Comprehensive biomechanical and anatomical atherosclerotic plaque metrics predict major adverse cardiovascular events: A new tool for clinical decision making

BACKGROUND AND AIMS

Anatomical imaging alone of coronary atherosclerotic plaques is insufficient to identify risk of future adverse events and guide management of non-culprit lesions. Low endothelial shear stress (ESS) and high plaque structural stress (PSS) are associated with events, but individually their predictive value is insufficient for risk prediction. We determined whether combining multiple complementary, biomechanical and anatomical plaque characteristics improves outcome prediction sufficiently to inform clinical decision-making.

METHODS

We examined baseline ESS, ESS gradient (ESSG), PSS, and PSS heterogeneity index (HI), and plaque burden in 22 lesions that developed subsequent events and 64 control lesions that remained quiescent from the PROSPECT study.

RESULTS

86 fibroatheromas were analysed from 67 patients. Lesions with events showed higher PSS HI (0.32 vs. 0.24, p<0.001), lower local ESS (0.56Pa vs. 0.91Pa, p = 0.007), and higher ESSG (3.82 Pa/mm vs. 1.96 Pa/mm, p = 0.007), while high PSS HI (hazard ratio [HR] 3.9, p = 0.006), high ESSG (HR 3.4, p = 0.007) and plaque burden>70 % (HR 2.6, p = 0.02) were independent outcome predictors in multivariate analysis. Combining low ESS, high ESSG, and high PSS HI gave both high positive predictive value (80 %), which increased further combined with plaque burden>70 %, and negative predictive value (81.6 %). Low ESS, high ESSG, and high PSS HI co-localised spatially within 1 mm in lesions with events, and importantly, this cluster was distant from the minimum lumen area site.

CONCLUSIONS

Combining complementary biomechanical and anatomical metrics significantly improves risk-stratification of individual coronary lesions. If confirmed from larger prospective studies, our results may inform targeted revascularisation vs. conservative management strategies.

Sex-related differences in plaque characteristics and endothelial shear stress related plaque-progression in human coronary arteries

BACKGROUND AND AIMS

Clinical atherosclerosis manifestations are different in women compared to men. Since endothelial shear stress (ESS) is known to play a critical role in coronary atherosclerosis development, we investigated differences in anatomical characteristics and endothelial shear stress (ESS)-related plaque growth in human coronary arteries in men compared to women.

METHODS

1183 coronary arteries (male/female: 944/239) from the PREDICTION study were studied for differences in artery/plaque and ESS characteristics, and ESS-related plaque progression (6-10 months follow-up) among men and women and after stratification for age. All characteristics were derived from IVUS-based vascular profiling and reported per 3 mm-segments (13,030 3-mm-segments (male/female: 10,465/2,565)).

RESULTS

Coronary arteries and plaques were significantly smaller in females compared to males; but no important differences were observed in plaque burden, ESS and rate of plaque progression. Change in plaque burden was inversely related to ESS (p<0.001) with no difference between women versus men (β: -0.62 ± 0.13 vs -0.68 ± 0.05, p=0.62). However, stratification for age demonstrated that ESS-related plaque growth was more marked in young women compared to men (<55 years, β: -2.02 ± 0.61 vs -0.33 ± 0.10, p=0.007), reducing in magnitude over the age-categories up till 75 years.

CONCLUSIONS

Coronary artery and plaque size are smaller in women compared to men, but ESS and ESS- related plaque progression were similar. Sex-related differences in ESS-related plaque growth were evident after stratification for age. These observations suggest that although the fundamental processes of atherosclerosis progression are similar in men versus women, plaque progression may be influenced by age within gender.

Spatial relationships among hemodynamic, anatomic, and biochemical plaque characteristics in patients with coronary artery disease

BACKGROUND AND AIMS

We aimed to characterize the spatial proximity of plaque destabilizing features local endothelial shear stress (ESS), minimal luminal area (MLA), plaque burden (PB), and near-infrared spectroscopy (NIRS) lipid signal in high- vs. low-risk plaques.

METHODS

Coronary arteries imaged with angiography and NIRS-intravascular ultrasound (IVUS) underwent 3D reconstruction and computational fluid dynamics calculations of local ESS. ESS, PB, MLA, and lipid core burden index (LCBI), for each 3-mm arterial segment were obtained in arteries with large lipid-rich plaque (LRP) vs. arteries with smaller LRP. The locations of the MLA, minimum ESS (minESS), maximum ESS (maxESS), maximum PB (maxPB), and maximum LCBI in a 4-mm segment (maxLCBI_4mm) were determined along the length of each plaque.

RESULTS

The spatial distributions of minESS, maxESS, maxPB, and maxLCBI_4mm, in reference to the MLA, were significantly heterogeneous within and between each variable. The location of maxLCBI_4mm was spatially discordant from sites of the MLA (p<0.0001), minESS (p = 0.003), and maxESS (p = 0.003) in arteries with large LRP (maxLCBI_4mm ≥ 400) and non-large LRP. Large LRP arteries had higher maxESS (9.31 ± 4.78 vs. 6.32 ± 5.54 Pa; p = 0.023), lower minESS (0.41 ± 0.16 vs. 0.61 ± 0.26 Pa; p = 0.007), smaller MLA (3.54 ± 1.22 vs. 5.14 ± 2.65 mm²; p = 0.002), and larger maxPB (70.64 ± 9.95% vs. 56.70 ± 13.34%, p<0.001) compared with non-large LRP arteries.

CONCLUSIONS

There is significant spatial heterogeneity of destabilizing plaque features along the course of both large and non-large LRPs. Large LRPs exhibit significantly more abnormal destabilizing plaque features than non-large LRPs. Prospective, longitudinal studies are required to determine which patterns of heterogeneous destabilizing features act synergistically to cause plaque destabilization.