C-Reactive Protein and Cardiac Troponin T in Risk Stratification: Differences in Optimal Timing of Tests Early after the Onset of Chest Pain

BACKGROUND: Increased C-reactive protein (CRP) is an important prognostic indicator for early risk stratification in patients with an acute coronary syndrome (ACS), independent of, and in combination with, increased cardiac troponin T (cTnT). However, increases in both cTnT and CRP also occur secondary to myocardial damage. METHODS AND RESULTS: In 156 consecutive patients, early release kinetics of CRP and cTnT were analyzed. The cutoff values were 3.0 mg/L for CRP and 0.1 microgram/L for cTnT. In the 75 patients with a CRP below the cutoff on admission, there was little change in CRP until 8 h after the onset of symptoms. At 12 h after the onset of symptoms, the cumulative proportions of abnormal CRP and cTnT in non-ST elevation ACS patients were 27% and 89%, respectively (P <0.01). During the first 24 h after the onset of symptoms, the median time above the cutoff was 20 h for CRP and 5 h for cTnT (P <0.0001). CRP was below the cutoff on admission significantly more often among patients receiving thrombolytic therapy than in patients without an indication for reperfusion therapy (51% vs 28%; P = 0.004). CONCLUSIONS: Increased CRP as an early independent risk indicator should be measured as soon as possible after the onset of symptoms, whereas increased cTnT is most reliable at 12 or more hours after the onset of symptoms.