Beyond Traditional Risk Factor Analysis for Coronary Artery Dise
Beyond Traditional Risk Factor Analysis for Coronary Artery Dise
Coronary artery disease is often asymptomatic, leading to inefficient detection. Although coronary artery disease is associated with multiple risk factors, better methods for detection are needed. The quantity of coronary artery calcium as detected with electron beam computed tomography is indicative of plaque mass, and the likelihood of coronary obstruction and future coronary events is independent of other risk factors. Screening for coronary artery disease with electron beam computed tomography offers a complimentary way of detecting early atherosclerosis in asymptomatic patients.
Clinically significant coronary disease can be present in completely asymptomatic persons, and 50% of patients with newly diagnosed coronary artery disease (CAD) initially present with either an acute myocardial infarction or sudden death. One approach for identifying persons at risk for premature asymptomatic CAD is to analyze the presence of coronary risk factors associated with an increased incidence of CAD. However, the number of such risk factors is continuously increasing, and a comprehensive analysis of an individual patient is becoming increasingly complex and expensive. Furthermore, while extreme values of CAD risk factors are helpful in predicting the likelihood of a future coronary event, there is a significant overlap in baseline values between people destined to develop symptomatic CAD and those who will remain symptom-free, as demonstrated for serum concentrations of cholesterol, homocysteine, and glucose. Therefore, the presence of risk factors for CAD cannot be equated with the presence or extent of coronary plaque or for identification of most of the persons likely to benefit from lifestyle modification and medical therapy.
It is now generally accepted that the extent of disease, rather than the presence of risk factors per se, is the ultimate substrate for the overwhelming number of events, and that the absolute quantity of coronary plaque is the strongest determinant of the likelihood of coronary events. Grundy et al. have therefore suggested the incorporation of evidence of the presence and extent of subclinical atherosclerosis as modifying factors in cardiovascular disease risk assessment. However, applying this approach to the coronary vascular bed is limited by the difficulty of imaging the rapidly moving coronary arteries. This problem has led to the use of other large vessels, such as the carotid or femoral arteries, as surrogates to predict the extent of coronary atherosclerosis and the risk of future cardiac events. Unfortunately, the predisposing factors for atherosclerosis may vary among different vascular beds; for example, carotid artery disease is more closely related to blood pressure, whereas coronary disease is more closely correlated with low-density lipoprotein cholesterol concentration. Thus, the accuracy of using other vessels for predicting coronary plaque is controversial. Therefore, a method that quantifies coronary plaque burden should be useful for identifying persons at increased risk of coronary events.
Coronary artery disease is often asymptomatic, leading to inefficient detection. Although coronary artery disease is associated with multiple risk factors, better methods for detection are needed. The quantity of coronary artery calcium as detected with electron beam computed tomography is indicative of plaque mass, and the likelihood of coronary obstruction and future coronary events is independent of other risk factors. Screening for coronary artery disease with electron beam computed tomography offers a complimentary way of detecting early atherosclerosis in asymptomatic patients.
Clinically significant coronary disease can be present in completely asymptomatic persons, and 50% of patients with newly diagnosed coronary artery disease (CAD) initially present with either an acute myocardial infarction or sudden death. One approach for identifying persons at risk for premature asymptomatic CAD is to analyze the presence of coronary risk factors associated with an increased incidence of CAD. However, the number of such risk factors is continuously increasing, and a comprehensive analysis of an individual patient is becoming increasingly complex and expensive. Furthermore, while extreme values of CAD risk factors are helpful in predicting the likelihood of a future coronary event, there is a significant overlap in baseline values between people destined to develop symptomatic CAD and those who will remain symptom-free, as demonstrated for serum concentrations of cholesterol, homocysteine, and glucose. Therefore, the presence of risk factors for CAD cannot be equated with the presence or extent of coronary plaque or for identification of most of the persons likely to benefit from lifestyle modification and medical therapy.
It is now generally accepted that the extent of disease, rather than the presence of risk factors per se, is the ultimate substrate for the overwhelming number of events, and that the absolute quantity of coronary plaque is the strongest determinant of the likelihood of coronary events. Grundy et al. have therefore suggested the incorporation of evidence of the presence and extent of subclinical atherosclerosis as modifying factors in cardiovascular disease risk assessment. However, applying this approach to the coronary vascular bed is limited by the difficulty of imaging the rapidly moving coronary arteries. This problem has led to the use of other large vessels, such as the carotid or femoral arteries, as surrogates to predict the extent of coronary atherosclerosis and the risk of future cardiac events. Unfortunately, the predisposing factors for atherosclerosis may vary among different vascular beds; for example, carotid artery disease is more closely related to blood pressure, whereas coronary disease is more closely correlated with low-density lipoprotein cholesterol concentration. Thus, the accuracy of using other vessels for predicting coronary plaque is controversial. Therefore, a method that quantifies coronary plaque burden should be useful for identifying persons at increased risk of coronary events.
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