants or antiplatelet drugs with control, thus there is no evidence to support their routine use for the treatment of extracranial internal carotid artery dissection. There were also no randomised trials that directly compared anticoagulants with antiplatelet drugs and the reported non-randomised studies did not show any evidence of a significant difference between the two.

Microemboli monitoring by trans-cranial doppler in patient with acute cardioemboliogenic stroke due to atrial myxoma

This is the first reported attempt to examine the emboliogenic potential of cardiac myxoma in patients with acute stroke through the monitoring of microembolic signals (MES) by transcranial doppler. A 43-year old woman was brought to the emergency department because of acute onset of generalized tonic-clonic seizures and left hemiplegia. A CT scan of the brain demonstrated a large acute infraction in the territory of the right middle cerebral artery (MCA) and another smaller one in the territory of the posterior cerebral artery on the same side. Trans-cranial doppler (TCD) microemboli monitoring did not reveal MES. Transesophagial echocardiography (TEE) identified a 5 cm left atrial mass, which was highly suspected to be an atrial myxoma attached to the interatrial septum and prolapsed through the mitral valve. After the TEE results were obtained, another TCD monitoring was performed. Again, there were no MES found in either of the MCAs.Our findings showed the absence of MES on two consecutive TCD examinations, suggesting a spontaneous occurrence, rather than the permanent presence, of embolization, even in the most acute phase of stroke. Thus, the tendency of myxomas to spontaneously produce multiple emboli emphasizes the need for the surgical excision of myxomas.

Cervical artery dissection: pathology, epidemiology and management

BACKGROUND

Cervical artery dissection is often treated with anticoagulants to prevent ischemic stroke. The risk-benefit ratio of anticoagulation versus antiplatelet therapy is unclear.

OBJECTIVES

To provide an educational review of current data on the disease to explain the rationale for the treatment options and to explore the results of management studies in order to determine if anticoagulation is justified.

METHODS

We searched the databases MEDLINE and EMBASE as well as bibliographies for information on anticoagulants and antiplatelet agents in cervical, i.e. carotid and/or vertebral artery, dissection.

RESULTS

There are no randomized controlled trials on the treatment. One systematic review from 2003 identified 20 case series or cohort studies. We identified 9 additional studies with a total of 1,033 patients. Of those, 731 received anticoagulation sometimes followed by platelet inhibition vs. 282 patients treated with antiplatelet agents alone. The rate of ischemic stroke was 2.3% vs. 6.9% and bleeding complications were reported in 0.7% vs. 0%.

CONCLUSION

It cannot be excluded that there is a net benefit from anticoagulant therapy in cervical dissection, but the studies are flawed by considerable bias. Very ill patients at a high risk of ischemic stroke may have been given aspirin due to fear of hemorrhagic complications. A randomized controlled trial is planned and will be crucial to resolve this issue.

[A young patient with ischemic stroke due to carotid artery dissection in whom number of microembolic signals was followed-up]

A 23-year-old Japanese man with rheumatoid arthritis experienced attacks of the right hand weakness during the latest month. Megaloblastic anemia was diagnosed and he was admitted in the department of hematology. Seven days after admission, he developed mild consciousness disturbance and hemiparesis on the right side. Brain MRI revealed the cortical watershed infarction in the left cerebral hemisphere. The cause of the infarction was diagnosed spontaneous dissection of the left internal carotid artery. We detected 11 microembolic signals (MES) during 30 minutes' monitoring in the left middle cerebral artery using transcranial Doppler. MES decreased gradually with anticoagulant therapy. However, surgical therapy was performed to prevent progression of dissection or arterial rupture. MES detected on transcranial Doppler would be important to assess the risk of embolism and to discuss therapeutic strategy.

Cervical arterial dissection: current concepts

The increasing use and safety of noninvasive imaging in recent years has revealed the surprising frequency of dissection of the carotid and vertebral arteries (cervical arterial dissection [CAD]) as a cause of ischemic and hemorrhagic stroke. This review is an overview of current concepts and practice of patients with CAD, but our ideas are constantly evolving with new discoveries from neurovascular imaging and medical and surgical management in this area.