P6152Incremental prognostic utility of functionally non-significant coronary stenosis in patients undergoing coronary computed tomogram angiography

Abstract

Abstract Background In patients with suspected coronary artery disease (CAD) who underwent coronary computed tomographic angiography (CCTA), the prognostic value of nonobstructive stenosis is not entirely understood. Aims We sought to assess the long-term incremental prognostic utility of functionally non-significant CAD in patients without known prior CAD who underwent CCTA. Methods We included 2142 consecutive patients (51±14 years, 53% men) without prior documented CAD who underwent CCTA between 2008–2016 (excluding anomalous coronaries and functionally significant CAD). Traditional risk factors were recorded and pretest likelihood of CAD was calculated. All epicardial coronary arteries were classified as follows: No plaque, minimal luminal irregularities (<25%), mild (25–49%) stenosis and moderate (50–69%) stenosis. All moderate stenoses were confirmed to be not functionally significant by follow-up stress testing/invasive angiography with fractional flow reserve assessment. Plaque was characterized as noncalcified, calcified or mixed. High-risk plaque features (spotty calcification, napkin ring, low attenuation plaque and positive remodeling) were recorded. During follow-up, a composite of death or myocardial infarction was recorded. Results 188 (9%) patients had low, 1712 (80%) had intermediate and 242 (11%) patients had high pre-test likelihood of CAD. 45%, 10%, 52% and 22% had hypertension, diabetes, Dyslipedimia and history of smoking respectively. Breakdown of CAD severity was: 1197 (56%) none, 480 (22%) minimal, 267 (13%) mild and 198 (9%) moderate stenoses. 82 (4%) had noncalcified, 245 (11%) had calcified and 618 (29%) had mixed plaque. 465 (22%) had high-risk plaque features. At 6±3 years, 90 (4%) patients had composite events (68 deaths) and 24 (1%) needed coronary revascularization >90 days post-CCTA. 880 (41%) were on statins post-CCTA. Results of multivariable Cox Survival Analysis are shown in Figure 1A. Kaplan-Meier survival curves for a) more severe CAD and b) high-risk plaque features (vs. not) are shown in Figure 1B and C. Longer-term event rates for increasing CAD were 2.8%, 4.6%, 6% and 9.6%, respectively. Conclusion In mostly low/intermediate risk patients without documented CAD who underwent CCTA, a higher burden of nonobstructive coronary plaque (or presence of high-risk features) provide incremental prognostic value. Initiating statin therapy following detection of plaque on CCTA was associated with improved longer-term freedom from composite events.