The elasticity of canine and human coronary arteries with reference to postmortem changes.

Abstract

SUMMARY We 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, we made a preliminary study on the elasticity changes of a muscular artery (the femoral) after excision and cold storage. Dynamic (Ed^) and static (E*u) 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%), E^,, (77 and 173%), and E<i rn (46 and 99%). It is likely that these changes are applicable to the coronary arteries in view of the similarities in their medial structure. Ejyn for the canine LCCA was 1.23 ± 0.12 N.m~* x 10* and was in excellent agreement with published data for femoral and carotid arteries. The mean and SBM values of E*«t and Ejy. for six excised, human coronary arteries (subjects 14-40 years of age) were 2.31 ± 0.49 and 4.46 ± 1.21 (SEM) N.m~* x 10', respectively; 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., Edy, -1.2 N.m" 1 x 10*. Ore Res 45: 588-594, 1979 IN VIEW of the predilection of the epicardial coronary arteries for atherosclerosis and the role of mechanical factors in its pathogenesis (Glagov, 1965;Patel et al, 1974; Stehbens, 1975), it is important to have information about arterial elastic properties. To the best of our knowledge, no study has been made of the static and dynamic elastic properties of human epicardial coronary arteries, either in vivo or in vitro. For that matter, no such study has been made in vivo in other species because of the unique location of these vessels on the rapidly moving myocardium which precludes measurement with existing methods, either noninvasively or invasively. It can be anticipated that the wall motion due to pulsatile arterial pressure will be less than 100 jim, which places it beyond the resolution of angiography, while the large movement of the vessel on the heart makes ultrasound tracking of the vessel extremely difficult.In a recent paper, Gow et al. (1974) reported measurements of the dynamic and static elasticity of the excised left circumflex coronary artery (LCCA) of the dog, by means of an electrical caliper (Gow, 1966). This study was done after attempts to

Interpretation and physiological significance of diastolic coronary artery pressure-flow relationships in the canine coronary bed.

“…In our model, we assumed that large vessel arterial resistance (Ri) was constant during diastole. This approximation is consistent with studies of the dynamic elastic properties of excised canine epicardial coronary arteries which have demonstrated relatively small changes in vessel radius with rather large changes in perfusion pressure (Douglas and Greenfield, 1970;Gow and Hadfield, 1979). In addition, Vatner et al (1980), using an ultrasonic dimension gauge on the left circumflex coronary in the conscious dog, have shown that coronary artery diameter during diastole changes approximately 2-4%.…”

Evaluating the mechanical behavior of arterial tissue using digital image correlation

“…Pressure-diameter testing has remained a popular approach, but modern imaging techniques have been adopted to monitor changes in vessel geometry and volume that are associated with internal pressures. 2 August 7, 2002. methods for measuring mechanical properties of arterial tissues include the use of photo cells combined with a scanning laser, 5 sono-micrometers, 6 differential transformers, 7 pasted wire strain gages, 8 and electrolytic transducers. 9 Many of the techniques employed for evaluating arterial mechanics have been reviewed by Hayashi.…”

Differences in the Mechanical Properties of the Rat Carotid Artery In Vivo, In Situ, and In Vitro

“…34 This procedure alone cannot explain the differences found in vitro and in vivo because during the in situ measurements the artery length remained unchanged. Nevertheless, striking differences between in situ and in vivo measurements were also observed.…”