Papers

Prospective study of the role of cardiac troponin T in patients admitted with unstable angina

^a Academic Unit of Cardiovascular Medicine, Charing Cross and Westminster Medical School, Fifth Floor, South Wing, Charing Cross Hospital, London W6 8RF, ^b Mayday University Hospital, London CR7 7YE, ^c West Middlesex University Hospital, London TW7 6AF

Correspondence to: Dr Stubbs.

Abstract

Objective: To examine the prognostic significance and role in risk stratification of the biochemical marker troponin T in patients admitted with unstable angina.
Design: Single centre, blinded, prospective study of patients admitted with chest pain.
Setting: Coronary care unit of a district general hospital.
Subjects: 460 patients admitted with chest pain and followed up for a median of three years. 183 patients had a final diagnosis of unstable angina.
Main outcome measures: Cardiac death, need for coronary revascularisation, or readmission with non-fatal myocardial infarction as first events.
Results: 62 (34%) unstable angina patients were troponin T positive. This group had significantly increased incidence rates of subsequent cardiac death (12 cases (19%) v 14 (12%)), coronary revascularisation (22 (35%) v 26 (21%)), death or revascularisation (33 (53%) v 40 (33%)), and death or non-fatal myocardial infarction (18 (29%) v 21 (17%)) compared with the troponin T negative group. In multiple logistic regression troponin T status was a highly significant predictor for the end points coronary revascularisation and cardiac death or revascularisation as first events.
Conclusion: Troponin T in the serum of patients with unstable angina identifies a subgroup at higher risk of subsequent cardiac events and its measurement aids in risk factor stratification. The increased risk extends to two years after admission. Prospective randomised trials are required to identify optimum therapeutic strategies for this subgroup.

Introduction

Unstable angina represents a critical phase of ischaemic heart disease and is associated with a significant risk of subsequent myocardial infarction or death.^{1 2 3 4 5 6 7} A subset of patients with unstable angina have raised concentrations of the cardiac specific protein troponin T^{8 9 10 11} in their serum early in the admission period. Detection of troponin T indicates minor myocardial damage and was associated with an excess of cardiac events both in inpatients^{8 9 10 11} and on short term follow up.^{12 13} We evaluated the potential role of this marker in stratifying for risk patients with unstable angina admitted in routine clinical practice.

Subjects and methods

We conducted a single centre blinded study with follow up of patients admitted to a hospital coronary care unit with chest pain. Management decisions were based on clinical, electrocardiographic, and routine biochemical marker results (daily serum creatine kinase, aspartate transaminase, and hydroxybutyrate dehydrogenase activities). An additional sample was taken 12-24 hours after admission, when the cardiac troponin T concentration is at its most efficient for diagnosing myocardial damage in these patients.¹¹ All management decisions were made without knowledge of the patient's troponin T status.

Full clinical details of each patient were recorded on a form. Follow up for cardiac events was by examination of hospital records, necropsy reports when available and death certificates, questionnaires, and telephone contact when required. Survival status and cause of death were established for all patients. Cause of death was classified according to American Heart Association criteria.¹⁴

Diagnostic classifications--Unstable angina was diagnosed retrospectively if the World Health Organisation criteria for myocardial infarction were not met.¹⁵ All enzyme measurements (serum creatine kinase, aspartate transaminase, and hydroxybutyrate dehydrogenase activities) were below twice the upper limit of the 95% reference range throughout the routine sampling period. Evidence of ischaemic heart disease was shown by either a cardiac event during follow up, a positive coronary angiogram (stenosis of 50% or more in a major coronary segment), a positive treadmill test result (>0.1 mV ST segment depression 80 ms after the J point), or detection of ischaemia on thallium radioisotope study. Patients with a final diagnosis of unstable angina were considered to be troponin T positive if the troponin T concentration was >/=0.2 µg/l 12-24 hours after admission.^{11 13}

Troponin T concentrations were measured by an enzyme linked immunosorbent assay (ELISA) with an ES-300 immunoassay analyser (Boehringer Mannheim, Lewes, Sussex).¹¹

