Effect of revascularization on mortality associated with an elevated white blood cell count in acute coronary...

Inflammation is increasingly recognized as having an important role in patients with acute coronary syndromes. We sought to determine whether an elevated white blood cell (WBC) count would predict subsequent mortality and whether revascularization would have a protective effect. We analyzed data from 10,480 patients with acute coronary syndromes enrolled in the PURSUIT trial who had a WBC count measured on admission. WBC count values were stratified by quartiles, and death rates at 6 months were examined in univariate and multivariate analyses. Propensity analysis was performed to assess the effect of revascularization on the relation between WBC count and mortality. In the lowest quartile of WBC count, mortality was 4.0%; it was 5.8% in the second quartile, 6.7% in the third quartile, and 8.0% in the fourth quartile (p <0.001). In a multivariable model incorporating baseline demographic and clinical variables, an increasing WBC count was a significant predictor of death, with a hazard ratio of 1.07 per 1,000/microl increment in WBC count (p <0.001). Furthermore, the interaction term between mortality due to an elevated WBC count and benefit of in-hospital revascularization was significant (hazard ratio 0.94, p = 0.032), suggesting that the excess risk due to an elevated WBC count was attenuated by revascularization. An elevated WBC count at hospital admission, although only a crude index of inflammation, nevertheless is an independent predictor of death at 6 months in patients with acute coronary syndromes. This finding supports a pivotal role for inflammation in acute coronary syndromes. Importantly, this study suggests that in-hospital revascularization may mitigate some of the excess risk due to inflammation.