Plaque Can Block Arteries: Stay Aware of Risk Factors

The internal carotid arteries are among the most critical blood vessels in the body. Located on both sides of the neck, they deliver oxygen to the brain.

But that critical function may be affected by carotid artery stenosis, a narrowing of the arteries caused by plaque. Plaque is a waxy substance that can build within blood vessels just like rust can collect inside a water pipe.

As the layer of plaque within a blood vessel thickens over time, bits of it may break loose and reduce or block blood flow. Without a steady supply of oxygenated blood, brain tissue begins to die—a dangerous path to stroke, the fourth leading cause of death in the U.S. Plaque in the carotid arteries is, in fact, responsible for up to 20 percent of strokes.

Perhaps most alarmingly, plaque buildup often occurs without symptoms. It can progress silently for years—then suddenly become a stroke emergency.

Who tends to experience plaque buildup? What are the risks?

Harjit K. Chahal, MD, Cardiology: Atherosclerosis—fatty and inflammatory plaque buildup—is a natural process that begins early in life. Studies of young military recruits have shown that it can start in the late teens to early 20s, even among fit and active young people.

Depending on where the plaque forms, atherosclerosis can eventually become catastrophic. Besides stroke, it can cause complications if it blocks or narrows the arteries that feed the heart muscle (triggering heart attack) or lower legs (resulting in lack of blood flow there as well).

Bianca M. Cutler, CRNP, Vascular Surgery: Risks for atherosclerosis can include certain risk factors we can’t control—for example, some patients are genetically predisposed to plaque buildup, or tend to build it faster.

But more controllable risk factors include high blood pressure (or hypertension) and high cholesterol (hyperlipidemia). Diabetes can also be a factor as it increases the risk of both high blood pressure and high cholesterol. We can help decrease the odds of a patient developing carotid artery disease if we can prevent and control these other conditions through regular medical care.

Certain lifestyle factors, of course, can influence plaque build-up as well. Poor diet, lack of exercise, and excess weight can negatively impact blood pressure and cholesterol, and use of tobacco can increase both blood pressure and inflammation—all of which accelerate plaque development.

Dr. Chahal: The more we study atherosclerosis, the more we recognize and acknowledge the role of inflammation as a precursor to carotid artery disease. For example, we know that people with chronic inflammatory disorders like HIV or lupus are at higher risk. These connections are the subject of much current medical research.

How does a plaque blockage occur? What happens when it does?

Dr. Chahal: The carotid arteries run from the chest to the head, on either side of the neck. Each artery bifurcates—branches into an internal and an external artery—near the jaw; the internal one is responsible for supplying blood flow to the brain. These bifurcated vessels can be at higher risk for dangerous plaque buildup because blood flow naturally becomes more turbulent at the point of bifurcation.

Bianca: Plaque within carotid arteries typically builds without any symptoms or obvious signs. For many, carotid artery disease in a patient only manifests when obstructed blood flow causes a stroke, or a mini-stroke—also known as a transient ischemic attack or TIA.

In a stroke, brain tissue dies. In a TIA, the interruption to blood flow may spur symptoms similar to a major stroke, but symptoms often resolve within seconds or minutes. A TIA is a warning sign that a major stroke may be imminent.

Is there a screening process to detect arterial blockage?

Bianca: Unlike colon or breast cancer, regular screening for plaque buildup is not recommended for everyone. Our strategy primarily focuses on identifying and reducing risk.

We do encourage screening for patients with multiple potential risk factors—for example, a smoker with high blood pressure or high cholesterol, plus a personal or family history of ischemic stroke before age 60.

If a patient does have such risk factors, we evaluate for a carotid bruit [broo-EE], a type of murmur that can be heard via stethoscope as the blood pumps through the arteries. A bruit alone does not confirm artery disease—but, combined with other risk factors, it can be an important indicator that further evaluation or imaging is needed.

Dr. Chahal: The choice to screen is decided on a case-by-case basis and involves both patient and provider. When screening is indicated, we look for evidence of atherosclerosis throughout the body.

People with coronary or peripheral artery disease are certainly at risk of having carotid artery disease as well, and it’s quite reasonable to screen those patients. In addition, in our practice, we also screen anyone with a history of heart attack.

Bianca: Initial screening is done via ultrasound, which is non-invasive and painless. If the results show narrowing within certain criteria, we order CT imaging or carotid angiography, both of which combine X-ray with dye contrast. CT imaging delivers a more detailed view within the body. Angiography lets us clearly visualize the arteries.

