J Thorac Cardiovasc Surg 2006;132:732-733
© 2006 The American Association for Thoracic Surgery
I am afraid of using aprotinin because they say so?
Jeffrey H. Shuhaiber, MD
Department of Surgery, Loyola University Stritch School of Medicine, 614-G Laflin, Chicago, IL 60612
(Email: jeffrey01{at}mac.com).
To the Editor:
Cardiothoracic surgeons have become more aware of the worse outcomes associated with aprotinin after cardiac surgery, as discussed in the article by Mangano and colleagues1
published in the New England Journal of Medicine. It remains an observational study that, as the authors point out, is in need of randomized studies. The main concern of the authors that has not been addressed is the analysis of a larger sample size in the aprotinin group compared with that for other antifibrinolytics. The weighted average effect of a large sample size can have a larger effect when outcomes are analyzed.
I will address further potential confounding factors by Mangano and colleagues.1 The authors did not control for preoperative hemoglobin count. Zindrou and associates2 reported on a cohort of 2058 patients and demonstrated that a preoperative hemoglobin concentration of 10 g/L or less had a 5-fold higher in-hospital mortality rate after coronary artery bypass grafting mortality rates seen in those with a higher hemoglobin concentration, despite having had blood transfusions. Maintaining a patient's hematocrit value within the normal range and avoiding extremes is important. The main surgical factor that affects outcome in coronary artery bypass grafting is anastomosis of the internal thoracic artery to the left anterior descending artery. Moreover, the absence of critical disease in other vessels also affected outcome.3 Mangano and associates1 also provided no information about the mean number of grafts per patient, perioperative blood loss, blood-saving techniques, and "transfusion trigger." These issues are important because there is a dose-dependent association between blood transfusion and the development of severe postoperative infection and death in patients undergoing cardiac surgery.4 The authors also mentioned use of multiple variables that might or might not be clinically relevant and assigned propensity scores in the outcome models to adjust for antifibrinolytic use. I believe that such an analysis is suboptimal to propensity score matching in quantiles. Surgeons need to take a closer look and revisit the data published in this article before banning aprotinin from their practice.
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References
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- Mangano DT, Tudor IC, Dietzel C, et al. The risk associated with aprotinin in cardiac surgery. N Engl J Med. 2006;354:353-365.[Abstract/Free Full Text]
- Zindrou D, Taylor KM, Bagger JP. Preoperative haemoglobin concentration and mortality rate after coronary artery bypass surgery. Lancet. 2002;359:1747-1748.[Medline]
- Boylan MJ, Lytle BW, Loop FD, et al. Surgical treatment of isolated left anterior descending coronary stenosis. Comparison of left internal mammary artery and venous autograft at 18 to 20 years of follow-up. J Thorac Cardiovasc Surg. 1994;107:657-662.[Abstract/Free Full Text]
- Levy M, Cromheecke ME, de Jonge E, et al. Pharmacological strategies to decrease excessive blood loss in cardiac surgery. a meta-analyses of clinically relevant end points. Lancet. 1999;354:1940-1947.[Medline]
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