Statistical analysis--Baseline demographic values were expressed as proportions of patients or means and standard deviations. Cumulative hazard curves were computed by the Kaplan-Meier method. End points were cardiac death, need for coronary revascularisation, death or revascularisation, and death or non-fatal myocardial infarction as a first event. Non-cardiac death was treated as a censored observation. End point statistical evaluation was performed with the log rank test and the Mantel-Haenszel test. All significant variables identified in univariate analysis and also indices that have been used to stratify unstable angina patients for risk^{2 16 17 18 19 20} were entered into a multivariate one step logistic regression model. Statistical analysis was by the SAS statistical software package (SAS Institute Inc, Cary, North Carolina; version 6.08).

Results

Troponin T measurements were available for 460 patients and this cohort was followed up for a median of 1032 days (lower quartile 858, upper quartile 1307, range 3-1607). A total of 183 patients had a final diagnosis of unstable angina. Table 1 summarises the baseline demographic details of these patients. Sixty two (34%) patients were positive for troponin T (serum concentrations 0.2-6.1 µg/l) and 121 (66%) negative for troponin T. Baseline demographic values in the troponin T positive and troponin T negative patients showed very little difference clinically between the groups (table 1).

Table 1--Baseline demographic values. Except where stated otherwise figures are
whole numbers (percentages) of subjects
---------------------------------------------------------------------------------------------
                                                Unstable angina
---------------------------------------------------------------------------------------------
                                                           Troponin T
                                         Troponin T         negative
Variable                               positive (n = 62)    (n = 121)    Significance+
---------------------------------------------------------------------------------------------
Mean age (years) (SD)                     62.8 (10.3)       59.9 (11.8)     0.089
Male sex                                  42   (68)         91   (75)       0.231
Hypertension                              17   (27)         32   (26)       0.889
Diabetes mellitus                         13   (21)         16   (13)       0.182
Current smoker                            23   (37)         33   (27)       0.157
Previous myocardial infarction            20   (32)         46   (38)       0.444
Accelerated angina++                      27   (44)         49   (40)       0.692
Admission rest pain                       44   (69)         80   (66)       0.507
Mean time to coronary care from worst
 pain (hours) (SD)                         5.0 (6.5)         5.1 (8.9)      0.313
ST or T wave changes in admission
 electrocardiogram                        31   (50)         49   (40)       0.162
Intravenous heparin                       25   (40)         60   (50)       0.236
Nitrate therapy                           36   (58)         65   (54)       0.644
ß Blocker                            21   (32)         32   (27)       0.492
Calcium antagonist                        27   (45)         49   (40)       0.536
Pain as inpatient (>1)                    17   (27)         25   (21)       0.305
Electrocardiographic changes with pain    10   (16)         13   (11)       0.230
Mean length of stay (days) (SD)            9.7 (4.5)         7.1 (5.1)      0.0001
Discharge aspirin                         48   (77)         85   (70)       0.304
Mean No of discharge drugs                    1.9               1.6         0.035
---------------------------------------------------------------------------------------------
+Assessed by 2 for continuous variables and Mann-Whitney U for ordinal variables.
++Increasing chest pain in 48 hours before admission.

Figure 1 shows the cumulative hazard curves for the unstable angina groups dichotomised according to troponin T status. All the curves separated early and continued to separate for about two years after the index admission. For cardiac death the curves began to converge after this period. Twelve (19%) troponin T positive patients compared with 14 (12%) troponin T negative patients died (log rank test, P = 0.11). This difference reached significance when allowance was made for coronary revascularisation by means of the Mantel-Haenszel statistic (P = 0.035; relative risk 2.58 (95% confidence interval 1.07 to 6.24)). Twenty two (35%) troponin T positive patients underwent revascularisation and only one (5%) died. By contrast, of the 40 troponin T positive patients who did not undergo revascularisation, 11 (28%) died (log rank test, P = 0.028). In the logistic regression model (table 2) only the association with previous myocardial infarction reached the conventional level of significance (P = 0.04).

