Preferential vasoconstriction to cysteinyl leukotrienes in the human saphenous vein compared with the internal mammary artery: Implications for graft performance

Abstract

Background: Platelet aggregation with the release of their vasoactive mediators is an important factor contributing to the patency of coronary bypass grafts. However, the role of leukocyte-derived mediators on graft performance is unclear. Leukotrienes (LTs) are proinflammatory mediators released from a variety of leukocytes that possess both vasoactive and mitogenic properties. We have therefore compared the effects of the cysteinyl LTs (C4, D4, and E4) on the human saphenous vein (SV) and human internal mammary artery (IMA). Methods and Results: Human SVs from 43 patients (mean age, 58 years) and IMAs from 33 patients (mean age, 57 years) were obtained from individuals undergoing coronary artery bypass surgery for coronary artery disease. The samples were set up in organ baths to record changes in vessel wall tension. In undistended SVs the cysteinyl LTs elicited concentration-dependent contractions. The E(max) for LTE4 (4.23±1.0 mN; n=6) was significantly less than that observed with either LTC4 (25.7±4.01 mN; n=7; P