Pharmacology of coronary artery bypass grafts

Spasm of arterial and venous graft conduits can occur both during harvestin g and after the graft is connected. Attempts to overcome spasm during harve sting by probing or hydraulic distension can cause structural damage to the graft, which may impair short- and long-term patency. After a coronary art ery bypass graft is connected, spasm can cause major problems with myocardi al perfusion. To select the best pharmacologic agent to prevent or reverse vasoconstriction in a graft requires an understanding of the reactivity of that particular type of graft to vasoconstrictor and vasodilator agents. Th e pharmacologic reactivity of venous and arterial graft conduits has been d ocumented through extensive studies of isolated vessels in the organ bath a nd of in situ grafts in the body. In this review we summarize the current s tate of knowledge of the reactivity of arterial and venous grafts to vasoco nstrictor and vasodilator agents and describe the practical application of this knowledge in the operating room and in the postoperative period. (Ann Thorac Surg 1999;67:878-88) (C) 1999 by The Society of Thoracic Surgeons.