Neutrophil-Lymphocyte Ratio and Perihematomal Edema Growth in Intracerebral Hemorrhage

Background and Purpose-Although preclinical studies have shown inflammation to mediate perihematomal edema (PHE) after intracerebral hemorrhage, clinical data are lacking. Leukocyte count, often used to gauge serum inflammation, has been correlated with poor outcome but its relationship with PHE remains unknown. Our aim was to test the hypothesis that leukocyte count is associated with PHE growth. Methods-We included patients with intracerebral hemorrhage admitted to a tertiary-care stroke center between 2011 and 2015. The primary outcome was absolute PHE growth during 24 hours, calculated using semiautomated planimetry. Linear regression models were constructed to study the relationship between absolute and differential leukocyte counts (monocyte count and neutrophil-lymphocyte ratio) and 24-hour PHE growth. Results-A total of 153 patients were included. Median hematoma and PHE volumes at baseline were 14.4 (interquartile range, 6.3-36.3) and 14.0 (interquartile range, 5.9-27.8), respectively. In linear regression analysis adjusted for demographics and intracerebral hemorrhage characteristics, absolute leukocyte count was not associated with PHE growth (beta, 0.07; standard error, 0.15; P=0.09). In secondary analyses, neutrophil-lymphocyte ratio was correlated with PHE growth (beta, 0.22; standard error, 0.08; P=0.005). Conclusions-Higher neutrophil-lymphocyte ratio is independently associated with PHE growth. This suggests that PHE growth can be predicted using differential leukocyte counts on admission.