The Effectiveness of the Serum Surfactant Protein D (Sp-D) Level to Indicate Lung Injury in Pulmonary Embolism

Abstract

Background: Surfactant protein D (SP-D) is a biomarker specific to the lungs. Our aim was to investigate the relationship between clinical probability scores and the serum levels of SP-D to indicate the severity of lung injury that develops secondary to hypoxia in pulmonary embolism (PE). Methods: We included three groups in the study: non-massive PE (n = 20), sub-massive PE (n = 20), and the control group (n = 20), which consisted of healthy volunteers. The modified Geneva and Wells clinical probability scoring systems were performed for PE, and the patients were classified as low risk, moderate risk, and high risk. SP-D levels were determined by the enzyme-linked immunosorbent assay. Results: For risk factors, the most significant were deep vein thrombosis (DVT) and immobilization. There was no significant difference in SP-D levels between the patients identified with risk factors and those without risk factors in either the Geneva or Wells scores. Atelectasis was the most common radiographic finding, while tricuspid valve regurgitation was predominant in echocardiography. There was no significant difference between the non-massive PE group and the control group, while SP-D levels of the sub-massive group were significantly higher than the control group. Conclusions: In our study, SP-D levels were significantly higher in the sub-massive PE group overall. However, further prospective studies are required with a larger number of cases, including patients with massive PE, in order to clarify the findings.