Higher luminal stenosis, plague burden and pressure drop across the lesion were associated with shorter test-to-acute coronary syndrome (ACS) event time, with prognostic impact more pronounced within a two-year period, according to findings from the EMERALD II study published April 23 in JACC: Cardiovascular Imaging.

Seokhun Yang, MD, et al., looked at 351 patients who underwent coronary computed tomography angiography (CTA) and had an ACS event between one month and three years later. Based on invasive coronary angiography performed at the time of the ACS event, 363 lesions were categorized as culprit and 2,088 as nonculprit. The authors investigated the prognostic impact of four characteristics – degree of stenosis, plaque burden, number of adverse plaque characteristics (APC) and changes in coronary CTA-derived fractional flow reserve across the lesion (ΔFFR_CT).

Shorter test-to-event times were more likely in culprit lesions with higher luminal stenosis, plaque burden and ΔFFR_CT (p<0.001 for all), and predictability of culprit lesions, incorporating all four characteristics analyzed, significantly decreased after two years post coronary CTA (area under the curve: 0.851 for test-to-event less than one year vs. 0.741 for test-to-event two to three years; p=0.006).

Examining the proportion of ACS culprit lesions with test-to-event time less than two years, the authors found that lesions with all four of the following characteristics – obstructive lesions (stenosis ≥50%), APC ≥2, plaque burden ≥70%, ΔFFR_CT ≥0.10 – exhibited the highest risk, (49%; p<0.001) followed by those with three characteristics (obstructive lesions with plaque burden ≥70% and ΔFFR_CT ≥0.10: 33%; p<0.001; obstructive lesions with plaque burden ≥70% and APC ≥2: 31.2%; p<0.001) and then two characteristics (plaque burden ≥70% and ΔFFR_CT ≥0.10: 21.5%; p=0.016).

"When determining preventive strategies and the timing of follow-up tests, it is crucial not only to assess a patient's risk but also to understand the expected time frame for potential events in high-risk patients," write the authors. "The clinical application of this prognostic time frame of plaque and hemodynamic characteristics could offer a new framework for guiding primary ACS prevention strategies."

For more on the latest evidence and recommendations for the management of patients with ACS, explore the 2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes.