Ann Thorac Surg 2004;78:2138
© 2004 The Society of Thoracic Surgeons
Original Article: Cardiovascular
INVITED COMMENTARY
Song Wan, MD, PhD
Division of Cardiothoracic Surgery, Chinese University of Hong Kong Prince of Wales Hospital Hong Kong, China
It has been widely recognized that a complex chain of reactions of the systemic inflammatory response to cardiopulmonary bypass (CPB) is triggered by factors both material dependent (the exposure of blood to nonphysiologic surfaces and conditions) and material independent (surgical trauma and ischemia-reperfusion to the organs). In light of this, Lindholm and colleagues are to be congratulated for their timely and carefully conducted randomized study on biocompatibility of CPB circuits with the application of an improved systemic managing protocol.
At least three noteworthy points in the current study could be appreciated. First, the authors selected to pose their questions in the relative high-risk patients (the elderly, with expected long CPB duration owing to combined coronary and valvular procedures). As a result, their data echoed nicely some recent findings in patients undergoing either redo cardiac operations or thoracic organ transplantations. It appears now that the improved biocompatibility actually benefits these high-risk patients more than it does those with a low-risk profile.
Second, in contrast to many previous studies on the similar subject, the authors analyzed their hypothesis by testing a combination of variables for different systems (ie, inflammatory response, coagulation and fibrinolysis). Such an approach indeed helps to paint a more comprehensive picture of the situation. However, no cell-saver devices were used in the current study and all cardiotomy suction blood was directly retransfused back to the patient. This particular technical detail may deserve future investigation as it was found that pericardial blood can activate the extrinsic coagulation pathway through the expression of tissue factors. Unprocessed pericardial blood may also have elevated concentrations of some inflammatory mediators such as endotoxin.
Finally, the data of Lindholm and colleagues indicate that using the combined therapeutic protocol with closed perfusion system and heparin-coated circuits and centrifugal pump would be more efficient than applying each individual component alone to improve outcome. That is probably the most important observation of the study. Such findings are indeed along the same line of the available evidence and, if proved, may significantly impact on our daily practice. The meticulous nature of the current study was clearly reflected by the large number of laboratory tests performed. Nonetheless, this study could make even better sense if the authors were able to study the antiinflammatory response simultaneously. There is a general consensus now that preserving the balance between proinflammatory and antiinflammatory responses is crucial in improving the biocompatibility of CPB and, therefore, the ideal research approach we should take is to focus our attention on both Yin and Yang.
Related Article
-
A Closed Perfusion System With Heparin Coating and Centrifugal Pump Improves Cardiopulmonary Bypass Biocompatibility in Elderly Patients
- Lena Lindholm, Martin Westerberg, Anders Bengtsson, Rolf Ekroth, Eva Jensen, and Anders Jeppsson
Ann. Thorac. Surg. 2004 78: 2131-2138.
[Abstract]
[Full Text]
[PDF]
