Carotid Artery Dissection
There are three layers in the artery wall that provide strength, resilience, and flexibility to allow for adaptive blood flow in a constantly changing environment. The common carotid arteries are located on the right and left sides of the neck; they are responsible for blood supply to the brain and face.
A dissection is a sudden tear in the artery wall that allows blood flow to separate the wall layers. Blood flow into this "false" channel can grow to compress the true artery channel, resulting in a total artery blockage, or occlusion. Alternatively, pieces of the clotted blood in the false channel can break off and block smaller arteries in the brain resulting in a stroke. Separation of the wall layers may also weaken the artery and allow bulging to form a "pseudoaneurysm."
Dissection may develop without clear cause (spontaneous carotid artery dissection) or secondary to trauma (e.g., motor vehicle accident, sports injury, surgery, chiropractic neck manipulation).
Carotid Artery Dissection Risk Factors
Several conditions may predispose patients to this carotid dissection including fibromuscular dysplasia (accounting for 15 percent of spontaneous cases), Marfan's, Loeys-Dietz syndrome, and Ehlers-Danlos Vascular type IV. Mount Sinai is a renowned international referral center for the treatment of these disorders.
Treatment of the underlying disorder is paramount to recovery – if you have a disorder that increases your risk for a carotid dissection it is very important that you are under the care of a vascular specialist. For those without an underlying disorder, promoting vascular health including healthy diet, exercise, blood pressure, diabetes, and cholesterol control is important.
Carotid Artery Dissection Symptoms
Carotid dissection may present as a stroke with weakness on one-side of the body, visual disturbance, facial droop, and/or difficulty with speech. If stroke is suspected, the emergency room is the most appropriate setting for evaluation.
Some patients experience a "whooshing" noise in one ear known as pulsatile tinnitus.
Common carotid artery dissection symptoms include:
- Sudden head, face or neck pain with associated neurologic symptoms, such as an small pupil on one side and drooping eyelid (Horner's syndrome)
- Vision loss in one eye (amaurosis fugax)
Any of these symptoms should prompt an immediate evaluation by a physician.
Diagnosing Carotid Artery Dissection
The key to diagnosis is imaging. Mount Sinai is a multidisciplinary institution with advanced imaging, including the Vascular Diagnostic Laboratory, Cardiovascular Imaging Program, and Mount Sinai's Department of Radiology with computed tomography (CT), magnetic resonance imaging (MRI), and catheter-based angiography capabilities.
When carotid artery dissection is suspected, the following may be considered to make the diagnosis:
- Carotid artery duplex ultrasonography is a non-invasive ultrasound of the blood vessels in the neck that is readily available in hospital and many clinic settings. It is a fast, non-invasive, bedside examination, but generally it is not as accurate as the other imaging techniques and cannot determine if the patient has sustained a stroke.
- Catheter-based angiography involves introduction of a catheter into the groin arteries that is then fed up to the neck for the manual injection of contrast dye into the carotid arteries. Together with x-ray images, the artery can be evaluated – although with less accuracy than CT. Intervention can be performed, if required, such as the placement of a meshed tube to correct the dissection (known as a stent). Complications may result from the procedure in about one percent of patients.
- CT angiography (CTA) is a very accurate test that is rapidly becoming the "gold standard" in diagnosis of carotid artery dissection. The test involves an iodinated-contrast to highlight the arteries combined with accurate three-dimensional (3D) images created by CT. The exam is non-invasive, fast, and can determine if the patient has sustained a stroke; however, patients are exposed to radiation.
- MR angiography (MRA) is another very accurate test. Similar to the CT, the MRA combines contrast dye and magnetic waves to create 3D artery images. The study is non-invasive and can evaluate for stroke. In contrast to CT imaging, MRA does not expose the patient to radiation, but it requires much longer imaging time.
Carotid Artery Dissection Treatments
Treatment of carotid artery dissection depends on the patient's symptoms. Risk factors for a dissection such as trauma or an underlying disorder (e.g., Marfan's) may affect treatment decisions, and it is important information for the doctor to know. The primary goal is to prevent a stroke.
Typically, medications including aspirin plus other anti-platelet medications (e.g., clopidogrel, prasugrel, ticagrelor) are considered if the patient does not have on-going neurologic symptoms. Blood-thinning medications such as heparin or warfarin may be used instead of antiplatelet therapy.
In some cases, surgical intervention to correct the dissection may be necessary. Generally, this requires a minimally invasive procedure via a catheter placed in the groin. Balloons or mesh tubes (stents) to open the artery are deployed through the catheter in the artery. This is performed under local anesthesia, and patients are given mild sedation during the procedure. The interventional cardiologists, vascular surgeons, and neurointerventionalists at Mount Sinai work together to perform carotid artery stenting.
After Effects of a Carotid Artery Dissection
There are two major determinants in the long-term effects or prognosis of patients with a carotid artery dissection: the damage sustained to the brain if a stroke occurs and the underlying cause of the event.
Spontaneous carotid dissection accounts for 10 to 25 percent of strokes in patients ages 45 or younger. Most patients experience stroke symptoms; however, more than 75 percent make a full recovery. The risk of recurrence is two percent in the first month and one percent per year thereafter. For patients with carotid dissection secondary to trauma, the stroke rate may be as high as 50 percent, with a higher rate of long-term complications and mortality than patients with a spontaneous dissection.
Many patients experience recurrent headache or neck pain after dissection; sometimes, lasting years after the event. All patients who have had a carotid artery dissection should see a vascular specialist for long-term care and follow-up. Surveillance imaging with CTA, MRA, or ultrasound is often required to monitor for progression, complication, and/or progress of healing.
Division of Vascular and Endovascular Surgery
Vascular Interventions – Cardiac Cath Lab
1190 Fifth Avenue, 1st Floor
New York, NY 10029