Introduction: The association between a high calcium score at the level of the unstable coronary lesions and the different characteristic of culprit lesions which result in an acute coronary syndrome (ACS) has not been described yet. We aimed to study the correlation between the accumulation of calcium within the vessel wall of a coronary artery and the plaque burden of culprit lesions that develop an acute coronary event.
Material and methods: A total of 45 patients with ACS (22 unstable angina, 23 nonST elevation myocardial infarction) underwent 64-slice CCTA. In all patients a complex CT analysis of the culprit plaques was performed and the calcium score for each coronary artery was computed.
Results: We found a significant correlation between a calcium score higher than 100 and the plaque volume (r = 0.85. p = 0.01). Selecting a cut-off value of 100 HU for regional calcium score at the level of the coronary artery, we found that those arteries with Ca score higher than 100 presented significantly larger plaque volumes than the ones with calcium score below 100 (110.8 ml vs 82.4 ml, p <0.0001 for left anterior descending artery, 111.09 ml vs 82.5 ml, p = 0.0005 for circumflex artery, and 132.78 ml vs 76.23 ml for right coronary artery).
Conclusion: Our data shows that in ACS, the severity of the culprit lesions correlates with regional accumulation of calcium within the vessel wall.

Introduction: Coronary calcium score, as determined by Angio CT multislice, has been proved to represent a reliable parameter which reflects the global cardiovascular risk. We aimed to study the characteristics of culprit lesions in Acute Coronary Syndrome (ACS) patients with low versus high calcium score.
Material and methods: A total of 45 patients with ACS underwent 64-slice CCTA. Group 1 – 19 patients with Ca score below 400HU, Group 2 – 26 patients with calcium score >400HU. In all patients a complex CT analysis of the culprit plaque was performed.
Results: There were no significant differences between the groups at baseline as regard to age, gender, cardiovascular risk factors (p>0.2). In patients with high calcium score, culprit lesions presented a significantly larger amount of plaque burden than in patients with low calcium score (82.8ml versus 131.81ml, p <0.0001). This was also true when assessing in a subanalysis different cut-off points for definition of relatively higher calcium score (89.66ml versus 137.93ml, p <0.0001, for calcium score cut off 600HU, 97.88ml versus 137.57ml, p<0.0001 for calcium score cut-off of 1000HU).
Conclusion: Our data shows that patients with high calcium score who develop an acute coronary syndrome present larger atheromatous plaque than those with low calcium scores, and theseverity of the culprit lesions correlates with global cardiovascular risk as expressed by a high calcium score.