(CCSP093) IMPACT OF CORONARY ARTERY CALCIUM SCORING ON DOWNSTREAM CARDIAC TESTING AND OUTCOMES

Background: Coronary artery calcium (CAC) scoring is a method for cardiovascular disease risk stratification. While its use is supported by major guidelines, its impact on downstream testing patterns and clinical outcomes is not well established.

METHODS AND RESULTS: Consecutive CAC scans from Sunnybrook Health Sciences Centre and University Health Network between January 4, 2011, and April 30, 2019, were abstracted and linked to health administrative databases. A population-based, non-tested group was generated and matched using propensity scoring for age, sex, cardiac risk factors, and comorbidities relevant to receipt of testing. Patients were excluded if they had a prior history of cardiac catheterization, cardiac bypass (CABG), or coronary artery disease (CAD). Subsequent invasive and non-invasive testing and a composite outcome of acute myocardial infarction hospitalizations, stroke hospitalizations, congestive heart failure (CHF) hospitalizations, and CHF emergency department visits were determined 90 days and two years following CAC testing using validated algorithms and compared between the CAC tested and non-tested groups and amongst CAC score categories.

4,884 matched patients (Mean 57.1 years, SD 11.32, 46.1% women) underwent CAC scoring. Table 1 summarizes the baseline characteristics across the subgroups. The use of CAC scoring was associated with increased use of graded stress testing (GXT) (258 vs. 97 events, p < 0.001), coronary CT angiography (CCTA) (21-25 vs. *1-5, p = 0.002), cardiac MRI (95 vs. 10, p < 0.001), myocardial perfusion imaging (MPS) (116 vs. 67, p < 0.001), stress echocardiography (130 vs. 48, p < 0.001), invasive catheterization (314 vs. 27, p < 0.001) and CABG (31 vs. 0) at 90 days. Similar trends were observed at two years, summarized in Table 2. Increasing CAC score was associated with increasing use of GXT, MPS, stress echocardiography, invasive catheterization, and CABG (p trend < 0.001) but not CCTA (p = 0.482) or cardiac MRI (p = 0.209). There was no significant difference in the composite cardiac outcome at two years between those undergoing CAC testing and those who did not (52 vs. 40, p = 0.160).

Conclusion: In a propensity-matched and population-based study, CAC scoring was associated with higher downstream cardiac resource utilization at 90 days and two years. There were no significant differences in the combined clinical endpoint at two years between those who were tested and those who were not. Future research should focus on identifying populations most likely to benefit from CAC testing and evaluating its impact in well-powered outcomes trials.