Features of biomechanical properties of human coronary arteries

The mechanical properties, biochemical composition, and structure of proximal and distal parts of the right and anterior descending branch of the left coronary arteries were studied experimentally. The vessels were removed during an autopsy of 121 males and 84 females aged from one day to 80 years. The material was divided into six age groups. From the proximal and distal parts, branchless segments of 15-20 mm long vessels were cut out. The mechanical properties of the coronary arteries were determined by passing a fluid at a pressure ranging from 0 to 240 mm Hg. It was found that the part of the wall of the coronary artery adjacent to the myocardium was thicker than the other part of the arterial wall. With increasing age, the mean thickness of the wall of both coronary arteries increased, but the wall thickening process was nonuniform in character in the proximal and distal parts, and individual layers. The changes of the stretch ratio and tangential modulus in the circumferential direction with age and sex were also investigated. The greatest changes in the wall thickness and mechanical parameters were found in the left coronary artery wall for men over 40 years and in the right coronary artery wall for females over 50 years. The results of the biochemical and densitometric investigations agree well.