Aging of your Heart and Blood Vessels is Risky
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Will you have a heart attack as you age? You can identify and reduce your risk! Home


Introduction
What is Atherosclerosis?
Stages and Diagnosis of Coronary Artery Atherosclerosis
Age, the Number One Risk Factor For a Heart Attack
Prevalence of Coronary Atherosclerosis (Occult and Clinically Manifest)
Risk Factors For Coronary Heart Disease and Risk Assessment
Importance of Risk Assessment and The Framingham Algorithm
Why Risk Factors Need Intervention Now
Lack of Exercise: An Additional Risk Factor to be Considered
Other More Recently Identified Risk Factors
Emphasis On The Risk Factor of Aging
Better Ways Are Coming To Quantify the Risk Factor Of Aging
Can The CHD Risk Associated With Aging Be Prevented?


Introduction

A "heart attack" is jargon for a scenario in which an area of the heart wall's muscle is deprived of blood, resulting in the death of some of its muscle cells. The precise medical term for "insufficient blood flow" in the heart is myocardial ischemia, and the term for "death" of heart cells is myocardial infarction. The most common cause of a heart attack in Western Society is atherosclerosis of the coronary arteries, the vessels that supply blood to your heart (see Dr Ed's article #11 "The Inner Layer Of Your Aging Blood Vessels Is A Battlefield!").

 

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What is Atherosclerosis?

Coronary atherosclerosis is characterized by irregularly distributed lipid (fat) deposits and sclerotic plaques, which protrude through the inner layer of the coronary arteries. This layer is called the intima. The plaques are associated with fibrosis, scar tissue and calcium deposits. This build up of scar tissue and calcium deposits leads to narrowing of the arterial lumen. In due course rupture or erosion of these atherosclerotic plaques can occur. This encourages the formation of a blood clot within the vessels, called a thrombus. Blood clots reduce the flow of blood in the coronary arteries and thus decrease blood flow to the heart wall's muscle. This causes ischemia, which deprives the heart muscle of sufficient nutrients or oxygen transporting material and prevents removal of waste products. When the heart muscle experiences ischemia, chest pain (angina pectoris), usually, but not always, occurs. If ischemia lasts for an extended period of time (greater than 20-60 minutes) a myocardial infarction (heart attack) occurs, most often resulting in the death of heart cells.

Illustration I.
Source: The Ciba Collection of medical Illustrations Vol 5 HEART, Frank H. Netter, M.D

Degrees of Coronary Atherosclerotic Narrowing or Occlusion


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Stages and Diagnosis of Coronary Artery Atherosclerosis

Atherosclerotic coronary artery disease can be detected in two general stages. These are the hidden, or occult stage, and the clinically manifest stage. In clinically manifest coronary disease the atherosclerotic processes within the coronary arteries compromises blood supply to the heart muscle. This usually causes chest pain, shortness of breath, or a heart attack. In the occult stage, the disease is present within the coronary arteries, but it has not yet caused symptoms. Occult or silent coronary disease can be diagnosed prior to developing these "grave" symptoms by a simple supervised exercise test to make the heart work as hard as possible. This test can determine if the heart's "oxygen supplying" blood flow during exertion can meet the increased demand. This is called a treadmill stress test. During the exercise treadmill stress test the heart's electrical activity (EKG) is monitored. Insufficient blood flow to an area of the heart during exercise causes temporary changes (called ST segment changes) on the electrocardiogram.

Often a somewhat more elaborate test is done in conjunction with the EKG during the exercise stress test - pictures of the heart are taken immediately after the treadmill exercise stops. This is called a thallium scan, or thallium scintigraphy. Inefficient coronary blood flow to any area of heart muscle appears as a "cold spot" in the pictures. Essentially, this means that the thallium could not get to the area, because of a block or blockages in the coronary arteries that normally would supply blood to this location.

Finally, the definitive diagnosis and the extent of coronary artery atherosclerosis is determined by coronary angiography. This is a procedure in which dye is flushed throughout the coronary arteries to detect atherosclerotic plaques and arterial narrowing.


