Prognostic Value of Nonobstructive and Obstructive Coronary Artery Disease Detected by Coronary Computed Tomography Angiography to Identify Cardiovascular Events

Abstract

Several large, recent studies have demonstrated the impact of coronary CTA on prognosis, although the follow-up time has been relatively short.1,2 Only 1 study has evaluated the longer term follow-up of cardiovascular events among patients referred for coronary CTA.3 Because patients referred forBackground-The contribution of plaque extent to predict cardiovascular events among patients with nonobstructive and obstructive coronary artery disease (CAD) is not well defined. Our objective was to evaluate the prognostic value of plaque extent detected by coronary computed tomography angiography. Methods and Results-All consecutive patients without prior CAD referred for coronary computed tomography angiography to evaluate for CAD were included. Examination findings were classified as normal, nonobstructive (<50% stenosis), or obstructive (≥50%). Based on the number of segments with disease, extent of CAD was classified as nonextensive (≤4 segments) or extensive (>4 segments). The cohort included 3242 patients followed for the primary outcome of cardiovascular death or myocardial infarction for a median of 3.6 (2.1-5.0) years. In a multivariable analysis, the presence of extensive nonobstructive CAD (hazard ratio, 3.1; 95% confidence interval, 1.5-6.4), nonextensive obstructive (hazard ratio, 3.0; 95% confidence interval, 1.3-6.9), and extensive obstructive CAD (hazard ratio, 3.9; 95% confidence interval, 2.2-7.2) were associated with an increased rate of events, whereas nonextensive, nonobstructive CAD was not. The addition of plaque extent to a model that included clinical probability as well as the presence and severity of CAD improved risk prediction. Conclusions-Among patients with nonobstructive CAD, those with extensive plaque experienced a higher rate of cardiovascular death or myocardial infarction, comparable with those who have nonextensive disease. Even among patients with obstructive CAD, greater extent of nonobstructive plaque was associated with higher event rate. Our findings suggest that regardless of whether obstructive or nonobstructive disease is present, the extent of plaque detected by coronary computed tomography angiography enhances risk assessment. (Circ Cardiovasc Imaging. 2014;7:282-291.)

Temporal shifts in clinical presentation and underlying mechanisms of atherosclerotic disease

“…88 89 The lower incidence of STEMI and the concomitant increase in less lipid laden and inflamed plaques in the statin era raise similar notes of caution regarding the interpretation of and goals of imaging studies. Others share this view, refer to "the myth of the vulnerable plaque", and propose that the management of patients at risk of MI mandates a greater focus on atherosclerotic disease burden than on features of individual plaques 52 , an inference that derives support from studies with coronary computed tomography angiography in patients with non-obstructive coronary artery disease 90 .…”

Coronary CT Angiography: Variability of CT Scanners and Readers in Measurement of Plaque Volume

“…The importance of total coronary plaque burden was highlighted recently by a study (31) whose results showed that diffuse nonobstructive coronary artery disease is associated with rates of cardiovascular death and myocardial infarction that are comparable with those of obstructive coronary artery disease. Therefore, the assessment of total coronary plaque at coronary CT angiography may be clinically relevant and enhance risk stratification.…”

Impact of plaque characteristics on the degree of functional stenosis

“…Studies with CCTA have also demonstrated the prognostic value of some of these detailed plaque features like positive remodeling, the presence of low attenuation plaques and the presence of a napkin ring sign. Since several coronary plaques are frequently found in the coronary tree even in low to intermediate CAD probability patients undergoing CCTA to rule out coronary stenosis (15,16), and since detailed plaque evaluation is time consuming, requires very good image quality and can be associated with low interobserver variability, another possible approach is to provide the total coronary atherosclerotic burden as a score, and some have been developed and validated as prognostic tools (17)(18)(19), providing imagers and researcher with additional tools and a change of focus from just the vulnerable plaque to the vulnerable coronary tree (20).…”

“…In fact, lesions in this last subgroup can be considered "false negative" of CCTA and might explain the worse than expected prognosis of patients that don't have obstructive lesions but have high disease burden, as it has been recently demonstrated with the use of CCTA coronary atherosclerotic burden scores (17)(18)(19) that take in consideration all lesions independent of stenosis severity. As the knowledge of coronary disease pathophysiology advances, the traditional anatomic-based dichotomic concept of obstructive vs. nonobstructive is becoming more and more outdated and becoming replaced by a concept of high vs. low risk plaque features/burden, more in line with the recent evidence provided by both invasive and noninvasive atherosclerosis imaging.…”