CAC score of zero does not fully exclude coronary disease
MedWire News: Individuals with no coronary calcification might still be at risk for obstructive coronary artery disease (CAD), research shows.
Among individuals with a coronary artery calcium (CAC) score of zero, over 3% had stenosis of 50% or more, report Todd Villines (Walter Reed National Military Medical Center, Bethesda, Maryland, USA) and colleagues.
The study, which is published in the Journal of the American College of Cardiology, included 10,037 symptomatic patients without CAD who underwent coronary computed tomography angiography (CCTA) and CAC screening.
CAC is often used to determine if patients require further evaluation for obstructive CAD, note the researchers. In symptomatic patients, particularly in those with atypical symptoms, it can serve as a "filter" for invasive angiography and/or hospital admission.
However, several studies have shown high rates of coronary disease in patients with CAC scores of 0, leading some to question the approach. Among the patients in this analysis, 51% had a CAC score of 0. Of these, 84% had no evidence of CAD on CCTA and 13% had a nonobstructive stenosis However, 3.5% had a stenosis of 50% or more and 1.4% had even greater narrowing (≥70%).
After more than 2 years of follow-up, death rates did not differ among individuals with a CAC of 0 regardless of the presence of obstructive CAD.
Interestingly, comment Villines et al, individuals with a CAC score of 0 and stenosis in one coronary artery of 50% or more were nearly six times more likely to die, have a myocardial infarction, or undergo revascularization compared with individuals with a CAC score of 0 and nonobstructive disease (HR=5.7, p<0.001).
"This difference was primarily driven by an increase in late coronary revascularizations," explain Villines and colleagues.
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