Coronary artery disease: causes, symptoms, and complications

Coronary artery disease and coronary heart disease are interchangeable terms used to describe the "narrowing of the small blood vessels that supply blood and oxygen to the heart," (Chen 2011). The Journal of the American Medical Association uses the collective term acute coronary syndromes (ACS) to refer to coronary heart disease and related conditions caused by insufficient blood flow to the heart muscle (Torpy 2010). Also called acute myocardial ischemia, insufficient blood flow to the heart muscle is commonly caused by the narrowing of the blood vessels. The insufficient blood flow to the heart is usually caused by atherosclerosis: an accumulation of plaque made of hardened fat, cholesterol, calcium, and "other substances found in the blood," (National Institutes of Health 2009).

In addition to reducing blood flow to the heart, atherosclerosis "makes it more likely that blood clots will form in your arteries," which can even block blood flow entirely (National Institutes of Health 2009). Coronary artery disease is the most common type of heart disease and is the leading cause of death among both men and women in the United States as well as Great Britain ("Coronary Artery Disease" 2011; Hodgekiss 2011). According to Singh (2011), "coronary heart disease claims more lives in the United States than the next 7 leading causes of death combined." Between thirteen and fourteen million Americans have or are at risk for developing coronary heart disease (Byrg 2009; Singh 2011).

Symptoms

The primary symptoms of coronary artery disease include angina pectoris, or chest pain. Angina is sometimes felt as a pressure or squeezing sensation in the chest area, which can be "fleeting or sharp," (Mayo Clinic Staff 2010). Byrg (2009) notes that angina may be experienced as "discomfort, heaviness, pressure, aching, burning, numbness, fullness, squeezing or painful feeling." The pain but can also be felt in other body areas besides the chest including shoulders, neck, jaw, abdomen or back (National Institutes of Health 2009). Angina is sometimes mistaken for heartburn or indigestion (Byrg 2009). According to the Mayo Clinic Staff (2010), angina may be "triggered by physical or emotional stress," and symptoms will commonly disappear soon after the stressful situation passes.

Shortness of breath is another common symptom of coronary artery disease. Symptoms may manifest during physical exertion. Sometimes sweating may be a symptom accompanying coronary artery disease. Myocardial infarction, commonly known as heart attack, is one of the most severe symptoms of coronary artery disease, and often a sign that blood flow to the heart has been entirely cut off due to coronary artery disease.

The symptoms of a heart attack vary from person to person but may include "crushing pressure in your chest and pain in your shoulder or arm, sometimes with shortness of breath and sweating," (Mayo Clinic Staff 2010). Some women experience atypical symptoms of heart attacks including "nausea and back or jaw pain" or even no physical symptoms at all (Mayo Clinic Staff 2010). Coronary artery disease can also lead to arrhythmias (irregular heart beat), palpitations, skipped heartbeats, elevated heartbeat, a fatal rhythm disturbance, or cardiac arrest. According to Singh (2011), "symptoms usually occur during exercise or activity because the heart muscle's increased demand for nutrients and oxygen is not being met by the blocked coronary blood vessel."

Coronary artery disease can develop "over decades" and "can go virtually unnoticed until it produces a heart attack," (Mayo Clinic Staff 2010). People with diabetes are especially at risk for developing what is known as silent ischemia, or symptomless coronary artery disease (Byrg 2009). Arteries may be blocked 50% or more without the patient experiencing any symptoms of coronary artery disease (Singh 2011). Because of the potential lack of noticeable symptoms, it is crucial to understand risk factors that may lead to coronary artery disease. In almost all cases, coronary artery disease can be prevented and/or treated.

Risk and Causal Factors

Some of the risk factors for developing coronary artery disease are controllable and others are not. Among the most common uncontrollable risk factors, heredity, age, and gender are the most important. Heredity plays some role in coronary artery disease, as "children of parents with heart disease are more likely to develop it themselves," (American Heart Association 2011). "You are more likely to develop the condition if someone in your family has a history of heart disease -- especially if they had it before age 50," (Chen 2010).

