ADDED PREDICTIVE VALUE OF CORONARY ARTERY CALCIUM SCORING OVER MYOCARDIAL PERFUSION IMAGING ALONE IN EVALUATING PATIENTS WITH SUSPECTED CORONARY ARTERY DISEASE:

Abstract

Therapeutic Area: ASCVD/CVD Risk Assessment Background: Coronary Artery Calcium (CAC) scoring and Myocardial Perfusion Imaging (MPI) are non-invasive tests used to evaluate patients with suspected coronary artery disease (CAD). A normal MPI does not necessarily exclude significant coronary stenosis however a high CAC score increases the pretest probability of disease and increases the diagnostic accuracy of MPI. We present two patients with discordant CAC scores and MPI with subsequent high-grade stenosis on catheterization. Methods: Two males in their 50’s, with cardiac symptoms and a strong family history of CAD were evaluated with CAC and MPI within the same month with resultant catheterization. Results: Both patients were symptomatic, had positive ischemic EKG changes with normal MPI. Patient 1 had a CAC score of 1502, with subsequent catheterization revealing 95% RCA stenosis treated with drug eluting stent (DES) and 60% mid-LAD stenosis. Patient 2 had a CAC score of 1016 and cardiac catheterization revealed 80% stenoses of the proximal and mid-LAD treated with DES. Both patients reported relief of symptoms at interval follow up. Conclusions: With advancements in nuclear cardiology, MPI has provided a “one-stop” assessment tool in the evaluation of suspected CAD. Both these patients had significant coronary pathology irrespective of having normal MPI, which raises concerns for diagnostic accuracy especially in symptomatic individuals.Limited data is available to evaluate the synergistic relationship of these two tests, however previous studies have identified that in patients referred for CAC scoring after nonischemic MPI, 17.5% were identified as having CAD based on a CAC score greater than 100. Other studies have also concluded that CACS are the single most important predictors of cardiac events and/or death in patients with a normal MPI.CAC scoring and MPI should be considered complementary approaches rather than individual parameters for assessing patients with suspected CAD or high-risk patients. CAC scoring should possibly be regarded as a necessary adjunct test to establish diagnosis of coronary pathology in the setting of a negative MPI and thus improve clinical outcomes.