Atherosclerosis, marked as hardening of the arteries, is a disease where fat collects on the walls of affected arteries. Arteries have an important role in the human body; they transport blood rich in oxygen and nutrients to tissues, and their flexible walls maintain optimal blood pressure values. It is therefore important that the arteries circulate enough blood to satisfy the need of the tissues. If fat collects on the artery walls, the arteries become narrower or even blocked, starving the surrounding tissues of blood. Nowadays there are many diseases based on atherosclerosis and these illnesses are the cause of about half the total number of deaths in developed countries.
Manifestations of Atherosclerosis
The essence of atherosclerosis is fat build-up, mainly cholesterol, on the walls of blood vessels. These gradually form atheroma plaque, which restricts blood flow in the affected artery. Later this can lead to significant narrowing of the artery, even complete blockage, in which case the artery is not able to ensure enough blood flow to the tissues. The tissues then suffer from lack of oxygen due to blood starvation. In this stage, typical manifestations include pain in the blood restricted area. If the artery is only narrowed and a small amount of blood is still able to pass, pain in the affected area appears only during physical activity, when the tissue requires more oxygen which the narrowed artery is not able to provide. Pain usually disappears with rest. If the artery is completely blocked, the area can be so starved of blood and oxygen that necrosis of the body part or area can occur. In this case the affected body can no longer continue to perform its function. Atherosclerosis can affect most of the arteries in the body but usually the arteries in the brain, heart, lower limbs or aorta are affected. In most of these situations very serious complications can follow, sometimes even death.
Risk Factors of Atherosclerosis
Risk factors that contribute to atherosclerosis can be divided into two categories: those which can be control and influenced, and those that cannot.
Uncontrollable Risk Factors
Uncontrollable risk factors include age, sex and congenital disposition. The incidence of atherosclerosis increases with age. Among middle-aged adults, men are more often affected than women, probably due to the protective influence of female sex hormones. In older years, after menopause, the balance is readjusted and women become just as likely as men to suffer from atherosclerosis. Hereditary predisposition can also led to a more rapid progression of the disease.
Controllable Risk Factors
The second group of risk factors include those that can be significantly influenced and controlled, for example by leading a healthy and balanced lifestyle. Risk factors include an elevated level of fat in the blood, usually cholesterol. The normal cholesterol level is up to approximately 5.2 mmol/l. If this level is higher, more cholesterol collects on the arterial walls. Smoking is also a risk factor for atherosclerosis as it has been proven that smokers are more likely to suffer from damaged arteries in the lower limbs, and die of heart attacks, regardless of the influence that cigarettes have on the developments of cancers. Danger increases with age and with the number of smoked cigarettes. High blood pressure is considered another risk factor as it affects the arterial walls and accelerates the process of atherosclerosis. A major risk factor is diabetes, especially because it causes diabetics to have higher cholesterol levels. Lack of exercise being overweight and a stressful lifestyle are also significant factors contributing to this disease.
Complications of Atherosclerosis
As mentioned above, atherosclerosis is a disease of the arteries and is the cause of many illnesses. Atherosclerosis can affect any of us, but it may not manifest any symptoms. In the case of a change in the affected artery, such as rupturing or thrombus formation, complications of atherosclerosis arise. These include:
- Myocardial Infarction, or heart attack, is starvation of blood in a part of the heart muscle. This typically occurs after the development of a thrombus, blood clot, in the coronary arteries affected by atherosclerosis. It is manifested by chest discomfort and pain in the left upper arm which may radiate towards the left half of the jaw or shoulder. The patient may also experience shortness of breath, pallor and cold sweats. This is an acute condition and requires transport to a hospital as soon as possible.
- Angina pectoris is a condition where atherosclerosis causes narrowing of the arteries. It causes less oxygen to be able to reach tissues during physical activity, a time when tissues require an increased amount of oxygenated blood. This narrowing, however, is not enough to cause myocardial infarction. Angina pectoris manifests itself with chest discomfort and shortness of breath, both of which may occur during physical activity or at rest, depending on the type. Angina pectoris needs to be treated as it is considered to be a pre-heart attack state.
- A stroke or cerebrovascular accident (sometimes also known as a "brain-attack") is a serious condition that requires emergency care. One type of stroke is caused by atherosclerosis, when narrowing of the cerebral arteries occurs. Blood clots form and blood flow to the brain is reduced, causing ischemia; local blood starvation in the brain leading to a stroke. It is manifested by unexplained dizziness, weakness, possible paralysis of half the body, impaired speech and/or sight and even complete loss of consciousness. The patient should be transported as soon as possible to a specialized unit called a stroke unit, which is equipped to treat such acute conditions.
- Peripheral vascular disease is a disease of the lower limbs which can be caused by narrowing of the arteries due to atherosclerosis. This condition leads to decreased blood flow in the lower limbs, manifested by intermittent claudation; pain in the leg during physical activity. Eventually this pain may even appear at rest. With this condition the lower limbs tend to be cold, they may develop gangrene, and extreme cases may require leg amputation. Nowadays, this condition is treated pharmacologically with anti-clotting medication, or surgically by widening the narrowed arteries.
A diagnosis of atherosclerosis is made in patients suffering from complications of this disease and on the basis of the risk factors identified in the medical history. To confirm the presence of atherosclerosis a number of examinations are necessary. The most basic test is the duplex ultrasonography, a painless procedure where ultrasounds are used to measure blood pressure and blood flow through the vessels. Another option is a contrast angiogram, where a contrasting agent is introduced into the artery through a catheter and with the help of x-rays, images are created where changes in the arteries are visible. Other, less used methods are magnetic resonance imaging (MRI) and computer tomography.
Treatment of atherosclerosis is based on treating the causes that led to the disease. Atherosclerosis can affect anyone practically from birth, but individuals can influence its further development. Given that high blood pressure, high cholesterol, diabetes and smoking contribute to the development of atherosclerosis, it is necessary to fight against these conditions and effectively treat them.
- Treating high cholesterol is an important step in the fight against atherosclerosis. Treatment includes the administration of medications called statins and fibrates. Resins are recommended for children.
- The treatment of high blood pressure decreases further damage to the arteries. Lifestyle modification is most important; abstinence from smoking and alcohol, reducing body mass index, and an increased intake of fruits and vegetables. Diuretics are also necessary such as ACE-inhibitors, beta-blockers or calcium channel-blockers.
In order to prevent atherosclerosis, or at least slow down its development, it is important to fight against the above mentioned risk factors. This means lifestyle modification, avoiding smoking and frequent consumption of fatty and otherwise unhealthy foods, increasing physical activity and avoiding excessive stress. It is also important to maintain an appropriate weight and blood pressure values. In the case where medications are being taken against certain above mentioned risk factors, it is important to take them regularly and follow the doctor's instructions.