Ann Thorac Surg 2007;83:1766-1767
© 2007 The Society of Thoracic Surgeons
Original Articles: Cardiovascular
Invited Commentary
Michael Jessen, MD
Department of Cardiovascular & Thoracic Surgery, University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8879
(Email: michael.jessen{at}utsouthwestern.edu).
The development of cardiopulmonary bypass (CPB) more than 50 years ago enabled the correction of previously untreatable cardiac defects. However, extracorporeal circulation came with a cost: it caused adverse effects from the initiation of a systemic inflammatory response from the production of fat and fibrin emboli and from hemodilution. To counteract these problems, CPB circuitry evolved with advances in oxygenator design, centrifugal pumps, biocompatible surface coatings, and recently with reductions in circuit size.
This report by Huybregts and colleagues [1] provides an evaluation of a new mini-CPB system (Synergy; Cobe Cardiovascular, Arvada, CO), which further reduces circuit size and surface area in an effort to decrease the inflammatory response and to decrease the hemodilution that accompanies extracorporeal circulatory support. This prospective randomized clinical trial identified a decrease in inflammatory markers (likely as a sequelae of a decreased blood to surface interface), confirming observations by other authors using similar technologies. This study is also significant in that maximal efforts were made to reduce priming volumes both in the mini-CPB group and the standard control circuits. Retrograde priming was applied to both arms of the study and led to a reduction in priming volume of approximately 1 L in patients treated with the mini-CPB circuit, in which an average priming volume of <400 mL was achieved. This was undoubtedly a major contributor to the reduction in hemodilution and to the lower transfusion requirements seen in the patients in the mini-CPB group, adding to the potential clinical benefit.
However, does reduced inflammation and less hemodilution equate to superior clinical results? A novel finding in this study is the observation of a protective effect on proximal renal tubular injury and intestinal and tissue injury as assessed by urinary levels of acetyl-glucosaminidase and intestinal fatty acid binding protein. One may surmise that this may translate into clinical benefits in some high-risk patients, although further studies will be needed to demonstrate a concrete clinical advantage. This study has also provided important new information on the safety of the mini-CPB circuit in which small priming volumes and absence of venous reservoirs can pose risks of air embolism in patients. Significant patient safety issues that have been reported in prior trials examining mini-circuits may have been avoided in Huybregts and colleagues’ study [1] by the inclusion of a venous bubble trap. Further research into this promising evolution of cardiopulmonary bypass circuitry is warranted and may lead to significant improvements in outcomes for patients with cardiac surgical disease.
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- Huybregts RAJM, Morariu AM, Rakhorst G. Attenuated renal and intestinal injury after use of a mini-cardiopulmonary bypass system Ann Thorac Surg 2007;83:1760-1767.[Abstract/Free Full Text]
Related Article
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Attenuated Renal and Intestinal Injury After Use of a Mini-Cardiopulmonary Bypass System
- Rien A.J.M. Huybregts, Aurora M. Morariu, Gerhard Rakhorst, Stefan R. Spiegelenberg, Hans W.A. Romijn, Roel de Vroege, and Willem van Oeveren
Ann. Thorac. Surg. 2007 83: 1760-1766.
[Abstract]
[Full Text]
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