Severe Symptomatic Carotid Artery Disease Medical Essay

Carotid artery disease is a condition in which fatty material called plaque builds up inside the carotid arteries which are the main arteries that carried blood to the brain. It can be very serious because the presence of fatty deposits in the carotid arteries of the neck is the most significant risk factor for ischemic stroke, which represents 80% of all strokes.2 Stroke can be fatal, and even people who survive from it may have paralyzed arms or legs, or may not be able to talk and eat normally. Even there are some very encouraging new treatment for stroke today, but once a stroke has occurred there is some permanent brain damage .As for all artery disease, there are usually no advance warning signs for early form of carotid artery disease until the carotid arteries are severe narrowed (stenosis)14, 23 .Severe stenosis means that 70%or more of the carotid artery is blocked. This condition can cause TIA (transcient ischemic attack). The patients who have experienced TIA are categorized as symptomatic patients and these conditions known as severe symptomatic carotid artery disease. Symptoms of TIA are similar to those of stroke. TIA typically last a couple of minutes and then resolve completely. However, this should not be ignored. It is a warning sign that a person is at risk for a stroke. Research has shown that 1/3 of TIA patients will go on to have an actual stroke.18 So what is the current available treatment can reduce the risk of stroke for symptomatic patients who have experienced TIA due to severe carotid artery disease?

A POSIBBLE SOLUTION

SURGERY-CAROTID ENDARTERECTOMY (CEA).

CEA is performed to remove plaque from the carotid arteries in the neck. This procedure takes about an hour to perform. The patients will be given a preoperative injective about an hour before surgery to dry up the internal fluids and to encourage drowsiness. General anesthesia is usually administered and sometimes the local anesthetic also is used. During the procedure, an incision is made on the neck to expose the blocked section of the carotid artery. Blood that normally flows through the artery must be diverted in order to perform the surgery. This is accomplished by rerouting the blood through a tube (shunt) connecting the vessels below and above the surgical site. The carotid artery is opened and the waxy fat deposit is removed, sometimes in one piece. A graft using a vein from the patient's leg may be created and stitched (grafted) onto the artery to enlarge or repair it if the carotid artery is observed to be too narrow or too damaged to perform the critical job of delivering blood to the brain. The shunt is then removed and incisions in the blood vessels, the carotid artery, and the skin are closed. After the procedure, the patients generally stay in the hospital for about 1-2 days.16, 30 The recovery from surgery is usually rapid and patients can quickly resume their normal activities without any restriction. CEA is also a safe and durable treatment.7, 8 However, after the surgery the patients have to maintain a healthy lifestyle to avoid repeat narrowing of carotid arteries.

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Figure 2: The process of carotid endarterectomy.16 http://www.daviddarling.info/encyclopedia/C/carotid_endarterectomy.html 543 words

The figure 3: The material that can be removed from the artery during carotid endarterectomy.  The browny-red areas are blood clot.11 http://www.vascular.co.nz/Carotid%20endarterectomy,%20TIAs%20and%20strokes.htm

The effectiveness of carotid endarterectomy

CEA is performed to reduce the risk of stroke and prevent stroke22, 29, 30 It also has been shown to be effective for preventing stroke in carotid artery disease.25 It is most effective when carried out within two weeks of a TIA.20

The finding of research:

The sooner the surgery was performed after a patient had their first symptoms, TIA (symptomatic carotid stenosis), the more beneficial it was in reducing the risk of subsequent, and more serious, strokes. [study from Carotid Endarterectomy Trialists'Collaboration, and funded by The Stroke Association]1

