Impact of prodromal angina pectoris and white blood cell count on outcome of patients with acute myocardial infarction

Background Elevation of white blood cell (WBC) count at admission is associated with adverse outcome after acute myocardial infarction (AMI). Prodromal angina, by the mechanism of ischemic preconditioning, improves left ventricular (LV) function and survival after reperfusion therapy in patients with AMI. Recent experimental studies have reported that preconditioning has anti-inflammatory effect. Methods This study consisted of 598 patients with first anterior wall AMI who underwent coronary angiography within 12 h after symptom onset. WBC count was measured at the time of hospital admission. Prodromal angina was defined as angina occurring within 24 h before the onset of AMI. Serial measurements of LV ejection fraction (EF) were obtained before reperfusion therapy and before discharge in 421 patients (71%). Results High WBC count (>10.2×103/mm3, n=297) was associated with higher 30-day mortality (8% vs. 4%, p=0.02) and lower predischarge LVEF (51±15% vs. 57±14%, p<0.001), although there was no significant difference in acute LVEF (47±10% vs. 49±11%, p=0.07). High WBC count was an independent predictor of 30-day mortality (p=0.009) and predischarge LVEF (p=0.002). Prodromal angina was associated with lower 30-day mortality (3% vs. 7%, p=0.02) and preserved predischarge LVEF (57±15% vs. 53±14%, p=0.006). Patients with prodromal angina had lower WBC count (10.0±3.3×103/mm3 vs. 11.0±3.9×103/mm3, p=0.001) and prodromal angina was an independent predictor of WBC count (p<0.001). Conclusions Elevation of WBC count and lack of prodromal angina were associated with impaired LV function and mortality after reperfusion in patients with AMI. Prodromal angina might have contributed to favorable outcome after AMI through its anti-inflammatory effect.