Coronary Atherosclerosis And Angioplasty Biology Essay

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Coronary atherosclerosis is the major cause of death and premature disability in develop societies. Current predictions estimate that by the year 2020, cardiovascular disease especially coronary atherosclerosis will become the leading global cause of total disease burden. Actually, most of the people around 20 and above have atherosclerosis beginning in their body but they don't realize that. According to a study in 2001, more than half of the participants had certain level of coronary atherosclerosis present in their body. The percentage reached 85% in the group of participants who were over the age of50 and 17% for teenagers. (1) For your information, coronary atherosclerosis is the main cause of a group of CVDs especially stroke or heart attack, angina and myocardial infarction. Therefore, what are the alternative ways to treat coronary atherosclerosis?

Figure 1 Coronary atherosclerosis.


Possible treatment

Coronary Angioplasty

When someone has serious coronary atherosclerosis, the blood flow become partly or totally blocked by plaque. A clot may even form simply because the endothelial lining in coronary atherosclerosis patient is damage because of high blood pressure or smoking. The clot and block the whole coronary artery, particularly already narrowed by plague. Coronary thrombosis will occur in this occasion. When the coronary artery is been blocked, heart muscle will starved from oxygen and nutrients, and this is often lead to heart attack, angina or myocardial infarction. Possible treatment for atherosclerosis is Coronary Angioplasty and stent placement. Angioplasty is the technique of mechanically widening the blockage or narrowed blood vessel caused by atherosclerosis. Usually, surgeon will make a surgical cut in patient's groin after using some numbing medicine. Then, a catheter will be inserted through the cut into an artery until it reaches the blockage in the artery. Fluoroscopy (live X-ray) would be used in this process in order to see the artery clearly. Next, a guide wire would be passed through the catheter to the blockage. Another catheter with a very small balloon on the end will be pushed over the guide wore and into the blockage. Then the balloon catheter, which known as an empty and collapsed balloon on a guide wire is passed into the narrowed artery and then inflated to a fixed size using water pressure. The balloon is blown up for 30-60 seconds with a pressure of 75 to 500 time's normal blood pressure. This squashes the atherosclerotic plaque and widens the narrowed artery. ( The balloon presses against the inside wall of patient's blocked artery. This opens the artery and restores proper blood flow and thus reduces risks for those unwanted disease such as heart attack, stroke, aneurysm or blood clot.

Figure 2 Angioplasty-the expansion of the balloon and placement of a stent.


Coronary Artery Bypass Graft (CABG)

Figure 3 Coronary Artery Bypass Graft.

Source: severe coronary atherosclerosis happens in patient, oxygen does not reach the heart muscle and damage occurs. Open heart bypass surgery is considered the gold standard treatment. During an open heart bypass surgery, a bypass is created by grafting a piece of vein above and below the blocked area of coronary artery in order to allow blood flow across the hindrance. Veins are usually taken from patient's leg but arteries from the chest or arm may also be used to create a bypass graft. (4) Patient would be given some drugs to slow the heart beat during the surgery, so that a heart-lung bypass machine is not needed. Open-chest surgery can be replaced by keyhole procedures or minimally invasive procedures. Usually, keyhole surgery uses several smaller openings in the chest and may or may not require a heart-lung machine.

There are some risks after open heart bypass surgery. Basically, patient would have chest pain or angina after the surgery. Severe angina may return shortly after operation in about 4 out of 100 people. (21) In general, after 5 years, about 4 out of 100 people need another operation. After 10 years, about 12 out of 100 people need another surgery. (22) Apart from that, other risks of CABG may include risks associated with heart attack, stroke, excessive breeding infection or subtle problems in long-term memory, comprehension, calculation skills and concentration. Patients would also have oedema at their affected ankle as veins are taken from patient's leg during CABG. Apart from that, they are not allowed to carry anything more than 10 pounds, not to drive for the first 4 weeks after surgery and not advice to have sexual activity until they fully recover. (23)


Economic Issue

Table 1 Table above shows that the prices for Coronary Angioplasty in various countries. (4)One economical issue that I encountered while carrying out this research is that the cost of coronary angioplasty is really expensive especially in this era of economic retrenchment and budget deficits. Coronary Angioplasty is an effective way to treat coronary atherosclerosis but this benefit comes at a significantly higher initial price. The cost is around £8,500 in UK and USD 15,000 in US. While the price of CABG is around USD 22,000 in US.

Table 2 : The prices of CABG in different countries. (5)

This brings a large economic burden for those from poor families. Most of them gave up the treatment because of this reason. This financial issue calls for government subsidies for those patients from poor families. Government need to be financially stable in order to provide wide access to hospitalization.

Ethical Issue

Apart from government hospitals, many private hospitals also carry out these 2 kinds of treatment such as Coronary Angioplasty and Open Heart Bypass Surgery. In this case, some of the private hospitals are publishing information regarding to the mortality rate and success rate of these operations on the internet. Unfortunately, some of the information given is not according to the reliable source. They even claimed that patients who carry out the operation in their private hospital will have a higher survival rate. Moreover, some of the surgeons do not give enough explanations and information to their patients. Do their patients really know that the risk of the surgery? Do patients have a very clear image regarding symptoms after the operation? Do patient realize that surgery does not cure them but just palliates their symptoms? Do their patients know that they have to undergo second surgery within a short period (about 7 years) and the risk is higher and less successful then the first? (6) Do their patients know that there is higher risk for those who are older (men greater that 45 and women greater that 55). (7) The ethical issue I want to raise here is that, patients have the priority to know the treatment and surgery they undergo. Surgeons must give a good explanation to them beside than getting consent from them. This is because surgeons have to know that, once they made any mistakes, patients will die.

