Specialist for Internal Medicine and Cardiology
Vienna University Department of Internal Medicine II (Cardiology), AKH-Vienna
1190 Wien, Heiligenstädter Straße 46-48
Tel: 0699/ 194 653 18
Phone:
0699 194 653 18
Fax:
02243 20 675
www.kardiologie-praxis.at
Risk factors for coronary artery disease
The risk factors for coronary artery disease are the same as the ones for arteriosclerosis. Non-influenceable risk factors include increasing age, male gender as well as genetic disposition.
Avoidable risk factors are:
- High blood pressure
- Disorders of the lipometabolism
- Diabetes mellitus
- Overweight
- Smoking
- Stress
A high number of these risk factors are due to lack of physical exercise, malnutrition and high intake of alcohol. It is difficult to predict the individual influence of each of these risk factors, however, it is certain that the unhealthier the life style is and the more risk factors accumulate, the higher the risk of developing a coronary artery disease and/or a heart attack.
High blood pressure
Arterial hypertension, also called high blood pressure in everyday language, is a disorder, where the blood pressure of the arterial system is chronically increased. According to the WHO definition, systolic blood pressure over 140 mmHg or diastolic blood pressure over 90 mmHg is considered hypertension. Reasons for hypertension are conditions of the hormone system, the cardiovascular system, as well as kidney problems.
The majority of hypertension cases, however, are due to unknown causes. Quite frequently, hypertension goes unnoticed for a number of years, as it does not cause any problems in its early stages, and is thus often only diagnosed after the onset of any complications. Consequential damage, like coronary artery disease with its possible sequelae of heart attacks, kidney failure and strokes, is responsible for the majority of the death cases in developed countries.
There are different groups of medications available, which in connection with changes of the life style, can decrease the blood pressure and thus reduce the risk of complications.
Consequences of acute hypertension
(hypertensive crisis: increase in blood pressure > 120 mmHg diastolic):
- Cardiac: Angina pectoris (chest pain), breathing problems, cardiac arrhythmia,
stroke, acute left ventricular failure with pulmonary oedema, aortic dissection - Cerebral: Head ache, nausea, impaired vision, confusion, coma, intracerebral bleeding
- Renal: Acute kidney failure
Consequences of chronically increased blood pressure:
- With heart involvement = hypertensive heart condition
- Cardiac hypertrophy
- Coronary arterioscleroses, heart attack
- Cardiac insufficiency
- 70% of all hypertonic patients die from cardiovascular sequelae
(heart attack, cardiac insufficiency, stroke)
- With brain involvement = stroke
- With kidney involvement = hypertensive nephropathy, chronic kidney failure
- With vessel involvement = arterial obstruction
Disorder of lipoid metabolism
The human body produces cholesterol by itself and absorbs it from food. A cholesterol rich diet with high quantities of meat, egg, milk, butter and other milk products) leads to an increase cholesterol level, which in turn leads to arteriosclerosis and thus clogging of the arteries. Since the majority of heart attacks are caused by arteriosclerosis, one can consider a cholesterol rich diet one of the main causes of heart attacks. There are, however, hereditary disorders of the lipoid metabolism (hyperlipidemia), which lead to high cholesterol values of the blood regardless of the diet.
A differentiation is made between different types of cholesterol: total cholesterol, HDL-cholesterol, and LDL-cholesterol.
|
Total cholesterol: |
<200 mg/dl |
HDL-cholesterol: |
>35 mg/dl |
|
LDL-cholesterol: |
<130 mg/dl |
In case of high cholesterol levels, a change in diet is necessary. The cholesterol level
can also be decreased by physical exercise. The effect would be a decreased risk for heart
attack and/or stroke. In pronounced cases, taking of medication to decrease the level of
cholesterol might be indicated.
Triglycerides are a mixture of a hundred different combinations of the fat molecules glycerin and fatty acids. They serve as the cells’ fuel to generate energy. Part of them is, however, produced by the organism itself. The higher unsaturated fatty acids are absorbed from food.
In case of elevated levels of triglycerides (>180 mg/dl) it is advised to abstain from alcohol and sugary foods.
