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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Coronary heart disease is caused by interaction or reinforcement of multiple risk factors Kusmana 1996. Risk factors are characteristics associated with the occurrence of a particular
disease or a condition that can cause a disease Kusmana Hanafi 1996; Frayn Stanner 2005. This term includes lifestyle risk factors that can be modified such as lifestyle and diet, biochemical
and physiological characteristics, and individual characteristics that cannot be modified such as age, gender, and family history of the disease Frayn Stanner 2005.
There are several factors for coronary heart disease consists of unmodifiable and modifiable factors. National Cholesterol Education Program 2002 divides the factors the unmodifiable factors
into increasing age, gender men are more at risk, and a family history of heart disease. Meanwhile, the other type of risk factor consists of high low density lipoprotein LDL cholesterol, low high
density lipoprotein HDL cholesterol, hypertension, diabetes, obesity, physical inactivity, smoking, atherogenic diet high intake of saturated fat and low intake of vegetables, fruits, and whole cereals.
Thom et al. 2006 in DeBruyne, Pinna, Whitney 2008 showed that about 90 of patients with CHD have at least one of four classical risk factors; smoking, high LDL cholesterol, high blood
pressure, and diabetes. Meanwhile, Mann and Truswell 2002 added that psychosocial factors include lower socioeconomic classes, stressful situations, and unhealthy behaviors as well as
geographical factors include climate and cold air also increases the risk of coronary heart disease. The modifiable factors of coronary heart disease are highly related to diet and lifestyle.
Mann and Truswell 2002 stated that vegetarians have lower risk of CHD than meat eaters, although further research still required. High salt intake can also increase the risk of high blood pressure
affecting the higher risk of coronary heart disease DeBruyne, Pinna, Whitney 2008. Obesity, overweight condition characterized by body mass index over 30, is the biggest risk factor resulting
from perennially improper diet. Some risk factors for coronary heart disease is shown in Table 1. Table 1. Risk factors for coronary heart disease
Clinical Measures
Modifiable by Dietary Factors
Direct of Association Relevance to
Coronary Heart Disease
Age No
Increases with age Increased prevalence as population ages
Gender No
Males at higher risk Risk in men and women is equalized after the
menopause, possibly due to protection by estrogens in younger women
Socioeconomic status
No Lower socioeconomic
status increases risk Highly related to other factors e.g. diet,
smoking, physical inactivity Smoking
No Smoking increases risk
Increases oxidative stress and impairs endothelial function
Total blood cholesterol
Yes Higher level increases risk Uptake of cholesterol by macrophages is the
origin of the core of the atherosclerotic plaque LDL
cholesterol Yes
Higher level increases risk
LDL particles carry cholesterol that may be deposited in arterial wall
HDL cholesterol
Yes Lower level increases
risk HDL may transport excess cholesterol to liver
for excretion Triglycerides
level Yes
Higher level increases risk Inversely related to HDL cholesterol Body Mass
Index Yes
Overweight and obesity increase risk
Increases risk partly via other factors e.g. blood pressure, smoking, diabetes
Blood pressure Yes
Higher pressure increases risk
Hypertension induces endothelial dysfunction and exacerbates atherosclerotic process
Source: Frayn and Stanner 2005
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