Long-term prognostic value of coronary artery calcium scanning, coronary computed tomographic angiography and stress myocardial perfusion imaging in patients with suspected coronary artery disease

Abstract

BackgroundWe compared the long-term prognostic value of coronary artery calcium (CAC) scanning, coronary computed tomographic angiography (CCTA), and stress single-photon emission computed tomography myocardial perfusion imaging (MPI) in patients with suspected coronary artery disease (CAD). Methods and ResultsA total of 164 patients were studied. CAC score was measured according to the Agatston method and patients were categorized into 3 groups (0, 1-300, and >300). The following events were recorded: cardiac death, nonfatal infarction, and unstable angina requiring revascularization. Follow-up was 95% complete during a mean period of 82 ± 34 months. During follow-up, 22 events occurred (14% cumulative event rate). Event-free survival decreased with worsening of CAC score category (P < .001) and it was worse (P < .001) in patients with significant CAD (≥50% stenosis) and in those with stress-induced ischemia (summed difference score >2). At multivariable analysis, CAC (P = .001) and ischemia (P = .012) were independent predictors of events. MPI data added prognostic information to a model including clinical variables, CAC and CCTA findings, increasing the global Chi-square from 36.2 to 41.9 (P = .013). The decision curve analyses in patients with CAC score >0 indicate that the prognostic model including MPI resulted in a higher net benefit across a wide range of decision threshold probabilities. ConclusionsCAC and MPI, but not CCTA, are independent predictors of cardiac events. Stress MPI appears to improve risk stratification over clinical variables, CAC scanning and CCTA findings.