Association of Hemodynamic Disease Severity and Distribution With Risk of Future Acute Coronary Syndrome.

Background

Although physiological assessment has been used in decision-making for revascularization, its role in predicting the future risk of acute coronary syndrome (ACS) remains underexplored.

Objectives

This study aims to investigate the independent and combined prognostic significance of hemodynamic disease severity and distribution in identifying ACS culprit vessels, in conjunction with lumen and plaque characteristics.

Methods

The EMERALD-II study is an international, multicenter, internal case-control study enrolling 351 patients with ACS who underwent coronary computed tomography angiography (CTA) 1 month to 3 years before the event. Culprit and nonculprit vessels were identified by matching invasive coronary angiography with coronary CTA findings. High-risk plaque (HRP) characteristics, including minimum lumen area 2, plaque burden ≥70%, low-attenuation plaque, positive remodeling, spotty calcification, and napkin-ring sign, were assessed by a core laboratory, with HRP defined as ≥3 HRP characteristics. From coronary CTA, the authors derived both the hemodynamic severity of the disease (fractional flow reserve derived from computed tomography [FFRCT]) and its spatial distribution (diffuse vs focal), as assessed by the pullback pressure gradient derived from coronary CTA (PPGCT). Vessels were categorized into 4 hemodynamic disease patterns: nonischemic (FFRCT >0.80), hemodynamic diffuse (FFRCT ≤0.80 and PPGCT ≤0.50), mixed (FFRCT ≤0.80 and 0.50 CT ≤0.60), and focal disease (FFRCT ≤0.80 and PPGCT >0.60).

Results

Among 873 vessels, the mean FFRCT was 0.74 ± 0.17 and the mean PPGCT was 0.54 ± 0.14. Both lower FFRCT and higher PPGCT were independently associated with higher ACS risk (OR per 0.1 increase in FFRCT: 0.71 [95% CI: 0.65-0.77]; P CT (differences in FFRCT across the lesion) demonstrated superior model performance compared with models incorporating FFRCT and PPGCT, higher PPGCT was additionally associated with increased ACS risk, particularly among vessels with maximal ΔFFRCT ≥0.10.

Conclusions

Hemodynamic disease distribution, as measured by PPGCT, complements FFRCT in predicting ACS risk. The integration of hemodynamic disease patterns provides additional prognostic value beyond lumen and plaque characteristics, with hemodynamic focal disease emerging as an independent predictor and a potential therapeutic target for ACS prevention. (Exploring the Mechanism of Plaque Rupture in Acute Coronary Syndrome Using Coronary CT Angiography and Computational Fluid Dynamics II [EMERALD II]; NCT03591328).