Ann Thorac Surg 2008;86:827. doi:10.1016/j.athoracsur.2008.05.068
© 2008 The Society of Thoracic Surgeons
Original Articles: Adult Cardiac
Invited Commentary
Jan T. Christenson, MD, PhD
Division of Cardiovascular Surgery, University Hospital of Geneva, 24 rue Micheli-du-Crest, CH-1211 Geneva, CH-1211 Switzerland
(Email: jan.christenson{at}hcuge.ch).
In the article by Takami and Masumoto [1], the hemodynamic effects of intra-aortic balloon counterpulsation (IABC) on graft flow in coronary artery bypass grafts (CABGs) was studied using transit-time flowmetric measurements. There are so few studies addressing this important issue, and the authors are to be congratulated for a solid and well-performed clinical study. The authors have convincingly demonstrated that IABC significantly increases global graft flow in various types of conduits, such as saphenous vein grafts, radial artery, gastroepiploic artery, and internal thoracic arteries. In addition, they also demonstrated an increase in its diastolic components. Differences in flow between different graft materials may certainly be a reflection of the inherent characteristics of each material used, but it is also related to the peripheral resistance. The peripheral resistance is increased when the distal grafted vessel is stenosed or occluded as in infracted myocardium. Therefore, this study is an interesting complement to previous studies that have demonstrated a significantly positive effect of preoperative, proactive IABC in high-risk patients undergoing myocardial revascularization compared with the controls [2, 3]. The preoperative IABC increases preoperative cardiac index, thus resulting in myocardial revascularization on a less ischemic heart [4]. This may result in a decreased resistance in the outflow vascular bed, which in itself may result in an increased graft flow reported in the article of Takami and Masumoto [1]. Does increased graft flow result in better graft patency? The authors did not have a sufficient number of occluded grafts or the sufficient data to answer this question in the present study. Future studies are encouraged in this field of research. Intraoperative transit-time flow measurements were used in this study to assess anastomotic quality and perhaps to be useful in predicting early graft failure. However, the major drawback with the transit-time flowmetry, as the authors correctly stated in the article, is the lack of a recognized cut-off point.
In view of an increasing number of studies showing the beneficial effect of proactive IABC, a better understanding of the hemodynamic impact on graft flow is needed, and thus further studies are encouraged to evaluate the predictive graft patency value using intraoperative graft flow measurements and investigating the impact of IABC on flow pattern in relation to different target coronary vessels with various degrees of peripheral disease.
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References
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- Takami Y, Masumoto H. Effects of intra-aortic balloon pumping on graft flow in coronary surgery: an intraoperative transit-time flowmetric study Ann Thorac Surg 200886:823–7.
- Christenson JT, Badel P, Simonet F, Schmuziger M. Preoperative intra-aortic balloon pump enhances cardiac performance and improves the outcome of redo CABG Ann Thorac Surg 1997;64:1237-1244.[Abstract/Free Full Text]
- Holman WL, Li Q, Kiefe CI, et al. Prophylactic value of preincision intra-aortic balloon pump: analysis of a statewide experience J Thorac Cardiovasc Surg 2000;120:1112-1119.[Abstract/Free Full Text]
- Christenson JT, Simonet F, Badel P, Schmuziger M. Optimal timing of preoperative intraaortic balloon pump support in high risk coronary patients Ann Thorac Surg 1999;68:934-939.[Abstract/Free Full Text]
Related Article
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Effects of Intra-Aortic Balloon Pumping on Graft Flow in Coronary Surgery: An Intraoperative Transit-Time Flowmetric Study
- Yoshiyuki Takami and Hiroshi Masumoto
Ann. Thorac. Surg. 2008 86: 823-827.
[Abstract]
[Full Text]
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