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Coronary atherosclerosis is an inflammatory disease characterized by the accumulation of white blood cells, cell debris, fatty substances (cholesterol and fatty acids), calcium, and fibrous tissue (plaque or atheromas) on the walls of the coronary arteries that supply the heart muscle. As plaque slowly increase in size over many years, the artery narrows in places (stenosis), and blood flow to the heart is reduced. Cholesterol-containing plaques are highly dangerous even without narrowing of the vessel because the fibrous cap can be softened and rupture suddenly during acute heavy exercise or activity (e.g., extreme athletic effort, shoveling snow). This can cause bleeding from the blood vessel wall, resulting in blood clot formation that may obstruct the vessel. The stenosis may become so significant that the blood supply is inadequate to meet the needs of the heart (myocardial ischemia), and the affected part of the heart muscle no longer functions normally. Myocardial ischemia typically results in chest pain (angina pectoris), but may also cause no symptoms (silent ischemia). Total blockage of a coronary artery results in a heart attack (myocardial infarction).
Risk: Risk factors for coronary atherosclerosis include male gender, advanced age, family history of atherosclerosis particularly before age 50, high blood pressure (hypertension), diabetes mellitus, a high level of total cholesterol and/or a high level of low-density lipoprotein (LDL) cholesterol and a low level of high-density lipoprotein (HDL) cholesterol (dyslipidemia). Other risk factors include high levels of certain fats (triglycerides) in the blood especially among women, smoking and exposure to second-hand smoke, obesity and poor physical fitness. Emotional stresses including hostility, anger, depression, and anxiety are thought to predispose individuals to developing coronary artery disease. The term “metabolic syndrome,” encompasses many risk factors for coronary atherosclerosis, including obesity, hypertension, insulin resistance, and dyslipidemia.
Among individuals younger than 65 years who do not smoke, coronary atherosclerosis is primarily a disease of men. This difference in early risk is attributed to the protective effects of estrogen for women before menopause (Pearlman). Increased age becomes a risk factor for both sexes later in life. Men older than 45 years and women older than 55 years are at increased risk for developing coronary atherosclerosis (“Coronary Artery Disease”).
Research continues into additional risk factors that may contribute to the development of coronary atherosclerosis. Untreated sleep apnea (the abrupt starting and stopping of breathing during sleep) is believed to increase risk of hypertension and diabetes and is often the origin of a stroke. Inflammatory disease processes, such as the development of rheumatoid arthritis, may predispose individuals to developing coronary artery disease. Tests for elevated levels of C-reactive protein (CRP) in the blood, indicative of inflammation developing somewhere in the body, may help identify individuals at increased risk as may tests for elevated levels of the amino acid homocysteine.
In contrast to high LDL cholesterol ("bad" cholesterol), high levels of high-density lipoprotein (HDL) cholesterol ("good" cholesterol) decrease the risk for developing coronary atherosclerosis. Incidence and Prevalence: Coronary atherosclerosis is the most common form of heart disease and the leading cause of death for both men and women in the US (“Coronary Artery Disease”). It accounts for 650,000 deaths and is a factor in 1.25 million myocardial infarctions in the US each year (Pearlman). |
Source: Medical Disability Advisor
| History: Symptoms are not always apparent in the early stages of coronary atherosclerosis. In later stages, symptoms typically include exertional chest pain and pressure (angina) occasionally with radiation of pain to the neck or jaw that is relieved by rest. Individuals may have a history of heart attack (myocardial infarction). Individuals experiencing heart failure may report shortness of breath (dyspnea). Physical exam: The exam is usually not directly helpful in this diagnosis, although it may reveal risk factors, such as hypertension, obesity, or metabolic syndrome. Tests: Blood cholesterol testing evaluates total cholesterol, HDL cholesterol, and LDL cholesterol, with high total cholesterol and LDL cholesterol readings suggesting coronary artery disease may be present. Other blood tests measure triglycerides, relevant blood sugar, and protein levels. A plain chest x-ray may reveal signs of heart failure, as well as any related abnormalities in the lungs or nearby blood vessels. An electrocardiogram (ECG) at rest looks for electrical abnormalities of the heart. An ECG during physical exertion (exercise stress test) can detect heart abnormalities induced by lack of blood flow, and subsequent lack of oxygen, to the heart muscle. If an individual cannot exercise to the degree needed for the stress test, a drug can be given to simulate the effect of exercise on the heart (physiologic stress test).
Nuclear scanning during a stress test (radionuclide stress test) involves injecting a radioactive isotope into a vein before imaging. During the test, the examiner can watch the flow of blood through the heart and can identify areas in which blood flow is decreased. Ultrasound (echocardiography), positron emission tomography (PET), and cardiac MRI also may be used during a stress test to observe heart rhythm, rate, and function during exertion and at rest.
