ABSTRACT
Intraluminal injection of papaverine may be employed to dilate the internal mammary artery for use as a coronary artery bypass graft. The biochemical and morphological consequences of exposing the endothelium of the internal mammary artery to papaverine have been investigated. Biochemical injury was assessed by measuring changes in basal and vortex-stimulated prostaglandin I2 production, and morphological damage by scanning electron microscopy. Segments of internal mammary artery from 10 patients were placed in one of three solutions; papaverine (1.5 mg/ml of normal saline), normal saline acidified to the pH of the papaverine solution, and normal saline alone. Basal production of prostaglandin I2 was similar in the three groups but vortex-stimulated production was significantly lower in segments stored in papaverine (18.3 pg/mg) and acidified saline (19.1 pg/mg) compared with that of saline alone (43.6 pg/mg). No consistent morphological difference was found by scanning electron microscopy. It was concluded that the low pH of the papaverine solution injured the endothelium of the internal mammary artery.
Subject(s)
Endothelium, Vascular/drug effects , Mammary Arteries/drug effects , Papaverine/adverse effects , 6-Ketoprostaglandin F1 alpha/analysis , Endothelium, Vascular/metabolism , Endothelium, Vascular/ultrastructure , Epoprostenol/biosynthesis , Humans , Hydrogen-Ion Concentration , In Vitro Techniques , Mammary Arteries/metabolism , Mammary Arteries/ultrastructureABSTRACT
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.
