Incremental prognostic significance of left ventricular dysfunction to coronary artery disease detection by 64-detector row coronary computed tomographic angiography for the prediction of all-cause mortality: results from a two-centre study of 5330 patients

Abstract

Early reports indicate a prognostic value of coronary artery disease (CAD) detection by coronary computed tomographic angiography (CCTA), although studies have been limited by small samples in single centres. Coronary computed tomographic angiographic measures of left ventricular ejection fraction (LVEF) to add incremental prognostic value beyond CAD detection have not been examined. We evaluated 5330 consecutive patients without known CAD undergoing CCTA at two centres. Stenosis severity by CCTA was graded as none (0%), mild (1-49%), moderate (50-69%), or obstructive (> or = 70%). Left ventricular ejection fraction was graded as normal (>50%) or reduced (< or = 50%). About 2.3 +/- 0.6 year follow-up of patients for all-cause mortality was performed using multivariate and Cox proportional hazards models; 100 deaths occurred (1.9%). Detection of obstructive CAD correlated with mortality [hazards ratio (HR) 2.44, 95% confidence interval (CI) 1.61-3.72, P < 0.001]. Compared with those without obstructive CAD, individuals with increasing numbers of vessels with obstructive CAD experienced increased risk of death: 1-vessel (HR 2.23, 95% CI 1.34-3.72), 2-vessel (HR 3.29, 95% CI 1.62-6.71), or 3-vessel (HR 7.35, 95% CI 3.79-14.29) (P < 0.001 for all). Compared with those with LVEF >50%, those with LVEF < or = 50% exhibited higher rates of death (HR 1.56, 95% CI 1.04-2.36, P = 0.03). Annualized mortality rates in those with non-obstructive CAD and LVEF >50% were low (0.51%) and increased accordingly for non-obstructive CAD and LVEF < or = 50% (0.74%), obstructive CAD and LVEF >50% (1.76%), and obstructive CAD and LVEF < or = 50% (3.97%) (log-rank test P < 0.001). In a large two-centre cohort of patients without known CAD, obstructive CAD detection by CCTA was related to incident death by the absolute presence of as well as increasing numbers of vessels with obstructive CAD. The addition of LVEF by CCTA enhanced risk correlation for death.