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High coronary artery calcium scores pose an extremely elevated risk for hard events
Roberto Wayhs1, Allan Zelinger, Paolo Raggi
1Christ Hospital and University of Illinois, Oak Lawn, Illinois, USA.
Insights
Asymptomatic individuals with high coronary calcium scores (CS) over 1,000 on screening electron beam tomography (EBT) face a significantly elevated short-term risk of hard coronary events (HCEs). This risk surpasses that of severe perfusion abnormalities on myocardial perfusion imaging (MPI).
Area of Science:
- Cardiology
- Radiology
- Preventive Medicine
Background:
- Coronary calcium scoring via electron beam tomography (EBT) correlates with atherosclerotic plaque burden.
- Prognostic significance of coronary calcium remains debated, with some suggesting plaque stabilization.
Purpose of the Study:
- To evaluate the natural history of asymptomatic individuals with very high coronary calcium scores (CS ≥ 1,000) detected by screening EBT.
- To compare the outcomes of this cohort with historical controls exhibiting severe myocardial perfusion imaging (MPI) abnormalities.
Main Methods:
- Prospective follow-up of 98 asymptomatic subjects with initial CS ≥ 1,000 for an average of 17 months.
- Assessment for hard coronary events (HCEs), defined as myocardial infarction or coronary death.
- No further testing was performed after the initial EBT scan.
Main Results:
- 36% of subjects experienced an HCE during follow-up, all within the first 28 months.
- Higher initial CS was observed in subjects who suffered HCEs (1,561 ± 270 vs. 1,199 ± 200, p < 0.001).
- The annualized HCE rate for CS ≥ 1,000 (25%) was significantly higher than for severe MPI abnormalities (7.4%, p < 0.0001).
Conclusions:
- A high CS (≥ 1,000) on screening EBT in asymptomatic individuals indicates a very high short-term risk of HCE.
- This risk is notably greater than that associated with severe perfusion abnormalities on MPI.
Objectives:
We sought to assess the natural history of a cohort of asymptomatic individuals with very high (> or = 1,000) calcium scores (CSs) on a screening electron beam tomography (EBT) not submitted to further testing after the initial scan. We also compared the outcome of our prospective cohort with that of historical controls with severe abnormalities on myocardial perfusion imaging (MPI).
Background:
Coronary calcium detected on EBT imaging has been shown to correlate with the total plaque burden. However, there is still controversy as to the prognostic significance of calcium, as some investigators believe that the presence of coronary calcification may stabilize the atherosclerotic plaque.
Methods:
Ninety-eight asymptomatic subjects (mean age: 62 +/- 10) were followed for an average of 17 +/- 11 months (range: 4 to 36 months) after undergoing EBT screening for the occurrence of hard coronary events (HCEs), defined as myocardial infarction or coronary death. All patients had an initial CS > or = 1,000, and in none did the results of the EBT screening lead to further invasive or non-invasive testing.
Results:
During the follow-up period, 35 patients (36%) suffered an HCE. All events were recorded in the first 28 months of follow-up. Subjects with HCEs had higher initial CSs than subjects not suffering HCEs (1,561 +/- 270 vs. 1,199 +/- 200, p < 0.001). The annualized event rate in subjects with a CS > or = 1,000 was significantly greater than that of historical controls with severe perfusion abnormalities on MPI (25% vs. 7.4%, respectively; p < 0.0001).
Conclusions:
A high CS (> or = 1,000) on a screening EBT in an asymptomatic person portends a very high risk of an HCE in the short term. This risk appears to be greater than the risk associated with a severe perfusion abnormality on MPI.