Mortality risk in symptomatic patients with nonobstructive coronary artery disease: a prospective 2-center study of 2,583 patients undergoing 64-detector row coronary computed tomographic angiography.

OBJECTIVES We examined mortality risk in relation to extent and composition of nonobstructive plaques by 64-detector row coronary computed tomographic angiography (CCTA). BACKGROUND The prognostic significance of nonobstructive coronary artery plaques by CCTA is poorly understood. METHODS We prospectively evaluated consecutive adults from 2 centers undergoing 64-detector row CCTA without prior documented coronary artery disease (CAD) and without obstructive (≥50%) CAD by CCTA. Luminal diameter stenosis severity was classified for each segment as none (0%) or mild (1% to 49%), and plaque composition was classified as noncalcified, calcified, or mixed. RESULTS During 3.1 ± 0.5 years, 54 intermediate-term (≥90 days) deaths occurred among 2,583 patients (2.09%), with 4 early (<90 days) deaths. Adjusted for CAD risk factors, the presence of any nonobstructive plaque was associated with higher mortality (hazard ratio [HR]: 1.98, 95% confidence Interval [CI]: 1.06 to 3.69, p = 0.03), with the highest risk among those exhibiting nonobstructive CAD in 3 epicardial vessels (HR: 4.75, 95% CI: 2.10 to 10.75, p = 0.0002) or ≥5 segments (HR: 5.12, 95% CI: 2.16 to 12.10, p = 0.0002). Higher mortality for nonobstructive CAD was observed even among patients with low 10-year Framingham risk (3.4%, p < 0.0001) as well as those with no traditional, medically treatable CAD risk factors, including diabetes mellitus, hypertension, and dyslipidemia (6.7%, p < 0.0001). No independent relationship between plaque composition and incident mortality was observed. Importantly, patients without evident plaque experienced a low rate of incident death during follow-up (0.34%/year). CONCLUSIONS The presence and extent of nonobstructive plaques augment prediction of incident mortality beyond conventional clinical risk assessment.