Objectives:

We assessed the relationship between stress-induced myocardial ischemia on myocardial perfusion single-photon emission computed tomography (MPS) and magnitude of coronary risk factors (CRF), coronary artery calcification (CAC) by X ray tomography in 28 elderly patients undergoing both tests. There has been little evaluation regarding the relationship between metabolic syndrome, inducible ischemia or parameters that might modify this relationship.

Methods:

A total of 28 patients with known coronary disease, all asymptomatic underwent coronary risk factors (Cooper and Framingham classification) Stress MPS and CAC tomography within 60 days. The frequency of ischemia by MPS was compared to the magnitude of CRF and CAC abnormality.

Results:

Among 28 patients (65 +/- 8 years) with ischemic MPS, the CAC scores were 0-99 in 21%; 100-399 in 18%; 400-999 in 18%; and >1000 in 43%. The frequency of ischemic MPS was <39% with CAC scores <400 and increased progressively with CAC >400 (P for trend <.001). Elderly patients with symptoms, and high CRF (Cooper and Framingham) with CAC scores >400 had increased likelihood of MPS ischemia versus those without symptoms (P =.025). Absolute rather than percentile CAC score was the most patent predictor of MPS ischemia by multivariable analysis. Importantly, 61% of patients with abnormal MPS had CAC scores >400; 61% with light ischemia and 39% with moderate to severe ischemia.

Conclusions:

Ischemic MPS is associated with a high likelihood of clinical atherosclerosis by CAC, but is rarely seen for CAC scores <100 (21%). A high calcium score cannot be interpreted properly in the absence of information on the underlying coronary risk assessment; in patients with metabolic syndrome.