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About vascular disease
Vascular disease
is
the leading cause of death and a primary cause of heart attacks and
strokes in the United States. Vascular disease can manifest itself in many
ways: hypertension, coronary artery disease, peripheral artery disease,
arteriosclerosis, aneurysm, stroke, kidney failure and retinopathy. |
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Disease statistics According to the American Heart Association, 79 million Americans have some form of cardiovascular disease, and hypertension is the leading cardiovascular disease. Coronary heart disease affects 15.8 million Americans and is the nation’s number one killer. Approximately 72 million Americans (nearly one quarter of the adult population in the United States) have been diagnosed as suffering from hypertension, typically defined as a blood pressure greater than 140 millimeters of mercury ("mmHg") systolic pressure and/or greater than 90 mmHg diastolic pressure. Nearly 75% of those (37.5 million) are not properly treated for the condition and thus facing significantly increased risk for heart and kidney disease and strokes. According to the Johns Hopkins White Papers on Hypertension (2007), one in five Americans are estimated to have prehypertension, defined as a blood pressure reading 120-139 mmHg. These individuals have an increased risk of developing hypertension and they have a greater risk of cardiovascular events than people with lower blood pressure.
The Silent Killer Hypertension can easily go undetected and has been called the "silent killer" because it usually produces no symptoms until after it seriously damages the heart, kidneys, brain or some other organ. Elevated blood pressure indicates that the heart is working harder than normal, putting both the heart and the arteries under greater strain. Over time, these arteries become scarred, hardened and less elastic, accelerating the process of atherosclerosis and leaving one susceptible to heart attacks, strokes, kidney failure, and eye damage. According to the Archives of Internal Medicine (March 24, 1997), high blood pressure is of particular concern to older adults, as levels increase with age, and is present in more than half of Americans age 60 or older. The seriousness of this problem increases as the population grows older because individuals with sustained high blood pressure have an increased overall death rate from stroke, heart attack and kidney disease.
Hypertension is a deadly disease that damages both large and small arteries, leading to pathological changes in the tissues or organs supplied by the damaged arteries, and accelerating the development of atherosclerosis (the formation of plaque and the accumulation of fatty deposits lining the walls of the artery which affect blood flow) in large blood vessels, and the arteries supplying blood to the brain, heart, kidneys and legs. Atherosclerotic plaques can cause mini-strokes (transient ischemic attacks) due to diminished blood flow (ischemia) to parts of the brain; angina from partly obstructed coronary arteries; or pain in the leg muscles when walking, a result of poor blood supply to the legs (peripheral arterial disease). Blood clots, which tend to occur at the sites of atherosclerotic narrowing, can totally block a vessel and cause a stroke or heart attack.
Atherosclerosis begins in the wall of the artery with an early abnormality in the lining of the arterial wall called the endothelium. The endothelium helps to maintain the flexibility or elasticity of the artery and normally inhibits the accumulation of lipid and cellular deposits into the arterial wall of the artery.
Arterial Cross-section I: A normal elastic artery. The walls of arteries (endothelium) are composed of three concentric zones: Tunica adventitia (outer), tunica media (middle), and tunica intima (inner layer). The walls of all arteries (large and small) throughout the body are distensible: they expand and contract as blood pressure waves from the heart pass through the lumen, the passageway for blood within the arterial walls. It is this distensibility that enables the arterial system to act as an elastic reservoir that stores part of the energy of each cardiac contraction, maintaining blood pressure and flow during diastole to perfuse all bodily tissues.
Arterial Cross-section II: Early stages of atherosclerosis where changes in the arterial wall have begun to impact blood flow and reduce arterial elasticity. The middle zone of the endothelium (tunica media) thickens, and scar tissue forms within. Plaque begins to form causing the tunica intima to become rigid.
Arterial Cross-section III: Advanced stage of atherosclerosis. Arterial elasticity is reduced and plaque formation has restricted blood flow within the artery. Plaque invades the tunica media. Plaque can now cause minimal strokes (transient ischemic attacks) due to diminished blood flow (ischemia) to parts of the brain; angina from partly obstructed coronary arteries; or pain in the leg muscles when walking, a result of poor blood supply to the legs (peripheral arterial disease). Blood clots, which tend to occur at the sites of atherosclerotic narrowing, can totally block a vessel and cause a stroke or heart attack.
Abnormal function of the endothelium and the associated structural changes in the wall result in a loss of elasticity of the small arteries. Detection of this loss in elasticity can identify individuals with abnormal arterial structure and function long before plaque formation can cause morbid cardiovascular events. Furthermore, demonstration of normal arterial structure and function might suggest that the individual does not have early atherosclerosis and may not need aggressive risk factor management.
Diabetes Diabetes mellitus is a disease caused by a deficiency of insulin. Classified into two main types, Diabetes affects more than 20 million Americans. Type 1 diabetes (insulin-dependent), affects 5%-10% of those with diabetes with diagnosis or onset occurring in childhood or adolescence. Type 2 diabetes (non-insulin- dependent) is the more common type, affecting 90%-95% of those with diabetes. Type 2 diabetes onset usually occurs after age 40. Approximately one-third of all cases go undiagnosed. Diabetes currently ranks 7th among leading causes of death in the U.S. and about 2,200 new cases are diagnosed every day. Diabetes caused more than 224,000 deaths in 2002 alone. Patients face the risk of debilitating complications such as blindness, kidney disease, and lower-extremity amputations. About 73% of those with Diabetes have high blood pressure, and a person with Diabetes has two to four times the risk of heart attack and stroke.
Risk factors A number of risk factors for atherosclerosis have been identified, including elevated blood pressure, elevated cholesterol level, smoking, diabetes and a family history of atherosclerosis. Clinical events associated with atherosclerosis, including heart attacks (myocardial infarction), strokes, angina (myocardial ischemia), peripheral vascular ischemia (claudication) and renal failure are late manifestations of the disease as a result of plaque formation that impinges on blood flow. Some specific risk factors:
The absence of a clinically applicable method to detect the presence of atherosclerosis prior to plaque obstruction of the lumen (the inner space in the blood vessel through which blood passes) has led to widespread efforts to identify the risk factors in the entire population and to intervene on those who harbor such risk factors. The problem with this approach is two-fold: (a) patients without these risk factors will not be identified even though up to half of the atherosclerotic clinical events occur in individuals without any of the traditional risk factors; and (b) patients who have one or more risk factor may be subjected to therapy even though they do not have the atherosclerotic process the therapy is designed to inhibit. It is a well-known clinical finding that elastic and flexible arteries are healthy vessels, and that stiff and hardened arteries are not healthy. Learn
about vascular disease assessment
Related Articles Papers on Early Detection of Vascular Disease through Arterial Waveform Analysis
American Association of Clinical Endocrinologists American College of Cardiology American College of Phys./Am. Society of Internal Medicine
American
Diabetes Association
International
Society of Hypertension National Heart, Lung and Blood Institute
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To
learn more about HDI and cardiovascular profiling, email infoteam@hdii.com |
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