Dissection, Carotid and Vertebral Artery

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Dissection, Carotid and Vertebral Artery

BASICS

DESCRIPTION

CAD is responsible for 10-25% of all ischemic strokes in younger-aged patients (1)[B]. ГЎ

The average age of CAD patients is approximately 45 years. When experiencing CAD, men are on average 5 years older than women. ГЎ

Intramural hematoma is the pathophysiologic hallmark of CAD. ГЎ

The following genetic disorders have been implicated with CAD: ГЎ

Close follow-up for an extended period of time is recommended in patients with underlying connective tissue disorders, as they are at a higher risk of recurrence. ГЎ

11 Yesilot Barlas ГЎN, Putaala ГЎJ, Waje-Andreassen ГЎU, et al. Etiology of first-ever ischaemic stroke in European young adults: the 15 cities young stroke study. Eur J Neurol. 2013;20(11):1431-1439.22 Lee ГЎVH, Brown ГЎRDJr, Mandrekar ГЎJN, et al. Incidence and outcome of cervical artery dissection: a population-based study. Neurology. 2006;67(10):1809-1812.33 B Д™jot ГЎY, Daubail ГЎB, Debette ГЎS, et al. Incidence and outcome of cerebrovascular events related to cervical artery dissection: the Dijon Stroke Registry. Int J Stroke. 2014;9(7):879-882.44 Debette ГЎS, Grond-Ginsbach ГЎC, Bodenant ГЎM, et al. Differential features of carotid and vertebral artery dissections: the CADISP study. Neurology. 2011;77(12):1174-1181.55 Beletsky ГЎV, Nadareishvili ГЎZ, Lynch ГЎJ, et al. Cervical arterial dissection: time for a therapeutic trial? Stroke. 2003;34(12):2856-2860.66 Arnold ГЎM, Nedeltchev ГЎK, Sturzenegger ГЎM, et al. Thrombolysis in patients with acute stroke caused by cervical artery dissection: analysis of 9 patients and review of the literature. Arch Neurol. 2002;59(4):549-553.77 Engelter ГЎST, Rutgers ГЎMP, Hatz ГЎF, et al. Intravenous thrombolysis in stroke attributable to cervical artery dissection. Stroke. 2009;40(12):3772-3776.88 Nebelsieck ГЎJ, Sengelhoff ГЎC, Nassenstein ГЎI, et al. Sensitivity of neurovascular ultrasound for the detection of spontaneous cervical artery dissection. J Clin Neurosci. 2009;16(1):79-82.99 Droste ГЎDW, Junker ГЎK, St Г‚gbauer ГЎF, et al. Clinically silent circulating microemboli in 20 patients with carotid or vertebral artery dissection. Cerebrovasc Dis. 2001;12(3):181-185.1010 Patel ГЎRR, Adam ГЎR, Maldjian ГЎC, et al. Cervical carotid artery dissection: current review of diagnosis and treatment. Cardiol Rev. 2012;20(3):145-152.1111 Engelter ГЎST, Brandt ГЎT, Debette ГЎS, et al. Antiplatelets versus anticoagulation in cervical artery dissection. Stroke. 2007;38(9):2605-2611.1212 Engelter ГЎST, Dallongeville ГЎJ, Kloss ГЎM, et al. Thrombolysis in cervical artery dissection-data from the Cervical Artery Dissection and Ischaemic Stroke Patients (CADISP) database. Eur J Neurol. 2012;19(9):1199-1206.1313 Zinkstok ГЎSM, Vergouwen ГЎMD, Engelter ГЎST, et al. Safety and functional outcome of thrombolysis in dissection-related ischemic stroke: a meta-analysis of individual patient data. Stroke. 2011;42(9):2515-2520.1414 Pham ГЎMH, Rahme ГЎRJ, Arnaout ГЎO, et al. Endovascular stenting of extracranial carotid and vertebral artery dissections: a systematic review of the literature. Neurosurgery. 2011;68(4):856-866.

