Letter to the Editor
Ischemic postconditioning for acute myocardial infarction: Standardized end points to reduce the potential selection bias We read with great interest the article by Khan et al 1 online published in the Journal in July 2014. They included 19 studies in the pooled analysis and tried to summarize the effect of ischemic postconditioning on cardiac enzyme levels, left ventricular ejection fraction, and infarct size in patients with acute myocardial infarction. The I 2 value of heterogeneity test among the included studies was 92.0%, 69.0%, and 80.0% for the 3 prementioned end points, respectively. Minimizing the heterogeneity is an effective approach to increase the robustness of the results in the meta-analysis. However, the reporting results for these 3 end points are with different scales or measurements. For cardiac enzyme levels, peak or area under curve of troponin levels, creatine kinase levels, or creatine kinase-MB levels was used simultaneously in 1 study. 2-4 The similar phenomena also existed in left ventricular ejection fraction (Cardiac Magnetic Resonance or echocardiograpy) 4 and infarct size (percentage of left ventricular mass or grams) 5 results. The principal for this selection must be rational and consistent (such as preference or priority). 6 Nevertheless, the author did not report their detailed principals in the process of data extraction. Hence, I would like to know the related selection criteria for this important point. Am Heart J 2015;169:e1. 0002-8703 © 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ahj.2014.10.014
Yang Yu, MD Chenghui Zhou, MD, PhD Department of Anesthesiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, 100037, China Reprint requests: Chenghui Zhou, MD, PhD, Department of Anesthesiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, 100037, China. E-mail: [email protected]
References 1. Khan AR, Bin Abdulhak AA, Alastal Y, et al. Cardio-protective role of ischemic postconditioning in acute myocardial infarction: a systematic review and meta-analysis. 2. Thibault H, Piot C, Staat P, et al. Long-term benefit of postconditioning. Circulation 2008;117:1037-44. 3. Sorensson P, Saleh N, Bouvier F, et al. Effect of postconditioning on infarct size in patients with ST elevation myocardial infarction. Heart 2010;96:1710-5. 4. Freixa X, Bellera N, Ortiz-Perez JT, et al. Ischaemic postconditioning revisited: lack of effects on infarct size following primary percutaneous coronary intervention. Eur Heart J 2012;33:103-12. 5. Tarantini G, Favaretto E, Marra MP, et al. Postconditioning during coronary angioplasty in acute myocardial infarction: the POST-AMI trial. Int J Cardiol 2012;162:33-8. 6. Zhou C, Yao Y, Zheng Z, et al. Stenting technique, gender, and age are associated with cardioprotection by ischaemic postconditioning in primary coronary intervention: a systematic review of 10 randomized trials. Eur Heart J 2012;33:3070-7.
Ischemic postconditioning for acute myocardial infarction: Standardized end points to reduce the potential selection bias We read with great interest the article by Khan et al 1 online published in the Journal in July 2014. They included 19 studies in the pooled analysis and tried to summarize the effect of ischemic postconditioning on cardiac enzyme levels, left ventricular ejection fraction, and infarct size in patients with acute myocardial infarction. The I 2 value of heterogeneity test among the included studies was 92.0%, 69.0%, and 80.0% for the 3 prementioned end points, respectively. Minimizing the heterogeneity is an effective approach to increase the robustness of the results in the meta-analysis. However, the reporting results for these 3 end points are with different scales or measurements. For cardiac enzyme levels, peak or area under curve of troponin levels, creatine kinase levels, or creatine kinase-MB levels was used simultaneously in 1 study. 2-4 The similar phenomena also existed in left ventricular ejection fraction (Cardiac Magnetic Resonance or echocardiograpy) 4 and infarct size (percentage of left ventricular mass or grams) 5 results. The principal for this selection must be rational and consistent (such as preference or priority). 6 Nevertheless, the author did not report their detailed principals in the process of data extraction. Hence, I would like to know the related selection criteria for this important point. Am Heart J 2015;169:e1. 0002-8703 © 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ahj.2014.10.014
Yang Yu, MD Chenghui Zhou, MD, PhD Department of Anesthesiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, 100037, China Reprint requests: Chenghui Zhou, MD, PhD, Department of Anesthesiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, 100037, China. E-mail: [email protected]
References 1. Khan AR, Bin Abdulhak AA, Alastal Y, et al. Cardio-protective role of ischemic postconditioning in acute myocardial infarction: a systematic review and meta-analysis. 2. Thibault H, Piot C, Staat P, et al. Long-term benefit of postconditioning. Circulation 2008;117:1037-44. 3. Sorensson P, Saleh N, Bouvier F, et al. Effect of postconditioning on infarct size in patients with ST elevation myocardial infarction. Heart 2010;96:1710-5. 4. Freixa X, Bellera N, Ortiz-Perez JT, et al. Ischaemic postconditioning revisited: lack of effects on infarct size following primary percutaneous coronary intervention. Eur Heart J 2012;33:103-12. 5. Tarantini G, Favaretto E, Marra MP, et al. Postconditioning during coronary angioplasty in acute myocardial infarction: the POST-AMI trial. Int J Cardiol 2012;162:33-8. 6. Zhou C, Yao Y, Zheng Z, et al. Stenting technique, gender, and age are associated with cardioprotection by ischaemic postconditioning in primary coronary intervention: a systematic review of 10 randomized trials. Eur Heart J 2012;33:3070-7.
