Mechanical properties of coronary arteries and internal mammary arteries beyond physiological deformations

Passive circumferential and axial mechanical properties of porcine coronary arteries and internal mammary arteries (IMA) were measured and compared. The cylindrical specimens were subjected to axial stretch and internal pressures up to 300 mmHg. Stress-strain relations of the arteries were calculated from the measured data and compared. It was found that the stresses in the IMA were much higher and that the IMA is stiffer than the coronary artery, especially in the circumferential direction. The axial stress in the coronary artery increased substantially after axial stretching, this in contrast to the axial stress in the IMA.