title: High coronary artery calcium scores pose an extremely elevated risk for hard events.
abstract: OBJECTIVE
  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.
authors.affiliation: Christ Hospital and University of Illinois, Oak Lawn, Illinois, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Wayhs
authors.forename: Allan
authors.initials: A
authors.lastname: Zelinger
authors.forename: Paolo
authors.initials: P
authors.lastname: Raggi
mesh_terms: D000368:Aged; D002114:Calcinosis / Q000378:metabolism*; D002118:Calcium / Q000032:analysis*; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000401:mortality; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000401:mortality; D011446:Prospective Studies; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed
chemical_list: D002118:Calcium