Lyrer ГЎP, Engelter ГЎS. Antithrombotic drugs for carotid artery dissection. Cochrane Database Syst Rev. 2010;(10):CD000255. ГЎ

Cervical artery dissection (CAD) is subcategorized to internal carotid artery dissection (ICAD) and vertebral artery dissection (VAD).
CAD accounts for 2-2.5% of all ischemic strokes.

EPIDEMIOLOGY

Dissection of the carotid artery accounts for approximately 20% of strokes in patients <45 years of age.

The ratio of extracranial ICAD: VAD is nearly 2:1, with 1.7 to 3.0 per 100,000 inhabitants per year for ICAD and 0.97 per 100,000 inhabitants per year for VAD. This is supported by a multinational registry across 18 centers (mostly European) (4)[B].
However, data from the Canadian Stroke Consortium showed VAD as more prevalent than ICAD (5)[B]. A recent French-based epidemiologic study revealed incidence rates of 1.21 per 100,000 per year and 1.87 per 100,000 per year for ICAD and VAD, respectively (3)[B].

ETIOLOGY AND PATHOPHYSIOLOGY

Caused by a subintimal tear into the arterial wall of the carotid and vertebral artery
Intramural blood accumulation subjacent to the adventitia can cause Horner syndrome, arterial narrowing, and subsequent cerebral ischemia.
Arterial rupture can result in subarachnoid hemorrhage (SAH) or pseudoaneurysm.
Originating from the injured intima, these cerebral ischemic events are more often due to embolism rather than hemodynamic compromise.
Iatrogenic dissections can also occur due to catheter manipulation or balloon angioplasty.

Fibromuscular dysplasia
Ehlers-Danlos syndrome type IV
Marfan syndrome
в•¬в–’1-Antitrypsin deficiency
Type 1 collagen point mutation
Migraine
Cystic medial necrosis
Moyamoya disease
Giant cell arteritis
Temporal arteritis
Low-lying carotid bifurcation

RISK FACTORS

Coils, kinks, loops
Irradiated blood vessels
Neck manipulation

GENERAL PREVENTION

COMMONLY ASSOCIATED CONDITIONS

Retinal ischemia and ischemic optic neuropathy (CAD)
Spinal cord ischemia and cervical radiculopathies (VAD)
Horner syndrome (CAD more often than VAD)

DIAGNOSIS

HISTORY

CAD presents as TIA or stroke in approximately 2/3 of patients, though often, affected individuals present with both ischemic and localized symptoms.
In spontaneous ICAD dissections, pain is most frequently the initial symptom.Headaches are typically unilateral, affecting the frontotemporal area, nonthrobbing in nature, with gradual onset, although it can also present as an acute-onset severe "thunderclap"ЕЃ or orbital pain.Orbital pain (~50%)In <10% of ICAD patients, pain is the only presenting symptom.Cranial nerve palsies present in approximately 12% of patients. There is a predilection to lower cranial nerves. The most commonly affected nerve is the hypoglossal (XII) given its proximity to the carotid sheath. Oculomotor (III), trigeminal (V), and facial nerves (VII) can also be affected. The combination of oculosympathetic palsy and lower cranial nerve palsy may mimic a brain stem infarct.Pulsatile tinnitus (~25%)Symptoms of cerebral ischemia (50-95%)Amaurosis fugax and TIA are early warning signs. Up to 20% of patients with ischemic stroke present without warning signs.
The triad of ipsilateral facial pain, partial Horner syndrome (oculosympathetic palsy), and subsequent ischemia present in <1/3 of ICAD patients. Oculosympathetic palsy is defined as ptosis with meiosis without anhidrosis.Maintain a high-index of suspicion in patients with at least two of these symptoms or with nonspecific focal neurologic complaints, particularly in the setting of trauma.Found in up to 50% of cases, any patient with a partial Horner syndrome should be considered to have an ICAD until proven otherwise.
VAD presents with posterior neck pain, followed by ischemic manifestations in the posterior circulation.Also presents as occipital headache extending anteriorly or involving the entire craniumMay affect the thalamus, the cerebral and cerebellar hemispheres, other areas of the brain stem and, rarely, the spinal cord in isolationMay present as a lateral medullary syndromeWallenberg syndrome, specifically if the dissection is localized in the 3rd or 4th segment of the vertebral artery.Rarely presents with upper extremity weakness from involvement of the C5-C6 nerve roots.

