Ischemic Stroke, Carotid Artery Disease, and its Prevention and Treatment

Carotid Artery Disease Specialist - located throughout Maryland: Vascular Surgery Associates, LLC: Vascular Surgery

The leading cause of death in our country is cardiovascular disease. This category includes heart disease, which is the leading cause of death both internationally and in America, as well as stroke, which is the second leading cause of death internationally and the 4th-5th leading cause of death in America from year to year.

The most common cause of stroke is ischemic stroke, meaning loss of brain tissue resulting from an interruption in blood flow to part of the brain. The brain is a highly metabolically active organ and requires constant blood and oxygen supply to avoid damage to the brain cells. Even temporary interruption in circulation can cause irreversible damage to brain cells, resulting in stroke. Other causes of stroke include hemorrhagic stroke, meaning bleeding into the brain tissue, which is caused by other factors and is a separate disease process.

The brain receives blood supply from four arteries. There are paired carotid arteries that originate in the chest from the aortic arch (the large artery that comes out of the heart), and these vessels travel through the neck and eventually supply circulation to the brain. Along with the paired carotid arteries which supply the front of the brain, there are a set of paired vertebral arteries that run along the back of the neck and supply the back of the brain.

Carotid artery stenosis occurs as a result of the development of atherosclerosis or plaque in the carotid arteries. Atherosclerosis, also known as hardening of the arteries, is a common disease process seen in the arteries all over the body. Atherosclerosis can affect all the arteries in the body, including the arteries of the head and neck (including the carotid and vertebral arteries), the coronary arteries supplying the heart, the aorta, the arteries supplying the intestines (mesenteric arteries) and kidneys (renal arteries), and the vessels supplying the arms and legs (peripheral artery disease).

When atherosclerosis affects the carotid arteries, it causes carotid artery stenosis. Usually carotid carotid artery stenosis is asymptomatic, meaning that it is not causing any symptoms or problems. However, as the disease process progresses, the involved artery becomes progressively more narrow as plaque growth encroaches on the lining of the vessel. As the plaque grows and evolves, it eventually increases the risk of stroke.

If you have been diagnosed with carotid stenosis, you will undergo a variety of imaging studies to determine the degree of blockage in the arteries supplying the brain. Depending on the degree of carotid stenosis identified, you will be counseled by our providers if you require medial management or surgical management for your degree of carotid stenosis.

All patients diagnosed with carotid artery stenosis require initiation of medical management with an antiplatelet drug (such as aspirin of clopidogrel), as well as a statin medication. Some patients are already taking these medications as a result of their other medical problems, while some require initiation of these drugs. Depending on the appearance of the plaque or the percent blockage caused by the plaque, certain patients benefit from a carotid procedure to stent or remove the plaque to prevent risk of stroke. This is an individual case-by-case determination made by a vascular surgeon. If surgical management of carotid stenosis is recommended, there are three surgical options for management of this disease process. Each procedure has advantages and disadvantages:

(1) Carotid endarterectomy is an open surgery performed in the operating room. The procedure is typically performed under general anesthesia. A neck incision is made on the side of the neck to surgically expose the carotid artery. After the artery is dissected free from its surrounding tissues, it is clamped above and below the plaque. The artery is then opened with a longitudinal incision and the plaque is surgically removed. A variety of techniques are used to close the artery, and then blood flow is restored to the brain after removing the clamps on the artery. The neck is then closed and the patient is awakened and removed from anesthesia.

Advantages:
- Durable (long-lasting result) with minimal rate of carotid blockage
returning
- Less of a need for multiple antiplatelet medicines after the procedure

Disadvantages:
- Requires a larger neck incision
- Higher risk of complications such as nerve injury
- Slightly higher risk of stroke and heart attack

(2) Transfemoral carotid angioplasty and stent placement is performed through an access in the femoral, or groin artery. Wires and catheters are passed through the aorta, and the involved carotid artery is selected with wires and catheters. Once a wire is passed through the carotid plaque, a small umbrella (or embolic protection device) is opened to catch any plaque or debris that are freed and would travel to the brain and cause a stroke or neurologic event (stroke) during the procedure.

The plaque is then opened up with a balloon angioplasty and a stent is placed to maintain flow through the artery. Once the stent is deployed, the umbrella is removed and the wires and catheters are withdrawn and removed and the hole in the groin artery is closed with a small closure device. This procedure is performed in an endovascular catheterization suite, and you are typically kept awake for the procedure.

Advantages:
- Minimally invasive as can be performed through small groin puncture
- Ability to treat patients whose carotid arteries are not easily accessible
for surgery due to previous neck surgery which causes scarring, or
history of neck radiation
- Lower risk of heart attack

Disadvantages:
- Highest risk of stroke among carotid procedures
- Requires dual antiplatelet therapy (two blood thinning antiplatelet
medicines) which slightly increases risk of bleeding

(3) Trans carotid artery revascularization (TCAR) is a procedure that allows carotid balloon angioplasty and stent placement through an incision at the base of the neck and an IV access in the groin. The carotid artery low in the neck is exposed through a small incision and the vessel is accessed with a needle and wire. After placing a vascular access sheath and a groin IV sheath, a reversal of flow is established from the brain to the groin IV sheath. This reversal of flow is passive, from the high pressure artery in the brain to the low pressure groin vein, and passes through a tube with a filter. At this point, a wire is passed through the carotid plaque, and the plaque is opened with a balloon angioplasty and a stent while flow reversal is established, and any plaque or debris that break free gets trapped in the filter in the flow reversal circuit before going back into the body. The wires and sheaths are then removed, the hole in the artery and neck are closed, and the IV is removed from the groin. The procedure can be performed under general anesthesia, conscious sedation (similar to a colonoscopy), or even awake.

Advantages:
- Minimally invasive, state-of-the-art procedure for treatment of carotid
artery stenosis
- Lowest stroke risk of any carotid procedure

Disadvantages:
- Anatomy has to be appropriate, and not every patient’s anatomy is
compatible with performing this procedure
- Requires dual antiplatelet therapy (two blood thinning antiplatelet
medicines) which slightly increases risk of bleeding

Trans carotid artery revascularization (TCAR) is the newest and most state-of-the-art procedure for treatment of carotid stenosis and is associated with the lowest stroke risk of any carotid procedure. At Vascular Surgery Associates, our group has performed more TCAR procedures than any other vascular surgery group in the state of Maryland. Come in for an office consultation with our highly trained surgeons to learn whether TCAR or an alternative technique is the most appropriate option for treatment of your carotid disease.

Author

Michael Osgood, MD Michael Osgood, MD, is a board-certified vascular surgeon at Vascular Surgery Associates, LLC, serving patients living in Bel Air, Columbia, and Ellicott City, Maryland.