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

Area of Science:

• Cardiology
• Nuclear Medicine
• Radiology

Background:

• Limited research exists on the relationship between coronary artery calcification (CAC) and inducible myocardial ischemia.
• Understanding factors that modify the CAC-ischemia relationship is crucial for accurate cardiovascular risk assessment.

Purpose of the Study:

• To evaluate the association between stress-induced myocardial ischemia, assessed by myocardial perfusion single-photon emission computed tomography (MPS), and the extent of coronary artery calcification (CAC) measured by X-ray tomography.
• To determine the predictive value of CAC scores for inducible ischemia in patients undergoing both diagnostic tests.

Main Methods:

• A cohort of 1,195 patients without known coronary artery disease underwent both stress MPS and CAC tomography.
• The frequency of inducible ischemia detected by MPS was compared against varying magnitudes of CAC scores.
• Multivariable analysis was employed to identify the most potent predictors of MPS ischemia.

Main Results:

• Ischemic MPS was observed in 95% of patients with CAC scores >0, and 88% with CAC scores >=100.
• The likelihood of ischemic MPS was less than 2% for CAC scores <100, increasing progressively with higher CAC scores (p<0.0001).
• Notably, 56% of patients with normal MPS results exhibited CAC scores >=100, indicating significant subclinical atherosclerosis.

Conclusions:

• Stress-induced myocardial ischemia on MPS is strongly linked to subclinical atherosclerosis detected by CAC, particularly when CAC scores exceed 100.
• Low CAC scores (<100) appear to effectively rule out significant inducible ischemia, potentially obviating the need for further noninvasive testing.
• The high prevalence of extensive atherosclerosis in patients with normal MPS suggests a valuable role for subsequent CAC screening in this population.