| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Department of Cardiothoracic Surgery, The Royal Melbourne Hospital, PO Box 954, Eltham, VIC 3095, Australia
(Email: alistair.royse{at}unimelb.edu.au).
Ever since Carpentier abandoned the radial artery in 1974 [1] and its revival by Acar in 1992 [2], there has been strong belief that arterial grafts in general, and radial artery grafts in particular, fail due to acute spasm postoperatively. To combat this assumed pathology, the postoperative use of vasodilators was considered of paramount importance for many years, and they continue to be considered very important by some, even today. Certainly, it is still widely believed that vasoconstrictors should be avoided in the setting of arterial coronary artery bypass grafts, even in the presence of hypotension, for fear of precipitating acute graft spasm and therefore acute graft failure.
This article by Ryu and coworkers [3] is a simple and elegant study involving the internal mammary artery and gastroepiploic artery in the presence and absence of a relatively high-dose vasoconstrictor. They demonstrate four important findings.
Contrary to popular expectations, there was no conduit vasoconstriction as evidenced by an increase in flow through the conduits rather than a reduction. The cause for this increase in flow appeared to be due to an increase in systemic arterial blood pressure, which highlights the importance of maintaining good systemic arterial blood pressure postoperatively rather than accepting hypotension. Although the gastroepiploic artery should theoretically be more prone to vasoconstriction than the internal mammary artery due to the presence of more β-receptors, there was no reduction in relative or absolute terms through the gastroepiploic artery compared with the internal mammary artery. Finally, in the presence of a relatively high-dose vasoconstrictor, there appeared to be no relative change to the flow in either limb of a Y composite graft compared with the flows noted before the vasoconstrictor. This would indicate that there was no differential effect between the gastroepiploic artery or the internal mammary artery, or the distal coronary vascular beds to which these two conduits applied.
For almost 15 years, we have used vasoconstrictors in most patients receiving total arterial coronary revascularization to treat a low vascular resistance state and maintained a systolic arterial blood pressure of a minimum of 100 mm Hg to facilitate graft perfusion. This article by Ryu and colleagues provides specific evidence to support this empiric policy. In the past 2 years, we have used intravenous norepinephrine in all cardiac surgical cases, including all arterial coronary grafting patients, to additionally counteract the intraoperative and postoperative vasodilation caused by the anesthetic, cardiopulmonary bypass, and the systemic inflammatory response syndrome to normalize vascular tone, as a means by which hemodilution can be minimized.
Clinicians and researchers who frequently or routinely use arterial coronary bypass conduits might reconsider their vasodilator and vasoconstrictor policies in light of the findings of this article.
 |
References |
|---|
 Top References |
|---|
Related Article
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