View larger version (29K): [in this window] [in a new window]   Fig 1--Kaplan-Meier cumulative hazard function curves for unstable angina according to troponin T status and end points +Mantel-Haenszel statistic. ++Log rank statistic.

Table 2--Multiple logistic regression analysis of variables for each end point
-------------------------------------------------------------------------------------------
                                                                    Odds  95% Confidence
End point and variable                                Significance+ ratio    interval
-------------------------------------------------------------------------------------------
Cardiac death
Previous myocardial infarction                           0.040      3.66    1.06 to 12.65
Troponin T status                                        0.507      1.50    0.43 to 5.41
Further pain or electrocardiographic changes, or both    0.765      1.20    0.36 to 4.03
Coronary revascularisation
Accelerated angina++                                     0.001      3.74    1.70 to 8.22
Troponin T status                                        0.007      3.18    1.37 to 7.37
Troponin T or accelerated angina, or both                0.0007     5.39    2.04 to 14.33
Further pain or electrocardiographic changes, or both    0.017      3.19    1.23 to 8.33
Cardiac death or revascularisation
Troponin T status                                        0.008      2.55    1.28 to 5.08
Accelerated angina                                       0.038      1.98    1.04 to 3.79
Troponin T or accelerated angina, or both                0.0007     3.55    1.71 to 7.40
Further pain or electrocardiographic changes, or both    0.041      2.16    1.03 to 4.54
Cardiac death or non-fatal myocardial infarction
Diabetes mellitus                                        0.007      4.56    1.51 to 13.7
Age                                                      0.009      1.08    1.02 to 1.14
Previous myocardial infarction                           0.037      2.83    1.06 to 7.57
Troponin T status                                        0.123      1.21    0.42 to 3.47
Further pain or electrocardiographic changes, or both    0.739      0.84    0.31 to 2.29
-------------------------------------------------------------------------------------------
+Assessed by 2.
++Increasing chest pain in 48 hours before admission.

Twenty two (35%) troponin T positive patients versus 26 (21%) troponin T negative patients underwent either coronary artery bypass grafting (14 (23%) versus 18 (15%) patients respectively) or percutaneous transluminal coronary angioplasty (eight (13%) versus eight (7%)) as first events (log rank test, P = 0.032; relative risk 2.09 (1.06 to 4.03)) (fig 1). In the regression model both accelerated angina (increasing chest pain in the 48 hours before admission) and troponin T status were highly significant for this end point (table 2).

Thirty three (53%) troponin T positive patients versus 40 (33%) troponin T negative patients either died or underwent revascularisation as a first event (log rank test, P = 0.004; relative risk 2.45 (1.30 to 4.61)) (fig 1). In the logistic regression model troponin T status was the most significant single variable predictor for this end point (P = 0.008; relative risk 2.55 (1.28 to 5.08)). Again the presence of either variable--that is, accelerated angina or troponin T status--was highly significant for this end point (P = 0.0007) (table 2).

Eighteen (29%) troponin T positive patients versus 21 (17%) troponin T negative patients either died or suffered a non-fatal myocardial infarction as a first event (fig 1) (log rank test, P = 0.07). This difference reached significance when allowance was made for coronary revascularisation by means of the Mantel-Haenszel statistic (P = 0.042; relative risk 2.16 (1.03 to 4.53)). In the logistic regression model patients with diabetes (table 2) had a significantly increased risk for this end point. The association with troponin T status did not reach significance (P = 0.12).

Comment

The overall finding from this study is that, though it should not be used as a sole discriminator of future risk, a serum troponin T concentration >/=0.2 µg/l measured 12-24 hours after admission will identify a subgroup of patients with unstable angina in routine clinical practice who are at increased risk of cardiac events on long term follow up. Prospective randomised trials are required to identify optimum therapeutic strategies for this subgroup.

Funding: None.

Conflict of interest: None.

