Relationship Between Baseline White Blood Cell Count and Degree of Coronary Artery Disease and Mortality in Patients With Acute Coronary Syndromes A TACTICS-TIMI 18 Substudy

OBJECTIVES This study was designed to determine the relationship between baseline white blood cell (WBC) count and angiographic and clinical outcomes in patients with unstable angina (UA)/non–ST-segment elevation myocardial infarction (NSTEMI) and to see if WBC count was a significant predictor of outcomes independent of other biomarkers. BACKGROUND Inflammation has been shown to play a role in atherosclerosis and acute coronary syndromes. METHODS We evaluated the relationship between baseline WBC count, other baseline variables and biomarkers, angiographic findings, and clinical outcomes in 2,208 patients in the Treat angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative StrategyThrombolysis In Myocardial Infarction 18 (TACTICS-TIMI 18) trial. RESULTS Higher baseline WBC counts were associated with lower Thrombolysis In Myocardial Infarction (TIMI) flow grades (p 0.0045) and TIMI myocardial perfusion grades (p 0.03) as well as a greater extent of coronary artery disease (CAD) (p 0.0001). A higher baseline WBC count was predictive of higher six-month mortality, ranging from 1.5% to 3.6% to 5.1% for patients with low, intermediate, and high WBC counts, respectively (p 0.0017). In a multivariable proportional hazards model, patients with a low C-reactive protein (CRP) but an elevated WBC remained at significantly higher risk of death at six months (hazard ratio [HR] 4.3, p 0.049), and patients with a high CRP were at even higher risk (HR 8.6, p 0.004). CONCLUSIONS In patients with UA/NSTEMI, elevations in a simple, widely available blood test, the WBC count, were associated with impaired epicardial and myocardial perfusion, more extensive CAD, and higher six-month mortality. After adjustment for traditional risk factors and other biomarkers, assessment of two inflammatory markers, WBC count and CRP, can be used to stratify patients across an eightfold gradation of six-month mortality risk. (J Am Coll Cardiol 2002;40:1761–8) © 2002 by the American College of Cardiology Foundation