In addition to family background, race and ethnicity are also potential risk factors. Higher rates of obesity and diabetes among non-white groups including African-Americans, Latinos, Native Americans, native Hawaiians, and some Asian-Americans are linked to higher instances of coronary artery disease among these populations (American Heart Association 2011). However, the increased risk for may be due less to ethnicity than to lifestyle habits related to socio-economic conditions. For example, the connection between race and heart disease may also be due to socio-economic factors that lead to poor diet. One genetic factor that may be related to coronary artery disease is creased earlobes: "more than 80 per cent of people under the age of 40 who had succumbed to coronary artery disease had earlobe creases," (Hodgekiss 2011).

Age is a risk factor in coronary artery disease, too. The older a patient gets, the more likely he or she is to die from coronary artery disease. According to the American Heart Association (2011), "over 83% of people who die of coronary heart disease are 65 or older." Gender is also correlated with coronary heart disease prevalence, with men significantly more likely than women to develop the condition at all age levels (American Heart Association 2011).

Other possible risk factors are relatively rare. They include "higher-than-normal levels of inflammation-related substances, such as C-reactive protein and fibrinogen," as well as "increased levels of a chemical called homocysteine, an amino acid," (Chen 2010). Hodgekiss (2011) notes, "lower levels of testosterone are clearly linked to an increased risk of heart disease." Having several older siblings actually increases one's risk for developing coronary artery disease because of elevated testosterone levels in the womb (Hodgekiss 2011).

Many of the risk factors for developing coronary artery disease are controllable. These include proximate and distant causes. Among the distant causes, the most common preventable risk factors for developing coronary artery disease include "high blood pressure, high cholesterol, diabetes or obesity," (Mayo Clinic Staff 2010). Thus, there is a high rate of comorbidity with coronary artery disease and obesity, diabetes, high blood pressure, and high cholesterol. Another condition associated with coronary artery disease is called metabolic syndrome: described as a combination of "high triglyceride levels, high blood pressure, excess body fat around the waist, and increased insulin levels," (Chen 2010). Chronic kidney disease may also be a risk factor for coronary artery disease (Chen 2010). Stroke and other aneurysms may also increase risk for coronary heart disease (Chen 2010).

Persons diagnosed with high cholesterol, diabetes, high blood pressure, and other conditions that place them at risk for developing an acute coronary syndrome or coronary artery disease should take precautions. More than one of these conditions enhances the risk that a patient will develop a coronary artery condition. Likewise, any one of these conditions combined with other risk factors such as lifestyle, age, or gender, complicates coronary artery disease significantly.

Proximate causes for coronary artery disease include lifestyle factors such as lack of exercise, smoking, chewing tobacco, excessive drinking of alcohol, or the exposure to radiation (Mayo Clinic Staff 2010). Poor diet, especially one that is high in fat, can also be a proximate cause of coronary artery disease (Singh 2011; Torpy 2010). Being a "Type A personality" characterized by "impatient, aggressive, competitive" behaviors, or experiencing consistently high levels of emotional stress are also risk factors in coronary artery disease (Singh 2011). Going to bed late is associated with coronary heart disease, although that may be due to the fact that persons more likely to stay up late are staying up late smoking and drinking (Hodgekiss 2011). Dehydration, sexually transmitted diseases, loneliness, and even adultery are tentatively associated with the development of coronary heart disease (Hodgekiss 2011).

Conclusions

Coronary artery disease is a major killer worldwide. The disease is, however, largely preventable. Although genetic factors may predispose some persons towards having coronary artery disease, lifestyle factors play a strong role in the development of heart problems. Persons with high cholesterol, diabetes, and other preexisting conditions may also be at risk for developing coronary heart disease. Therefore, all patients should be checked regularly for coronary heart disease. Likewise, all persons should take lifestyle precautions that reduce risk and promote heart health.