EXTENSIVE PERIPHERAL ARTERY CALCIFICATION AND OBSTRUCTIVE CAD BUT A CORONARY ARTERY CALCIUM SCORE OF ZERO: AN UNDERAPPRECIATED SUBGROUP

Background Coronary Artery Calcium Score (CACS) testing has sensitivity and negative predictive values approaching 100% for diagnosing obstructive coronary artery disease (CAD). In high pretest probability patients with acute chest pain, it has limited utility. The recent RAPID CTCA trial suggested harm associated with false positive CACS. An important subgroup to be considered are those with false-negative CACS results. Case A 52 year old male with a smoking and hypertension history presented with 4 hours of crushing substernal chest pain. Electrocardiogram was not consistent with acute myocardial ischemia and initial troponin was undetectable. Coronary computed tomography angiography showed no stenosis and a CACS of 0. Aspirin and heparin infusion were administered. Cardiac catheterization was attempted but both femoral arteries could not be accessed due to extensive calcification. Catheterization achieved via left brachial artery access revealed 90% ostial stenosis and 75% mid stenosis of right coronary artery, and 2 stents were placed. Decision-making The patient had an intermediate-high pretest probability of obstructive CAD. Even with a CACS of 0, a high index of suspicion for acute coronary syndrome (ACS) prompted catheterization reattempts. Conclusion A CACS score of 0 does not rule out ACS in a patient with chest pain. Appropriate utilization of CACS requires interpretation in the optimal setting. An important subgroup of patients to consider are those with false-negative CACS. [Formula presented]