November 9th, 2011
Obstructive Lesions Found in Patients with Calcium Scores of Zero
A small but significant number of symptomatic patients with calcium scores of zero have obstructive coronary artery disease (CAD), according to a new study published in the Journal of the American College of Cardiology.
Todd Villines and colleagues studied 10,037 symptomatic patients without known CAD enrolled in the CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter) registry who underwent coronary CT angiography (CCTA). Half of the patients (51%) had a coronary artery calcium (CAC) score of 0 and although most (84%) had no CAD, 13% had a nonobstructive stenosis, 3.5% had a stenosis of 50% or greater, and 1.4% had a stenosis of 70% or greater. Some 3.9% of patients with a CAC score of 0 and obstructive CAD had an adverse event during follow-up as compared to 0.8% in the group with a CAC score of 0 and no obstructive CAD.
The authors write that their results reaffirm “the importance of properly assessing patient pretest probability for obstructive CAD” when calcium scores are used in symptomatic patients. They conclude that “the absence of CAC reduces but does not fully eliminate the occurrence of obstructive CAD” and that calcium scoring “does not appear to offer significant incremental prognostic information when combined with clinical risk factors and CAD severity on CCTA.”