BACKGROUNDBaseline white blood cell (WBC) count was correlated with ischemic events occurrence in patients with ST-elevated myocardial infarction (STEMI). However, circulating WBC count is altered after percutaneous coronary intervention (PCI). The aim of this study was to assess the relationship between postprocedural WBC count and clinical outcomes in STEMI patients who underwent PCI.

METHODSA total of 242 consecutive acute STEMI patients who underwent successful primary PCI were enrolled and followed up for two years. WBC counts were measured within 12 hours after PCI. ST-segment resolution (ST-R) and myocardial blush grades (MBG) were evaluated immediately after PCI. Left ventricular ejection fraction (LVEF) was obtained at baseline and 12 - 18 months after PCI.

RESULTSPostprocedural WBC count was an independent inverse predictor of ST-R (OR 0.80, P < 0.0001) and MBG 3 (OR 0.82, P < 0.0001). It was negatively correlated with LVEF (baseline r = -0.22, P = 0.001; 12 - 18 months r = -0.29, P < 0.0001). The best cutoff value of WBC for predicting death was determined to be 13.0 × 10(9)/L. The patients with a postprocedural WBC count above 13.0 × 10(9)/L showed a significantly lower cumulative survival rate (30 days, 82.4% vs. 99.0%, P < 0.0001 and 2 years 75.0% vs. 96.4%, P < 0.0001). Multivariate Cox regression analysis showed that a postprocedural WBC count was a strong independent predictor of 30-day mortality (HR 8.48, P = 0.019) and 2-year mortality (HR 4.93, P = 0.009).

CONCLUSIONSIncreased postprocedural WBC count is correlated with myocardial malperfusion and left ventricular dysfunction, and is an independent predictor of poor clinical outcomes in STEMI patients who underwent PCI.