AIMS & OBJECTIVES:In the era before the use of mechanical reperfusion therapy, an elevated white blood cell (WBC) count was associated with a higher risk of adverse events following Myocardial Infarction (AMI). We examined the relationship between the WBC count and angiographic findings to gain insight into its relationship with occurrence of slow/no reflow (NR) in acute coronary syndrome patients (ACS).METHODS:We evaluated 337 patients within 24 hrs of the onset of€S and who underwent PCI in the acute phase. Patients with conditions likely to raise the WBC count other than ACS were excluded. Demographic and angiographic parameters were compared within the quartiles of WBC count. RESULTS: The WBC count ranged from 3500 to 282000 per cmm. The median WBC count was 9400 per cmm and the interquartile interval was 7790 to 11800 per cmm. Patients with NR exhibited significantly higher (mean±SD) WBC count (11379 ± 3498 per cmm vs. 9577 ± 3194 per cmm in patients without NR; p<0.01). NR was strongly associated in patients in the highest quartile of WBC count. Sub grouping the data into ST elevation Myocardial infarction (STEMI) and unstable angina/Non STEMI patients (UA/NSTEMI) revealed that patients with STEMI showed significantly higher WBC count as compared to UA/NSTEMI patients (11710 ±10891per cmm vs.
8988 ± 2442 per cmm, p<0.001). Further, the highest quartile of WBC count was more strongly associated with occurence of no reflow in STEMI (50% vs 15% in 1st; 6% in 2nd and 29% in 3rd quartiles, p<0.01 for all) while it showed no significant difference in UA/NSTEMI patients (37% vs 26 % in 1st, 22% in 2nd and 15% in 3rd quartile, p=NS for all). In addition, a higher WBC count was associated with poorer TIMI flow and myocardial perfusion grades.CONCLUSIONS:The WBC count is of great importance for stratifying patient risk and was found to be a strongly associated with occurrence of no reflow during high risk PCI in ACS patients. Higher WBC count appears to be better predictor of NR in STEMI as compared to UA/NSTEMI.