Headaches are typically unilateral, affecting the frontotemporal area, nonthrobbing in nature, with gradual onset, although it can also present as an acute-onset severe "thunderclap"ЕЃ or orbital pain.
Orbital pain (~50%)
In <10% of ICAD patients, pain is the only presenting symptom.
Cranial nerve palsies present in approximately 12% of patients. There is a predilection to lower cranial nerves. The most commonly affected nerve is the hypoglossal (XII) given its proximity to the carotid sheath. Oculomotor (III), trigeminal (V), and facial nerves (VII) can also be affected. The combination of oculosympathetic palsy and lower cranial nerve palsy may mimic a brain stem infarct.
Pulsatile tinnitus (~25%)
Symptoms of cerebral ischemia (50-95%)
Amaurosis fugax and TIA are early warning signs. Up to 20% of patients with ischemic stroke present without warning signs.

Maintain a high-index of suspicion in patients with at least two of these symptoms or with nonspecific focal neurologic complaints, particularly in the setting of trauma.
Found in up to 50% of cases, any patient with a partial Horner syndrome should be considered to have an ICAD until proven otherwise.

Also presents as occipital headache extending anteriorly or involving the entire cranium
May affect the thalamus, the cerebral and cerebellar hemispheres, other areas of the brain stem and, rarely, the spinal cord in isolation
May present as a lateral medullary syndrome
Wallenberg syndrome, specifically if the dissection is localized in the 3rd or 4th segment of the vertebral artery.
Rarely presents with upper extremity weakness from involvement of the C5-C6 nerve roots.

PHYSICAL EXAM

Partial Horner syndrome (oculosympathetic palsy): ptosis and miosis without anhidrosis
Cerebral ischemiaICAD: most commonly affects the middle cerebral artery perfusion territory, which includes most of the outer cortex of the brain, the basal ganglia, and the posterior and anterior internal capsules. Therefore, sequelae of an ischemic injury include a wide range of motor and/or sensory deficits.VAD: typically affects the brainstem, cerebellum, and occipital lobes, resulting in a range of medullary syndromes, ataxias, and visual impairments

ICAD: most commonly affects the middle cerebral artery perfusion territory, which includes most of the outer cortex of the brain, the basal ganglia, and the posterior and anterior internal capsules. Therefore, sequelae of an ischemic injury include a wide range of motor and/or sensory deficits.
VAD: typically affects the brainstem, cerebellum, and occipital lobes, resulting in a range of medullary syndromes, ataxias, and visual impairments

DIFFERENTIAL DIAGNOSIS

Migraine, cluster, or tension headaches
Neck trauma and cervical spine fracture
Ischemic stroke, hemorrhagic stroke
Retinal artery or vein occlusion

DIAGNOSTIC TESTS & INTERPRETATION

No specific labs
The diagnosis of CAD is confirmed by the presence of at least one of the following neurovascular criteria (6,7)[B]:Visualization of a mural hematomaAneurysmal dilatationLong tapering stenosisIntimal flapDouble lumenOcclusion greater than 2 cm above the carotid bifurcation revealing an aneurysmal dilatation or a long tapering stenosis after recanalization in the internal carotid or vertebral artery
These imaging features are most accurately visualized by MRI (identification of mural hematoma by fat-suppressed T1 sequences). MRI detection of mural hematoma can be falsely negative in the very acute stage. The lengthy time for image acquisition also limits the use of MRI in emergencies.
CT angiography (CTA) has been reported to show similar results to magnetic resonance techniques, with CTA as the preferred modality in emergency situations and trauma cases.
Ultrasound with pulsed Doppler and duplex color flow can be used to image the extracranial cerebral circulation. Neurosonography may depict CAD characteristics, including mural hematoma, even early after CAD onset (8)[B].
Transcranial Doppler (TCD) monitoring studies may reveal microembolic signals (MESs) downstream of the dissected arteries (25%-60%).In ICAD, MESs may be detected in the middle cerebral artery and in the posterior circulation for VAD (9)[B].
Ultrasound does have pitfalls:Operator-dependentA high-carotid artery bifurcation situated behind the ramus of the mandible cannot be reliably imaged.

