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Correspondence  |   December 2010
From Creatine Kinase-MB to Troponin: Do We Really Need to Differentiate between Myocardial Injury and Infarction?
Author Affiliations & Notes
  • Jochen D. Muehlschlegel, M.D., M.Sc.
    *
  • *Brigham and Women's Hospital, Boston, Massachusetts.
Article Information
Correspondence
Correspondence   |   December 2010
From Creatine Kinase-MB to Troponin: Do We Really Need to Differentiate between Myocardial Injury and Infarction?
Anesthesiology 12 2010, Vol.113, 1479-1480. doi:10.1097/ALN.0b013e3181fabf56
Anesthesiology 12 2010, Vol.113, 1479-1480. doi:10.1097/ALN.0b013e3181fabf56
To the Editor:
We commend Archan et al.  1 for their excellent review on creatine kinase-MB fraction and troponin for the diagnosis of perioperative myocardial infarction (MI) in noncardiac surgery patients. We, too, recently investigated the utility of creatine kinase-MB and cardiac troponin I for predicting clinically relevant myocardial injury in two cohorts of patients who had undergone coronary artery bypass surgery (N = 1,576).2 Similar to the studies the authors1 reviewed, we also found cardiac troponin I to be superior to creatine kinase-MB in its association with increased hospital length of stay and mortality.2 
When creating a universal definition for MI guidelines, the Joint European Society of Cardiology, American College of Cardiology, American Heart Association, and World Heart Federation Task Force identified five clinical classifications, although MI associated with coronary artery bypass surgery is the only category for perioperative MI.3 From a mechanistic point of view, noncardiac surgical perioperative MI would likely be classified as a type 2 MI, “myocardial infarction secondary to ischemia due to either increased oxygen demand or decreased supply, for example coronary artery spasm, coronary embolism, anemia, arrhythmias, hypertension, or hypotension.”4 
As Archan et al.  1 correctly note, the universal definition requires a combination of biomarker elevation and angina symptoms, electrocardiogram, imaging, or angiography to diagnose MI. This definition is problematic in the perioperative setting, however, because angina symptoms are not reliable in patients undergoing general anesthesia and receiving analgesics and sedatives. In addition, as a diagnostic tool, electrocardiogram is often not sensitive enough to detect ischemia—particularly after cardiac surgery.2 Therefore, even in the absence of outcome data, we suggest using troponin as the primary criteria for identifying clinically significant myocardial injury in all perioperative settings.
We respectfully disagree with Archan et al.  1 regarding the relevance of differentiating between myocardial injury and myocardial infarction. They correctly point out that troponin elevation may result from a variety of etiologies, including physiologic stress associated with marathon running or mountain climbing.5 Furthermore, the extraordinary sensitivity of currently available biomarker assays permits detection of a single troponin molecule release even after minimal exercise.6 At present, however, imaging modalities and cellular detection technology are unable to differentiate between troponin release from the cytosol or damaged cells that are likely to recover (myocardial injury) and irreversible cellular necrosis (myocardial infarction). Therefore, we suggest that increased concentrations of circulating troponin, in fact, reflect a spectrum of myocardial injury. Consequently, the assignment of a specific cutoff point in an attempt to differentiate between injury and infarction may be counterproductive to efficient identification of therapeutic interventions.
*Brigham and Women's Hospital, Boston, Massachusetts.
