Abstract 539: Multiple Small Calcifications on Non-contrast CT in Asymptomatic Patients Who Subsequently Experience Adverse Cardiovascular Events
Background: A potential measure of “spotty” coronary arterial calcium - frequently found in plaques responsible for acute coronary syndrome - is the presence of multiple small coronary calcifications on non-contrast CT. This can be routinely assessed during coronary calcium scoring (CCS) and may improve prediction of major adverse cardiovascular event (MACE) risk.
Methods: From 2751 asymptomatic patients without known CAD and 4-year follow-up for MACE (cardiac death, myocardial infarction, stroke, late revascularization) after undergoing non-contrast CT for CCS, we compared 58 patients who experienced MACE (“EVENTS”) to 174 event-free controls (1:3 MACE-to-control ratio) matched by sex and a propensity score to account for age, traditional risk factors, and CCS. From each CT, we obtained the following two measures: number of calcifications with Agatston score < 50 (noC<50), and number of calcifications with volume < 6mm3 (noC<6mm3). Relationships to MACE were evaluated using multivariable logistic regression.
Results: MACE group had higher mean noC<50 (6.2±5.0 vs. 3.8±3.4, p<0.001), and noC<6mm3 (2.3±2.1vs. 1.4±1.6, p<0.001). These parameters were significantly associated with MACE in the initial model accounting for age, traditional risk factors, and CCS (Odds Ratio (OR) 1.17, 95%CI 1.05–1.30 for noC<50; OR 1.26, 95%CI 1.04 –1.53 for noC<6mm3) and remained so after the models were adjusted for Framingham Risk Score and CCS (OR 1.15 for noC<50; OR 1.26 for noC<6mm3, see Table⇓). Correlations with CCS were moderate-to-weak (0.45 for noC<50, 0.30 for noC<6mm3, p<0.0001). There was strong correlation between noC<6mm3 and noC<50 (0.76, p<0.0001).
Conclusions: Patients who experience MACE exhibit greater small calcifications on pre-MACE non-contrast CT than matched event-free controls, suggesting that number of small coronary calcifications at time of CCS has added value in predicting adverse cardiovascular outcomes.