Background-There is a clear relationship between absolute calcium scores (CS) and severity of coronary artery disease.However, hard coronary events have been shown to occur across all ranges of CS. Methods and Results-We conducted 2 analyses: in group A, 172 patients underwent electron-beam CT (EBCT) imaging within 60 days of suffering an unheralded myocardial infarction. In group B, 632 patients screened by EBCT were followed up for a mean of 32Ϯ7 months for the development of acute myocardial infarction or cardiac death. The mean patient age and prevalence of coronary calcification were similar in the 2 groups (53Ϯ8 versus 52Ϯ9 years and 96% each). In group B, the annualized event rate was 0.11% for subjects with CS of 0, 2.1% for CS 1 to 99, 4.1% for CS 100 to 400, and 4.8% for CS Ͼ400, and only 7% of the patients had CS Ͼ400. However, mild, moderate, and extensive absolute CSs were distributed similarly between patients with events in both groups (34%, 35%, and 27%, respectively, in group A and 44%, 30%, and 22% in group B). In contrast, the majority of events in both groups occurred in patients with CS Ͼ75th percentile (70% in each group). Conclusions-Coronary calcium is present in most patients who suffer acute coronary events. Although the event rate is greater for patients with high absolute CSs, few patients have this degree of calcification on a screening EBCT. Conversely, the majority of events occur in individuals with high CS percentiles. Hence, CS percentiles constitute a more effective screening method to stratify individuals at risk. (Circulation. 2000;101:850-855.)
This phase 3 trial shows that regadenoson provides diagnostic information comparable to a standard adenosine infusion. There were no serious drug-related side effects, and regadenoson was better tolerated than adenosine.
Background-Detection of subclinical coronary artery disease (CAD) before the development of life-threatening cardiac complications has great potential clinical relevance. Electron beam computed tomography (EBCT) is currently the only noninvasive test that can detect CAD in all stages of its development and thus has the potential to be an excellent screening technique for identifying asymptomatic subjects with underlying myocardial ischemia. Methods and Results-Over 2.5 years, we prospectively studied 3895 generally asymptomatic subjects with EBCT, 411 of whom had stress myocardial perfusion tomography (SPECT) within a close (median, 17 days) time period. SPECT and exercise treadmill results were compared with the coronary artery calcium score (CACS) as assessed by EBCT. The total CACS identified a population at high risk for having myocardial ischemia by SPECT although only a minority of subjects (22%) with an abnormal EBCT had an abnormal SPECT. No subject with CACS Ͻ10 had an abnormal SPECT compared with 2.6% of those with scores from 11 to 100, 11.3% of those with scores from 101 to 399, and 46% of those with scores Ն400 (PϽ0.0001). CACS predicted an abnormal SPECT regardless of subject age or sex.
Conclusions-CACS
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