Mortality incidence of patients with non-obstructive coronary artery disease diagnosed by computed tomography angiography.

It was previously reported that event-free survival rates of symptomatic patients with coronary artery disease (CAD) diagnosed by computed tomographic angiography decreased incrementally from normal coronary arteries to obstructive CAD. The aim of this study was to investigate the clinical outcomes of symptomatic patients with nonobstructive CAD with luminal stenoses of 1% to 49% on the basis of coronary plaque morphology in an outpatient setting. Among 3,499 consecutive symptomatic subjects who underwent computed tomographic angiography, 1,102 subjects with nonobstructive CAD (mean age 59 ± 14 years, 69.9% men) were prospectively followed for a mean of 78 ± 12 months. Coronary plaques were defined as noncalcified, mixed, and calcified per patient. Multivariate Cox proportional-hazards models were developed to predict all-cause mortality. The death rate of patients with nonobstructive CAD was 3.1% (34 deaths). The death rate increased incrementally from calcified plaque (1.4%) to mixed plaque (3.3%) to noncalcified plaque (9.6%), as well as from single- to triple-vessel disease (p <0.001). In subjects with mixed or calcified plaques, the death rate increased with the severity of coronary artery calcium from 1 to 9 to ≥ 400. The risk-adjusted hazard ratios of all-cause mortality in patients with nonobstructive CAD were 3.2 (95% confidence interval 1.3 to 8.0, p = 0.001) for mixed plaques and 7.4 (95% confidence interval 2.7 to 20.1, p = 0.0001) for noncalcified plaques compared with calcified plaques. The areas under the receiver-operating characteristic curve to predict all-cause mortality were 0.75 for mixed and 0.86 for noncalcified coronary lesions. In conclusion, this study demonstrates that the presence of noncalcified and mixed coronary plaques provided incremental value in predicting all-cause mortality in symptomatic subjects with nonobstructive CAD independent of age, gender, and conventional risk factors.