ELASTICITY OF CANINE AND HUMAN CORONARY-ARTERIES WITH REFERENCE TO POSTMORTEM CHANGES

The authors did this study to provide data on the elastic properties of coronary arteries, such being essential when considering the role of mechanical factors in coronary heart disease. In view of the necessity of using postmortem material to study human arteries, they made a preliminary study on the elasticity changes of a musscular artery (the femoral) after excision and cold storage. Dynamic (Edyn) and static (Estat) incremental, elastic moduli of all arteries were calculated from simultaneously recorded pressure and diameter traces, the latter, in most instances, being obtained with an existing electrical caliper. A new, light-weight, strain-gauge caliper was developed to allow direct diameter records to be obtained from the left circumflex coronary artery (LCCA) on the beating canine heart. After excision and overnight cold storage, respectively, the canine femoral artery showed increases in diameter (9.2 and 11.6%), Estat (77 and 1773%), and Edyn (46 and 99%). It is likely that these changes are applicable to the coronary arteries in view of the similarities in their medial structure. Edyn for the canine LCCA was 1./23 ± 0.12 N.m-2 x 106 and was in excellent agreement with published data for femoral and carotid arteries. The mean and SEM values of Estat and Edyn for six excised, human coronary artieres (subjects 14-40 years of age) were 2.31 ± 0.49 and 4.46 ± !.21 (SEM) N.m-2 x 106, respecttvely; these are higher in comparison to the above in vivo data but agree with published values from other excised human vessels. On the basis of the above reported postmortem increases in elasticity, it is concluded that human coronary and femoral arteries probably have similar elastic properties, i.e., Edyn = 1.2 N.M-2 x 106.