Arterial Dissection and Stroke

Arteries are the highways through which oxygen-rich blood flows toward oxygen-hungry organs, such as the kidneys, heart, and brain. The main arteries that bring blood to the brain are the carotid and vertebral arteries. Dissection in these arteries can bring about a stroke.

What is Arterial Dissection?

Arterial dissection refers to the abnormal, and usually abrupt, formation of a tear along the inside wall of an artery.

As the tear becomes larger, it forms a small pouch which doctors call a “false lumen.” The blood that accumulates inside this false lumen can lead to a stroke in any of the following ways:

  • Blood pools inside the wall of the artery until it begins to impede blood flow. The growing pool of blood in the wall of the artery is known as a “pseudoaneurysm.” Pseudoaneurysms can lead to symptoms of stroke by pressing on brain structures located nearby. They can also burst and cause major bleeding into the brain (hemorrhagic strokes). When this occurs, the pseudoaneurysm is referred to as a “dissecting aneurysm” or “dissecting pseudoaneurysm.”
  • The blood inside the false lumen can clot and extend slowly into the area where blood normally flows. This can limit or completely interrupt blood flow to a part of the brain.
  • Small pieces from the growing blood clot can break off, flow upstream, and become trapped inside a smaller artery in the brain. This event is known as an “artery-to-artery thromboembolism.”

    Is Dissection a Common Cause of Stroke?

    Spontaneous dissection of the carotid and vertebral arteries is a relatively uncommon cause of stroke. It's responsible for less than 2% of all cases, although it accounts for up to one-quarter of all strokes in young and middle-aged people specifically. Each year in the United States, between 12,000 and 15,000 people are affected by spontaneous dissection of the carotid or vertebral arteries.

    Causes of Carotid and Vertebral Artery Dissection

    The carotid and vertebral arteries can be damaged by neck injuries or even forceful neck movements. The following are some situations that have been associated with dissection of the carotid and vertebral arteries:

    Dissection of the carotid and vertebral arteries can also occur spontaneously in association with the following diseases:


    Typical symptoms include:

    • Pain on one or both sides of the neck, face, or head
    • Eye pain, or one unusually small pupil
    • A droopy eyelid or double vision
    • A sudden change in ability to taste food
    • Ringing in the ears, dizziness or vertigo
    • Paralysis of any of the muscles of the neck and face on one side (e.g., inability to close one eye)

    Symptoms of a stroke or transient ischemic attack can occur a few days to a few weeks after the onset of any of the symptoms described above.


    The most common test used to diagnose a dissection of the carotid or the vertebral artery is an angiogram. In this test, a contrast dye is injected inside of one of the arteries that bring blood to the brain. An x-ray is used to look at the shape of the carotid and vertebral arteries as the dye travels through them (see picture). Dissection is diagnosed when the angiogram shows an artery that appears to be split into two separate parts, one of which is the previously described false lumen.

    When the dissection is so severe that it completely prevents blood flow through the affected artery, the dye tapers off and disappears at the point where the artery is completely closed off.

    When dissection causes a pseudoaneurysm, the angiogram shows an accumulation of dye inside the wall of the dissected artery.

    Other tests used for the diagnosis of carotid and vertebral dissection include magnetic resonance angiography (MRA), and duplex ultrasound.


    Carotid and vertebral artery dissection tend to be more commonly treated with heparin, a medication that prevents the extension of the blood clot in the area of the dissection. Heparin, which is normally given intravenously, is changed to Coumadin (warfarin) after a person leaves the hospital, as it can be taken by mouth. In general, a person is on their prescribed medication for 3 to 6 months. However, if follow-up tests don’t show a significant improvement after 6 months, medication is prescribed for longer periods. If no improvement can be achieved after that, surgery or percutaneous balloon angioplasty and stenting are attempted in some patients.


    Most people who suffer strokes related to dissection experience an adequate recovery and fewer than 5% of them die as a consequence of the event. More than 90% of cases in which the carotid artery is critically narrowed, and more than 66% of cases in which it is totally blocked by dissection, resolve within the first few months after symptoms are experienced. In some cases, a persistent headache might linger for a few weeks or months.

    Aneurysms related to dissection almost never rupture, but they can lead to the formation of blood clots and thromboembolic stroke in rare cases.


    Bradley G Walter, Daroff B Robert, Fenichel M Gerald, Jancovic, Joseph Neurology in clinical practice, principles of diagnosis and management. Fourth Edition, Philadelphia Elsevier, 2004.

    Wouter I. Schievink, M.D., Spontaneous Dissection of the Carotid and Vertebral Arteries, New England Journal of Medicine; 2001; Vol 344; 898-906

    Continue Reading