P6157Indexed coronary volume - A potential novel low-dose CCTA derived predictor for cardiovascular events

Abstract

Abstract Background Coronary computed tomography angiography (CCTA) provides incremental prognostic information over traditional risk factors in patients with suspected coronary artery disease. However, little is known about the long-term predictive performance of CCTA-derived coronary volumes and mid-diastolic left ventricular (LV) mass. Purpose To assess long-term prognostic value of coronary volumes and mid-diastolic LV mass as novel potential imaging predictors derived from low-dose prospectively ECG-triggered CCTA. Methods Consecutive patients with suspected or known coronary artery disease, referred for low-dose CCTA, were included. Patients with previous revascularization were excluded. The following parameters were evaluated: calcium score, segment involvement score (SIS: 1 point for each coronary segment with presence of plaque), coronary volume, mid-diastolic LV mass and coronary volume indexed to LV mass. Major adverse cardiovascular events (MACE) were defined as all-cause death, non-fatal myocardial infarction and revascularization (PCI or CABG). The association between CCTA measures and the occurrence of events was quantified using cox regression hazard and Kaplan Meier analysis. Results A total of 147 consecutive patients were included in the study. Of them, 93 (63.3%) were male and 79 (53.7%) hat one or more traditional cardiovascular risk factors. There was a weak but statistical significant inverse correlation between indexed coronary volume and both calcium score (R=-0.3, p=0.01) and SIS (R=-0.24, p=0.005). After a median follow-up of 5.8 years 30 MACE occurred in 25 patients, including 3 deaths, 26 revascularizations and 1 non-fatal myocardial infarction. In univariate cox regression hazard analysis calcium score (HR=12.69, 95% CI 2.99–53.83, p<0.001), SIS (HR=1.66, 95% CI 1.43–1.94, p<0.001), LV mass (HR=1.02, 95% CI 1.01–1.03, p=0.007) and indexed coronary volume (HR=0.89, 95% 0.82–0.96, p=0.004) were associated with outcome. In multivariate analysis, indexed coronary volume, remained an independent predictor for MACE when adjusted for traditional risk factors and SIS (HR=0.93, 95% CI 0.87–1.00, p=0.05), while LV mass did not reach statistical significance (p=0.46). By ROC curve analysis, a value of 21.85 mm3/gr was defined as optimal cutoff for indexed coronary volume. In Kaplan Meier plots, patients with low indexed coronary volume (<21.85 mm3/gr) showed higher event rates (log rank p<0.001) compared to high indexed coronary volume (≥21.85 mm3/gr). Conclusions Indexed coronary volume, derived from low-dose CCTA, independently predicts cardiovascular events. Larger studies are mandated to confirm the predictive value of this potential new biomarker.