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Figure 4: The effectiveness of CEA at different percentage of stenosis12

http://www.princetoncme.com/public/2006-174/report2.php

According to the bar chart above, CEA has only marginal benefits on annuals rate of ipsilateral stroke for patients with asymptomatic or moderate lesions. While dramatic benefits were seen for high-grade symptomatic stenosis. This statement also supported by http://www.nejm.org/doi/full/10.1056/NEJM199811123392002 5Apart from that, the survey also has been found it is highly beneficial for persons who have a severe stenosis of 70%to 99% and has warning sign of stroke. In this group, surgery reduces the estimated 2 years risk of stroke by more than 80%from greater than 1 in 4 to less than 1 in 10.This method also reduces the 5 years risk of stroke by 6.5 percent for patients with 50 to 69% of stenosis .4, 6, 21 In short, the effectiveness of CEA in preventing stroke has been established in symptomatic patients.26

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Figure5: http://www.hemodinamiadelsur.com.ar/journals/journal_100.asp

Besides, CEA is three times more effective than treatment with medicine alone in preventing stroke for people who have symptoms that can be attributed to a 70% to99% blockage of the carotid arteries.9, 10, 28 As shown on the bar chart above, the CEA method is more effective than the best medical therapy in patients with advanced (>70%) symptomatic carotid artery disease.

"The CREST trial results show that we now have two safe and effective methods to treat carotid artery disease directly, the tried and true CEA, and the new kid on the block, CAS," said Thomas G. Brott, M.D., professor of neurology and director for research at Mayo Clinic in Jacksonville, and the study's national principal investigator.  Sources from NIH News National Institutes of Health: Embargoed for Release on February 26, 2010.13

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SOCIAL IMPLICATION OF DISEASE

The awareness of TIA due to severe carotid stenosis is less among some of the members in the public. Many people ignore TIA symptoms. In my opinion, they might not know this symptom has a high risk of having real stroke. Based on the National Stroke Association's survey, of 10,112 people selected at random, found that 2.5 percent of the respondents had been told they have had a TIA. Furthermore, 8 percent of the respondents might possibly have experienced a TIA in the past--but had not since gone to see a doctor.3

''Stroke has a devastating and lasting impact on the lives of people and their family. Individual often lives with the effect for the rest of their lives. The effect can be aphasia, physical disability, loss of cognitive and communication skills, depression and other mental health problems ''Nation Stroke Strategy 19

Cleary stroke is a devastating illness both to patients, their families and to the health care system.31 Thus, more public health education should be held in order to give public more information of severe carotid disease which can cause TIA. The patients should get an immediate treatment if they have experienced TIA.

ECONOMIC IMPLICATION OF DISEASE AND TREATMENT

Economically, this problem also will become the burden of government. This is because the probability of having stroke due to severe symptomatic carotid artery disease is high. Stroke is a responsible for the high number of disabled adults in the United States; two million stroke survivors have some permanent disability. The annual cost to the country for treating stroke and disabilities caused by stroke is about $40 billion.2

In addition, some patients especially for whom from poor background and have low wages will face financial and economic problem for the treatment because the CEA procedure require a huge amount of money. According to my research, the total average cost for the diagnostics test, surgical procedure, hospitalization and follow up care is about $15000.

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BENEFITS

The result of successful surgery for plaque removal is excellent.CEA is safe and provides durable freedom from stroke. 7, 8,24Within 3 weeks after having CEA, most of the patients are able to go back to their normal activities with an appropriate and healthy lifestyle to prevent plaque buildup, blood clot, and other problems in the carotid arteries over times.

LIMITATION AND RISK.

However, there are no benefits in having an operation once the artery is completely blocked. In patient with more severe narrowing greater than 70%, the risk of stroke or death reduced by 80% after having CEA .But, patients with 50% stenosis or lower do not show enough benefits from CEA to outweigh the risk of the procedure.4

No. of CEs/y

Average No. of Hospitals

Total No. of Cases

No. (%) of Deaths

1-10

22.6

532

13 (2.4)

11-25

17

1 427

14 (1.0)

26-50

15

2 648

39 (1.5)

>50

12.2

5 962

55 (0.9)

All surgeries

10 569

121 (1.1)

Figure6: Mortality Rates for CE by Hospital Volume of Medicare CE Surgeries, 1991-1995 http://stroke.ahajournals.org/cgi/content/full/29/1/46/T6

As with all surgical operations, there are some risks associated with CEA. The most important is the risk of future stroke because the operation is performed on a diseased artery carrying blood to the brain. The risk is ranging 1-3% .7 There is also a smaller risk of death which around 1%or less. 11 as shown in figure 6. Another recognized risk is injury to the nerves on the neck.