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Age, the Number One Risk Factor For a Heart Attack

Coronary heart disease (CHD), another term used for atherosclerosis of the coronary arteries, is the number one cause of disability and death in older persons. In fact, the results of several large studies have concluded that the major risk factor for having this disease is age, per se. The magnitude of the problem of heart attack as a function of age is shown in Table 1.

Table 1.

Source: Framingham Heart Study, 26-year follow-up in U.S.A.


Note the marked increase in heart attacks with increasing age. Note, also, that women lag behind men at younger ages, then the risk increases sharply following menopause. Eventually, women catch up to the men at older ages. Some explanations for the connection between this disease and the effects of aging upon your arteries have been discussed in a previous article (Article #11 "The Inner Layer of Your Aging Blood Vessels is a Battlefield!").


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Prevalence of Coronary Atherosclerosis (Occult and Clinically Manifest)

The hidden, or occult, stage of coronary artery disease, like the clinically manifest stage, has also been discovered to increase with age. Remember that most people with occult disease are unaware that they have it. These persons feel healthy, have no cardiovascular signs or symptoms and thus take no cardiac medications. The occult stage usually progresses to the clinical stage where the patient develops symptoms such as chest pain (angina), myocardial infarction or sudden death.

A silent heart attack is also a possibility. Although it causes myocardial damage, a silent heart attack causes no pain and therefore the patient is unaware of it happening. Often it is picked up on the patient's EKG during a regular check-up. The Framingham study estimates that one in four elderly persons may have had a silent heart attack. If we add up the clinically proven and the hidden cases of coronary atherosclerosis, which often include silent heart attacks, we arrive at the conclusion that, on average, approximately 50% of all persons over age 65 years in Western Society have one form of this disease! This estimation is supported by autopsy studies.


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Risk Factors For Coronary Heart Disease and Risk Assessment

The Framingham Heart Study collected data that estimated the lifetime risk of developing Coronary Heart Disease. Almost 8,000 individuals ages 40 to 94 were studied. It was determined that the risk of developing CHD at an age greater than 40 years was 1 in 2 for men and 1 in 3 for women.

Table 2 shows the role that several known risk factors (smoking cigarettes, high cholesterol and high blood pressure) play in the development of heart attacks. Note that this table does not take into account the effect of aging as a risk factor for this disease.


Table 2.
This chart shows how a combination of three major risk factors can increase the likelihood of heart attack. This chart uses an abnormal blood pressure level of 150 systolic and cholesterol level of 260 in a 55-year-old male and female.
Source: Framingham Heart Study, section 37: The Probability of Developing Certain Cardiovascular Diseases in Eight Years at Specified Values of Some Characteristics (Aug. 1987)


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Importance of Risk Assessment and The Framingham Algorithm

Risk assessment tools are important in the prevention of coronary disease or decreasing its progression. With the proper use of such tools the physician and patient can identify specific risk factors that need to be controlled. Specific strategies can then be implemented to modify those risk factors that contribute to a certain individual's increased risk for coronary disease. This helps reduce the overall risk of the patient having a heart attack.

The results of the Framingham Studies regarding the risk for CHD have been incorporated into practical tools for such an assessment of a given individual's risk for developing clinical CHD. These are called "The Framingham Algorithms". One algorithm developed using the Framingham data evaluates the following factors as they relate to the development of coronary disease: gender, age, LDL cholesterol, HDL cholesterol, systolic blood pressure, cigarette smoking, diabetes, and whether or not the patient has an enlarged left heart which is sometimes indicated by an EKG. The physician, with the patient, first fills out a "prediction chart". See Table A.

Table A: Framingham Algorithm Prediction Chart
Data Required: Enter: Information/values Data Points:
1. gender (M or F)    
2. age    
3. total cholesterol (in mg/dL)    
4. HDL cholesterol (in mg/dL)    
5. systolic blood pressure (in mm Hg)    
6. Does you smoke cigarettes? (Yes or No)    
7. Does you have diabetes? (Yes or No)    
8. Do you have left ventricular hypertrophy on ECG (Yes or No)    
    Total Score:
_____________

This particular version of the Framingham Algorithm provides estimates of the average 10-year risk of incurring coronary heart disease for a person's present age and gender. You can get an idea of how it works by filling in the information in Table A for yourself and totaling the data points. By engaging in this exercise you can see how your risk can be increased or decreased by modifiable changes in life style and health such as starting or stopping smoking, and increasing or decreasing your blood pressure and cholesterol levels. In addition is shows clearly the increased risk if you have diabetes or have been diagnosed with a thickened or enlarged left ventricle (the left side pumping chamber of your heart).

