Sex-related differences in geometry, plaques and shear stress related plaque-progression in human coronary arteries

Background

Atherosclerosis manifests itself differently in women compared to men. Since the pathophysiology of atherosclerotic plaques is known to be related to endothelial shear stress (ESS), it was hypothesized that female compared to male coronary arteries demonstrate a different i) ESS and ii) ESS related plaque progression.

Methods

1183 coronary arteries (male/female:944/239) from the PREDICTION trial were studied for differences in vessel geometry (plaque area (PA) and lumen area (LA)), hemodynamic parameters (flow, minimal ESS over 90 degree arc (minESS) and maximal ESS over 90 degree arc (maxESS)) and ESS related plaque progression (1 year follow up) measured as change in maximal plaque thickness and plaque burden comparing female to male arteries. Arterial geometry and ESS measures were derived from IVUS-based vascular profiling and reported per 3 mm segments. For plaque progression studies minESS was subdivided into low, mid and high (<1,1–1.7,>1.7 Pa). To test statistical differences univariate anova or linear mixed models were used.

Results

13030 3mm-segments (m/f: 10.465/2565) were analyzed. Female compared to male coronary arteries were smaller and presented with less plaque area (Table I). No differences in average ESS, minESS and maxESS were found for male versus female coronary arteries, partly explained by the lower flows in female arteries (Table I). The ESS-related plaque growth showed for both sexes an significant inverse relationship between maximal wall thickness (Figure, left) and plaque burden (Figure, right) and the three minESS categories. However, ESS-related plaque growth was not different for male vs females.

Conclusion

Our data demonstrated that vessel and plaque size are smaller in female compared to male coronary arteries. However, ESS and ESS related plaque progression were not different.

Shear stress related plaque progression

Funding Acknowledgement

Type of funding source: None

Coronary plaque natural history displays significant longitudinal heterogeneity along the length of individual coronary plaques

Background

The natural history of plaque growth is, among other systemic risk factors, related to the blood flow induced local shear stress. Especially at regions of low shear stress plaques are initiated. Upon plaque encroachment into the lumen, plaques will be exposed to high shear stress. Interestingly, it has been observed that individual plaques are very heterogeneous regarding the local shear stress exposure and remodeling patterns along the plaque length. However no information is available on the spatial heterogeneity of temporal changes in plaques burden. We studied the longitudinal spatial heterogeneity of plaque burden progression, regression, quiescence in human coronary plaques.

Methods

591 coronary arteries from 302 patients with coronary artery disease who presented with an acute coronary syndrome from the PREDICTION study were investigated for local plaque progression, regression, quiescence patterns after 6–10 months follow up. Arterial geometry was derived from angiography/IVUS-based vascular profiling and reported in 3 mm segments. Plaques were defined as >3 consecutive segments with maximal wall thickness>0.5 mm. Plaque progression was defined as >5% increase, regression as <−5% decrease, and quiescence as no change in plaque burden (plaque area/ total vessel area * 100%). Logistic mixed model regression analysis was performed with plaque progression features as outcome and plaque length as independent variable with vessel as random factor to account for clustering of the data.

Results

5658 3mm-segments of 661 plaques were analyzed. Plaque burden changes over time ranged from −22% to +20%, with an average of −0.4%±4% which was not significant different from 0. Among all plaques, 56% showed segments with plaque progression of more than 5%, 60% with plaque regression (<−5%) and 96% of the plaques had segments that did not change over time (quiescence). On average, 17% of the plaque length displayed plaque progression, 20% regression and 63% was quiescent. The presence and number of features (progression, regression, quiescence) within the plaque were significantly related to the plaque length (figure).

Conclusion

Plaques are very heterogeneous in plaque progression patterns. Most of the plaques show within the plaque length simultaneously more than one plaque progression feature (segments that do not change in plaque burden, segments that regress or progress). The number of observed plaque progression features was related to the plaque length.

Funding Acknowledgement

Type of funding source: None