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Therefore anyone undergoing this procedure should be sure their surgeon is experience in performing this procedure and that medical centre has complications rates less than 6%. The most important thing is we have to realize that risk of having stroke once the patients have TIA due to severe carotid artery disease is greater than the risk associated with the procedure.20

ALTERNATIVE SOLUTION

Figure 7: carotid angioplasty http://images.healthcentersonline.com/heart/images/article/Angioplasty_Expanded.jpg

CAROTID ANGIOPLASTY AND STENTING

After refer to so much information about carotid artery disease I found that carotid angioplasty and stenting may be used as an alternative to carotid endarterectomy for some patients who are at high risk of surgery and cannot undergo CEA15. During the procedure, an extremely thin catheter tube is inserted into an artery in the groin and threaded through the circulatory system until it reaches the blocked area in the carotid artery. The doctor either breaks up the clot or inflates a tiny balloon against the blood vessels walls. The doctor then typically leaves a circular wire mesh (stent) inside the vessel to keep it open after temporarily inflating the balloon. Patients are awake during the procedure, and are usually discharged from the hospital the following day. Most patients are able to resume normal activities when they get home. As the CEA, complication can occur after this procedure.

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MEDICINE

Antithrombotic drug

Antithrombotic drugs include anti platelet agent and anticoagulant agents which are the most popular classes of drug used to reduce the risk of stroke. The most widely known and used antiplatelet are aspirin and others included clopidogrel, ticlopidine and dipyridamole. While anticoagulants included warfarin, heparin and enoxaparin .Their functions are preventing clotting by decreasing the activity of platelets, blood cells that contributed to the clotting property of blood .29 In my opinion, these drugs are suitable used as an alternative method for those who have high risk to undergo surgery and facing financial problem to take surgery as a treatment. Although the result of the drugs is not as effective as CEA but it is a cheaper treatment.

Besides, the drugs such as aspirin in low doses will be given to the patient who had surgery on clogged arteries (CEA) as a "blood thinner '' to prevent blood clot and reduce complication.

STATIN:

One study has showed that the risk of CEA can be reduced by taking statin medicine before surgery. People in the study who had taken a statin for at least a week before surgery were much less likely to have stroke or die than those who did not take statin .27

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EVALUATION

Carotid endarterectomy is found to reduce the risk of stroke and highly beneficial for persons who have experience the warning sign of a stroke(TIA) and have severe stenosis of 77-99% from the reference [http://www.ninds.nih.gov/disorders/stroke/carotid_endarterectomy_backgrounder.htm] This source is reliable since it is also agree with other sources ( 4, 21, and 22). Besides this website is published by National Institute of Neurological Disorder and Stroke (NINDS) which is the part of National Institute of Health (NIH) . NIH is the nation's leading supporter of research on the brain and nervous system. While NINDS conducts, fosters, coordinates, and guides research on the causes, prevention, diagnosis, and treatment of neurological disorders and stroke, and supports basic research in related scientific areas. Therefore, I strongly believe that the information from this website is reliable and trustable.

The other sources that I have used is www.stroke.org.uk which providing all the information, support, recovery, research and survey about stroke. It is a website of National Stroke Association which is the only national non-profit health care organization focusing on 100 percent of its resources an attention on stroke. In its brief history, it has become a leading national resource and stroke and driving force behind efforts to improve stroke prevention, treatment and rehabilitation. So in my opinion the information from this websites is reliable and trustable. I retrieved the information on the effectiveness and important of carotid endarterectomy to be carried out as soon as possible for the severe symptomatic carotid artery disease from http://www.stroke.org.uk/document.rm?id=1477.

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