Successful reperfusion for acute ST elevation myocardial infarction is associated with a decrease in WBC count

Background: Elevated white blood cell (WBC) count on admission in patients with ST segment elevation myocardial infarction (STEMI) has been associated with an adverse prognosis. Whether successful reperfusion by primary percutaneous coronary intervention (PCI) is associated with a decrease in WBC count is unknown. Methods: In this subanalysis of the On-TIME trial, WBC count was measured on admission and 6 h and 24 h after primary PCI for STEMI (n = 364). Angiographic measurements of reperfusion, including TIMI-flow and myocardial blush grade, were compared with changes in WBC count. Results: Restoration of TIMI 3 flow by primary PCI was associated with a significant decrease in median WBC count (11.5 (9.7–14.2), 10.7 (9.0–12.5), 9.9 (8.5–11.5) at baseline, 6 h and 24 h), whereas after unsuccessful PCI (TIMI < 3 flow) WBC count remained elevated (12.5 (9.5–14.6), 12.1 (9.9–14.4), and 11.4 (9.2–15.2)). Improved myocardial blush was also related to a decrease in WBC count. After multivariate analysis, improved myocardial perfusion (TIMI 3 flow and myocardial blush grade 3) was an independent predictor of a decrease of WBC count after PCI. Conclusion: Impaired myocardial reperfusion after primary PCI for STEMI is associated with persistent WBC elevation.