Delayed Occlusion after Internal Carotid Artery Dissection under Heparin

Quantitative evaluation for intravascular structures of vertebral artery dissection with a novel zoomed high-resolution black-blood MR imaging

BACKGROUND

Although non-stroke vertebral artery dissection (VAD) is diagnosed using MRI, detecting the subtle intravascular structure remains challenging. This study aimed to evaluate the validity of quantitative intravascular scanning based on novel zoomed high-resolution black blood (Z-HB) MRI for distinguishing VAD from other vessel pathologies.

METHODS

Twenty-one patients with non-stroke VAD and 18 with symptomatic atherosclerotic plaques in their vertebral artery underwent Z-HB MRI and subsequent profile curve processing. Axial Z-HB imaging was obtained from dissected and normal segments in patients with VAD and atherosclerotic plaque in patients with ischemia. We investigated the qualitative categorization of the scanning patterns of the intravascular signals. We also evaluated the quantitative ability of each profile curve to discriminate multiple vessel pathologies by analyzing the receiver operating characteristics curves.

RESULTS

Profile curve processing of 140 Z-HB images categorized the intravascular signal patterns into luminal, asymmetrical, and omega types. The asymmetrical type included both dissecting and atherosclerotic vessels, and the omega type included dissecting and normal vessels. In the asymmetrical type, quantitative evaluation successfully distinguished intramural hematomas of VAD from atherosclerotic plaque with an area under the curve of 0.80. The intimal flap of the VAD was distinguished from the blood flow artifact of the normal vessel with an area under the curve of 0.93 in the omega type.

CONCLUSIONS

A combination of novel Z-HB MRI and profile curve processing provided an ultra-high-resolution analysis of the intravascular structure of non-stroke VAD and successfully distinguished VAD from normal vessels or atherosclerotic plaques.

Spontaneous bilateral internal carotid and vertebral artery dissections with dominant-hemisphere circulation maintained by external carotid artery–ophthalmic artery anastomoses

Spontaneous cervical artery dissection (sCAD) is a major cause of stroke in young adults. Multiple sCAD is a rarer, more poorly understood presentation of sCAD that has been increasingly attributed to cervical trauma such as spinal manipulation or genetic polymorphisms in extracellular matrix components. The authors present the case of a 49-year-old, otherwise healthy woman, who over the course of 2 weeks developed progressive, hemodynamically significant, bilateral internal carotid artery and vertebral artery dissections. Collateral response involved extensive external carotid artery–internal carotid artery anastomoses via the ophthalmic artery, which were instrumental in maintaining perfusion because circle of Willis and leptomeningeal anastomotic responses were hampered by the dissection burden in the corresponding collateral vessels. Endovascular intervention by placement of Pipeline embolization devices and Atlas stents in bilateral internal carotid arteries was successfully performed. No syndromic or systemic etiology was discovered during a thorough workup.

[Ischemic stroke with vertebrobasilar artery dissection extended to posterior cerebral artery]

A 45-year-old woman was admitted with headache following sudden disturbance of consciousness that occurred two hours beforehand. A neurological examination identified disorientation, left homonymous hemianopia, left hemiplegia, and sensory disturbance in the left limbs. Brain MRI DWI showed acute infarcts in the right occipital lobe and bilateral thalami, and MRA poorly depicted right vertebral artery and right posterior cerebral artery. Anticoagulation was started to treat acute ischemic stroke, but her consciousness level deteriorated at 12 hours after onset. MRI revealed a double lumen in the basilar artery, indicating a diagnosis of vertebrobasilar artery dissection. Serial MRA findings showed that images of the basilar artery and posterior cerebral artery changed over time, suggesting vertebral artery dissection extension to the posterior cerebral artery.

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.

Dynamic Changes of Intramural Hematoma in Patients with Acute Spontaneous Internal Carotid Artery Dissection

Background

We prospectively investigated temporal and spatial evolution of intramural hematomas in patients with acute spontaneous internal carotid artery dissection using repeated magnetic resonance imaging over six-months. Aim The aim of the present study was to assess dynamic changes of intramural hematoma in patients with acute spontaneous internal carotid artery dissection at multiple follow-up time-points with T1w, PD/T2w, and magnetic resonance angiography.

Methods

We performed serial multiparametric magnetic resonance imaging in 10 patients with spontaneous internal carotid artery dissection on admission, at days 1, 3, 7–14 and at months 1·5, 3, and 6. We calculated the volume and extension of the hyperintense intramural hematoma using T1w and PD/T2w fat suppressed sequences and assessed the degree of stenosis due to the hematoma using magnetic resonance angiography.

