Ann Thorac Surg 2006;82:1444-1445
© 2006 The Society of Thoracic Surgeons
Original Articles: Cardiovascular
Invited commentary
Davide Pacini, MD
c/o Unità Operativa di Cardiochirurgia, Università degli studi di Bologna, Policlinico S. Orsola-Malpighi, Via Massarenti, 9, 40138 Bologna, Italy
(Email: dpacini{at}hotmail.com).
Hemodynamic tolerance during the off-pump procedure has been studied by various investigators, but since that time, little attention has been paid to postoperative hemodynamic outcomes. The current study by Tatoulis and colleagues [1] compares, in a randomized fashion, postoperative systemic vascular resistence (SVR) and other hemodynamic values in a group of patients undergoing on-pump and off-pump procedures. They concluded that there are no differences between the two groups in terms of hemodynamic variables and clinical outcomes.
Although the present study has several weaknesses, including a weak primary end point, SVR (which could be influenced by a number of preoperative, intraoperative and postoperative factors), and the absence of inflammatory biochemical markers measurements, it addresses several interesting topics:
- 1 Postoperative hemodynamic response to coronary revascularization. Very little has been published on postoperative hemodynamic patterns after on-pump and off-pump surgery. The hemodynamic state and its changes, including SVR, SVR index, cardiac index, blood pressure, and temperature, were similar in off-pump and on-pump patients in the present article. The mean SVR, contrarily to what was expected and to common knowledge, fell immediately postoperatively and continued to fall over the first 18 hours postoperatively in both groups. Furthermore, the mean cardiac index rose, as would be expected, corresponding to the SVR changes. These findings are in agreement with a previous article by Louagie and colleagues [2] even if they reported an increased need for inotropic support and an higher creatine phosphokinase-MB release in on-pump patients. However, the study by Louagie and colleagues was not randomized, but it was a retrospective case-matched study.
- 2 Importance of the cardiopulmonary bypass (CPB) in the systemic inflammatory response (SIR). CPB is considered to be one of the major causes of postoperative SIR in combination with surgical trauma as well as pulmonary and cardiac reperfusion. Various studies, which are indicated in the present article, have demonstrated a reduction in cytokine release in off-pump surgery; however, these differences in the SIR have not been shown to result in clinically relevant benefits. In contrast, others studies have shown that surgical trauma appears to represent the predominant factor in the postoperative inflammatory response. The postoperative SVR changes that occurred in the present study could be considered a clinical surrogate of SIR and seem to confirm that CPB bypass may be less important for immune response than previously suspected.
- 3 The completeness of coronary revascularization in off-pump surgery. Finally, also in this study, the off-pump patients received fewer bypass grafts than the on-pump patients. This finding suggests that intraoperative considerations may drive the surgeon to perform fewer bypasses during the off-pump procedure. Even if this difference did not have any short-term impact on clinical outcome, whether or not this will increase the long-term need for additional surgery or the occurrence of cardiac events for off-pump patients remains to be determined.
The authors should be congratulated for producing this important article in a relatively uninvestigated field.
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References
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- Tatoulis J, Rice S, Davis P, Goldblatt JC, Marasco S. Patterns of postoperative systemic vascular resistance in a randomized trial of conventional on-pump versus off-pump coronary artery bypass graft surgery Ann Thorac Surg 2006;82:1436-1445.[Abstract/Free Full Text]
- Louagie Y, Jamart J, Broka S, Collard E, Scavée V, Gonzalez M. Off-pump coronary bypass grafting: a case-matched comparison of hemodynamic outcome Eur J Cardithorac Surg 2002;22:552-558.[Abstract/Free Full Text]
Related Article
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Patterns of Postoperative Systemic Vascular Resistance in a Randomized Trial of Conventional On-Pump Versus Off-Pump Coronary Artery Bypass Graft Surgery
- James Tatoulis, Suzanne Rice, Penelope Davis, John C. Goldblatt, and Silvana Marasco
Ann. Thorac. Surg. 2006 82: 1436-1444.
[Abstract]
[Full Text]
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References