Relationship between stress-induced myocardial ischemia and atherosclerosis measured by coronary calcium tomography

ObjectivesWe assessed the relationship between stress-induced myocardial ischemia on myocardial perfusion single-photon emission computed tomography (MPS) and magnitude of coronary artery calcification (CAC) by X-ray tomography in patients undergoing both tests.BackgroundThere has been little evaluation regarding the relationship between CAC and inducible ischemia or parameters that might modify this relationship.MethodsA total of 1,195 patients without known coronary disease, 51% asymptomatic, underwent stress MPS and CAC tomography within 7.2 ± 44.8 days. The frequency of ischemia by MPS was compared to the magnitude of CAC abnormality.ResultsAmong 76 patients with ischemic MPS, the CAC scores were >0 in 95%, ≥100 in 88%, and ≥400 in 68%. Of 1,119 normal MPS patients, CAC scores were >0, ≥100, and ≥400 in 78%, 56%, and 31%, respectively. The frequency of ischemic MPS was <2% with CAC scores <100 and increased progressively with CAC ≥100 (p for trend <0.0001). Patients with symptoms with CAC scores ≥400 had increased likelihood of MPS ischemia versus those without symptoms (p = 0.025). Absolute rather than percentile CAC score was the most potent predictor of MPS ischemia by multivariable analysis. Importantly, 56% of patients with normal MPS had CAC scores ≥100.ConclusionsIschemic MPS is associated with a high likelihood of subclinical atherosclerosis by CAC, but is rarely seen for CAC scores