Racial differences in coronary calcium prevalence among high-risk adults.

A total of 1,461 asymptomatic high-risk adult subjects were studied with digital subtraction fluoroscopy and conventional cinefluoroscopy to detect coronary calcium. Ethnicity and risk factor data were recorded. No subject had a history or electrocardiographic evidence of prior myocardial infarction. The prevalence of coronary calcium by digital subtraction fluoroscopy was high (58%). Substantial ethnic differences in prevalence were noted: 36% of African American subjects, 60% of Caucasian subjects, and 60% of Asian American subjects had definite radiographic evidence of coronary calcium. The difference in prevalence between African American and other subjects was significant (p < 0.0001) by chi-square test for all 3 races. These differences persisted in the unsubtracted cinefluoroscopic images (p < 0.0001) and after controlling for age, gender, and other risk factors (p = 0.003). After 20 +/- 11 months of follow-up, African Americans had more coronary artery disease events (13%) than Caucasians (6%) or Asian Americans (5%) (p = 0.04). Thus, African Americans have a significantly lower prevalence of coronary calcium than do Caucasians or Asian Americans. Based on the follow-up results, these differences in prevalence are not explained by differences in coronary artery disease risk.

Prognostic significance of cardiac cinefluoroscopy for coronary calcific deposits in asymptomatic high risk subjects.

OBJECTIVES: This research investigated the prognostic significance of radiographically detectable coronary calcific deposits. BACKGROUND: Coronary calcific deposits are almost always associated with coronary atherosclerosis. We investigated the association between fluoroscopically determined coronary calcium and coronary heart disease end points at 1 year of follow-up. METHODS: This prospective population-based cohort study was conducted in the suburbs of Los Angeles. Fourteen hundred sixty-one asymptomatic adults with an estimated > or = 10% risk of having a coronary heart disease event within 8 years underwent cardiac cinefluoroscopy for assessment of coronary calcium at initiation of the study. Clinical status including angina, documented myocardial infarction, myocardial revascularization and death from coronary heart disease were determined after 1 year. RESULTS: The prevalence of calcific deposits was high (47%). A follow-up examination at 1 year was successfully completed in 99.9% of subjects. Six subjects (0.4%) had died from coronary heart disease and 9 (0.6%) had had a nonfatal myocardial infarction. Thirty-seven subjects (2.5%) reported angina pectoris, and 13 (0.9%) had undergone myocardial revascularization. Fifty-three subjects had at least one event during the 1-year period. Radiographically detectable calcium was associated with the presence of at least one of these end points, with a risk ratio of 2.7 (confidence limits 1.4, 4.6). The presence of coronary calcium was an independent predictor of at least one end point when controlling for age, gender and risk factors. However, three deaths due to coronary heart disease and two nonfatal myocardial infarctions occurred in subjects without detectable coronary calcium. CONCLUSIONS: The presence of coronary calcific deposits incurs an increased risk of coronary heart disease events in asymptomatic high risk subjects at 1 year. This increased risk is independent of that incurred by standard risk factors.

Prevalence of fluoroscopic coronary calcific deposits in high-risk asymptomatic persons.

Coronary calcific deposits are always associated with coronary atherosclerosis. Sensitive radiographic technology can detect coronary calcium before atherosclerosis becomes symptomatic. A total of 1461 asymptomatic high-risk adult subjects were studied with digital subtraction fluoroscopy to detect coronary calcium. Risk factor data were recorded including age, sex, family history, smoking history, diabetes history, body mass index, systolic blood pressure, left ventricular hypertrophy on ECG, total serum cholesterol level, high-density lipoprotein (HDL) cholesterol, and total cholesterol/HDL ratio. Digital subtraction fluoroscopy in the left anterior oblique projection was performed in all subjects. The prevalence of calcific deposits in at least one major coronary artery was high (58.3%). Eleven percent had coronary calcium in all three major arteries. Multivariate logistic regression analysis showed significant correlations (p < 0.05) between the prevalence of coronary calcium and age, smoking history (relative risk = 1.30), diabetes history (relative risk = 1.24), and family history (relative risk = 1.26). In older subjects (at least 65 years of age), smoking and serum lipoproteins assumed greater importance as contributors to coronary calcium, whereas in younger subjects a history of diabetes was more significant. Coronary calcific deposits are prevalent in high-risk asymptomatic subjects. Their occurrence is closely related to most known risk factors.

Diagnostic accuracy of predicting coronary artery disease related to patients' characteristics.

Patients' demographic and clinical characteristics may affect diagnostic accuracy of cardiologists. We asked a group of experienced cardiologists from three institutions to estimate the pretest probability of coronary artery disease in 257 patients referred for diagnostic coronary angiography and with no history of previous myocardial infarction nor valvular heart disease. Physicians pretest estimates were compared with the diagnostic findings of coronary angiography. We tested the influence of five variables on the accuracy of the pretest estimates: age, sex, chest pain characteristics, rest electrocardiogram and electrocardiographic exercise test result. Cardiologists tended to overestimate the presence of coronary artery disease and this tendency was particularly remarkable in the group of patients showing a negative exercise test. Pretest diagnostic accuracy was 0.72 when the test result was negative and 0.85 when the test result was positive (95% confidence interval of the difference 0.03 to 0.23; p < 0.001). The diagnosis of coronary artery disease was also more accurate for male than for female patients (0.81 vs 0.70; 95% confidence interval of the difference 0.02 to 0.21; p < 0.02). Characteristics of chest pain, age and rest electrocardiogram did not affect the level of pretest diagnostic accuracy. Cardiologists should be cognizant of correctly interpreting a negative exercise test and the clinical data of female patients; in both cases, they should move circumspect of the diagnosis of coronary artery disease.

Clinical assessment of the probability of coronary artery disease: judgmental bias from personal knowledge.

Probability estimates of angiographic coronary artery disease made by experienced, board-certified staff cardiologists were compared with those of cardiologists in training (fellows). In addition, estimates made before coronary angiography were compared with those made several months later based on written clinical summaries of 15 items of objective clinical and test data. Cardiologists were asked to estimate the probabilities of coronary artery disease, multivessel disease, and triple-vessel or left main disease. The study population consisted of 510 consecutive patients without valvular disease referred for the first time for coronary angiography to three hospitals. Both staff and fellows consistently overestimated the pre-angiographic probability of coronary artery disease. The probabilities estimated from patient summaries were always significantly lower than the pre-angiographic assessments. Only staff cardiologists reliably assessed the probabilities of coronary artery disease during the second assessment (p less than 0.05). Thus, estimates of disease probability based on clinical judgment vary according to the source of information, and these estimates are more accurate when physicians have objective data on hand and do not know the identities of the patients.