Troponin-T in Patients with Unstable and Stable Angina Pectoris Undergoing Coronary Bypass Surgery

Background: Troponin-T is a sensitive indicator of minor myocardial damage during coronary bypass surgery. Methods: Troponin-T levels were assessed before and repeatedly for 64 hours after coronary bypass surgery in 100 patients with unstable and 100 with stable angina pectoris. Results: Postoperative troponin-T levels rose significantly within 6 hours followed by a decline until 64 hours. In unstable patients who had pain within two days and an acute myocardial infarction within two weeks before the operation (Braunwald class IIIC), Troponin-T rose to high levels that persisted for 64 h. Sixty-seven percent of these patients had an elevated troponin-T > 0.10 µg/l already before the operation and a perioperative myocardial infarction was recorded in 27 %. In contrast, postoperative troponin-T levels in remaining patients classified as unstable were similar to those in patients with stable angina. Elective operations in the control group were performed with a low risk of adverse postoperative events. Conclusions: Patients with Braunwald class IIIC unstable angina suffered to a great extent myocardial cell damage following coronary bypass surgery.

Key words:

Unstable angina - - Troponin-T - - Coronary artery bypass grafting

References

• 1 Burlina A, Zaninotto M, Secchiero S, Rubin D, Accorsi F. Troponin-T as a marker of ischemic myocardial injury.  Clin Biochem.. 1994;  27 113-21
• 2 Stubbs P, Collinson P, Moseley D, Greenwood T, Noble M. Prospective study of the role of cardiac troponin-T in patients admitted with unstable angina.  BMJ.. 1996;  313 262-4
• 3 Seino Y, Tomita Y, Takano T, Hayakawa H. Early identification of cardiac events with serum troponin-T in patients with unstable angina.  Lancet.. 1993;  342 1236-7
• 4 Patel D J, Holdright D R, Knight C J, Mulcahy D, Thakrar B, Wright C. et al . Early continuous st segment monitoring in unstable angina: prognostic value additional to the clinical characteristics and the admission electrocardiogram.  Heart.. 1996;  75 222-8
• 5 Cannon C P, Matsumoto M, McCabe C H, Stone P H, Rogers W J, Schactman M, Thompson B W. et al . The electrocardiogram predicts one-year outcome of patients with unstable angina and non-q wave myocardial infarction: results of the TIMI III registry ancillary study. Thrombolysis in myocardial ischemia.  J Am Coll Cardiol.. 1997;  30 133-40
• 6 Olatidoye A G, Wu A H, Feng Y J, Waters D. Prognostic role of troponin-T versus troponin I in unstable angina pectoris for cardiac events with meta-analysis comparing published studies.  Am J Cardiol.. 1998;  81 1405-10
• 7 Newby L K, Christenson R H, Armstrong P W, Thompson T D, Lee K L. Value of serial troponin-T measures for early and late risk stratification in patients with acute coronary syndromes. The GUSTO-IIa Investigators.  Circulation.. 1998;  98 1853-9
• 8 Carrier M, Pelletier L C, Searle N R. Does retrograde administration of blood cardioplegia improve myocardial protection during first operation for coronary artery bypass grafting?.  Ann Thorac Surg.. 1997;  64 1256-61
• 9 Caputo M, Dihmis W, Birdi I, Reeves B, Suleiman M S, Angelini G D. et al . Cardiac troponin-T and troponin I release during coronary artery surgery using cold crystalloid and cold blood cardioplegia.  Eur J Cardiothorac Surg.. 1997;  12 254-60
• 10 Machler H, Gombotz H, Sabin K, Metzler H. Troponin-T as a marker of perioperative myocardial cell damage.  Adv Pharmacol.. 1994;  31 63-73
• 11 Astorri E, Fiorina P, Grattagliano C, Medici D, Pinelli S, Albertini D. Cardiac Troponin-T to evaluate myocardial protection via intermittent cold blood or continuous warm blood cardioplegia in coronary artery bypass grafting.  J Cardiovasc Surg.. 1998;  39 797-802
• 12 Fremes S E, Goldman B S, Christakis G T, Ivanov J, Weisel R D, Salerno T A. et al . Current risk of coronary bypass for unstable angina.  Eur J Cardiothorac Surg.. 1991;  5 235-42
• 13 Carrier M, Pelletier L C, Martineau R, Pellerin M, Solymoss B C. In elective coronary artery bypass grafting, preoperative troponin-T level predicts the risk of myocardial infarction.  J Thorac Cardiovasc Surg.. 1998;  115 1328-34
• 14 Braunwald E. Unstable angina. A classification.  Circulation.. 1989;  80 410-4
• 15 Spjotvoll E, Stoline M R. An extension of the T-method of multiple comparisons to include the cases with unequal sample sizes.  J Amer Stat Assoc.. 1973;  68 976-8
• 16 Giri S, Waters D D. Pathophysiology and initial management of the acute coronary syndromes.  Curr Opin Cardiol.. 1996;  11 351-60
• 17 Koh T W, Hooper J, Kemp M, Ferdinand F D, Gibson D G, Pepper J R. Intraoperative release of troponin-T in coronary venous and arterial blood and its relation to recovery of left ventricular function and oxidative metabolism following coronary artery surgery.  Heart.. 1998;  80 341-8
• 18 Birdi I, Angelini G D, Bryan A J. Biochemical markers of myocardial injury during cardiac operations.  Ann Thorac Surg.. 1997;  63 879-84
• 19 Kallner G, Lindblom D, Forssell G, Kallner A. Myocardial release of troponin-T after coronary bypass surgery.  Scand J Thorac Cardiovasc Surg.. 1994;  28 67-72
• 20 Jeroudi M O, Cheirif J, Habib G, Bolli R. Prolonged wall motion abnormalities after chest pain at rest in patients with unstable angina: a possible manifestation of myocardial stunning.  Am Heart J.. 1994;  127 1241-50
• 21 de Zwaan C, Bar F W, Dassen W R, Vermeer F, Wellens H J. Changes in wall motion in patients treated for unstable angina. A suggestion of the stunned and hibernating myocardium in humans. UNASEM Collaborative Study Group. Unstable Angina Study Using Eminase.  Chest.. 1995;  108 903-11
• 22 Sharma G V, Deupree R H, Luchi R J, Scott S M. Identification of unstable angina patients who have favorable outcome with medical or surgical therapy (eight-year follow-up of the Veterans Administration Cooperative Study).  Am J Cardiol.. 1994;  74 454-8