BASICS
DESCRIPTION
- 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
CAD is responsible for 10-25% of all ischemic strokes in younger-aged patients (1)[B]. á
- Dissection of the carotid artery accounts for approximately 20% of strokes in patients <45 years of age.
Incidence
The incidence of CAD has been reported to be 2.6 to 3.0 per 100,000 inhabitants per year (2,3)[B]. á
- 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].
Prevalence
The average age of CAD patients is approximately 45 years. When experiencing CAD, men are on average 5 years older than women. á
ETIOLOGY AND PATHOPHYSIOLOGY
Intramural hematoma is the pathophysiologic hallmark of CAD. á
- 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.
Genetics
The following genetic disorders have been implicated with CAD: á
- Fibromuscular dysplasia
- Ehlers-Danlos syndrome type IV
- Marfan syndrome
- ╬▒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
No specific prevention measures are known. á
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"Ł 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 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 ischemia
- 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
Initial Tests (lab, imaging)
- 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 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
- 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-dependent
- A high-carotid artery bifurcation situated behind the ramus of the mandible cannot be reliably imaged.
Diagnostic Procedures/Other
- 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."Ł
- Can exhibit fusiform dilation with proximal or distal narrowing, termed the "string and pearl sign"Ł
- 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 artery
- Multiple TIAs/strokes (same circulation)
- Free-floating thrombus
- Features: against early anticoagulation/antiplatelets preferred (11)[B]
- Severe clinical deficit (NIHSS score 15)
- Accompanying intracranial dissection
- Local compression syndromes without ischemic events
- Concomitant diseases with increased bleeding risk
First Line
- 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.
Second Line
See "Surgery/Other Procedures."Ł á
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.
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.
Patient Monitoring
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. á
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
11 Yesilot Barlas áN, Putaala áJ, Waje-Andreassen áU, 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 áVH, Brown áRDJr, Mandrekar áJN, et al. Incidence and outcome of cervical artery dissection: a population-based study. Neurology. 2006;67(10):1809-1812.33 B ęjot áY, Daubail áB, Debette áS, 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 áS, Grond-Ginsbach áC, Bodenant áM, et al. Differential features of carotid and vertebral artery dissections: the CADISP study. Neurology. 2011;77(12):1174-1181.55 Beletsky áV, Nadareishvili áZ, Lynch áJ, et al. Cervical arterial dissection: time for a therapeutic trial? Stroke. 2003;34(12):2856-2860.66 Arnold áM, Nedeltchev áK, Sturzenegger áM, 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 áST, Rutgers áMP, Hatz áF, et al. Intravenous thrombolysis in stroke attributable to cervical artery dissection. Stroke. 2009;40(12):3772-3776.88 Nebelsieck áJ, Sengelhoff áC, Nassenstein áI, et al. Sensitivity of neurovascular ultrasound for the detection of spontaneous cervical artery dissection. J Clin Neurosci. 2009;16(1):79-82.99 Droste áDW, Junker áK, St Âgbauer áF, et al. Clinically silent circulating microemboli in 20 patients with carotid or vertebral artery dissection. Cerebrovasc Dis. 2001;12(3):181-185.1010 Patel áRR, Adam áR, Maldjian áC, et al. Cervical carotid artery dissection: current review of diagnosis and treatment. Cardiol Rev. 2012;20(3):145-152.1111 Engelter áST, Brandt áT, Debette áS, et al. Antiplatelets versus anticoagulation in cervical artery dissection. Stroke. 2007;38(9):2605-2611.1212 Engelter áST, Dallongeville áJ, Kloss áM, 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 áSM, Vergouwen áMD, Engelter áST, 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 áMH, Rahme áRJ, Arnaout áO, et al. Endovascular stenting of extracranial carotid and vertebral artery dissections: a systematic review of the literature. Neurosurgery. 2011;68(4):856-866.
ADDITIONAL READING
Lyrer áP, Engelter áS. Antithrombotic drugs for carotid artery dissection. Cochrane Database Syst Rev. 2010;(10):CD000255. á
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.