Kills two birds with one stone: Biomechanical properties and three-dimensional modeling of human aortic root with new method of micro-CT

Introduction

The micro-CT obtain very high-quality of the aortic roots and three-dimensional modeling of aortic leaflets. Different tests (biaxial test) are used to know the biomechanical properties. We propose a new method, which combines pressurization of the aortic root with micro-CT to obtain at the same time, the geometry, and biomechanical properties.

Objective

The aim is to investigate healthy aorta mechanical property using a micro-CT under pressure and compare them with literature.

Methods

This study was approved by committee on human research at the French agency of biomedicine (PFFS 20-026). Ten aortic roots were obtained fresh from unused donor hearts with non-cardiac causes of death. We used aortic root under pressure at different pressure level (every 20 mmHg) in order to obtain diameter, geometry, stress-strain curve and Young modulus.

Results

All aortic roots (n = 10) obtained a three-dimensional modeling of aortic leaflets with excellent quality. The mean age was 61.2 years [49.5–65.6]. The median of sino-tubular junction diameter was 32.2 mm [29–36] at 80 mmHg. The non-linear stress-strain curves of healthy aortic root were characterized. Young moduli were significantly smaller in low pressure (between 20 and 80 mmHg) 0.6 [0.5–0.8] MPa than high pressure (between 80 and 120 mmHg) 3.2 [2.5–5.6] MPa, P = 0.001 (Fig. 1).

Conclusion

Our new method allows a 3D model of the aortic root associated with measurements of biomechanical properties. Our results are found to be consistent with literature data. This new method evaluates the biomechanical properties while keeping the aortic roots intact and maintaining its geometrical complexity for future global aortic root simulation.