Long-term outcome prediction by functional parameters derived from coronary computed tomography angiography

Abstract

Background: Estimation of hemodynamic relevance of a coronary stenosis from coronary computed angiography (CCTA) has raised substantial interest. Recently, the corrected coronary opacification (CCO) decrease and the transluminal attenuation gradient (TAG) have been suggested as faster alternatives to the FFR_CT. The aim of the study was to evaluate whether the diagnostic accuracy of CCO decrease and TAG translates into an added prognostic value in patients evaluated for coronary artery disease (CAD).

Methods: This retrospective study consists of 162 consecutive patients referred for evaluation of known or suspected CAD by CCTA. CCO decrease was defined as difference of mean luminal coronary attenuation normalized to aorta attenuation proximal-distal of a stenosis. To calculate TAG, mean attenuation was measured at 5-mm intervals from the ostium to a distal segment with a minimal cross-sectional area of 2.0mm². Death, myocardial infarction, unstable angina requiring hospitalization, and coronary revascularization were defined as major adverse cardiac events (MACE). Multivariate analysis included covariates age, sex, ≥3 cardiovascular risk factors and stenosis severity.

Results: Follow-up was completed in 154 patients, CAD was found in 72. During median follow-up of 6.1years (interquartile range, 5.8-6.9years), 55 patients experienced a MACE. Among CAD patients, the presence of an abnormal CCO decrease (p<0.05) but not TAG (p=0.894) was associated with a worse MACE-free survival. In multivariate analysis, CCO decrease was an independent predictor of MACE (HR, 2.27; 95% CI, 1.14-4.52; p=0.02) while TAG was not predictive (p=0.895).

Conclusion: In CAD patients, CCO decrease adds long-term prognostic value over clinical characteristics and stenosis severity while TAG does not.

Keywords: CCO decrease; Corrected coronary opacification; Outcome; TAG; Transluminal attenuation gradient.