Relation of Aortic Valve Calcium to Myocardial Ischemic Perfusion in Individuals With a Low Coronary Artery Calcium Score

The absence of coronary artery calcium (CAC) is associated with minimal atherosclerosis. Nonetheless, morbid and mortal cardiovascular events occur in patients with low CAC. This study attempts to identify whether calcific deposits outside the coronary arteries or traditional cardiovascular risk variables are associated with myocardial ischemia in patients with low CAC scores. From 1998 to 2006, a total of 605 patients with an Agatston CAC score of 0 to 10 were referred for stress echocardiography or myocardial perfusion imaging. There was a low rate (1.2%) of myocardial ischemia. Seven of 303 patients (2.3%) had ischemia on perfusion imaging. Zero of 302 stress echocardiograms were abnormal. Traditional risk-factor analysis did not predict the presence of ischemia. No differences in age, gender, or self-reported hyperlipidemia, diabetes mellitus, tobacco use, hypertension, or family history of premature heart disease were noted. Contrary to previous belief, patients with myocardial ischemia were not younger or female. Aortic valve calcium (AVC) was associated with ischemia (p = 0.02), with a >10-fold likelihood of having ischemia detected by MPS versus those without AVC (20.0% vs 1.7%). In conclusion, a CAC score <10 is associated with a low rate of myocardial ischemia. AVC may identify a subset of patients who may be at higher risk.