Integrating Prior Qualitative Coronary Artery Calcium Assessment into an Established Chest Pain Algorithm: Effect on Risk Stratification Outcomes

BackgroundChest pain (CP) patients with moderate elevations of high sensitivity cardiac troponins benefit from additional risk stratification strategies to improve Emergency Department decision-making. In the present study we evaluated the impact of adding the results of opportunistic detection of coronary calcium (ODCAC) from prior routine chest computed tomography scans (CT) to both high sensitivity troponin T (hsTnT) accelerated diagnostic protocol and determination of the HEART score (HS). MethodsRetrospective study of 1,525 consecutive patients evaluated for CP with moderate peak elevations of hsTnT (12-51 ng/L). Thirty-day major adverse cardiovascular events (MACE) were assessed based on peak hsTnT, HS, and ODCAC on chest CT performed within 5 years of CP presentation. Firths penalized logistic regression was employed to assess the combined predictive power of these variables. ResultsThe median age of the cohort was 69, 59% were male, and 81% had ODCAC on review of chest CT. Patients with MACE had higher peak hsTnT, median HS, and higher proportion of ODCAC+ versus those without MACE. Absence of ODCAC demonstrated a negative predictive value of 99.1% for excluding MACE. A logistic regression model including peak hsTnT, HS and ODCAC was successfully fitted (model p=0.002) and revealed that peak hsTnT was the strongest predictor of MACE (OR 1.05 per unit increase, 95% CI 1.02-1.09, p=0.005). A HEART score >3 had borderline-significant association (OR 14.71, 95% CI 0.88-246.19, p=0.061). In this comprehensive model the direct statistical effect of ODCAC was attenuated (p=0.111). ConclusionThe presence of ODCAC was a predictor of and its absence yielded a high negative predictive value for MACE. However, ODCAC did not add incremental risk stratification to a risk algorithm including hsTnT and HS. The lack of additive prognostic value of ODCAC in this particular cohort may be related to the advanced age and resultant high background rate of CAC.