Any kink in our vascular system—a malformed, entangled, or ruptured vessel—can lead to serious disabilities and life-threatening conditions.

Yale Medicine's neurosurgeons have extensive experience identifying and treating vascular abnormalities.

“Vascular abnormalities are often associated with a lot of fear—and rightfully so, because they can potentially be a serious problem,” says Yale Medicine neurosurgeon Charles Matouk, MD. “But the vast majority of aneurysms can be detected when they are very small and don't pose a substantial risk to the patient.”

Several types of blood vessel abnormalities can threaten a patient’s health. These include the following:

• Aneurysms occur when a weak blood vessel begins to swell or blow up like a balloon. In the most dangerous cases, an aneurysm can burst, causing blood to spill on the surface of the brain. A ruptured brain aneurysm is the most common and the most deadly vascular brain abnormality, with a 50 percent fatality rate.
• AVM or arteriovenous malformation. This is a dangerous but rare condition with about 3,000 cases occurring each year in the U.S. This happens when a tangle of blood vessels either irritates another part of the brain, causing a stroke, or ruptures and causes bleeding within the brain. Unlike a cavernous malformation, an AVM holds blood flowing at high pressure. It’s less deadly than an aneurysm, but a patient with the condition can continue to re-bleed over time and develop serious neurological problems. AVM is believed to be congenital condition.
• Cavernous Malformation is similar to AVM, but instead of being described as a tangle, it’s more like a small ball of blood vessels that carries low blood-pressure blood. As with an AVM or aneurysm, a cavernous malformation can rupture.
  While it’s usually the least lethal of the three abnormalities, it can lead to seizures, brain bleeds, and serious neurological deficits.

Unfortunately, most patients with vascular abnormalities don’t know they have a problem until a rupture occurs.

Sometimes patients may experience minor symptoms—such as difficulty seeing or enlarged pupils—but more often, they’ll experience no symptoms.

For patients who have an aneurysm—the most common of the three vascular abnormalities—the moment of rupture can feel like the worst headache of a lifetime.

“Often it knocks patients off their feet,” says Dr. Matouk. “Usually family members or friends find them and bring them to the hospital.”

Similarly, with an AVM or cavernous malfunction, a patient will have no warning until she experiences a stroke or a blood vessel rupture that requires immediate attention.

Researchers are still investigating the factors that may contribute to vascular abnormalities. While there is no clear answer yet, there are strong indications that a combination of genetic and environmental factors greatly increase the risk:

• Family history. People with a family history of brain aneurysms are more likely to experience an aneurysm. Thanks to research by Yale Medicine and others, we now have evidence that many abnormalities can be linked to specific variations of genes.
• High blood pressure. High blood pressure puts extra strain on blood-vessel walls, increasing a person’s risk of aneurysms and AVMs.
• Medical history. If you’ve already experienced a brain aneurysm, you’re more likely to experience it again.
• Sex. Women are slightly more likely to experience brain aneurysm than men, according to the National Institute of Neurological Disorders and Stroke.
• Smoking. Smoking has been linked to a higher risk of aneurysm—especially among people who have a genetic predisposition to the condition. For them, smoking may increase the risk fivefold.

Unfortunately, vascular abnormalities are rarely detected before a patient suffers a rupture. It’s more common for a vascular abnormality to be identified after the fact, by computerized tomography imaging—also known as a CT scan.

When a patient comes in with bleeding in the brain due to an aneurysm, AVM, or cavernous malformation, the most important step is to stop the bleeding before more damage is done, says Dr. Matouk. If the aneurysm ruptures and bleeds a second time, it is more likely to be fatal.

In order to stop the bleeding, the surgeon will perform a craniotomy (removing a section of the skull) in order to find the abnormal blood vessel. Once found, the doctor will put what looks like a bobby pin or a clip on it to prevent it from rupturing again.

Physicians are also increasingly using minimally invasive methods to help patients with aneurysm or related blood-vessel malformations.

Endovascular surgery allows the surgeon can make an incision in a patient’s leg and snake a very narrow catheter up through the blood vessels to the brain. When the catheter reaches the brain, the surgeon can then fill the aneurysm with a metallic thread called coils, which prevent blood from getting into the aneurysm and protect the patient from another rupture.

A patient who survives a ruptured aneurysm, AVM, or cavernous malformation may suffer from some neurologic deficits—such as trouble with speech or motor skills—that will require some rehabilitation.

Yale Medicine’s neurosurgeons are connected to a network of rehabilitation centers, so patients will be able to recover under the care of their original physicians.

Our neurosurgeons martial the resources of a world-class research institution to provide patients with the latest technologies and therapies.

“Here, we can use advanced imaging protocols, as well as the science we’ve forwarded with genetics, to determine whether or not an unruptured aneurysm should be treated,” says Dr. Matouk.

“We also offer both microsurgical and endovascular options, tailored to each patient’s individual needs," he adds.