Coronary Computed Tomography Angiography (CTA) is an established technique for the detection of coronary artery disease (CAD). However, the prognostic value of non-obstructive CAD is not well defined. Thus, the aim of this analysis is to determine the prognostic value of non-obstructive CAD detected on CTA.
In the Multi-Center Multi-Ethnic Coronary Computed Tomography Angiography (MECCA) Study, 3209 subjects without known CAD underwent CTA. Patients with obstructive CAD were excluded from this analysis. Patients with = 70% luminal coronary artery stenosis in vessels other than the left main were classified to have non-obstructive CAD while patients without any plaque were considered to have normal CTA. Patients were followed up for a median duration of 3.4 years for all-cause mortality (ACM). Multivariable Cox models were used to determine the independent predictors of event-free survival.
A total of 1455 subjects had non-obstructive CAD and 1382 subjects had normal coronary arteries. Subjects with non-obstructive CAD were older (55.9±11 vs 46.2±11 years, p<0.001) and more likely to be males (56.8% vs 50.5%, p=0.001) and had more prevalent traditional risk factors. A total of 83 ACM were observed (4.4% in the non-obstructive group and 1.3% in the normal group, p<0.001). Patients with clinical events were older (61.8±14 vs 50.9±12 years, p<0.001) and have more prevalence of DM(42.2% vs 31.4%, p=0.031) and HTN (72.3% vs 54.3%, p=0.001). In Multivariable Cox models, non-obstructive CAD was associated with increased event rate ( Hazard ratio 1.75, 95% CI 1.01 – 3.01, p=0.45).
Patients with non-obstructive CAD on CTA have a higher rate of all-cause mortality. Non-obstructive CAD on CTA enhances risk stratification among subjects suspected with CAD and should call for more aggressive guidelines directed medical therapy.