1. Fuster V, Badimon L, Cohen M, Ambrose JA, Badimon JJ, Chesebro J. Insights into the pathogenesis of acute ischemic syndromes. Circulation 1988;77:1213-20. [Free Full Text]
2. De Servi S, Berzuini C, Poma E. Long term survival and risk factor stratification in patients with angina at rest undergoing medical treatment. Int J Cardiol 1989;22:43-50. [Medline]
3. Mulcahy R, Daly L, Graham I, Hickey N, O'Donoghue S, Owens A, et al. Unstable angina: natural history and determinants of prognosis. Am J Cardiol 1981;48:525-8. [Medline]
4. Davies MJ, Thomas AC, Knapman PA, Hangartner JR. Intramyocardial platelet aggregation in patients with unstable angina suffering sudden ischemic cardiac death. Circulation 1986;73:418-27. [Abstract/Free Full Text]
5. Falk E. Unstable angina with fatal outcome: dynamic coronary thrombosis leading to infarction and/or sudden death: autopsy evidence of recurrent mural thrombosis with peripheral embolisation culminating in total vascular occlusion. Circulation 1985;71:699-708. [Abstract/Free Full Text]
6. Nordlander R, Nyquist O. Patients treated in a coronary care unit without acute myocardial infarction: identification of a high risk sub-group for subsequent myocardial infarction and/or cardiovascular death. Br Heart J 1979;41:647-53. [Abstract/Free Full Text]
7. Heng M-K, Norris RM, Singh BN, Partridge JB. Prognosis in unstable angina. Br Heart J 1976;38:921-5. [Abstract/Free Full Text]
8. Katus HA, Remppis A, Neumann FJ, Scheffold T, Diederich KW, Vinar G, et al. Diagnostic efficiency of troponin T measurements in acute myocardial infarction. Circulation 1991;83:902-12. [Abstract/Free Full Text]
9. Hamm CW, Ravkilde J, Gerhardt W, Jorgensen P, Peheim E, Ljungdahl L, et al. The prognostic value of serum troponin T in unstable angina. N Engl J Med 1992;327:146-50. [Abstract]
10. Seino Y, Tonita Y, Takano T, Hayakawa H. Early identification of cardiac events with serum troponin T in patients with unstable angina. Lancet 1993;342:1236-7. [Medline]
11. Collinson PO, Moseley D, Stubbs P, Carter D. Troponin T for the differential diagnosis of ischaemic myocardial damage. Ann Clin Biochem 1993;30:11-6.
12. Collinson PO, Stubbs P. The prognostic value of serum troponin T in unstable angina. N Engl J Med 1992;327:1760-1. [Medline]
13. Ravkilde J, Horder M, Gerhardt W, Ljundahl L, Petterson T, Tryding N, et al. Diagnostic performance and prognostic value of serum troponin T in suspected acute myocardial infarction. Scand J Clin Lab Invest 1993;53:677-85. [Medline]
14. Gillum RF, Fortmann SP, Prineas RJ. International diagnostic criteria for acute myocardial infarction and acute stroke. Am Heart J 1984;108:155-8.
15. Working Group on Establishment of Ischaemic Heart Disease Registers. Report of fifth working group. Copenhagen: World Health Organisation, 1971. (WHO, Eur 8201 (5).)
16. Braunwald E. Unstable angina: a classification. Circulation 1989;80:410-4. [Free Full Text]
17. Murphy JJ, Connell PA, Hampton JR. Predictors of risk in patients admitted with unstable angina to a district general hospital. Br Heart J 1992;67:395-401. [Abstract/Free Full Text]
18. Gazes PC, Mobley EM Jr, Faris HM Jr, Duncan RC, Humphries GB. Preinfarctional (unstable) angina--a prospective study--ten year follow-up: prognostic significance of electrocardiographic changes. Circulation 1973;48:331-7. [Abstract/Free Full Text]
19. Olson HG, Lyons KP, Aronow WS, Stinson PJ, Kuperus J, Waters HJ. The high risk angina patient: identification by clinical features, hospital course, electrocardiography and technetium-99m stannous pyrophosphate scintigraphy. Circulation 1981;64:674-84. [Abstract/Free Full Text]
20. Quale J, Kimmelsteil C, Schrem S. Identification of risk factors for acute myocardial infarction and serious ventricular arrhythmias in patients with unstable angina. Am J Cardiol 1987;58:703-4.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    StumbleUpon    Technorati    Twitter    What's this?

