How Arterial Dissection Can Cause a Stroke

Arteries are the blood vessels through which nutrient and oxygen-rich blood flow toward organs such as the kidneys, heart, and brain. Oxygen and nutrients are essential for the survival of every organ in the body.

The main arteries that bring blood to the brain are the carotid and vertebral arteries. Any problem with blood flow in these arteries can cause a stroke. A relatively uncommon type of defect of the arteries, called an arterial dissection, can cause a stroke.

Arterial dissection refers to the abnormal, and usually abrupt, the 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 on the wall of the artery is known as a “pseudoaneurysm.” Pseudoaneurysms can lead to symptoms of a 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 “artery-to-artery thromboembolism.”

Arterial dissection is responsible for less than 2 percent of all strokes. However, arterial dissection 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.

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
• Inability to close one eye
• A sudden change in the 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

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 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:

• Neck extension during hair-washing at a beauty parlor
• Chiropractic manipulation of the neck
• Whiplash injuries
• Blunt trauma to the neck
• Extreme neck extension during yoga
• Painting a ceiling
• Coughing, vomiting, and sneezing
• Neck extension while receiving mouth-to-mouth during cardiopulmonary resuscitation (CPR)

Spontaneous dissection of the carotid and vertebral arteries is a relatively uncommon cause of stroke. A spontaneous dissection refers to an arterial dissection that does not have an immediately identifiable cause. Dissection of the carotid and vertebral arteries can also occur spontaneously in association with the following diseases:

• Marfan’s syndrome
• Polycystic kidney disease
• Osteogenesis imperfecta
• Fibromuscular dysplasia

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 travel through them.

Dissection is diagnosed when the angiogram shows an artery that appears to be split into two separate parts, one of which is described as a 'false lumen' (described below.) 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 may be treated with heparin, a medication that prevents the extension of the blood clot in the area of the dissection. Heparin is an intravenous medication. When it is time to leave the hospital, Coumadin (warfarin) is a blood thinner that can be taken by mouth.

In general, someone recovering from an arterial dissection is expected to take prescription blood thinners for 3 to 6 months. However, if follow-up tests do not show a significant improvement after 6 months, medication is prescribed for longer periods of time. If there is still no improvement, surgery or percutaneous balloon angioplasty and stenting may be another option.

Most people who experience strokes related to arterial dissection experience a good recovery. In fact, fewer than 5% of those who have an arterial dissection arterial 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.

Arterial dissection is a fairly complex condition. But with expert medical management, most people who have an arterial dissection survive and go on to do quite well. If you or a loved one has had a stroke caused by an arterial dissection, you also will need some time to recover from the stroke. Stroke rehabilitation often requires active participation and maybe tiring, but you will see recovery and improvement as time goes on.