The most definitive test related to coronary atherosclerosis is the coronary angiogram. During x-ray angiography, a thin catheter is inserted into a vein in the arm, groin, or neck and guided into the opening of the coronary arteries. Once it is in place, radiopaque contrast dye is injected through the catheter into the coronary arteries. An x-ray visually captures the movement of the dye through the heart. Through this procedure, the exact location and degree of blockage can be identified.
Techniques to improve diagnosis and early detection of coronary atherosclerosis continue to be developed. Among the newest is electron-beam computed tomography (EBCT), which detects and measures calcium deposits in and around the coronary arteries. Calcification of blood vessels is considered a risk factor for development of coronary atherosclerosis.
Although x-ray angiography remains the gold standard for imaging existing coronary atherosclerosis and blockages, advances in MRI and CT technology, such as 64-slice multidetector-row CT angiography (CTA), and multidetector row CT (MDCT), show promise and may in some cases provide alternatives to x-ray angiography (Pearlman). X-ray angiography, however, offers the advantage of allowing diagnosis and treatment in the same session. |
Source: Medical Disability Advisor
| Risk factors should be addressed to help prevent progression of coronary artery disease and, to some extent, reverse it. Many risk factors are potentially modifiable. Cessation of smoking is essential, as is avoiding second-hand smoke. Hypertension can be managed through diet (salt restriction), exercise, stress management, and medication. Diabetes also can be managed by diet, exercise, and medication, if necessary. Diet and exercise are also helpful in modifying cholesterol levels. If this approach is not adequate, cholesterol-lowering drugs can be added to treatment regimens. Drugs, specifically statins, have proven effective in both primary and secondary prevention of coronary atherosclerosis and offer other beneficial effects in reducing cardiovascular disease. The Jupiter Study, whose results were released in November 2008, showed a primary prevention effect of cholesterol-lowering therapy in healthy individuals, although questions remained about long-term use of these drugs in healthy individuals. In some cases, statins may be used in conjunction with a selective cholesterol absorption inhibitor (e.g., ezetimibe). A small daily dose of an anti-platelet drug (e.g., clopidogrel, abciximab, aspirin) may be prescribed to help inhibit blood clotting.
Severe coronary atherosclerosis may require a procedure to remove areas of stenosis. Coronary angioplasty uses a catheter inserted into the coronary arteries to the site of blockage. On the end of the catheter is a deflated balloon. Once the catheter is in place, the balloon is inflated to widen the artery. In some cases, a small mesh tube (stent) is placed within the widened artery to help keep it open after the procedure. Some stents are coated with medications that are slowly and continuously released into the bloodstream to help keep the artery from becoming blocked again, although the benefit of drug-eluting stents is controversial. If this approach is not successful, coronary artery bypass surgery may be needed. The blocked portion of coronary artery is removed and replaced with a healthy portion of blood vessel from the leg, chest, or arm. |
Source: Medical Disability Advisor
| Once coronary atherosclerosis develops, it must be managed for life. The risk of subsequent cardiac events or disruption of the general circulation depends on control of the disease through lifestyle changes and medication. These changes can prevent disease progression by reducing future deposits of cholesterol and plaque in the coronary arteries. Statins, which are sometimes prescribed with a selective cholesterol absorption inhibitor, can dramatically reduce plaque already present, raise levels of HDL cholesterol, and possibly reduce the inflammatory process believed to be responsible for the development and progression of coronary atherosclerosis. Medication has the additional effect of softening plaque deposits, making them less likely to break away from the artery wall and block blood vessels within the heart.
Surgical procedures, such as coronary angioplasty and bypass surgery, successfully remove cholesterol deposits or diseased portions of blood vessels, but the risk of blockage by future plaque deposits remains. |
Source: Medical Disability Advisor
| Rehabilitation for coronary atherosclerosis is similar to that of other cardiac conditions for which surgery is performed. In either case, the exercise program follows three basic progressive phases.
Phase 1 often begins in the hospital with low-intensity exercise to prevent some of the negative effects of bed rest, especially muscle weakness and joint stiffness. Mild exercise also can help reduce episodes of dizziness due to low blood pressure when assuming an upright position (orthostatic hypotension) and maintain overall mobility. Exercise may begin in the coronary care unit of a hospital. Individuals perform low-intensity exercises while lying on their backs (supine position). Individuals progress to exercises while sitting and, eventually, while standing. Progressive walking and, eventually, stair climbing are important components of the exercise program. Intensity is gradually increased until the individual is discharged from the hospital.
Phase 2 usually begins after the individual is discharged from the hospital. Individuals who have not been hospitalized usually begin rehabilitation at this phase. Goals are to improve functional capacity by increasing physical endurance and promoting return to activity. This is done in an outpatient setting, such as a cardiac rehabilitation center. Electrocardiographic electrodes attached to the individual are used to record the continuous electrical activity of the heart muscle.
