Stress-Only Adenosine CMR Improves Diagnostic Yield in Stable Symptomatic Patients With Coronary Artery Calcium.

Objectives: This study assessed whether adenosine stress-only perfusion cardiac magnetic resonance (CMR) following a positive coronary artery calcium (CAC) score improved the diagnostic yield of invasive coronary angiography (CAG) in patients with stable chest pain. The study also established the association between positive CAC scores and stress-induced myocardial ischemia.

Background: The diagnostic yield of catheterization among patients with suspected coronary artery disease (CAD) is low. Improved patient selection and diagnostic testing are necessary. The CAC score can minimize unnecessary diagnostic testing, and in low-risk patients, normal CMR results have a high negative predictive value. Less comprehensive protocols may be sufficient to guide further work-up.

Methods: A total of 642 consecutive patients (mean age: 63 years; 50% women) with stable chest pain and CAC scores of >0 who were referred for CMR were enrolled. Patients with a perfusion defect were subsequently examined by CAG. Patients were followed up for 1 year. Outcome was obstructive CAD.

Results: Obstructive CAD was present in 12% of patients. For CAD diagnosis, the sensitivity of adenosine CMR was 90.9% (95% confidence interval [CI]: 88.7 to 93.1), specificity was 98.7% (95% CI: 97.9 to 99.6), positive predictive value was 92.0% (95% CI: 89.8 to 94.1), and negative predictive value was 98.6% (95% CI: 97.6 to 99.5). A CAC score between 0.1 and 100 without typical angina was associated with obstructive CAD in only 3% of patients. Patients with nonanginal chest pain and a CAC score ≥400 had obstructive CAD (16%).

Conclusions: Stress-only adenosine CMR had high diagnostic accuracy and served as an efficient gatekeeper to CAG in stable patients with a CAC score >0. Patients with CAC scores between 0.1 and 100 could be deferred from further testing in the absence of clinical features that suggested high risk. However, in patients with CAC score ≥400, functional testing should be indicated, regardless of the type of chest pain.