High-Density Calcified 1K Plaque Associated With Reduced Risk of Acute Coronary Syndrome

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This multicenter, case-control cohort study examined the association between high-density calcified coronary plaque and risk of acute coronary syndrome (ACS). Propensity score matching was used to match 189 patients who experienced laboratory-verified ACS after undergoing baseline CCTA and 189 controls who also underwent CCTA but did not have ACS. Plaque was classified by Hounsfield units (HU) as low-density (<130 HU) or as calcified plaque (>350 HU). Calcified plaque was further substratified into three groups. The highest of these, >1000 HU, was termed 1K plaque. Participants were followed for a mean of 3.9 years. Although overall mean calcified plaque volume (>350 HU) was similar between the ACS and control groups, the ACS group exhibited significantly less 1K plaque versus the control group. Compared with individuals in the lower three quartiles, participants in the highest quartile of 1K plaque had a lower percentage of plaque that was classified as low-density.

These data suggest that analysis of 1K plaque may provide important information on a per-patient and per-lesion basis about future ACS risk.