II.
LITERATURE REVIEW
A. CORONARY HEART DISEASE
Coronary heart disease is a chronic disease caused by restricted blood supply to the heart muscle which, in the most chronic level, can lead to sudden death by heart attack Frayn Stanner
2005. Disruption or lack of blood supply occurs because of the partial or total blockage of one or more heart coronary arteries. Due to this blockage, the chemical energy supply to the heart muscle
myocardial is reduced, resulted in impaired balance between energy supply and demand. Some of the clinical presence of coronary heart disease is the occurrence of angina pectoris, infark miocardia,
weak heart ischemic heart disease, and sudden death Maulana 2007. Coronary heart disease is caused by the atherosclerosis process in the coronary arteries of
the heart Frayn Stanner 2005; Maulana 2007. Atherosclerosis is the narrowing of blood vessels due to the accumulation and thickening of fat in artery walls. Illustration of atherosclerosis in the
coronary arteries of the heart can be seen in Figure 1. Layer of fatty tissue called atheroma begins to accumulate since childhood and increases the risk with age Patel 1994; Libby 2011. The plaque is
yellowish in colour, pasty substance, and composed mainly of blood, lipids, cholesterol, and triglycerides. Furthermore, Libby 2011 explained that high cholesterol levels can lead to the
formation of plaque in the younger age. The plaque or pieces is vulnerable, can break off and move to a smaller blood vessels,
resulting in blood flow blockade Kusmana 1996; Libby 2011. When the pieces are broken, injury occurs in the walls of blood vessels, resulted a lesion. As a response to the inflammatory process,
smooth muscle cells from the deeper layer of the artery are relocated to the inflammatory area, and an intermediate lesion is formed. As the inflammation progresses, macrophages and lymphocytes are
accumulated, eventually leading to necrosis or blood freezing within the lesion. As the final step, the lesion is covered by a fibrous cap, resulting in a complicated lesion. This complicated lesion can
become unstable and rupture, leading to thrombosis, thus reducing arterial blood flow Klingberg 2012.
Figure 1. Atherosclerosis progress in heart coronary artery
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