Distension Produces Medial but Not Endothelial Damage in Porcine Internal Mammary Artery

Abstract

The influence of intraluminal distension on porcine internal mammary artery was studied using adenosine 5′-triphosphate (ATP) concentration and prostacyclin production as biochemical markers of medial and endothelial functional integrity respectively. Distension reduced mean (95% confidence limits) tissue ATP concentrations from 459 (337–581) nmol/g wet weight to 314 (193–435) nmol/g wet weight (n = 10, P < 0.01). Stimulated prostacyclin production was similar in undistended (25.8(15.9–35.9) pg/min per mg wet weight) and distended arteries (33.2(21.4–45.1)pg/min per mg wet weight) (n = 8, not significant). The data demonstrate that distension of the internal mammary artery results in acute medial but not endothelial damage. Distension-induced medial damage is unlikely to be rapidly reversible and might have implications for the early and long-term function of the artery as a bypass graft.