Visualization of a mural hematoma
Aneurysmal dilatation
Long tapering stenosis
Intimal flap
Double lumen
Occlusion greater than 2 cm above the carotid bifurcation revealing an aneurysmal dilatation or a long tapering stenosis after recanalization in the internal carotid or vertebral artery

In ICAD, MESs may be detected in the middle cerebral artery and in the posterior circulation for VAD (9)[B].

Operator-dependent
A high-carotid artery bifurcation situated behind the ramus of the mandible cannot be reliably imaged.

Catheter angiography has traditionally been the gold standard for evaluating CAD, though in most centers, it has been supplanted by CTA or MRI.Shows segmental arterial stenosis or "string sign."ЕЃCan exhibit fusiform dilation with proximal or distal narrowing, termed the "string and pearl sign"ЕЃAn intimal flap is shown as an occlusion of the vessel usually tapered to a point.A double lumen reveals retention of the contrast in the false lumen well into the venous phase.The pathognomonic signs of dissection such as the double lumen and the intimal flap are seen in fewer than 10% of cases.

Shows segmental arterial stenosis or "string sign."ЕЃ
Can exhibit fusiform dilation with proximal or distal narrowing, termed the "string and pearl sign"ЕЃ
An intimal flap is shown as an occlusion of the vessel usually tapered to a point.
A double lumen reveals retention of the contrast in the false lumen well into the venous phase.
The pathognomonic signs of dissection such as the double lumen and the intimal flap are seen in fewer than 10% of cases.

TREATMENT

MEDICATION

Anticoagulation therapy, short-acting (acute phase)
Typically heparin with bridge to warfarin (10)[A]
Thrombolytics such as tPA are not contraindicated if patient presents with acute ischemic stroke with CAD (10)[A].
Antiplatelet therapy (acute phase) typically aspirin
Anticoagulation therapy, long-acting (subacute phase)-3 to 6 months with warfarin, goal INR 2 to 3 (10)[A]
Antiplatelet therapy (chronic phase)
The choice of early anticoagulation versus antiplatelet therapy can be guided by clinical presentation and findings on imaging.
Features: in favor of early anticoagulation (11)[B]MESs (transcranial neurosonology) despite treatment with one antiplatelet medication.Pseudo-occlusion of the dissected arteryMultiple TIAs/strokes (same circulation)Free-floating thrombus
Features: against early anticoagulation/antiplatelets preferred (11)[B]Severe clinical deficit (NIHSS score 15)Accompanying intracranial dissectionLocal compression syndromes without ischemic eventsConcomitant diseases with increased bleeding risk

MESs (transcranial neurosonology) despite treatment with one antiplatelet medication.
Pseudo-occlusion of the dissected artery
Multiple TIAs/strokes (same circulation)
Free-floating thrombus

Severe clinical deficit (NIHSS score 15)
Accompanying intracranial dissection
Local compression syndromes without ischemic events
Concomitant diseases with increased bleeding risk

Intravenous thombolysis (IVT) in CAD can be beneficial by inducing recanalization of the arterial thrombosis at the site of dissection or of a distal embolus (12)[B].
Controversy exists in the use of IVT for first-line treatment.One meta-analysis reported the safety and outcome measures of IVT in patients with CAD-associated stroke appeared similar to those for IVT in patients with stroke due to all causes (13)[A].A separate study suggests a less favorable recovery of CAD patients after IVT, measured by a lower modified Rankin scale (mRS) score (12)[B].Potential complications of thrombolysis include an increase in size of mural thrombus with worsening of the luminal stenosis, or even mobilization of the mural thrombus with distal embolization. IVT could also result in SAH/pseudoaneurysm because of leakage.

