Central Core Laboratory versus Site Interpretation of Coronary CT Angiography: Agreement and Association with Cardiovascular Events in the PROMISE Trial

Abstract

Purpose To assess concordance and relative prognostic utility between central core laboratory and local site interpretation for significant coronary artery disease (CAD) and cardiovascular events. Materials and Methods In the Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE) trial, readers at 193 North American sites interpreted coronary computed tomographic (CT) angiography as part of the clinical evaluation of stable chest pain. Readers at a central core laboratory also interpreted CT angiography blinded to clinical data, site interpretation, and outcomes. Significant CAD was defined as stenosis greater than or equal to 50%; cardiovascular events were defined as a composite of cardiovascular death or myocardial infarction. Results In 4347 patients (51.8% women; mean age ± standard deviation, 60.4 years ± 8.2), core laboratory and site interpretations were discordant in 16% (683 of 4347), most commonly because of a finding of significant CAD by site but not by core laboratory interpretation (80%, 544 of 683). Overall, core laboratory interpretation resulted in 41% fewer patients being reported as having significant CAD (14%, 595 of 4347 vs 23%, 1000 of 4347; P < .001). Over a median follow-up period of 25 months, 1.3% (57 of 4347) sustained myocardial infarction or cardiovascular death. The C statistic for future myocardial infarction or cardiovascular death was 0.61 (95% confidence interval [CI]: 0.54, 0.68) for the core laboratory and 0.63 (95% CI: 0.56, 0.70) for the sites. Conclusion Compared with interpretation by readers at 193 North American sites, standardized core laboratory interpretation classified 41% fewer patients as having significant CAD. © RSNA, 2017 Online supplemental material is available for this article. Clinical trial registration no. NCT01174550.

Figures

Figure 1:

Flowchart of patient enrollment from the anatomic coronary CT angiography (CTA) arm of the PROMISE trial.

Figure 2:

Graph shows Kaplan-Meier curves for cardiovascular events (cardiovascular death or myocardial infarction) based on concordance of local site and core laboratory interpretation of coronary CT angiography. Group A = concordant for no significant CAD; Group B = discordant, with significant CAD by site interpretation but not by core laboratory interpretation; Group C = discordant, with significant CAD by core laboratory interpretation but not site interpretation; and Group D = concordant for significant CAD.

Figure 3:

Bar graph shows core laboratory and site agreement for significant CAD (≥50% stenosis) by CAC category. Greater CAC was associated with greater rates of discordant interpretations (P < .001). Values in parentheses are percentages.