Relationship of admission neutrophil count to microvascular injury, left ventricular dilation, and long-term outcome in patients treated with primary angioplasty for acute myocardial infarction

Abstract

Background: The relationship of admission neutrophil count to the degree of microvascular injury, left ventricular (LV) volume, and long-term outcome after acute myocardial infarction (AMI) was examined in the present study. Methods and Results: The study group comprised 228 consecutive patients with a first anterior wall AMI who underwent primary angioplasty within 12h of onset. The degree of microvascular injury was evaluated by Doppler guidewire. Adverse cardiac events were recorded during an average follow-up of 52±28 months. Using a receiver-operating characteristic analysis, a neutrophil count ≥7,260 cells/mm3 was the best predictor of future cardiac events. By regression analysis, the neutrophil count significantly correlated with diastolic deceleration time (r=-0.40, p<0.0001), coronary flow reserve (r=-0.43, p<0.0001), and LV end-diastolic volume at 4 weeks (r=0.32, p<0.0001). Kaplan-Meier survival analysis showed a higher incidence of adverse cardiac events in patients with a high neutrophil count (p=0.002). By multivariate analysis, a neutrophil count ≥7,260 cells/mm3 was an independent predictor of long-term adverse cardiac events (odds ratio 3.8, p=0.002). Conclusion: Neutrophilia on admission is associated with impaired microvascular perfusion, LV dilation, and long-term adverse cardiac events in patients treated with primary angioplasty for AMI.