Arterial Dissection

An arterial dissection is a tear along the inside lining of an artery and can occur in a child's head, neck, or spine. It can cause serious neurologic problems, such as stroke. It may be referred to as a vertebral dissection (involving arteries supplying blood to the brainstem and upper spinal cord) or a carotid dissection (involving arteries feeding the hemispheres of the brain, as well as the head and neck). In one type of arterial dissection, called a dissecting pseudoaneurysm, the tear in the artery wall can enlarge to form a small pouch in which blood collects, known as a false lumen.

With proper treatment, many children recover completely from arterial dissection. However, some children may be left with deficits in brain function that can range from mild to severe. Children with conditions that predispose them to arterial dissection may be advised to permanently avoid rough contact sports or high-risk activities that could stress the vessels.

In most cases, arterial dissection is diagnosed after a stroke or during evaluation after head or neck trauma. Many children have neck pain or headache around the time that the dissection occurs, and if a blood clot has formed, the child may have symptoms of a stroke or transient ischemic attack. However, symptoms can vary widely, depending on whether the dissection is the result of trauma, whether it is located in the head and neck versus the brain, and whether it involves the vertebral or carotid artery. Vertebral dissection, for example, can cause speech and swallowing problems.

Arterial dissection can cause serious complications. In some cases, injury to the lining of the artery may narrow it enough to block the flow of blood. Alternatively, the injury can cause a clot to form at the site of the vascular dissection. Potentially, the clot can break off, travel into the brain's arteries, interrupt blood flow, and cause an arterial ischemic stroke. Sometimes the false lumen (the abnormal passageway created by the dissection) can behave like an aneurysm and burst, causing a hemorrhagic stroke (major bleeding into the brain).

Arterial dissection can occur as a result of head or neck trauma (either serious or minor), but sometimes it has no identifiable cause. Certain medical conditions, such as Marfan syndrome, Ehlers-Danlos syndrome, coarctation of the aorta, and inflammatory disorders, can weaken the blood vessel walls and make children susceptible to arterial dissection.

Treatment for arterial dissection depends on the location of the blood vessel tear and the extent of the damage. To determine these, physicians use a number of imaging tests to get detailed images of your child's blood vessels and brain tissue. Tests can include:

• CT angiography (CTA), which uses X-ray equipment and powerful computers to create cross-sectional images (often called "slices") of the head, neck, and brain. CTA uses a special dye (known as contrast) that is injected into a vein. A computer generates detailed 3-D images of the blood vessels.
• Magnetic resonance angiography (MRA), which visualizes blood vessels in the brain, head, and neck, but without the need for X-rays. Unlike CTA, many MRA scans can be done without injecting a dye into the veins to generate images of the vessels.
• Catheter angiography, which is done under general anesthesia. A catheter (a flexible tube about the width of spaghetti) is placed directly into the child's arteries. The catheter is used to inject a special dye, known as contrast, allowing us to get more detailed images.

The treatment team will provide advance instructions on how to prepare for these tests. In addition to the above imaging tests, neurologists may conduct a variety of specific tests to assess your child's brain function.

Treatment of arterial dissection is tailored to each child depending on the location of the blood vessel tear and its severity.

Dissection in the head and neck

If the dissection is in blood vessels in the neck rather than the head (known as extracranial dissection) and is relatively small, physicians in the Stroke and Cerebrovascular Center usually place children on anticoagulant (blood-thinning) drugs for at least three to six months. This decreases the chance of a clot forming and then flowing into the brain. They will use imaging tests to make sure that the vessel has healed before stopping the medication.

If the vessel tear is too severe to heal on its own, there are two options: Your child's physician can place a stent (a thin, flexible metal mesh tube) inside the artery to create a new, stable inside surface, or they can close the injured artery to prevent it from becoming a source of clots that might flow into the brain. If an artery is to be closed, they will perform extensive testing (known as balloon test occlusion) beforehand to ensure that there will be enough blood supply from neighboring bridging arteries.

Dissection in the brain

When the dissection is in vessels within your child's brain, the artery is usually too injured to remain viable. In this case, the child is at greater risk for a brain hemorrhage than for a blood clot. Treatment is usually aimed at closing the torn vessels before they cause bleeding, which can be done either surgically or through catheter-based endovascular techniques.

If healthy nearby arteries cannot supply enough blood in place of the dissected arteries, a direct arterial bypass may be necessary as a first step. The most common form of this operation is known as a superficial temporal to middle cerebral artery anastomosis or STA-MCA bypass, in which neurosurgeons join a blood vessel from your child's scalp directly to a vessel in the brain to improve blood flow.

Neck or cranial arterial dissection is most often found after a child has had a stroke that is related to its occurrence. Children who have experienced a stroke as the result of an arterial dissection receive treatment from the team of experts in our Stroke and Cerebrovascular Center. Both the stroke and the arterial dissection are usually diagnosed by careful examination and MRI. Commonly, a child with neck or brain dissection, especially if accompanied by stroke, is treated with anticoagulation.

The Cerebrovascular Surgery and Interventions Center at Boston Children's Hospital offers a number of different treatments for arterial dissection, based on your child's needs and the results of careful and detailed imaging. Because we see many children with arterial dissection, we are able to track the efficacy of specific treatments over time and use this information to guide our practice.