Please recognize that this exercise is meant to make you aware of the role that risk factors play in the development of coronary heart disease and to show you how medical algorithms work. In particular, it is meant to show you how aging plays a role coronary disease. In no way should the score derived from this algorithm be used in place of a medical examination or consultation with your physician.


Working the Algorithm

1. First, answer the eight questions in Table A.
(If your don't know some values like HDL, LDL your physician can assist you in determining these.)

2. Second, determine your data points for questions 1 -5 (gender/age, total cholesterol, HDL cholesterol and systolic blood pressure) from Tables B, C, D and E: enter these data points in Table A.

Questions 1 and 2.
For age, be certain to enter the number that corresponds to your gender (male or female). For example, a 44-year-old woman would enter +3, a man the same age would enter +7.

Table B: Data Points for Gender and Age
Age female male Age female male Age female male Age female male
30 -12 -2 41 1 5 52 7 11 63 10 15
31 -11 -1 42 2 6 53 8 11 64 10 15
32 -9 0 43 2 6 54 8 11 65 10 16
33 -8 0 44 3 7 55 8 12 66 10 16
34 -6 1 45 4 7 56 9 12 67 10 16
35 -5 2 46 4 8 57 9 13 68 11 17
36 -4 2 47 5 8 58 9 13 69 11 17
37 -3 3 48 5 9 59 9 13 70 11 17
38 -2 3 49 6 9 60 9 14 71 11 18
39 -1 4 50 6 10 61 10 14 72 11 18
40 0 5 51 7 10 62 10 15 73 11 18
74 11 19

 

Table C: Total Cholesterol (TC)
0
139 -3
152 -2
167 -1
183 0
200 1
220 2
240 3
263 4
289 5
316 6
331 NA
Total cholesterol (TC) is the value for blood cholesterol, which includes LDL-cholesterol (low density lipoproteins), HDL-cholesterol (high density lipoproteins), and VLDL (very low density lipoproteins) cholesterol.

 

Table D: High Density Lipoprotein
(HDL-Cholesterol)
0
25 7
27 6
30 5
33 4
36 3
39 2
43 1
47 0
51 -1
58 -2
61 -3
67 -4
74 -5
81 6
88 7
HDL or High-density lipoproteins carry cholesterol away from body cells and tissues to the liver for excretion from the body. Low levels of HDL are associated with an increased risk of CHD. Therefore, the higher the HDL level, the better.

 

Table E: Systolic blood pressure
(Sys BP)
0
98 -2
105 -1
113 0
121 1
130 2
140 3
150 4
161 5
173 8
186 NA

Systolic blood pressure is the force which blood exerts against the artery walls when the heart contracts and pumps blood into the aorta.



3. Third, answer questions 6, 7 and 8 using the following guidelines.

Question 6.
If you smoke add +4 for both males and females. The number is 0 if you are a non-smoker.

Question 7.
If you are a diabetic, (your doctor can advise you about this) add +3 if you are male and +6 if you are female. It is 0 if you do not have diabetes.

Question 8.
If your doctor has told you that you have left ventricular hypertrophy, add +9 for both males and females, otherwise it is 0.

4. Fourth, add up your Total Score.

5. Finally, compare your Total Score to the scores in Table F to determine your calculated risk according to this algorithm.

Table F: 10 Year Risk (from your total score in percent)
Score 10 year risk Age 10 year risk Age 10 year risk
-25 <2 13 8 26 29
2 2 14 9 27 31
3 2 15 10 28 33
4 2 16 12 29 36
5 3 17 13 30 38
6 3 18 14 31 40
7 4 19 16 32 42
8 4 20 18    
9 5 21 19    
10 6 23 23    
11 6 24 26    
12 7 25 27    

If you have done the exercise correctly, added up your total score and looked-up your 10-year risk in Table F, you now have some idea as to where you stand with regard to an approximate relative risk for developing coronary heart disease within the next ten years.

