Flow Diverter: A New Approach to Aneurysms

An aneurysm is a bulging, weakened area in the wall of an artery, resulting in an abnormal widening or ballooning. Catching and treating this condition are crucial to avoid a ruptured aneurysm.

A new device known as a “flow diverter” is being used by doctors at Baptist Health Neuroscience Center to treat un-ruptured aneurysms in an innovative approach.

The strategy is a shift from the more traditional methods of utilizing stents or coils, procedures aimed directly at the aneurysm itself. With the so-named Pipeline Device—one type of flow diverter— the parent blood vessel is essentially rebuilt, restoring natural blood circulation.

This flow diverter is actually a special stent built with more dense mesh than the traditional small tubes used to restore blood flow in narrow or weak arteries. The Pipeline Device is a braided cylindrical mesh. And it is the first flow diverter approved by the U.S. Food and Drug Administration.

During a flow-diversion procedure, a microcatheter is navigated past the aneurysm. Then, the flow-diverting device is deployed across the neck of the aneurysm in the “parent blood vessel” where the aneurysm is present.

Flow diversion removes the need to enter the aneurysm during surgery, which is the most dangerous part of endovascular treatment of aneurysms, according to medical experts. The risk of rupturing during surgery is greatly diminished by not placing a device inside the aneurysm.

Interventional neuroradiologists Guilherme Dabus, M.D., and Italo Linfante, M.D., are designated proctors, providing instruction and guidance on the intricate procedure of placing the diverter in patients with large or wide-necked brain aneurysms. Dr. Dabus has traveled around the U.S. as a proctor, showing other physicians the procedure. Dr. Linfante is also a proctor for the Pipeline Device and has assisted Ajay Wakhloo, M.D., Ph.D., the inventor of another flow diverter under development called Surpass.

A Leader in Use of Flow Diverters
Dr. Dabus and Dr. Linfante have taken part in more than 50 such procedures using the flow diverter over the past two years at Baptist Health Neuroscience Center.

For now, the flow diverter is used in a relatively small percentage of unruptured aneurysm cases. But its benefits will lead to development of similar devices to treat a wider range of smaller aneurysms, say Drs. Linfante and Dabus. The Pipeline Device is self-encompassing, meaning it does not require additional procedures, improving recoveries for aneurysm patients.

“The idea of the Pipeline Device is to divert blood flow away from the aneurysm and into the parent blood vessel,” says Guilherme Dabus, M.D., medical director, Fellowship Program in Interventional Neuroradiology, Baptist Health Neuroscience Center. “That slows down the flow into the aneurysm, and then ideally new cells will cover the stent and occlude the aneurysm forever.”

Most unruptured aneurysms are discovered incidentally during routine imaging of the brain, such as an MRI or CT scan.

“Here we have a completely different philosophy of treating the artery instead of the aneurysm,” says Italo Linfante, M.D., medical director, Interventional Neuroradiology, Baptist Health Neuroscience Center. “The flow diverter is a good tool that won’t replace using coils for ruptures or other stents, but its use will grow and expand to smaller aneurysms.”

Someone with a family history of brain aneurysms would be encouraged to have screening performed, experts say. Additionally, some might be prompted due to the onset of other neurological symptoms. Symptoms can be minimal or range from headaches, dizziness or eye pain to blurry vision and seizures.

Aneurysm Facts from American Stroke Association

What is a cerebral aneurysm?

An aneurysm is a weak area in a blood vessel that usually becomes enlarged. It’s often described as a “ballooning” of the blood vessel. People usually aren’t born with aneurysms. Most occur after age 40. Aneurysms usually develop at branching points of arteries and are caused by constant pressure from blood flow.

How common are aneurysms?

• About 1.5 to 5 percent of the general population has or will develop a cerebral aneurysm.
• About 3 million to 5 million people in the United States have cerebral aneurysms, but most are not producing any symptoms.
• Between 0.5 and 3 percent of people with a brain aneurysm may suffer from bleeding.

Brain aneurysms vary in size, shape and location.

• Small aneurysms are less than 5 mm (1/4 inch).
• Medium aneurysms are 6–15 mm (1/4 to 3/4 inch).
• Large aneurysms are 16–25 mm (3/4 to 1 1/4 inch).
• Giant aneurysms are larger than 25 mm (1 1/4 inch).

Image: An aneurysm is seen “ballooning” in the picture on the left. On the right is the same patient after a flow diverter has been placed, essentially rebuilding the parent blood vessel and restoring normal blood flow.