One meta-analysis reported the safety and outcome measures of IVT in patients with CAD-associated stroke appeared similar to those for IVT in patients with stroke due to all causes (13)[A].
A separate study suggests a less favorable recovery of CAD patients after IVT, measured by a lower modified Rankin scale (mRS) score (12)[B].
Potential complications of thrombolysis include an increase in size of mural thrombus with worsening of the luminal stenosis, or even mobilization of the mural thrombus with distal embolization. IVT could also result in SAH/pseudoaneurysm because of leakage.

SURGERY/OTHER PROCEDURES

Endovascular treatment has been effectively used for surgical treatment of CAD. A systematic review of endovascular stenting showed the following (14)[A]:High technical success rate (99% [ICAD] and 100% [extracranial VAD])Periprocedural complications occurred in 1.3% (ICAD) and 0% (VAD), respectively.Carotid in-stent steno-occlusive complications in three cases (3/150, 2%) and vertebral in-stent thrombosis was detected in one case (1/7, 14%).Within a mean follow-up period of 17.7 months (range 1 to 72 months), clinical complications occurred in 1.4% of ICAD patients. There were no clinical complications in the VAD group.Endovascular treatment has not been demonstrated as superior to IVT. It is usually reserved for CAD patients in whom antithrombotic therapy has failed, in particular in rapidly deteriorating patients or when hemodynamic infarction is impending, in ruptured dissecting aneurysm, or in iatrogenic CADs.
Arterial surgery carries a poorer outcome and is limited to those cases of progression of symptoms in anatomically accessible lesions and patients with contraindications against stenting.

High technical success rate (99% [ICAD] and 100% [extracranial VAD])
Periprocedural complications occurred in 1.3% (ICAD) and 0% (VAD), respectively.
Carotid in-stent steno-occlusive complications in three cases (3/150, 2%) and vertebral in-stent thrombosis was detected in one case (1/7, 14%).
Within a mean follow-up period of 17.7 months (range 1 to 72 months), clinical complications occurred in 1.4% of ICAD patients. There were no clinical complications in the VAD group.
Endovascular treatment has not been demonstrated as superior to IVT. It is usually reserved for CAD patients in whom antithrombotic therapy has failed, in particular in rapidly deteriorating patients or when hemodynamic infarction is impending, in ruptured dissecting aneurysm, or in iatrogenic CADs.

FOLLOW-UP RECOMMENDATIONS

Follow-up with a neurologist is highly recommended.
Antiplatelet therapy or anticoagulation with heparin with bridge to warfarin should be initiated for at least 3 to 6 months.
Repeat imaging is useful to guide further treatment decisions.
Anticoagulants are usually maintained for no longer than 6 months. Following this period, anticoagulation is either stopped or substituted by antiplatelet therapy, which can be continued for 2 years or longer if indicated.

PROGNOSIS

If dissections are diagnosed while patients are asymptomatic or mildly symptomatic, up to 90% have a full functional recovery.
Patients presenting with a fixed neurologic deficits have a less favorable prognosis, with a mortality rate up to 20% in 1 week, and up to 50% carrying a significant residual disability (with only up to 40% making a good recovery).
Dissections caused by trauma carry the prognosis of the respective associated comorbidities and the severity of shock.

REFERENCES

ADDITIONAL READING

CODES

ICD10

I77.71 Dissection of carotid artery
I77.74 Dissection of vertebral artery
I72.8 Aneurysm of other specified arteries
I72.0 Aneurysm of carotid artery

ICD9

443.21 Dissection of carotid artery
443.24 Dissection of vertebral artery
442.81 Aneurysm of artery of neck

SNOMED

Internal carotid artery dissection (disorder)
Vertebral artery dissection
Pseudoaneurysm of vertebral artery (disorder)

CLINICAL PEARLS

CAD is comprised of ICAD and VAD and is a major cause of stroke in the young.
A majority of patients have both ischemic and localized symptoms.
In the radiographic detection of CAD, MRI has a higher sensitivity than neurosonology, but can be falsely negative in the very acute stage of CAD. CTA is widely available and reliably used for emergencies.
TCD monitoring studies may reveal MESs downstream of the dissected arteries.
Endovascular treatment is an effective treatment for select patients and is not superior to IVT.
Antiplatelets and anticoagulants are used to prevent stroke in CAD patients.