Abstract
BACKGROUND: Risk prediction rules are important to establish appropriate treatment and management strategy for patients with different risk classification of pulmonary embolism (PE). Neutrophils are considered to be related to PE as an essential marker of inflammation. However, few studies have reported the association between neutrophil levels and risk classification of acute PE (APE). The aim of this study was to investigate the role of neutrophil levels upon admission in the assessment of risk classification of APE. METHODS: A total of 299 consecutive APE patients and 90 patients without APE confirmed by computed tomographic pulmonary angiography were retrospectively screened. APE patients were stratified into two subgroups according to clinical guidelines: low- (n = 233) and intermediate- and high-risk (n = 60) APE. RESULTS: The neutrophil levels in intermediate- and high-risk APE patients were significantly higher compared to low-risk APE or non-APE patients (P < 0.001). In multivariable logistic regression analysis, neutrophil levels were significantly and independently associated with intermediate- and high-risk APE (odds ratio = 1.239, 95% confidence interval [CI] 1.055-1.455, P = 0.009). Neutrophil levels were positively correlated with the pulmonary embolism severity index score (r = 0.357, P < 0.001), high sensitive C-reactive protein, D-dimer and pulmonary artery obstruction index (PAOI), in the overall population of APE patients. Receiver-operating characteristic curve analysis revealed that neutrophils had a better diagnostic value for intermediate- and high-risk APE (area under the curve [AUC] = 0.760, 95% CI 0.695-0.826; P < 0.001) compared to PAOI (AUC = 0.719) and D-dimer (AUC = 0.645). CONCLUSIONS: High neutrophil levels upon admission were significantly and independently associated with intermediate- and high-risk APE, which could be regarded as an indicator of inflammation and thrombosis in APE simultaneously. The potent diagnostic role of neutrophil levels and their competitive advantage over PAOI and D-dimer for the assessment of APE risk classification are suggested.