Yale: Acute Coronary Syndrome: C-Reactive Protein and Troponin Levels

CONTENTS

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C-Reactive Protein and Troponin Levels
Independantly Predict Mortality in Patients
with Acute Coronary Syndrome

C-reactive protein (CRP) is an acute phase reactant associated with adverse outcome in patients with unstable ischemic syndromes. The predictive value of Tn T versus CRP was examined in patients with unstable angina or NQWMI in the TIMI IIA study. (1,2)

Both markers were measured in 437 patients at least 6 hours after onset of symptoms. Nearly 20% of patients with a negative Tn T assay still had a CRP > 1.55 (i.e.: > 99th percentile value in normals).

Fig. 1. Risk Stratification by CRP (mg/dl) and rapid assay status expressed as 14-day mortality by CRP and rapid troponin T result.

Morrow, et al. JACC 1998 31:7, 1460-1465.

All cause 14 day mortality was high compared with normal-range levels, even with a negative Tn T assay (5.6% vs. 0.3%, respectively, p=0.006). Mortality was highest when both markers were elevated (9.1%) and lowest when both markers were negative (0.4%).

Fig. 2. Mortality rate at 14 days by CRP concentration in all patients, and in those with positive and negative troponins (a TIMI-11A substudy).

Morrow, et al. JACC 1998 31:7, 1460-1465.

In summary, though high levels of troponin indicates increased risk, a negative test result (low troponin level) does not assure a good prognosis, particularly when CRP levels are elevated.

Furthermore, recent studies have documented that the rise in CRP levels is suppressed with tirofiban and heparin but not with heparin alone in patients with unstable angina and NQWMI. In the PRISM-PLUS study, CRP was measured at study start, 6 hours, 24 hours, at study discontinuation (approx. 72 hours) and 24 hours thereafter. CRP levels increased progressively following development of UA/NQWMI. The mean CRP level was significantly lower in patients treated with tirofiban and heparin (15.9 + 2.7) vs. heparin alone (31.8 + 6.1) 24 hours after drug discontinuation (p=0.007).

Table 1. Rise in CRP levels is suppressed with tirofiban + heparin but not with heparin alone in patients with USA/NQWMI

Table 1.

Theroux et al. J Am Coll Cardiol. 330A, 1999.

1. Morrow, D., Rifai, N., Antman, E. et al. C-Reactive Protein is a Potent Predictor of Mortality independantly of and in Combination with Troponin T in Acute Coronary Syndrome: A TIMI 11A Substudy. J Am Coll Cardiol. 31; 1460-1465, 1998.

2. Theroux, P., Barr, E., Snapinn, S., et al. Rise in C-Reactive Protein Levels is Suppressed with Tirofiban and Heparin but not with Heparin Alone in Patients with Unstable Angina/Non-Q-Wave Myocardial Infarction. J Am Coll Cardiol. 330A, 1999.

Last modified: October 14, 1999 (PL)

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