Benefits and Disadvantages

Which treatment is better? This question always comes to the mind of the patients of coronary atherosclerosis. There is no definite answer for this question and it depends largely on the severity of disease. Usually, patients with coronary atherosclerosis which limits that blood flow in the coronary artery will receive angioplasty. If narrowing or blockage in multiple area of coronary artery, CABG is recommended.

Graph 1: Results from the Duke database comparing percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG). The preferred method of therapy depends on the extent and severity of coronary disease. PTCA seems to be superior in patients with less extensive disease, whereas CABG is more advantageous for patients with more extensive coronary disease. (15)

In coronary angioplasty, patients need not undergo a massive operation as CABG does. It is an easier procedure that able to improve blood flow to the heart muscle and this reduce the symptoms of chest pain and also increase the tolerance for patients when doing exercise. A hurt-lung machine is not needed and its risk is low. (8)It is non-invasive and thus patients could be discharged earlier because this angioplasty only takes 1 to 2 hours to complete. Patients' chest need no to be opened and can be performed under local anesthesia. Apart from that, it also reduces pain and less scarring to the patients. (9) Besides that, patients also able to carry out their daily routine and without causing any trouble to their families members.

There are also some disadvantages of coronary angioplasty such as the artery will become narrow again. (10) Besides that, clotting also will reform within the stent and thus reduce the blood flow to the cardiac muscle in that region. So emergency surgery to re-open a clogged coronary artery or repair the torn coronary artery. Sometimes,

heart attack, infection, abnormal heart rhythms will happen to the patients as the side effect. Some patients are allergic to the dye injection during the process. (11)

The benefits of CABG surgery vary from person to person and also depend on the severity. First of all, CABG enables patients with severe coronary atherosclerosis to increase their life span and make their life better by reducing the medication they are taking. The symptoms of angina and heart attack also will be reduced.


5% risk of heart attack on the table, a 2% risk of dying, and about a 10% risk of serious complication, such as stroke, weakening of the heart muscle, or infection. (14)

Thomas A. Preston, MDHowever, there are more disadvantageous of CABG compared to coronary angioplasty. CABG has a higher mortality rate which is about 3-4%. Sometimes, second operation is needed because of the chest infection and lung complications. (12) Below is a statistics quoted from Thomas A. Preston, MD. There is also a clear increase in mortality rates with the increase of age.

Bar Chart of Mortality Rate for CABG Against The Age group.

Bar Chart 1: Shows that the mortality rate with the increase of age. (13)

The comparison between Coronary Angioplasty and CABG.


Alternative Treatments

Medications (Drugs)

Antiplatelet drugs

Diagram 1: Diagram besides shows that Antiplatelets drugs and targets for platelet function inhibition. The ticlopidine and clopidogrel inhibit the ADP-receptor of platelets. Asprine targets platelet cycloaxygenase (COX).Antiplatelet drugs is a kind of drug which able to reduce the ability of platelets in our blood to stick together. This may prevent blood clot or thrombosis in medical and surgical patient or patients that have symptoms of atherosclerosis. Most of the physician will prescribe Aspirin, Clopidogrel, Dipyridamole and Ticlopidine to their patients.

Source: Jameson JN, Kasper DL, Harrison TR, Braunwald E, Fauci AS, Hauser SL, Longo DL. (2005). Harrison's principles of internal medicine (16th ed.). New York: McGraw-Hill Medical Publishing Division. ISBN 0-07-140235-7. OCLC 54501403

Anticoagulant Drugs

Anticoagulant drugs are used to prevent the blood from clotting. The mechanism of anticoagulant drug is that it will interfere the manufacture of prothrombin in the body and cause the blood to become thinner. Warfarin, Heparin, Heparinoids, Pentasaccharides Fondaparinux and Direct Thrombin Inhibitors (DTI) are the examples of anticoagulant drugs.

Graph 1: Graph 1 shows that comparison between 2 type of medicines such as Warfarin (anticoagulant) and Aspirin (antiplatlet). Both of them show positive effect towards patients with coronary atherosclerosis. (20)

Modification of Risk Factors

Changing lifestyle

As we know, cigarette or tobacco smoking will increase the rate of coronary atherosclerosis no matter males or females at all ages and increase the risk of various kind of CVDs and it is responsible for more than $50 billion in annual healthcare expenditures. (16) It is estimated that each year in United States more that 430,000 deaths are link to cigarette smoking and three-quarter of deaths related to various kind of CVDs. (17) The prevention of atherosclerosis is a long-term challenge to patients. It needs high cooperation between patients and health care professionals. Physicians should advice patients about the health risks of tobacco use and provide guidance in order for patients to quit smoking.

Likewise, physicians must counsel patients regarding the benefits of having prudent dietary and exercise habits for maintaining ideal body weight. Patients are advice to eat food which is low in fats especially in saturated fats, LDL cholesterol and sugar.

Graph 2: Graph above is a conceptual graph that showing the relation between low-density lipoprotein cholesterol (LDL-C) levels and relative risk and coronary heart disease and baseline LDL-C levels in several recent studies. (18)

Obesity impairs the treatment of other risk factors and increases the risk of adverse coronary events. Being obesity also increase the risk of suffering from high blood pressure which will cause damage to the endothelial lining of blood vessels leading to coronary atherosclerosis because heart needs to work harder to move the blood through all the extra tissue. Good exercise habits such as yoga, meditation, jogging can slow the heart rate, lower down the blood pressure, lower blood cholesterol levels and balance the lipoproteins in our blood. (19)