Unstable angina: raised troponin T levels indicated a worse prognosis.

Clinical bottom line (level 1b)

  1. About a quarter of patients presenting to an emergency department with chest pain had unstable angina.
  2. Patients with unstable angina and a raised troponin T were very likely to die, have an MI or require revascularisation in the next three weeks.
Wu et al: American Journal of Cardiology 1995; 76 (1): 970-972
Expires July 2003

The study

Inception cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: emergency department, university hospital, USA

131 patients (aged mean 67 years, 59% male) admitted with chest pain and a final diagnosis of unstable angina


Multivariate logistic regression was performed to adjust for other risk factors (raised cholesterol, hypertension or diabetes, family history of coronary disease, current smoker).

100% followed for 3 weeks
Outcomes studied:
  • any major event
  • MI
  • revascularisation
  • refractory angina

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    any major event 3 weeks 46/104 44.2%
    (% to %)
    MI 3 weeks 3/104 2.88%
    (% to %)
    revascularisation 3 weeks 38/104 36.5%
    (% to %)
    refractory angina 3 weeks 8/104 7.69%
    (% to %)

    prognostic factor for
    any major event     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    raised troponin T 3 weeks 33
    (4.3 to 251)     		1
    (1 to 1)

    prognostic factor for
    MI     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    raised troponin T 3 weeks 14
    (3.4 to 58)     		3
    (1 to 14)

    prognostic factor for
    revascularisation     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    raised troponin T 3 weeks 3.0
    (1.2 to 7.1)     		1
    (1 to 14)

    • 8/131 had raised CK-MB levels (6.1%)- all had major events.
    • 27% of patients admitted with chest pain had a final diagnosis of unstable angina.

    Comments

    1. No details on blinding or exclusion criteria lower the validity of this study. Small numbers may explain extremely good results. No other study has demonstrated troponin T to be this useful.
    2. Although logistic regression used, uncertain which factors were not used in the analysis and may 'elevate' the utility of Troponin T.

    Citation

    1. Wu AHB, Abbas SA, Green S, et al: Prognostic value of cardiac troponin T in unstable angina pectoris. American Journal of Cardiology 1995; 76 (1): 970-972
    Contributor: Nick Shenker and Chris Ball, July 2000
    Reviewer: Andreas Michaelides

    Clinical Question.
    Patient unstable angina
    Intervention or Exposure troponin T
    Outcome death, MI, revasularisation