|
|
|
|
Carotid Artery Disease Carotid artery disease is the most common cause of stroke in the USA and early detection with accurate assessment is the key to prevention. How does the cerebrovascular system work? - Blood leaves the heart via the aorta and into the common carotid arteries (CCA) on each side of the neck. About half way up the neck, this artery branches into the external carotid (ECA) that supplies the face and scalp, and the internal carotid artery (ICA) that supplies the brain and the eye. The split or bifurcation is a common area for disease to occur. The vertebral arteries branch off the subclavian arteries, course along the spinal cord and supply the back of the brain. These 4 vessels make up the primary blood supply to the brain and these can be easily evaluated by noninvasive methods.
Atherosclerosis, commonly known as hardening of the arteries, is responsible for the majority of problems in the carotid arteries. Normally the inner wall of an artery called the intima is smooth and elastic, allowing blood to flow freely. In vessels affected by atherosclerosis, the intima becomes thickened and rough by a build up cholesterol or fatty materials. This build up, much like rust in a pipe, is called plaque. As this plaque increases, it obstructs the opening or lumen of the blood vessel and may alter or limit the flow of blood. If the artery is severely narrowed, the amount of blood getting past can be so limited, that various symptoms can result. However, as long as this is a gradual process, the body is often very good at developing alternative pathways for blood flow called collaterals. As the artery narrows, the same amount of blood wants to get through so it has to speed up, much like a “kink” in a garden hose. This fast, turbulent blood flow can break down the surface of the plaque and cause pieces of plaque called emboli to break loose. These can travel to the brain or the eye often with dire consequences. Turbulent blood flow can produce a sound called a bruit that can be heard with a stethoscope and is often the first sign of disease.
Diagrams of increasing build-up of deposits within the artery wall, gradually bulging the inner layer of the artery wall into the lumen or opening inside the vessel resulting in a restriction of the blood flow. Small plaques that do not result in flow disturbances are unlikely to cause symptoms. In contrast, narrowings that limit the blood flow cause increased blood velocities and turbulent flow (like a kink in a garden hose.) This results in stresses on the inside layer of the vessel. If this lining breaks down, particles called emboli are carried to the brain and can result in a stroke.
Symptoms - Lack of blood flow to the brain can cause a variety of symptoms. Stroke (cerebrovascular accident or CVA) occurs when there is permanent damage to the brain. If blood flow is restored quickly, symptoms may resolve (Transient Ischemic Attack or TIA). There are several “classical” warning signs that should alert a person to seek immediate medical attention.
Diagnosis - Diagnosis is most often made with ultrasound, a relatively inexpensive, completely safe and non-invasive technique that obtains pictures of the vessels and information about the blood flow. (for more info - click here to go to "What WE DO!) Plaque characteristics such as surface irregularities coupled with information about the blood flow allow an assessment of the risk a specific plaque presents to the patient. We are also able to evaluate the intracranial vessels for stenosis, arteriovenous malformation or vasospasm of the vessels within the skull. Traditionally, this information has only been obtainable by contrast angiography. Symptomatic patients without other explanation may benefit from this noninvasive test.
**Mouse over the images for a description!**
Most patients with carotid artery disease do not have symptoms and are treated very conservatively without any intervention. But what else can be done??
Diagram of a Guidant "Acculink" carotid stent with a device to catch any pieces that could break loose during the procedure.
|
|
Send mail to
bschroedter@qualityvascular.com with
questions or comments about this web site.
|