Relevant Article

Does measurement of troponin T add to ability to stratify risk?

R Lee Kennedy
BMJ 1996 313: 1330. [Extract] [Full Text]

This article has been cited by other articles:

• Bjessmo, S. (2009). Increased rehospitalization rate after coronary bypass operation for acute coronary syndrome: a prospective study in 200 patients.. Ann. Thorac. Surg. 88: 1148-1152 [Abstract] [Full text]  
• Collinson, P. O, Gaynor, G. H, Gaze, D. C (2008). Cardiac troponin I measurement using the ACS:180 to predict four-year cardiac event rate. Ann Clin Biochem 45: 184-188 [Abstract] [Full text]  
• Anderson, J. L., Adams, C. D., Antman, E. M., Bridges, C. R., Califf, R. M., Casey, D. E. Jr, Chavey, W. E. II, Fesmire, F. M., Hochman, J. S., Levin, T. N., Lincoff, A. M., Peterson, E. D., Theroux, P., Wenger, N. K., Wright, R. S., Smith, S. C. Jr, Jacobs, A. K., Adams, C. D., Anderson, J. L., Antman, E. M., Halperin, J. L., Hunt, S. A., Krumholz, H. M., Kushner, F. G., Lytle, B. W., Nishimura, R., Ornato, J. P., Page, R. L., Riegel, B. (2007). ACC/AHA 2007 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction) Developed in Collaboration with the American College of Emergency Physicians, the Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons Endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation and the Society for Academic Emergency Medicine. J Am Coll Cardiol 50: e1-e157 [Full text]  
• Devlin, G, Anderson, F A, Heald, S, Lopez-Sendon, J, Avezum, A, Elliott, J, Dabbous, O H, Brieger, D, for the GRACE Investigators, (2005). Management and outcomes of lower risk patients presenting with acute coronary syndromes in a multinational observational registry. Heart 91: 1394-1399 [Abstract] [Full text]  
• Norgaard, B L, Andersen, K, Thygesen, K, Ravkilde, J, Abrahamsson, P, Grip, L, Dellborg, M (2004). Long term risk stratification of patients with acute coronary syndromes: characteristics of troponin T testing and continuous ST segment monitoring. Heart 90: 739-744 [Abstract] [Full text]  
• Conroy, S, Kamal, I, Cooper, J (2004). Troponin testing: beware pulmonary embolus. Emerg. Med. J. 21: 123-124 [Abstract] [Full text]  
• White, H. D., French, J. K. (2003). Use of brain natriuretic peptide levels for risk assessment in non-ST-elevation acute coronary syndromes. J Am Coll Cardiol 42: 1917-1920 [Full text]  
• Luepker, R. V., Apple, F. S., Christenson, R. H., Crow, R. S., Fortmann, S. P., Goff, D., Goldberg, R. J., Hand, M. M., Jaffe, A. S., Julian, D. G., Levy, D., Manolio, T., Mendis, S., Mensah, G., Pajak, A., Prineas, R. J., Reddy, K. S., Roger, V. L., Rosamond, W. D., Shahar, E., Sharrett, A. R., Sorlie, P., Tunstall-Pedoe, H. (2003). Case Definitions for Acute Coronary Heart Disease in Epidemiology and Clinical Research Studies: A Statement From the AHA Council on Epidemiology and Prevention; AHA Statistics Committee; World Heart Federation Council on Epidemiology and Prevention; the European Society of Cardiology Working Group on Epidemiology and Prevention; Centers for Disease Control and Prevention; and the National Heart, Lung, and Blood Institute. Circulation 108: 2543-2549 [Full text]  
• Hyde, T A, French, J K, Wong, C-K, Edwards, C, Whitlock, R M L, White, H D (2003). Associations between ST depression, four year mortality, and in-hospital revascularisation in unselected patients with non-ST elevation acute coronary syndromes. Heart 89: 490-495 [Abstract] [Full text]  