How do you help patients manage carotid artery disease?

Dr. Chahal: We consider our first task to be education and disease prevention. We counsel our patients to recognize signs and symptoms of stroke and to understand the importance of getting emergency care if they think they’re experiencing one.

We also devote considerable time and effort to managing each patient’s controllable risk factors, such as cholesterol, blood pressure, diabetes, and smoking. With appropriate medication and risk factor optimization, the potential for stroke can be reduced to less than one percent.

Bianca: The steps we take can be dramatically effective for patients who are compliant, committed, and invested in their health.

Statin medication for high cholesterol or hyperlipidemia is one staple of treatment. Statins primarily work in the liver to lower total cholesterol. Interestingly, some recent studies have shown that they may also work in the arteries to smooth and stabilize existing plaque, making it less likely to break off and travel to the brain. So, I will often recommend use of a statin in the setting of carotid artery stenosis, even when cholesterol is at a healthy level.

We may also prescribe antiplatelet drugs that prevent clotting around the narrowed plaque areas within a blood vessel. We typically recommend a daily aspirin and, if narrowing is fairly progressed, the addition of a prescription drug such as Plavix.

When is surgery called for?

Bianca: Many patients do well with drug therapy and lifestyle modifications—especially when narrowing of one or more carotid arteries is discovered early. In more extreme cases, when medication alone is not effective, our team can perform a surgical procedure to remove the plaque.

But, because this is a serious surgery that can itself carry a small risk of stroke, we generally wait until an artery is narrowed approximately 70 percent or more in men, and at least 75 percent in women. Of course, our decision to recommend surgery may vary depending on other carefully considered factors, such as the patient’s advanced age, other medical conditions, and so forth.

Dr. Chahal: The reason for this difference is that men have historically fared better with the procedure. That may be due to a number of genetic or physiological variables. Women tend to be smaller in stature than men, with smaller arteries that can make the surgical removal of plaque a bit more complex.

The goal of surgical intervention is revascularization—increasing the blood supply to the brain. But because we’re placing instruments within the artery itself, we must be very careful not to dislodge any plaque or microemboli during the procedure. Today, surgeons are increasingly more experienced in removing blockage even from very tiny blood vessels.

What procedures are used to treat carotid artery disease at MedStar Washington Hospital Center?

Bianca: We are equipped to perform several different procedures that will effectively increase blood flow and decrease plaque burden within the carotid arteries.

In carotid endarterectomy (CEA), the surgeon makes an incision in the neck, opens the diseased artery, and removes the plaque causing the blockage. This takes about two to four hours and patients are generally discharged the next day.

Angioplasty and stenting is a minimally invasive approach used when a blockage is too difficult to treat via CEA or when a patient has other issues that make surgery risky. The doctor inserts a catheter—a thin, flexible tube—through a blood vessel in the patient’s arm, groin, or neck, and guides it to the site of the blockage. There, a balloon at the end of the catheter is inflated to widen the artery, and a stent is inserted—a small wire mesh tube that acts as a scaffold to keep the artery open.

Transcarotid artery revascularization (TCAR), is the newest and most advanced procedure, in which we briefly reverse the direction of blood flow during surgery. If blood is moving away from the brain, clots or loose plaque are much less likely to reach it. With this minimally invasive method, there’s less of a chance that a patient might experience complications. TCAR generally requires an overnight stay.

MedStar Washington Hospital Center has an abundance of experts that collaborate across a wide range of specialties. For example, Dr. Chahal and I team to share essential patient data and documentation quickly and can consult together to deliver a comprehensive, holistic approach to our patients’ diagnoses and treatment of arterial disease.

Dr. Chahal: Our team of experts works together cohesively across the areas of internal medicine, neurology, cardiology, vascular rehab, medicine, and sometimes interventional radiology.

And our Vascular Center is one of the busiest in the Washington, D.C., region. We perform a high volume of procedures to treat carotid artery disease, so we are experienced with the many possible ways that it can present.

What do you recommend to help people avoid plaque buildup and carotid artery disease?

Dr. Chahal: A good program of diet and exercise is 80 percent effective in preventing carotid artery disease.

We recommend that patients maintain a healthy weight, get regular physical activity, consider adopting a Mediterranean diet, practice proper glucose control, avoid tobacco in all forms, and effectively manage their blood pressure.

Bianca: And, of course, regular checkups with a healthcare professional are vital to help patients stay aware of potential warning signs, for this or any other disease.