The Prognostic Value of Percentage Total Plaque Score Adjusted to Age

Total plaque score (TPS) on coronary computed tomography angiography (CCTA) has been validated as a surrogate measure of coronary artery disease (CAD) burden and is prognostic. We propose a novel measure, percentage TPS adjusted to age (%TPS/age), that may reflect vascular age and potentially more rapidly progressive atherosclerosis and evaluate its potential prognostic value.

%TPS/age was calculated for consecutive patients prospectively enrolled into our institutional CCTA registry and evaluated for primary composite outcome of cardiac death, nonfatal myocardial infarction, and late revascularization.

Of 1896 patients identified (mean age 57.7 ± 11.4 years, 50.1% male, median follow-up 18.6 months [interquartile range: 15.3, 32.4]), 552 (29%) had %TPS/age = 0 (no atherosclerosis), with 1 (0.2%) primary outcome observed (annual event rate [AER] = 0.1%). Two events (0.4%, AER = 0.3%) were observed in %TPS/age < 0.314 category, 22 (5.0%, AER = 2.2%) in %TPS/age 0.314 to 0.699 category, and 54 (12.0%, AER = 5.7%) in %TPS/age ≥ 0.700 category. After adjusting for clinical predictors and obstructive CAD, higher %TPS/age category was associated with hazard ratio 1.95 (1.31-2.88, P < .001) for primary outcome on multivariable analysis, Harrell-C-Statistic 0.87 (confidence interval 95%: 0.84-0.90), and net reclassification improvement of 0.71 ( P < .001).

%TPS/Age has incremental prognostic value to traditional risk factors and CCTA measures of CAD and improves evaluation of burden of coronary atherosclerosis and clinical risk.