Association between baseline neutrophil count, clopidogrel therapy, and clinical and angiographic outcomes in patients with ST-elevation myocardial infarction receiving fibrinolytic therapy

Aims To investigate the association between neutrophil count, outcomes, and benefit of clopidogrel therapy in ST-elevation myocardial infarction (STEMI). Methods and results Baseline neutrophil count was measured in 2865 patients in CLARITY-TIMI 28, a randomized trial of clopidogrel vs. placebo in STEMI patients undergoing fibrinolysis. Angiography was performed at 2 - 8 days following enrolment. Analyses were adjusted for demographics, time from symptom onset, Killip class, peak CK-MB, and therapies received. A baseline neutrophil count in the highest quartile was independently associated with the risk of cardiovascular (CV) death [adj (adjusted) OR (odds ratio) 5.8, P < 0.001] and congestive heart failure (adj OR 3.0, P=0.009) at 30 days. Patients with higher neutrophil counts were less likely to achieve complete ST-segment resolution (adj OR 0.76, P=0.03) or TIMI myocardial perfusion grade 2/3 (adj OR 0.71, P=0.017). Clopidogrel had a lesser effect on reducing the odds of a closed infarct-related artery, or death or MI before angiography, in patients with a neutrophil count above the median (adjusted OR 0.83, 0.61-1.13) vs. in those below the median (adjusted OR 0.46, 0.33-0.64) (P-interaction= 0.008). Conclusion In patients with STEMI, higher baseline neutrophil count is associated with worse angiographic findings and increased CV mortality, as well as a diminished benefit of clopidogrel.