Results

Mean interval from symptom onset to first magnetic resonance imaging was two-days (SD 2·7). Two patients presented with ischemic stroke, three with transient ischemic attacks, and five with pain and local symptoms only. Nine patients had a transient increase of the intramural hematoma volume, mainly up to day 10 after symptom onset. Fifty percent had a transient increase in the degree of the internal carotid artery stenosis on MRA, one resulting in a temporary occlusion. Lesions older than one-week were predominantly characterized by a shift from iso- to hyperintese signal on T2w images. At three-month follow-up, intramural hematoma was no longer detectable in 80% of patients and had completely resolved in all patients after six-months.

Conclusions

Spatial and temporal dynamics of intramural hematomas after spontaneous internal carotid artery dissection showed an early volume increase with concomitant progression of the internal carotid artery stenosis in 5 of 10 patients. Although spontaneous internal carotid artery dissection overall carries a good prognosis with spontaneous hematoma resorption in all our patients, early follow-up imaging may be considered, especially in case of new clinical symptoms.

Progression of bilateral internal carotid artery dissection during antiplatelet therapy

Bilateral internal carotid artery dissection (ICAD) is a rare but important cause of stroke in young adults. Anticoagulant and/or antiplatelet agents are usually recommended for stroke prevention;however, such treatments remain highly controversial, and there are inadequate data to compare the efficacy of anticoagulation and antiplatelet therapy. We herein report the case of 30-year-old man presenting with progressive bilateral ICAD during antiplatelet treatment. This report suggests the possibility that intramural hematomas are enlarged by antiplatelet and anticoagulant agents and draws attention to the medications associated with ICAD.

Treatment Issues in Spontaneous Cervicocephalic Artery Dissections

The management of cervicocephalic arterial dissections raises many unsolved issues such as: how to best acutely treat patients who present with ischemic stroke or occasionally with sub-arachnoid hemorrhage? How to best prevent ischemic stroke in patients who present with purely local signs such as headache, painful Horner Syndrome or neck pain? How long and how should patients be treated after cervicocephalic arterial dissections? Can patients resume their sports activities and when? The consensus is that, given the well-established initial thromboembolic risk, an urgent antithrombotic treatment is required in patients with a recent nonhemorrhagic cervicocephalic arterial dissection, but the type of antithrombotic treatment – anticoagulants or aspirin – as well as the indication for a local arterial treatment such as angioplasty/stenting remain debated. Evidence from a randomized clinical trial would be welcome but such a trial raises major issues of methodology, feasibility and funding. Meanwhile, cervicocephalic arterial dissection remains a situation when a bedside clinician should use, on a case-by-case basis, best clinical judgment and adopt a stepped care approach in the minority of patients who deteriorate despite initial treatment.

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.

Bilateral spontaneous internal carotid artery dissection with both early and very late recanalization: A case report

Spontaneous bilateral internal carotid artery dissection has frequently been described in the literature as a cause of stroke. In more than half of the patients with internal carotid artery dissection, recanalization occurs early after the event and is unusual later than 6 months after onset of the dissection. We describe a patient with ischemic stroke due to left internal carotid artery occlusion in the extracranial segment. The patient was treated with anticoagulants and early vessel recanalization did not occur. Ten months later, he developed contralateral internal carotid occlusion in the intracranial tract, which was followed by early complete recanalization. Anticoagulation therapy was continued and, 16 months after the initial event, the left internal carotid artery unexpectedly also reopened.

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.

Cervical artery dissection

Spontaneous and traumatic cervical artery dissection is a common cause of stroke in the young. It generally carries an excellent prognosis if treatment is initiated early. Antiplatelet therapy may be as effective as or safer than warfarin, although no randomized prospective studies have addressed the issue of optimal medical therapy. Rarely, endovascular therapy may be indicated for the treatment of ruptured aneurysms or to prevent recurrent ischemia.

Stroke treatment: beyond the three-hour window and in the pregnant patient

For acute stroke patients who arrive at the hospital within 3 h of symptom onset, the focus of care involves screening for eligibility to receive intravenous tissue plasminogen activator. The publication of the National Institute of Neurological Disorders and Stroke recombinant tissue-type plasminogen activator (tPA, or alteplase) study in 1995 (Marler, J.R. 1995, New England Journal of Medicine333: 1581-1587) spurred protocol changes, which continue to evolve, throughout the health care system in an effort to streamline the patient through the Emergency Medical System. The need to expedite patient evaluation involving emergency department, laboratory, radiology, and clinical neurology testing is clear and has been a focus of many stroke centers. For some patients, intravenous thrombolysis within 3 h has a dramatic effect on outcome. However, that is not the only course of action for acute stroke patients. This article will review some of the effective treatments for stroke patients beyond the first 3 h of their care.