Phase 3 continues in an outpatient setting, such as a rehabilitation center, and begins 3 to 6 months from the start of rehabilitation. Depending on the individual's condition, this phase may last for several months. Individuals may stay involved with an outpatient program for up to a year while on modified work duty. Eventually, individuals perform higher intensity exercise and add recreational activities such as swimming and hiking. Light jogging at about 5 mph and cycling at about 12 mph is appropriate as long as the individual tolerates it. Because of the varying severity of coronary atherosclerosis, modifications may be made for individuals who have had a heart attack and/or undergone surgery. |
Source: Medical Disability Advisor
| Angina, the chest pain associated with worsening coronary atherosclerosis, may remain stable for long periods. With progression of the disease, anginal episodes may increase in severity and duration, become less responsive to medication, and be precipitated by less exertion. A worsening or less predictable pattern of angina is referred to as unstable angina.
A heart attack (myocardial infarction) can result if the obstruction in a coronary artery becomes complete. Coronary artery obstruction may be triggered by blood clotting (thrombosis) in a narrowed artery or a clot (embolism) that separates from the artery wall and blocks a smaller artery. A heart attack may cause death (necrosis) of part of the heart muscle due to lack of oxygen.
Individuals who survive massive or repeated heart attacks may be left with so little functioning heart muscle that the heart can no longer pump effectively (congestive heart failure). Ischemic or damaged heart muscle may also result in disturbances of heart rhythm (arrhythmias), such as atrial fibrillation or ventricular fibrillation. Atherosclerosis also may occur in other arteries throughout the body and cause impaired circulation.
Prompted by worry over lifestyle changes and potential heart problems, individuals diagnosed with coronary atherosclerosis may experience depression and anxiety in the aftermath of their diagnosis. |
Source: Medical Disability Advisor
| In the early stages of coronary atherosclerosis, work typically is not restricted. Although exercise is a recommended activity, it can be carried out after work hours. During periods of intense cardiac rehabilitation, time off may be required for visits to the physical therapist or participation in a rehabilitation program. Regularly scheduled doctor appointments to track blood pressure, cholesterol levels, blood sugar, and body weight are important to decrease the likelihood of coronary disease recurrence or progression. Addressing chronic emotional stress, including anxiety and depression, is important but may be more readily done in some work settings than others. Stress reduction techniques, including exercise and counseling, are an important part of overall cardiac rehabilitation, but some techniques may require the participation or supervision of a counselor or physician.
If the condition progresses and the arteries become increasingly obstructed, physical capacity is likely to decrease due to decreased coronary blood flow and poor oxygenation of the heart. At this point, work restrictions are made on the basis of stress test results and response to treatment. Individuals with strenuous physical job requirements may need a more sedentary job assignment. If angioplasty or bypass surgery is required, accommodations will be needed during the recovery period. |
Source: Medical Disability Advisor
| If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case. Regarding diagnosis:
- Does individual have other risk factors, such as advanced age, family history of atherosclerosis (particularly before age 50), hypertension, diabetes, high blood cholesterol, smoking, exposure to second-hand smoke, obesity, poor physical fitness, elevated homocysteine levels, or prolonged emotional stress?
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Does individual have angina or history of myocardial infarction?
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Has individual had complete blood lipid testing, ECG both at rest and during exercise?
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Was radionuclide stress test done? Stress echocardiography? Coronary angiogram?
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Were conditions with similar symptoms ruled out?
Regarding treatment:
- Did individual undergo coronary angioplasty?
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Did individual undergo coronary bypass surgery?
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Is individual taking cholesterol-lowering drugs?
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Is individual addressing unhealthy behaviors that increase risk of heart disease or heart attack?
Regarding prognosis:
- Is individual active in rehabilitation?
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Can individual's employer accommodate any necessary restrictions?
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Does individual have conditions that may affect ability to recover?
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Have any complications, such as unstable angina, myocardial infarction, congestive heart failure, and arrhythmias developed?
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Is individual depressed or anxious over diagnosis of coronary atherosclerosis?
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Does individual have atherosclerosis in other arteries throughout the body? Has circulation become impaired elsewhere?
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Source: Medical Disability Advisor
| "http://www.nhlbi.nih.gov/health/dci/Diseases/Cad/CAD_WhatIs.html." National Heart, Lung, and Blood Institute. Department of Health and Human Services. 27 Feb. 2009 <Coronary Artery Disease>.Pearlman, Justin D. "Coronary Artery Disease." eMedicine. Eds. Bernard D. Coombs, et al. 4 Apr. 2007. Medscape. 27 Feb. 2009 <http://emedicine.medscape.com/article/349040-overview>. Warber, S. L., and S. M. Zick. "Coronary Artery Disease." Integrative Medicine. 1st ed. Philadelphia: W.B. Saunders, 2003. 173-184. |
Source: Medical Disability Advisor
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