• Collinson, P O, Stubbs, P J, Kessler, A-C (2003). Multicentre evaluation of the diagnostic value of cardiac troponin T, CK-MB mass, and myoglobin for assessing patients with suspected acute coronary syndromes in routine clinical practice. Heart 89: 280-286 [Abstract] [Full text]  
• Newby, L. K., Goldmann, B. U., Ohman, E. M. (2003). Troponin: an important prognostic marker and risk-stratification tool in non-ST-segment elevation acute coronary syndromes. J Am Coll Cardiol 41: 31S-36S [Abstract] [Full text]  
• Miller, C, Lipscomb, K, Curzen, N (2003). Are district general hospital patients with unstable angina at a disadvantage?. Postgrad. Med. J. 79: 93-98 [Abstract] [Full text]  
• Bertrand, M. E., Simoons, M. L., Fox, K. A.A., Wallentin, L. C., Hamm, C. W., McFadden, E., De Feyter, P. J., Specchia, G., Ruzyllo, W. (2002). Management of acute coronary syndromes in patients presenting without persistent ST-segment elevation. Eur Heart J 23: 1809-1840 [Full text]  
• Meier, M. A., Al-Badr, W. H., Cooper, J. V., Kline-Rogers, E. M., Smith, D. E., Eagle, K. A., Mehta, R. H. (2002). The New Definition of Myocardial Infarction: Diagnostic and Prognostic Implications in Patients With Acute Coronary Syndromes. Arch Intern Med 162: 1585-1589 [Abstract] [Full text]  
• Douketis, J. D., Crowther, M. A., Stanton, E. B., Ginsberg, J. S. (2002). Elevated Cardiac Troponin Levels in Patients With Submassive Pulmonary Embolism. Arch Intern Med 162: 79-81 [Abstract] [Full text]  
• Dougan, J.P., Mathew, T.P., Riddell, J.W., Spence, M.S., McGlinchey, P.G., Nesbitt, G.S., Smye, M., Menown, I.B.A., Adgey, A.A.J. (2001). Suspected angina pectoris: a rapid-access chest pain clinic. QJM 94: 679-686 [Abstract] [Full text]  
• Lindahl, B., Diderholm, E., Lagerqvist, B., Venge, P., Wallentin, L., the FRISC II Investigators, (2001). Mechanisms behind the prognostic value of troponin T in unstable coronary artery disease: a FRISC II substudy. J Am Coll Cardiol 38: 979-986 [Abstract] [Full text]  
• Norris, R.M. (2001). Dissent from the consensus on the redefinition of myocardial infarction. Eur Heart J 22: 1626-1627  
• Heidenreich, P. A., Alloggiamento, T., Melsop, K., McDonald, K. M., Go, A. S., Hlatky, M. A. (2001). The prognostic value of troponin in patients with non-ST elevation acute coronary syndromes: a meta-analysis. J Am Coll Cardiol 38: 478-485 [Abstract] [Full text]  
• British Cardiac Society Guidelines and Medical Pra, , Royal College of Physicians Clinical Effectiveness, (2001). Guideline for the management of patients with acute coronary syndromes without persistent ECG ST segment elevation. Heart 85: 133-142 [Full text]  
• Huggon, A M, Chambers, J, Nayeem, N, Tutt, P, Crook, M, Swaminathan, S (2001). Biochemical markers in the management of suspected acute myocardial infarction in the emergency department. Emerg. Med. J. 18: 15-19 [Abstract] [Full text]  
• Kontos, M. C., Anderson, F. P., Alimard, R., Ornato, J. P., Tatum, J. L., Jesse, R. L. (2000). Ability of troponin I to predict cardiac events in patients admitted from the emergency department. J Am Coll Cardiol 36: 1818-1823 [Abstract] [Full text]  