References
Archan S, Fleisher LA: From creatine kinase-MB to troponin: The adoption of a new standard. Anesthesiology 2010; 112:1005–12Archan, S Fleisher, LA
Muehlschlegel JD, Perry TE, Liu KY, Nascimben L, Fox AA, Collard CD, Avery EG, Aranki SF, D'Ambra MN, Shernan SK, Body SC, CABG Genomics Investigators: Troponin is superior to electrocardiogram and creatinine kinase MB for predicting clinically significant myocardial injury after coronary artery bypass grafting. Eur Heart J 2009; 30:1574–83Muehlschlegel, JD Perry, TE Liu, KY Nascimben, L Fox, AA Collard, CD Avery, EG Aranki, SF D'Ambra, MN Shernan, SK Body, SC CABG Genomics Investigators,
Thygesen K, Alpert JS, White HD, Joint ESC/ACCF/AHA/WHF Task Force for the Redefinition of Myocardial Infarction, Jaffe AS, Apple FS, Galvani M, Katus HA, Newby LK, Ravkilde J, Chaitman B, Clemmensen PM, Dellborg M, Hod H, Porela P, Underwood R, Bax JJ, Beller GA, Bonow R, Van der Wall EE, Bassand JP, Wijns W, Ferguson TB, Steg PG, Uretsky BF, Williams DO, Armstrong PW, Antman EM, Fox KA, Hamm CW, Ohman EM, Simoons ML, Poole-Wilson PA, Gurfinkel EP, Lopez-Sendon JL, Pais P, Mendis S, Zhu JR, Wallentin LC, Fernández-Avilés F, Fox KM, Parkhomenko AN, Priori SG, Tendera M, Voipio-Pulkki LM, Vahanian A, Camm AJ, De Caterina R, Dean V, Dickstein K, Filippatos G, Funck-Brentano C, Hellemans I, Kristensen SD, McGregor K, Sechtem U, Silber S, Widimsky P, Zamorano JL, Morais J, Brener S, Harrington R, Morrow D, Lim M, Martinez-Rios MA, Steinhubl S, Levine GN, Gibler WB, Goff D, Tubaro M, Dudek D, Al-Attar N: Universal definition of myocardial infarction. Circulation 2007; 116:2634–53Thygesen, K Alpert, JS White, HD Joint ESC/ACCF/AHA/WHF Task Force for the Redefinition of Myocardial Infarction, Jaffe, AS Apple, FS Galvani, M Katus, HA Newby, LK Ravkilde, J Chaitman, B Clemmensen, PM Dellborg, M Hod, H Porela, P Underwood, R Bax, JJ Beller, GA Bonow, R Van der Wall, EE Bassand, JP Wijns, W Ferguson, TB Steg, PG Uretsky, BF Williams, DO Armstrong, PW Antman, EM Fox, KA Hamm, CW Ohman, EM Simoons, ML Poole-Wilson, PA Gurfinkel, EP Lopez-Sendon, JL Pais, P Mendis, S Zhu, JR Wallentin, LC Fernández-Avilés, F Fox, KM Parkhomenko, AN Priori, SG Tendera, M Voipio-Pulkki, LM Vahanian, A Camm, AJ De Caterina, R Dean, V Dickstein, K Filippatos, G Funck-Brentano, C Hellemans, I Kristensen, SD McGregor, K Sechtem, U Silber, S Widimsky, P Zamorano, JL Morais, J Brener, S Harrington, R Morrow, D Lim, M Martinez-Rios, MA Steinhubl, S Levine, GN Gibler, WB Goff, D Tubaro, M Dudek, D Al-Attar, N
Priebe HJ: Perioperative myocardial infarction—aetiology and prevention. Br J Anaesth 2005; 95:3–19Priebe, HJ
Apple FS, Quist HE, Otto AP, Mathews WE, Murakami MM: Release characteristics of cardiac biomarkers and ischemia-modified albumin as measured by the albumin cobalt-binding test after a marathon race. Clin Chem 2002; 48:1097–100Apple, FS Quist, HE Otto, AP Mathews, WE Murakami, MM
Sabatine MS, Morrow DA, de Lemos JA, Jarolim P, Braunwald E: Detection of acute changes in circulating troponin in the setting of transient stress test-induced myocardial ischaemia using an ultrasensitive assay: Results from TIMI 35. Eur Heart J 2009; 30:162–9Sabatine, MS Morrow, DA de Lemos, JA Jarolim, P Braunwald, E