Now, ask yourself this question, "What are your plans in the next ten years"? Do you have a grandson whose marriage you would like to attend? Are you looking forward to a special anniversary or a vacation somewhere special? Or, do you just want to retire in a few years and go fishing at that lake cabin you're planning to buy? Do any of these expectations fit in with a heart attack or even dying from coronary heart disease? Let's look at Mr. Jones as an example and see if there are some other options.

Mr. Jones is a 60-year-old diabetic who smokes. His total cholesterol is 240, his HDL cholesterol is 33 and he has a systolic blood pressure of 140. His doctor says his heart is not enlarged:

Mr. Jones receives 14 points just for being a 60-year-old male.
He uses Tables B, C, D, and E and gets 3 points for total cholesterol, 4 points for HDL cholesterol and 3 points for systolic blood pressure. At this point he already has 24 points. Next he adds 4 points for smoking, and 3 points for being diabetic. This gives him a total score of 31 points. If you look on Table F: The Risk Chart, you can see that with 31 points his 10-year risk for coronary disease is 40%.

Now, what if:
Mr. Jones stops smoking and controls his diet so that his total cholesterol drops to 183. He can subtracts 4 for smoking and 3 for total cholesterol. This gives him a total score of 24, and according to Table F his 10-year risk drops to 26%.

Next, with diet and exercise he also gets his systolic blood pressure under control and drops it to 121. He can subtract 2 more points, dropping his total score to 22 and his 10-year risk becomes 21%.

In the process of exercising to control his blood pressure his HDL (good cholesterol) increases from 33 to 39. He can subtract another 2 points making his total score 20 and reducing his 10-year risk to 18%.



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Why Risk Factors Need Intervention Now

After you have experimented with the Framingham Algorithm, totaled your score and played with some hypothetical "what if's" like Mr. Jones, you will understand why all risk factors that are changeable need intervention now, not in ten years. It becomes evident that these risk factors confer a very high risk for coronary heart disease in the long run. The Framingham Risk score estimates the risk of developing CHD within a 10 year time period. Thus, this risk score may not reflect the real long-term or lifetime decrease in the CHD risk of young adults if risk factors are reduced early in their lifetime. The lifetime risk is also affected by the interaction of the risk factors in the algorithm and age changes that occur in the blood vessels' walls - see article # 11 "The Inner Layer of Your Aging Blood Vessels is a Battlefield!"


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Lack of Exercise: An Additional Risk Factor to be Considered

Another important risk factor for coronary artery disease that is not considered by the algorithm we've been looking at is lack of exercise. While exercise has long been advocated as a preventive measure for coronary artery disease, the United States Surgeon General and the American Heart Association have now specifically elevated lack of exercise to the status of a bona-fide risk factor. Lack of exercise contributes to obesity, which is known to contribute to the development of adult onset diabetes, high blood pressure and increased blood lipids (cholesterol) levels. Lack of exercise has not yet been integrated into risk factor algorithms like The Framingham Algorithm we've been discussing.


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Other More Recently Identified Risk Factors

Scientists are now researching additional possible risk factors. These may soon emerge as leading risk factors, or perhaps even causes for the atherosclerotic process itself. These include blood homocysteine levels, Lp(a) levels and infectious agents. Homocysteine is an amino acid that may contribute to the build up of fat like substances in the arteries, increase the clotting of platelets, and cause stiffening or hardening of vessels. Lp(a) is a lipoprotein in your blood that binds LDL cholesterol. It may prevent the breakup of clots. Infectious agents, such as cytomegalovirus, chlamydia, and H. pylori have all been implicated, and are now being researched as possible agents that harm the vessel walls and begin the process of atherosclerosis.


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Emphasis On The Risk Factor of Aging

Along with all the changeable risk factors and the possible new risk factors to explore it's apparent that aging is a major factor in the process of atherosclerosis. Look back at Table B for determining data points in the Framingham Algorithm. You can see how the number used in the calculation for risk increases with each year of age for both males and females.

