Prognostic Time Frame of Plaque and Hemodynamic Characteristics and Integrative Risk Prediction for Acute Coronary...

The relevant time frame for predicting future acute coronary syndrome (ACS) based on coronary lesion characteristics remains uncertain.

The aim of this study was to investigate the association of lesion characteristics with test-to-event time and their prognostic impact on ACS.

The EMERALD II (Exploring the Mechanism of Plaque Rupture in Acute Coronary Syndrome Using Coronary CT Angiography and Computational Fluid Dynamics II) study analyzed 351 patients who underwent coronary computed tomography angiography (CTA) and experienced ACS between 1 month and 3 years of follow-up. Lesions identified on coronary CTA were classified as culprit (n = 363) or nonculprit (n = 2,088) on the basis of invasive coronary angiography findings at the time of ACS. Core laboratory coronary CTA analyses assessed 4 domains: degree of stenosis, plaque burden, number of adverse plaque characteristics (APC) (low-attenuation plaque, positive remodeling, spotty calcification, and napkin-ring sign), and changes in coronary CTA-derived fractional flow reserve across the lesion (ΔFFR_CT). Patients were categorized into short (<1 year), mid (1-2 years), and long (2-3 years) test-to-event time groups.

Patient characteristics, including cardiovascular risk factors, did not differ across short, mid, and long test-to-event groups (P > 0.05 for all), and the proportion of ACS culprit lesions was similar (P = 0.552). Among culprit lesions, shorter test-to-event time was associated with higher luminal stenosis, plaque burden, and ΔFFR_CT (P for trend < 0.001 for all). The predictability for ACS culprit lesions based on the combined 4 characteristics tended to decrease over time and significantly reduced beyond 2 years (AUC: 0.851 vs 0.741; P = 0.006). In predicting ACS risk within test-to-event time <2 years using obstructive lesions (stenosis ≥ 50%), APC ≥2, plaque burden ≥70%, and ΔFFR_CT ≥0.10, the risk was elevated compared to the average proportion of lesions becoming ACS culprit (12.1%) in the following subsets: lesions with 4 characteristics (proportion of lesions becoming ACS culprit: 49.3%; P < 0.001), lesions with 3 characteristics (obstructive lesions with plaque burden ≥70% and either ΔFFR_CT ≥0.10 [proportion of lesions becoming ACS culprit: 33.0%; P < 0.001] or APC ≥2 [proportion of lesions becoming ACS culprit: 31.2%; P < 0.001]), and lesions with 2 characteristics (plaque burden ≥70% and ΔFFR_CT ≥0.10; proportion of lesions becoming ACS culprit: 21.5%; P = 0.016).

Increased luminal stenosis, plaque burden, and ΔFFR_CT were associated with shorter test-to-ACS event time. The prognostic impact of lumen, plaque, and local hemodynamic characteristics was most relevant to ACS risk within a 2-year period, with higher risk observed when specific combinations of them were present. (Exploring the Mechanism of Plaque Rupture in Acute Coronary Syndrome Using Coronary CT Angiography and Computational Fluid Dynamics II [EMERALD II] Study; NCT03591328).