• Lindahl, B., Toss, H., Siegbahn, A., Venge, P., Wallentin, L., The FRISC Study Group, (2000). Markers of Myocardial Damage and Inflammation in Relation to Long-Term Mortality in Unstable Coronary Artery Disease. NEJM 343: 1139-1147 [Abstract] [Full text]  
• Dierkes, J., Domrose, U., Westphal, S., Ambrosch, A., Bosselmann, H.-P., Neumann, K. H., Luley, C. (2000). Cardiac Troponin T Predicts Mortality in Patients With End-Stage Renal Disease. Circulation 102: 1964-1969 [Abstract] [Full text]  
• Matetzky, S., Sharir, T., Domingo, M., Noc, M., Chyu, K.-Y., Kaul, S., Eigler, N., Shah, P. K., Cercek, B. (2000). Elevated Troponin I Level on Admission Is Associated With Adverse Outcome of Primary Angioplasty in Acute Myocardial Infarction. Circulation 102: 1611-1616 [Abstract] [Full text]  
• Al-Obaidi, M. K., Stubbs, P. J., Collinson, P., Conroy, R., Graham, I., Noble, M. I. M. (2000). Elevated homocysteine levels are associated with increased ischemic myocardial injury in acute coronary syndromes. J Am Coll Cardiol 36: 1217-1222 [Abstract] [Full text]  
• Braunwald, E., Antman, E. M., Beasley, J. W., Califf, R. M., Cheitlin, M. D., Hochman, J. S., Jones, R. H., Kereiakes, D., Kupersmith, J., Levin, T. N., Pepine, C. J., Schaeffer, J. W., Smith, E. E. III, Steward, D. E., Theroux, P., Gibbons, R. J., Alpert, J. S., Eagle, K. A., Faxon, D. P., Fuster, V., Gardner, T. J., Gregoratos, G., Russell, R. O., Smith, S. C. Jr (2000). ACC/AHA guidelines for the management of patients with unstable angina and non-st-segment elevation myocardial infarction: A report of the american college of cardiology/ american heart association task force on practice guidelines (committee on the management of patients with unstable angina). J Am Coll Cardiol 36: 970-1062 [Full text]  
• Bertrand, M.E, Simoons, M.L, Fox, K.A.A, Wallentin, L.C, Hamm, C.W, McFadden, E, de Feyter, P.J, Specchia, G, Ruzyllo, W (2000). Management of acute coronary syndromes: acute coronary syndromes without persistent ST segment elevation. Recommendations of the Task Force of the European Society of Cardiology: Recommendations of the Task Force of the European Society of Cardiology. Eur Heart J 21: 1406-1432  
• Collinson, P O, Premachandram, S, Hashemi, K, Kennedy, R L. (2000). Prospective audit of incidence of prognostically important myocardial damage in patients discharged from emergency department Commentary: Time for improved diagnosis and management of patients presenting with acute chest pain. BMJ 320: 1702-1705 [Abstract] [Full text]  
• Safstrom, K.a., Lindahl, B., Swahn, E., the FRISC-Study Group, (2000). Risk stratification in unstable coronary artery disease: Exercise test and troponin T from a gender perspective. J Am Coll Cardiol 35: 1791-1800 [Abstract] [Full text]  
• MAYNARD, S J, MENOWN, I B A, ADGEY, A A J (2000). Troponin T or troponin I as cardiac markers in ischaemic heart disease. Heart 83: 371-373 [Full text]  
• Fuchs, S., Kornowski, R., Mehran, R., Satler, L. F., Pichard, A. D., Kent, K. M., Hong, M. K., Slack, S., Stone, G. W., Leon, M. B. (1999). Cardiac troponin I levels and clinical outcomes in patients with acute coronary syndromes: The potential role of early percutaneous revascularization. J Am Coll Cardiol 34: 1704-1710 [Abstract] [Full text]  
