10-Year Follow-Up After Coronary Computed Tomography Angiography in Patients With Suspected Coronary Artery Disease

Abstract

Objectives: The aim of this study was to determine the long-term prognostic power of coronary computed tomography angiography (CTA) to predict cardiac death and nonfatal myocardial infarction.

Background: Prognostic usefulness of coronary CTA has been confirmed for short- and intermediate-term follow-up. However, long-term data for prognostic usefulness is still lacking, but is paramount because of the slowly progressing nature of coronary artery disease (CAD).

Methods: A total of 2,011 patients with suspected but not previously diagnosed CAD were examined by coronary CTA. Mean follow-up was 10.0 years (interquartile range [IQR]: 8.1 to 11.2 years). Cox proportional hazards analysis was used for the composite endpoint of cardiac death and nonfatal myocardial infarction. Event-free survival, which was defined as the years it took to reach a cumulative 1% risk for the composite endpoint and reclassification from clinical risk, was calculated.

Results: The study endpoint was reached in 58 patients (42 cardiac deaths, 16 nonfatal myocardial infarctions). Coronary CTA-assessed CAD severity (normal, nonobstructive, or obstructive) showed the best correlation with the endpoint, with an adjusted c-index of 0.704, compared with a univariate c-index of 0.622 for the clinical risk model (Morise score) alone. The annual event rate for patients with normal coronary arteries on baseline coronary CTA was 0.04%, which translated to an event-free survival period of 10 years. The highest annual event rate of 1.33% was found in patients with 3-vessel obstructive CAD. Reclassification from clinical risk (Morise score) was possible in approximately two-thirds of all patients (68%; p < 0.0001), which led to a substantial reduction of the intermediate-risk group (reduction from 74% to 15%) in favor of the low-risk group (increase from 20% to 83%).

Conclusions: Patients with normal coronary CTA results benefitted from an event-free survival period of 10 years against cardiac death and nonfatal myocardial infarction. Risk stratification according to coronary CTA results allowed for the delineation of clearly diverging prognostic groups and reclassified approximately two-thirds of all patients from clinical risk groups.

Keywords: coronary artery disease; coronary computed tomographic angiography; event-free survival; prognosis; reclassification.