Use of neutrophil count in early diagnosis and risk stratification of AMI.

BACKGROUND

Neutrophils are rapidly released into the circulation upon acute stress such as trauma or acute myocardial infarction (AMI). We hypothesized that neutrophil count might provide incremental value in the early diagnosis and risk stratification of AMI.

METHODS

We conducted a prospective observational multicenter study to examine the diagnostic accuracy of the combination of neutrophil count and cardiac troponin T from 1125 consecutive patients who presented to the Emergency Department with symptoms suggestive of acute myocardial infarction. The final diagnosis was adjudicated by 2 independent cardiologists.

RESULTS

Neutrophil count was higher in patients with acute myocardial infarction compared with other diagnoses (median 6.7 vs. 5.0×10(9)/L, respectively, P <.001). The accuracy of the neutrophil count for diagnosing acute myocardial infarction, quantified by the area under the receiver operating characteristic curve (AUC) was 0.69, which was significantly lower than that of cardiac troponin T (AUC 0.89, P <.001). The combination of the neutrophil count and cardiac troponin T did not improve the early diagnosis of acute myocardial infarction versus cardiac troponin T alone (P=.79). The prognostic accuracy of neutrophil count for death and AMI was significantly lower than that of cardiac troponin T. However, patients in the highest tertile of neutrophil count had a significantly increased risk of death and AMI at 90 and 360 days compared with patients in the lowest tertile (hazard ratios 2.47 [95% confidence interval, 1.63-3.72] and 2.28 [95% confidence interval, 1.55-3.36], respectively).

CONCLUSION

The neutrophil count does not improve the early diagnosis of AMI in patients presenting with chest pain but identifies patients at increased risk of death.