• Mathew, T., Menown, I., Smith, B., Smye, M., Nesbitt, S., Young, I., Adgey, A.A.J. (1999). Diagnosis and risk stratification of patients with anginal pain and non-diagnostic electrocardiograms. QJM 92: 565-571 [Abstract] [Full text]  
• Muller-Bardorff, M., Rauscher, T., Kampmann, M., Schoolmann, S., Laufenberg, F., Mangold, D., Zerback, R., Remppis, A., Katus, H. A. (1999). Quantitative Bedside Assay for Cardiac Troponin T: A Complementary Method to Centralized Laboratory Testing. Clin. Chem. 45: 1002-1008 [Abstract] [Full text]  
• Kontos, M. C., Jesse, R. L., Anderson, F. P., Schmidt, K. L., Ornato, J. P., Tatum, J. L. (1999). Comparison of Myocardial Perfusion Imaging and Cardiac Troponin I in Patients Admitted to the Emergency Department With Chest Pain. Circulation 99: 2073-2078 [Abstract] [Full text]  
• Newby, L. K., Christenson, R. H., Ohman, E. M., Armstrong, P. W., Thompson, T. D., Lee, K. L., Hamm, C. W., Katus, H. A., Cianciolo, C., Granger, C. B., Topol, E. J., Califf, R. M., Investigators, f. t. G.-I. (1998). Value of Serial Troponin T Measures for Early and Late Risk Stratification in Patients With Acute Coronary Syndromes. Circulation 98: 1853-1859 [Abstract] [Full text]  
• McCullough, P. A., O'Neill, W. W., Graham, M., Stomel, R. J., Rogers, F., David, S., Farhat, A., Kazlauskaite, R., Al-Zagoum, M., Grines, C. L. (1998). A prospective randomized trial of triage angiography in acute coronary syndromes ineligible for thrombolytic therapy: Results of the medicine versus angiography in thrombolytic exclusion (MATE) trial. J Am Coll Cardiol 32: 596-605 [Abstract] [Full text]  
• Greaves, K, Crake, T (1998). Cardiac troponin T does not increase after electrical cardioversion for atrial fibrillation or atrial flutter. Heart 80: 226-228 [Abstract] [Full text]  
• Hetland, O., Dickstein, K. (1998). Cardiac troponins I and T in patients with suspected acute coronary syndrome: a comparative study in a routine setting. Clin. Chem. 44: 1430-1436 [Abstract] [Full text]  
• Christenson, R. H., Duh, S.-H., Newby, L. K., Ohman, E. M., Califf, R. M., Granger, C. B., Peck, S., Pieper, K. S., Armstrong, P. W., Katus, H. A., the, E. J. T. f., Investigators, G.-I. (1998). Cardiac troponin T and cardiac troponin I: relative values in short-term risk stratification of patients with acute coronary syndromes. Clin. Chem. 44: 494-501 [Abstract] [Full text]  
• Baum, H., Braun, S., Gerhardt, W., Gilson, G., Hafner, G., Muller-Bardorff, M., Stein, W., Klein, G., Ebert, C., Hallermayer, K., Katus, H. A. (1997). Multicenter evaluation of a second-generation assay for cardiac troponin T. Clin. Chem. 43: 1877-1884 [Abstract] [Full text]  
• Haft, J. I., Saadeh, S. A., Stubbs, P., Collinson, P., Brogan, G. X., Hollander, J. E., Thode, H., Carbajal, E. V., Ohman, E. M., Califf, R. M., Topol, E. J., Antman, E. M., Tanasijevic, M. J., Cannon, C. P., Van de Werf, F. (1997). Cardiac Troponins in Acute Coronary Syndromes. NEJM 336: 1257-1259 [Full text]  
• Collinson, P. O. (1997). To T or Not to T, That Is the Question. Clin. Chem. 43: 421-423 [Full text]  
• Kennedy, R L. (1996). Does measurement of troponin T add to ability to stratify risk?. BMJ 313: 1330b-1330 [Full text]  
• (1996). Troponin T Predicts High Risk in Unstable Angina. Journal Watch Cardiology 1996: 14-14 [Full text]