Antiplatelets Versus Anticoagulation in Cervical Artery Dissection

Background and Purpose— The widespread preference of anticoagulants over antiplatelets in patients with cervical artery dissection (CAD) is empirical rather than evidence-based.

Summary of Review— This article summarizes pathophysiological considerations, clinical experiences, and the findings of a systematic metaanalysis about antithrombotic agents in CAD patients. As a result, there are several putative arguments in favor as well as against immediate anticoagulation in CAD patients.

Conclusions— A randomized controlled trial comparing antiplatelets with anticoagulation is needed and ethically justified. However, attributable to the large sample size which is required to gather meaningful results, such a trial represents a huge venture. This comprehensive overview may be helpful for the design and the promotion of such a trial. In addition, it could be used to encourage both participation of centers and randomization of CAD patients. Alternatively, antithrombotic treatment decisions can be customized based on clinical and paraclinical characteristics of individual CAD patients. Stroke severity with National Institutes of Health Stroke Scale score ≥15, accompanying intracranial dissection, local compression syndromes without ischemic events, or concomitant diseases with increased bleeding risk are features in which antiplatelets seem preferable. In turn, in CAD patients with (pseudo)occlusion of the dissected artery, high intensity transient signals in transcranial ultrasound studies despite (dual) antiplatelets, multiple ischemic events in the same circulation, or with free-floating thrombus immediate anticoagulation is favored.

Non-Atherosclerotic Vascular Disease in the Young

There are a large variety of non-atherosclerotic causes of ischemic stroke in the young. Arterial dissection, most commonly associated with non-traumatic causes, is among the most common. Both the carotid and vertebrobasilar circulations can be affected. The vasculitidies represent a rare, but potentially treatable series of conditions that can lead to stroke through diverse mechanisms. Moyamoya is a nonatherosclerotic, noninflammatory, nonamyloid vasculopathy characterized by chronic progressive stenosis or occlusion of the distal internal carotid arteries and/or proximal portions of the middle and/or anterior cerebral arteries. Moyamoya can be idiopathic (moyamoya disease) or the result of other conditions. An appreciation of the unusual causes of stroke in the young is important when considering secondary prevention measures.

Antithrombotic drugs for carotid artery dissection

BACKGROUND

Extracranial internal carotid artery dissection can lead to occlusion of the artery and hence cause an ischaemic stroke. It is the underlying stroke mechanism in approximately 2.5% of all strokes. It is the second leading cause of stroke in patients younger than 45 years of age. Anticoagulants or antiplatelets may prevent arterial thrombosis in extracranial internal carotid artery dissection, but these benefits may be offset by increased bleeding.

OBJECTIVES

To determine whether antithrombotic drugs (antiplatelet drugs, anticoagulation) are effective and safe in the treatment of patients with extracranial internal carotid artery dissection, and which is the better treatment.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched 3 October 2002). In addition we performed comprehensive searches of the Cochrane Central Register of Controlled Trials (Cochrane Library Issue 2, 2002), MEDLINE (January 1966 to May 2002) and EMBASE (January 1980 to June 2002), and checked all relevant papers for additional eligible studies.

SELECTION CRITERIA

Randomised controlled trials, controlled clinical trials assessing the efficacy of anticoagulants or antiplatelets for the treatment of extracranial internal carotid artery dissection, and non-randomised trials, e.g. case series (studies), that reported on any antithrombotic treatment with at least 4 patients, were eligible for inclusion. Data from all eligible studies were extracted independently by two reviewers. Disagreements were resolved by discussion.

DATA COLLECTION AND ANALYSIS

Data on the primary outcome measures were extracted systematically. These were: death (all causes) and death or disability. Secondary outcomes were: first stroke occurrence, stroke recurrence, any stroke during reported follow-up, extracranial haemorrhage, and intracranial haemorrhage. The first choice treatment was taken for analyses.

MAIN RESULTS

No randomised trials were identified. No reliable comparisons of antiplatelet drugs or anticoagulants with control were available. Twenty-six eligible studies including 327 patients (who either received antiplatelet drugs or anticoagulants) were to be included in the comparative analysis. There was no significant difference in odds of death comparing antiplatelet drugs with anticoagulants (Peto odds ratio (Peto OR) 1.59, 95% CI 0.22-11.59). There was also no significant difference in the odds of being dead or disabled (Peto OR 1.94, 95% CI 0.76-4.91). Few intracranial haemorrhages (0.5%) were reported for patients on anticoagulants, none for patients on antiplatelets.

REVIEWER'S CONCLUSIONS

There were no randomised trials comparing either anticoagulants or antiplatelet drugs with control. There is, therefore, 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. We suggest that a randomised trial including at least 1400 patients in each treatment arm with this condition is clearly needed.