Diabetes mellitus
Diabetes mellitus is a metabolic condition in which a person has high blood sugar levels as a result of the body not being able to absorb the glucose from the blood. At the beginning elevated sugar levels produce symptoms such as increased thirst, frequent urination, and fatigue.
If not treated and consequently the sugar level stays elevated over years, there will be damage to vessels and organs (arteriosclerosis, heart attack, retinal disorder, nephropathy, neuropathy, diabetic foot ulcers).
Diabetes is diagnosed if:
- Casual plasma glucose is at or above 200 mg/dl
- Fasting plasma glucose level at or above 126 mg/dl in two test results
- The long term plasma glucose HbA1c at or above 6,5%
Casual plasma glucose levels can be tested at any time of the day and even fasting is not required, however, for a fasting level, the patient is required to fast 8 hours before. Long term values do not depend on food intake and can be done at any time of the day.
Overweight
Body mass index (BMI) defines people as overweight when their BMI is over 25km/m2 and as obese as of 30kg/m2. The body mass index is calculated by dividing the subject's mass (kg) by the square of his or her height (m) (BMI = kg/m2). The decisive factor for a cardiovascular disease, however, is not only the BMI but also the fat distribution. Fat accumulations around the stomach and the inner organs have shown to be more harmful. Thus waist girth of over 92 cm in males and over 80 cm in females increases the risk of cardiovascular conditions. Weight reduction is advised in such cases.
Diet and life style should be reconsidered in case of obesity. The right choice of foods can have a positive influence onto metabolic disorders such as lipoid metabolic disorder or elevated blood sugar levels. High fiber foods, whole meal products, sufficient fluid intake, as well as a good variety of lettuce, fruit and vegetables are recommended. Known sources of fat like butter, nuts or mayonnaise as well sugary foods, salt and alcohol should be avoided.
Smoking
Smokers suffer from an 2-5 times increased risk of heart attack, depending on the number of cigarettes consumed per day and the years of smoking (pack-years). Nicotine penetrates into the autonomic nervous system and causes stenosis of the arteries, increases the heart beat and the blood pressure. In sum, the risk of arteriosclerosis is increased.
Stress
Stress is one of the core risk factors for coronary artery disease. It leads to an increase of the stress hormone cortisol, which triggers the production of molecules damaging the vessels. For a long time cardiologists considered the stress factor primarily in “manager-type” patients, i.e. people under huge pressure to perform, working more than 12 hours per day with no time to relax. Meanwhile, it has emerged that stress per se is not the decisive factor, rather the way stress is felt is more crucial.
If stress fires a person up and is connected with the feeling of success and achievement – psychologists call this eustress – it rarely has a negative impact onto the heart, of course under the condition that there is no consumption of performance-enhancing drugs, such as cocaine. Stress with a high level of frustration, called distress, has a much higher influence onto the function of the heart.
To reduce stress one should relax by regularly exercising or by methods such as autogenic training or mediation.
Lack of exercise
Lack of physical exercise might not directly lead to damage in the vessels, but all other risk factors for arteriosclerosis are avoided or improved by physical movement; and progression of the condition can be brought to a halt. At the same time, stamina increases.
Best results of the miracle exercise are achieved through regularity and adequate intensity, though excessive overtraining should be avoided. It is best to consult the physician first to assess which type of sports is appropriate. Personal performance limits can be established through exercise ECG.
Endurance sports such as walking, gentle running, cross country skiing, swimming and cycling are well suited. Training should last for a longer period (optimal: 30 mins) with low to medium intensity, whereby it has to be stated that frequency is better than duration.
Therefore, it is better to train 3 times a week for 30 minutes rather than once for 90. It is important not to demand too much from oneself and angina pectoris pain should not increase during exercise. Even extensive walks three to four times a week suffice to become healthier.
Power training with its short but intensive stress is less recommendable. Such sports include tennis, mountain biking, squash or weight training with heavy weights.
Genetic disposition
The risk for developing coronary artery disease is clearly increased in case of a positive family history (first degree relatives with coronary artery disease). The genetic disposition cannot be influenced, which means that the total of risk factors should be kept as low as possible (blood pressure, blood sugar, cholesterol, etc.).