Clinical and prognostic significance of neutrophil-lymphocyte ratio in patients with acute pulmonary embolism

Abstract

The aim – to evaluate the association of neutrophil-lymphocyte ratio (NLR) with the clinical course and hospital prognosis of pulmonary embolism (PE).
Materials and methods. The study included 291 patients with a diagnosis of PE, verified by multislice computed tomographic pulmonary angiography, with a calculated NLR according to clinical blood count. In addition to the standard general-clinical and laboratory-instrumental examination, patients were assessed for risk factors of PE and risk of early death according to ESC 2019 recommendations. The data obtained were statistically processed.
Results and discussion. Patients were divided according to the median NLR: group 1 included 145 patients with NLR <3.4, group 2 – 146 patients with NLR ≥3.4. Also, according to the value of the NLR obtained during the ROC analysis for predicting mortality during the hospital period: group 3 consisted of 245 patients with NLR ≤6.75, group 4 – 46 patients with NLR >6.75. Analyzing demographic indicators, it was found that in group 2, elderly patients (p=0.02) and males (p=0.037) were reliably more common than in group 1. Regardless of the method of division into groups, a reliable predominance of patients at high risk of early death from PE (p<0.001), PESI class V (p<0.01) and high-risk sPESI (p<0.01), with higher PESI scores (p<0.001) was obtained in groups with increased NLR (NLR ≥3.4 and NLR >6.5). In the same groups, analyzing the results of the objective examination, a reliably lower level of saturation (p<0.0001) and SBP (p<0.01) were found. When comparing laboratory parameters, it was found that the average leukocyte levels in the groups with NLR ≥3.4 and NLR >6.5 were reliably higher (p<0.001), and the level of troponin I was reliably increased (p=0.02) only in the group with NLR >6.5. Correlation analysis showed a reliable direct link between the level of NLR and age, heart rate, right atrium (RA) size, LVEDC, mean pulmonary arterial pressure (MPAP), leukocyte and troponin I levels, increased risk of early mortality from PE and hospital mortality, as well as an inverse link with the level of saturation, SBP, LV EF and hemoglobin. 
Conclusions. The link between the level of NLR and clinical and anamnestic parameters in patients with PE was established. Among patients with NLR above the median (≥3.4), elderly patients, males, and high-risk patients with reliably higher PESI scores predominated. A direct correlation between the level of NLR and age, heart rate, RA size, LVEDC, MPAP, leukocyte and troponin I levels, increased risk of early mortality from PE and hospital mortality, as well as an inverse correlation with saturation, SBP, LV EF and hemoglobin levels were established. NLR >6.5 is associated with an unfavorable prognosis – death in the hospital period, as well as with a higher level of troponin I, a marker of right ventricle dysfunction.