ELECTRON-BEAM COMPUTED TOMOGRAPHIC CORONARY CALCIUM AS A PREDICTOR OFCORONARY EVENTS - COMPARISON OF 2 PROTOCOLS

Background We assessed the accuracy of two electron beam computed tomo graphy (EBCT) protocols for predicting coronary events. Methods and Re sults In 1994, 24 months after enrollment in a longitudinal study, 326 high-risk adults underwent both 3- and 6-mm image-slice thickness EBC T scanning and were followed up for 32.0 +/- 4.0 additional months. Ev ents were defined as either coronary death, myocardial infarction, or revascularization. We monitored these subjects for the 3Z-month postsc anning period with yearly phone calls and acquisition of records for a ll hospital admissions. Ar the time of scanning, 11 subjects (3%) had already suffered 12 events (5 infarctions and 7 revascularizations) du ring the 24-month prescanning period. During the postscanning period, 18 subjects (6%) suffered 23 events (5 coronary deaths, 6 infarctions. and 12 revascularizations). Thus, 28 subjects (9%) suffered 35 events . Calcium quantities calculated for both protocols, performed on the s ame subjects, were sorted in ascending order and divided into equal qu artiles. When revascularizations were included, there was a significan t trend coward higher frequencies of events with increasing calcium qu antity (P<.01), However, coronary death and infarction were not signif icantly more frequent in higher quartiles, These relationships were pr esented in the subjects without prior events at the time of scanning, Conclusions Calcium quantities from the 3-mm and the more reproducible 6-mm scanning are equally accurate for predicting events. Coronary ca lcium amount appears to be a weak predictor of coronary death and infa rction. Its predictive accuracy is superior for predicting revasculari zation.