Inhibitory effects of heparin, aspirin and ketanserin on coronary artery vasoconstriction after arterial balloon injury in hypercholesterolemic miniature pigs

Objectives. The present study aimed to clarify the effects of heparin, aspirin and ketanserin on coronary artery vasoconstriction after arterial balloon injury. Background. The mechanisms of coronary artery vasoconstriction after coronary angioplasty are not well understood. Methods. After being fed a cholesterol-rich diet for 1 month, 71 Gottingen miniature pigs were randomly allotted to five groups; 16 pigs with no pretreatment (group A); 21 pigs pretreated with heparin, 3,000 U (group B); 13 pigs pretreated with aspirin, 50 mg/day orally for 2 days (group C); 11 pigs pretreated with ketanserin, 1 mg/kg body weight (group D); 10 pigs pretreated with aspirin, 50 mg/day for 2 days, heparin, 6,000 U and ketanserin, 1 mg/kg (group E). After this pretreatment, the left anterior descending or the left circumflex coronary artery, or both, was denuded by a 2F balloon catheter. Results. The coronary vasoconstriction at the injured sites reached a peak level 6 mil after the arterial injury and subsided within 30 min. The coronary vasoconstriction at the injured site 6 min after arterial injury was 56 ± 5% in group A, which was significantly greater than that in group B (28 ± 6%, p < 0.01), group C (25 ± 5%, p < 0.01), group D (26 ± 7%, p < 0.01) or group E (24 ± 5%, p < 0.01), whereas there was no significant difference in the coronary vasoconstriction among the latter four groups. Conclusions. These results suggest that serotonin released from aggregating platelets plays a major part in the platelet-dependent coronary artery vasoconstriction after arterial injury.