Coronary Artery Shape as a New Biomarker - Anatomical Features Linked to Adverse Haemodynamics

Coronary vessel geometry can create disturbed blood flow that is associated with adverse haemodynamics and atherosclerotic risk. Patient-specific haemodynamic assessments have led to some insights, however population assessments of adverse shape characteristics are lacking. Twenty patient-specific left main geometries (15 females, 5 males, 55 ± 9 years) were analysed for shape features and compared to haemodynamic simulations. Significant shape variation was present (angle A 129.9° ± 20.7°; inflow angle 15.9° ± 24.3°; angle B 75.3° ± 21.3°; radii 1.74 ± 0.64 mm, 1.42 ± 1.07 mm, 1.59 ± 0.46 mm, and tortuosity 1.09 ± 0.13, 1.02 ± 0.06 and 1.46 ± 0.68 for LM, LAD and LCx, respectively). A principal component analysis (PCA) showed that the bifurcations varied primarily in size, and secondly in curvature and angle. Geometric differences of larger radii and higher LAD tortuosity were found in patients with hypertension, and variations in LM shape were also evident across age groups. Interestingly, we found that an obtuse angle B is only unfavourable in combination with an acute LM inflow angle, which was shown to be a more dominant factor in local haemodynamics. An acute angle B (<60°) was also found adverse. Similarly, both radii and tortuosity appeared to have an optimal range with adverse haemodynamic effects outside that range. This demonstrates the potential of shape feature analysis combined with haemodynamic assessment and highlights the value of vessel shape as a clinical biomarker for adverse haemodynamics and atherosclerotic risk.