Background: Age and biological sex are well-known cardiovascular risk factors. Advanced age is correlated with vascular stenosis and turbulent flow, and studies suggest females experience increased coronary flow and vascular shear stress compared to males. These conditions increase risks for coronary calcification and luminal surface alterations, and subsequently, hemodynamic changes. Understanding the impact of age and sex on calcification and luminal surface topography in coronary arteries will yield insight not only on the mechanical pathophysiology of hemodynamic changes over time and between sexes, but also on refining risk stratification for cardiovascular diseases. In this study, we aim to detect, quantify, and compare the extent of calcification and luminal surface differences between age groups and sexes in cadaveric left anterior descending arteries (LADs) using a relatively novel approach–surface metrology. We hypothesized that LAD calcification and luminal surface complexity would increase in higher age groups and in the female sex.

Methods: LADs (n=18) were harvested from cadaveric hearts using a systematic dissection approach. To quantify the extent of calcification, each specimen was scanned using the Bruker Skyscan 1173 microCT scanner and subsequently underwent threshold-based image segmentation on Dragonfly by Object Research Systems. To quantify luminal surface complexity, each specimen was splayed open to expose their luminal surfaces and up to 15 scans were performed at 20X magnification using the Sensofar S Neox optical profiler. Each scan subsequently underwent surface metrologic scale-sensitive fractal analyses in SensoMap 10.

Results: We established 4 age groups: 60-69, 70-79, 80-89, and 90-99, and categorized our data to the corresponding age and sex groups. Our microCT findings demonstrated statistically significant reductions in LAD calcification in females compared to males, but no differences between age groups. Our surface metrology findings demonstrated statistically significant reductions in fractal complexity (Lsfc) and fractal dimension (Dls) in the highest age group compared to each of the lower age groups, but no differences in smooth rough crossover (SRC) and the scale of maximum complexity (Smfc) between each group. Additionally, no statistically significant differences were observed in SRC, Lsfc, Dls, and Smfc between males and females.

Conclusions: Our data suggests that males are significantly more prone to LAD calcification than females. Moreover, LAD luminal surfaces may increase in smoothness at a high age (>90) relative to lower ages (>60, but <90). Future studies will involve modeling blood flow across these surfaces using smooth particle hemodynamics (SPH) to evaluate the resulting hemodynamic changes.