Using coronary calcification to exclude an ischemic etiology for cardiomyopathy: A validation study and systematic review.

Background: Preliminary data suggests the absence of coronary artery calcification (CAC) excludes ischemic etiologies of cardiomyopathy. We prospectively validate and perform a systematic review to determine the utility of an Agatston score=0 to exclude the diagnosis of ischemic cardiomyopathy.

Methods And Results: Patients with newly diagnosed LV dysfunction were prospectively enrolled. Patients underwent CAC imaging and were followed until an etiologic diagnosis of cardiomyopathy was made. Eighty-two patients were enrolled in the study and underwent CAC imaging with 81.7% patients having non-ischemic cardiomyopathy. An Agatston score=0 successfully excluded an ischemic etiology for cardiomyopathy with a specificity of 100% (CI: 74.7-100%) and a positive predictive value of 100% (CI: 85.0%-100%). A systematic literature review was performed and studies were deemed suitable for inclusion if: 1) patients with CHF, cardiomyopathy or LV dysfunction were enrolled, 2) underwent CAC imaging and patients were assessed for an Agatston score=0 or the absence of CAC, and 3) the final etiologic diagnosis (ischemic or non-ischemic) was provided. Eight studies provided sufficient information to calculate operating characteristics for an Agatston score=0 and were combined with our validation cohort for a total of 754 patients. An Agatston score=0 excluded ischemic cardiomyopathy with specificity and positive predictive values of 98.4% (CI: 95.6-99.5%), and 98.3% (CI: 95.5-99.5%), respectively.

Conclusions: In patients with cardiomyopathy of unknown etiology, an Agatston score=0 appears to rule out an ischemic etiology. A screening CAC may be a simple and cost-effective method of triaging patients, identifying those who do and do not need additional CAD investigations.