Impact of leukocyte count on mortality and bleeding in patients with myocardial infarction undergoing primary percutaneous coronary interventions: analysis from the Harmonizing Outcome with Revascularization and Stent in Acute Myocardial Infarction trial.

Background: The relationship between white blood cell count (WBCc) and mortality in patients with ST-segment-elevation acute myocardial infarction treated with percutaneous coronary intervention is poorly understood. Furthermore, whether there is a relationship between WBCc and risk of noncardiac mortality and bleeding after percutaneous coronary intervention is unknown.

Methods And Results: The baseline WBCc was available in 3193 of 3345 patients (95.5%) who underwent percutaneous coronary intervention in the Harmonizing Outcome With Revascularization and Stent in Acute Myocardial Infarction (HORIZONS-AMI) trial. In a propensity-adjusted multivariable analysis, WBCc was an independent predictor of 1-year cardiac mortality (hazard ratio, 1.15; 95% confidence interval, 1.09 to 1.22), noncardiac mortality (hazard ratio, 1.19; 95% confidence interval, 1.10 to 1.29), and major bleeding (hazard ratio, 1.08; 95% confidence interval, 1.04 to 1.12). After adjustment for baseline creatinine phosphokinase levels and left ventricular ejection fraction, WBCc remained an independent predictor of 1-year all-cause mortality and cardiac mortality. In patients matched for baseline creatinine phosphokinase levels at hospital admission, the median peak creatinine phosphokinase level was significantly higher in patients with high WBCc (>11 000 per 1 mm(3)) compared with low WBCc (1851 U/L [range, 880-3307 U/L] versus 1241 U/L [range, 540 to 2,78], respectively; P<0.0001). In this subgroup of patients, WBCc was an independent correlate of peak creatinine phosphokinase level, and remained an independent predictor of 1-year mortality.

Conclusions: In patients with ST-segment-elevation acute myocardial infarction undergoing percutaneous coronary intervention, elevated baseline WBCc is an independent predictor of infarct size, as assessed by peak creatinine phosphokinase level, and of 1-year cardiac mortality, noncardiac mortality, and major bleeding.