Non-invasive detection of coronary inflammation using computed tomography and prediction of residual cardiovascular risk (the CRISP CT study): a post-hoc analysis of prospective outcome data.
Level 3 - non-randomized controlled study
Post-hoc prognostic analysis of two prospective observational cohorts
PubMed 30170852 · doi:10.1016/S0140-6736(18)31114-0
What was done
Researchers conducted a post-hoc analysis of prospective outcome data from two independent cohorts of consecutive patients undergoing coronary computed tomography angiography (CTA): a derivation cohort in Germany (n=1,872; median age 62 years; median follow-up 72 months) and a validation cohort in the USA (n=2,040; median age 53 years; median follow-up 54 months). They evaluated the perivascular fat attenuation index (FAI) around the proximal right coronary artery (RCA), left anterior descending artery (LAD), and left circumflex artery (LCx). Cox regression models adjusted for age, sex, cardiovascular risk factors, tube voltage, modified Duke coronary artery disease index, and CTA-derived high-risk plaque features to assess predictive value for all-cause and cardiac mortality.
What was found
High perivascular FAI around the proximal RCA and LAD correlated strongly and predicted mortality, whereas LCx perivascular FAI did not. Proximal RCA FAI was selected as a representative biomarker; higher values predicted cardiac mortality in both derivation (HR 2.15, 95% CI 1.33-3.48; p=0.0017) and validation cohorts (HR 2.06, 95% CI 1.50-2.83; p<0.0001). An optimal cutoff of -70.1 Hounsfield units (HU) or higher determined in the derivation cohort (cardiac mortality HR 9.04, 95% CI 3.35-24.40, p<0.0001; all-cause mortality HR 2.55, 95% CI 1.65-3.92, p<0.0001) was confirmed in the validation cohort (cardiac mortality HR 5.62, 95% CI 2.90-10.88, p<0.0001; all-cause mortality HR 3.69, 95% CI 2.26-6.02, p<0.0001). Perivascular FAI significantly improved risk discrimination and reclassification across both cohorts.
Why it matters
Perivascular fat attenuation on routine coronary CTA serves as a non-invasive quantitative marker of coronary inflammation that significantly enhances risk stratification beyond conventional plaque and anatomy scoring.
Limits
The study was a post-hoc analysis rather than a pre-specified prospective trial, and findings apply only to patients clinically referred for coronary CTA. The LCx measurement showed no prognostic utility. The abstract does not evaluate whether tailoring medical therapy to perivascular FAI levels improves clinical outcomes.
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