Vascular Diseases Overview
The Circulatory System
The blood vessels that comprise the vascular system are part of the circulatory, or cardiovascular, system. The heart is the major organ of this system. With each beat, it pumps blood into the vessels and through the body, bringing oxygen and other nutrients necessary to the life to the cells.
As the blood circulates, it also removes waste products, toxins and other harmful substances. The circulatory system works with many other systems. It plays an especially important role in:
- The Respiratory System. Blood circulates through the lungs where it exchanges carbon dioxide and oxygen.
- The Digestive System.
Blood circulates through the intestines where it absorbs nutrients from food that was eaten and digested.
- The Excretory System.
Blood circulates through the kidneys which filter out wastes that are removed from the body in the urine.
- Temperature Control.
As the blood flows, heat moves back and forth between the blood and the cells. This constant exchange of heat keeps all the body parts at the same temperature. This explains why people with circulatory problems often have cold feet or hands, or spots where the skin is warm to the touch.
The Blood Vessels
There are three types of vessels that aid in the transport of blood, and in keeping it in constant circulation from the heart to the body, and back to the heart:
- Arteries
- Veins
- Capillaries
The blood vessels are more than simple tubes through which blood flows. Each has its own characteristics, depending on the role it plays in the circulatory system.
Arteries are strong, flexible blood vessels that must expand to accept the blood pumped into them with each beat of the heart, and contract to squeeze blood into the veins when the heart relaxes.
Veins The veins that return blood to the heart are less “active” and elastic than the arteries. Veins have valves that open to let blood through, and close to prevent blood from pooling in the legs and elsewhere due to the pull of gravity. There are three types of veins:
Superficial veins lie near the surface of the skin. Larger veins that usually are buried in the muscles or deep compartments of the body are called
Deep Veins. Blood vessels that connect the superficial and deep veins are called “communicating” or
Perforating Veins.
 Capillaries, which look more like webs than vessels or tubes, lie in tangled “beds” in the tissues of the body. They are so tiny that blood cells must pass through them in single file. The exchange between the blood and the cells of the body takes place in the capillary beds. Here, blood takes oxygen from the cells and gives up carbon dioxide. Special capillaries in the kidneys, liver and elsewhere take waste products that are excreted from the body. As the capillaries spread out of their beds, they thicken and merge into small vessels called “venules” that, in turn, lead to larger veins that return blood to the heart.
Preventing Vascular Disease
The best way to prevent vascular disease is to live a “heart healthy” lifestyle – don’t smoke; eat nutritious, low fat foods; exercise; control risk factors and maintain a healthy weight.
 Life style changes. The single most effective steps you can take to prevent vascular disease are to quit smoking and control high blood pressure, high cholesterol, diabetes and other factors that contribute to vascular disease. Regular exercise, eating a balanced diet and maintaining a healthy weight also are important.
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Types of Vascular (Blood Vessel) Disease
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Most vascular diseases are caused by conditions that clog or weaken blood
vessels, or damage valves that control the flow of blood in and out of the veins. Most vascular disease is caused by arteriosclerosis, often called “hardening of the arteries” (although veins also can be affected). |
In this condition, a sticky substance called "plaque" builds up inside the blood vessels. Over time, the blood vessels may weaken or become so clogged that the blood supply to affected parts of the body is reduced or blocked. The flow of blood also may be affected when a blood clot (thrombus) gets stuck in a blood vessel.
Arterial Disease and Venous Disease
Aneurysms are weakened areas in the blood vessels that bulge like balloons when blood flows through them. Once they grow to a certain size, there is a risk of rupture and life-threatening bleeding.
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It is called "arterial disease" when
arteriosclerosis, blood clots and
other vascular conditions
occur in the arteries. Problems
that occur in the veins are called
“venous disease.” Some vascular
conditions occur only in arteries,
others are unique to the veins.
Some can affect either type of
vessel, such as aneurysms and
arteriovenous malformations
(AVM) (abnormalities in the brain or elsewhere in which the blood vessels are tangled and distended). Aneurysm and AVMS are called “silent killers” because they often produce no symptoms until they rupture.
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Arterial Disease
Common diseases affecting the arteries include:
- Peripheral vascular disease (PVD) (sometimes called peripheral arterial disease, or PAD) is a condition where the arteries that carry blood to the legs (and, less frequently, the arms) become narrow or clogged.
- Carotid artery disease is a condition in which the arteries in the neck that supply blood to the brain become clogged and may cause a stroke.
- Abdominal aortic aneurysm (AAA), or Triple A, is an area in the main artery of the heart (the aorta) that is weakened and bulges like a balloon. If it grows large enough, the aneurysm can rupture and cause life-threatening bleeding. Males over the age of 60 who smoke or have ever smoked and people with a history of AAA in their family are at highest risk for this disease.
Venous Disease
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Common conditions affecting the veins include:
- Blood Clots, Deep Vein Thrombosis (DVT)
- Venous Stasis Disease
- Phlebitis
- Varicose Veins (also called “varicoceles”)
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These conditions usually occur in the veins of the legs.
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Blood Clots and Deep Vein Thrombosis
(DVT)
The tendency of blood cells to "stick together" and form clots depends on a combination of two factors:
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1. Sluggish Blood Flow. Sitting still or lying down for a long time, such as on an airplane ride, can slow down the flow of blood. Prolonged bed rest after surgery or injury is especially likely to contribute to blood clots.
2. Clotting Factors. Clotting factors – substances in the blood that regulate the formation of clots – may increase after an operation or injury, or during pregnancy. Talking birth control pills may increase a woman’s risk of forming blood clots. Severe infection, an increase in red cells, certain types of cancer and an injury to the vein itself are other factors that can contribute to the formation of blood clots.
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It is not unusual for the blood to clot from time to time, but most clots go unnoticed. They are small, cause no symptoms, are dissolved over time by the body, and need no treatment. There are times, however, when the body cannot dissolve the clot on its own, or the clot causes health problems that must be treated. Clots that interfere with the normal flow of blood or may affect organs that are vital to health and life must be diagnosed and treated early to avoid serious illness or death. |
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Deep Vein Thrombosis
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The deep veins that lie near the center of the leg do most of the work of the venous system. Nearly all – 85 percent – of the circulating blood is returned to the heart through these veins. DVT – the formation of a clot (or thrombus) in any one of these veins – can be a very serious problem. Typically, the clot comes on suddenly and without warning. If not treated, DVT can block the blood supply to the legs and cause tissue death or gangrene that requires the removal (amputation) of all or part of the leg. DVT also can lead to valve damage in the vein and a chronic condition, called venous stasis disease, that is difficult to treat.
DVT may be related to prolonged periods of bed rest or inactivity, injury to the vein, surgery or pregnancy.
In addition to restricting the flow of blood, there is risk that the clot may break off, travel through the heart and get trapped in the lung (pulmonary embolism) – a potentially fatal complication.
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Risk Factors for Venous Disease
Factors that increase the chances of venous disease include:
- A family history.
- Increasing age that results in a loss of elasticity in the veins and their valves.
- Pregnancy.
- Illness or injury.
- Prolonged periods of inactivity – sitting, standing or bed rest.
- Hypertension, diabetes, high cholesterol or other conditions that affect the health of the cardiovascular system.
- Smoking.
- Obesity.
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