Health Tips

Carotid Artery Disease and Stroke: Are You at Risk?

Stroke is the third leading cause of death in this country, and is also one of the leading causes of catastrophic disability in adults. In this country alone, over 600,000 people will suffer a stroke each year. While these are some frightening facts regarding stroke, the overall outlook regarding stroke is one of increasing optimism. Recognition and management of the risk factors for stroke can help to prevent stroke.

Click here for Interactive Quiz: How Much Do You Know About Stroke?

What Causes a Stroke?

Stroke occurs when cells in the brain stop getting the oxygen and nutrients they need to survive. When this occurs, the brain cells die, and the resulting loss of function is what we recognize as a stroke. There are several ways that the brain can be deprived of oxygen and nutrients. Of all the strokes that occur, nearly 80% are "ischemic" or related to impaired blood flow to the brain tissue. The remaining 20% are related to hemorrhage or bleeding either into the brain itself or into the tissues within the skull around the brain. Hemorrhagic stroke is usually caused by rupture of a blood vessel in the skull. The bleeding squeezes the surrounding brain tissue making it impossible for the cells to get the necessary nutrients.

The more common form of stroke, ischemic stroke can occur when debris within the body's arteries travels "upstream" and blocks off an artery supplying blood to the brain. In many cases, a narrowed carotid artery in the neck is the source of this debris. Symptoms of a stroke can include sudden inability to move one or more extremities, one entire side of the body or the face (paralysis), difficulty speaking or difficulty understanding what others are saying, abnormal thinking, and even visual problems such as sudden loss of vision in one or both eyes.

It is important that everyone understand the signs of a stroke occurring, as often times the person having the stroke may not even recognize something is wrong due to the thinking problems the person may be experiencing. Recognizing a stroke in someone near you and calling early for professional medical attention can allow for early treatment and increases the possibility of a full recovery.

What Are the Risk Factors For Stroke?

Important risk factors for stroke include high blood pressure, elevated cholesterol, heart disease or angina, vascular claudication or blocked arteries to the legs, prior stroke, and transient ischemic attacks or TIA's. Many of these risk factors can be modified and treated, while some, such as having had a previous stroke, cannot be changed.

TIA's are often referred to as "mini-strokes." TIA's can have the same symptoms as a stroke, but which last for only a few minutes or hours and do not cause permanent disability such as paralysis. Patients with TIA's are at particularly high risk of having a stroke and should seek immediate medical attention.

What Is Carotid Artery Disease?

K. Craig Kent, MD Chief, Division of Vascular Surgery

One other important risk factor for stroke is narrowing of the artery supplying the majority of blood flow to the brain, the carotid artery. People with carotid artery disease are at a higher risk of stroke. Carotid artery disease is characterized by carotid stenosis, or narrowing of the carotid artery and is a very significant risk factor for stroke. This narrowing is generally made up of a substance called plaque which accumulates inside the artery decreasing the diameter of the artery. The danger with this accumulation of plaque is that over time, pieces can break off, traveling up toward the brain and lodging in a smaller branch of the artery and causing a stroke.

Many people who experience a TIA are found on screening to have carotid artery disease. Ultrasound is currently the best available screening study for carotid artery narrowing. The test is non-invasive, painless and uses sound waves to image the arteries to assess the degree of narrowing. Surgeons from the Division of Vascular Surgery at NewYork-Presbyterian Hospital recently participated in a nationwide program offering carotid artery ultrasound screening to patients at high risk. "Detecting carotid stenosis early can have a significant impact on a person's risk of stroke," says Dr. Craig Kent, chief of the Division of Vascular Surgery.
"We hope that by offering screening and awareness education regarding stroke, we can improve the outlook for patients. We would like to have a much larger impact on reducing the rate of this disease," Kent notes.

What Can Be Done To Reduce Risk Of Stroke In People With Carotid Artery Disease?

Studies completed in the 1990's have confirmed the benefits of a surgical procedure to clean out blocked carotid arteries called carotid endarterectomy. Carotid endarterectomy is currently one of the most commonly performed vascular surgeries in this country. In carotid endarterectomy, a surgical incision is made in the side of the neck and the carotid artery is opened and the blocking material removed. While there is dramatic reduction of the risk of stroke in patients who are having transient ischemic attacks or TIA's with this form of therapy, even those without symptoms related to the narrowing can have significant improvement in their stroke risk. Numerous studies as well have confirmed that those surgeons performing this operation frequently have better outcomes for patients, with lower risks of complications, especially the risk of having a stroke during the operation. Surgeons at NewYork-Presbyterian Hospital have one of the lowest rates of complications following carotid endarterectomy in the world. "Our results are indicative of our commitment to make this as safe as possible and to give patients the best chance to avoid a stroke. We are currently performing this operation at one of the safest levels ever seen. In addition, patients are now recovering sooner and returning to their normal activities in a very short period of time. Most patients leave the hospital after a one night stay on the night of the operation," says Kent.

What Are The "Minimally Invasive" Options For Treatment of Carotid Artery Disease?

While open surgery remains the best method of treating most people for carotid artery narrowing, there are a group of people who for a number of different reasons are not good candidates for carotid endarterectomy surgery to treat this problem. These people may have had prior surgery on the carotid artery or in the area of this artery in the neck. Some have other health problems, which can make traditional surgery more risky. For these patients, minimally invasive methods of treating the artery narrowing from within the blood vessel itself are being investigated. These methods include angioplasty or dilating of the narrowed segment of the artery with a balloon and stenting, which involves placing a metal mesh tube within the artery to hold it open. Carotid stenting does not require surgically opening the artery in the neck. Instead, the stent is "loaded" onto a deflated balloon on the end of a long thin tube called a catheter. The large blood vessel in the groin is accessed painlessly with a needle or a tiny incision. The catheter is guided up into the blocked carotid artery through the groin artery with the assistance of x rays. Once the stent is positioned within the blockage, the surgeon inflates the balloon and this expands the stent within the blockage. This procedure opens the narrowing and the stent is left in place to act as a scaffolding to keep the blockage open.

Surgeons at the NewYork-Presbyterian Hospital are participating in several studies to evaluate the effectiveness of this form of therapy for carotid artery stenosis. While currently this form of therapy is not ideal for everyone, there are clearly patients in whom this treatment option is beneficial. Carotid stenting offers the ability to avoid the incision in the neck and to avoid the small risk of damage to the nerves in the neck near the carotid artery itself. These nerves can be damaged during standard surgery.

In conclusion, our best defenses against stroke are to know the risk factors, be vigilant about the warning signs, and seek medical attention immediately should the symptoms of stroke or TIA occur.