In order to make the CHD risk assessment more useful for persons of a given age, the absolute estimated risk of having a CHD event within 10 years based solely on age and gender is shown in Table G, which is based on Framingham Data. Table G shows the estimated risk for individuals of varying age, without respect to any other risk factors. Thus, you can see that aging itself is a cause for ALARM.

Table G: Average Risk for CHD Based on Age and Gender Alone (in percent)
Age female male
0 NA NA
30 <1 3
35 <1 5
40 2 6
45 5 10
50 8 14
55 12 18
60 13 21
65 9 30
70 12 24
75 NA NA

 


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Better Ways Are Coming To Quantify the Risk Factor Of Aging

At this time, the algorithm we've discussed is quite useful as an evaluation tool to estimate risk. We know, however, that people age differently. Vascular aging is one area of aging that is being researched. Researchers using new and refined techniques are presently sorting out "successful" vs "unsuccessful" vascular aging. One such technique allows scientists to non-invasively evaluate the degree of intimal thickening and vascular stiffening that occurs with advancing age in large numbers of people. This can be done in the doctor's office as easily as taking a blood pressure - see article # 10 "How Badly Are Your Arteries Hardening With Aging?" Another allows us to look at the degree of calcification in the vessels by an innovative scanning method now being tested in large centers through the United States. Soon, we shall be able to adjust the age factor up or down in these algorithms to account for individual degrees of vascular stiffening and calcification, to better determine actual risk, and provide earlier treatment and preventative measures for those at increased risk.

For example: Suppose we use these new techniques to evaluate 70-year-old Mr. Flexy. We find very little calcification in his vessels and very little vascular stiffening. Essentially his vessels looked more like a 60-year-old's. We then adjust his age down to 60 in the algorithm. This age adjustment knocks off 3 points (17-14=3). Thus we can fine-tune the estimate for Mr. Flexy's risk for coronary disease.


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Can The CHD Risk Associated With Aging Be Prevented?

Aging is a risk factor we have previously believed that we can do nothing about. But we are not correct in this supposition. We now know that one risk associated with aging is due to changes that occur within blood vessels - see article #11 "The Inner Layer Of Your Aging Blood Vessels Is A Battlefield". Soon we will be able to detect these changes easily in the general population. In the near future doctors will be advocating intervention with new drugs and innovative treatments to prevent, delay and treat vascular aging.

But you don't have to wait for future medical advances and new medications to slow down vascular aging. You can start now! It's already known that physical exercise will help protect your blood vessels from aging. You cannot change your biological age, but you can reduce your risk for coronary heart disease by paying attention to as many of the known risk factors and predisposing causes of atherosclerosis as possible until these new medical, pharmacological and technological advances are approved and available to the general public.

Include in your life style those elements already known to slow the vascular aging process and reduce the coronary heart disease risk. Two of these would be exercise and a heart-healthy diet. Your doctor can advise you with regard to an optimal exercise prescription. Both exercise and diet help control obesity and hypertension, two of the leading risks for coronary heart disease. You can also eliminate from your lifestyle those elements which damage the vascular structure such as smoking. You're still going to count those burning wax reminders every year, but if you age wisely, perhaps you won't need help to blow out the flames.

To help you learn more about "your" specific risk factors Healthandage.com provides many interactive tools.

You can go directly to all the interactive tools by clicking here.

For tools specific to risk factor interaction go to:

Risk Factor Roulette and Common Risk Factors

To quickly assess your risk for heart attack within the next ten years you can go to Heart Attack Risk Calculator, answer a few questions and get an immediate assessment.

Also, I highly recommend you visit and use these interactive tools for your personal risk assessment:

Diabetes Type II Risk Calculator

Exercise Calculator

BMI Calculator

Ideal Weight Calculator

Nicotine Dependency Calculator


The next article in our series will address high blood pressure, a major risk factor for CHD and heart failure. I will discuss why it's important to control high blood pressure and explain to you how blood pressure medications work.


*Information obtained regarding the Framingham Algorithm that was used as an example in this article was obtained from The Medical Algorithms Project developed by John R Svirbely, MD, and MG Sriram, PhD.

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