Abstract TP410: Early Diagnosis of Stroke-associated Pneumonia by Blood Biomarkers. Correlation With Thoracic High-resolution Computer Tomography

Abstract

Introduction: One of the main limitations in biomarker research for stroke-associated pneumonia (SAP) is the lack of a gold-standard for clinical diagnosis. We aimed to evaluate the diagnostic accuracy of candidate biomarkers related to the features on thoracic high-resolution computed tomography (HRCT). Methods: Patients with ischemic stroke with baseline NIHSS>10 were enrolled between March-2016 and August-2017. Blood samples were collected at baseline, 24 and 48 hours after stroke onset, to determine C-reactive protein (CRP), serum amyloid protein A (SAA), mid-regional proadrenomedullin (MR-proADM), and soluble receptor of urokinase-type plasminogen activator (suPAR). Biomarkers were measured by immunoassays. Pneumonia was diagnosed as the presence of a new consolidation, infectious nodules or ground-glass pattern, in a thoracic HRCT performed 5-7 days after stroke. Results: From 46 included patients, thoracic HRCT was performed in 41 patients. Five (12.5%) were diagnosed as pneumonia and 3 (7.3%) with acute bronchitis. No blood marker was associated with pneumonia on thoracic HRCT at baseline. At 24 hours, a cut-off of MR-proADM>1.023 nmol/L had 80% sensitivity and 72.2% specificity for pneumonia. At 48 hours, both SAA>25.15 mg/dL (60% sensitivity, 85.7% specificity) and suPAR>3.14 ng/mL (80% sensitivity, 57.1% specificity) were associated with infections. The combination of SAA>25.15 mg/dL and suPAR>3.14 ng/mL at 48 hours had 80% sensitivity and 95.8% specificity when both biomarkers were above the cut-off, and 60% sensitivity and 94.1% specificity when one of them was above the cut-off. Conclusions: An objective diagnostic test such as thoracic HRCT could be of interest for future research in SAP. The evaluated biomarkers will require further validation in larger samples. However, these biomarkers represent promising tools to be evaluated in future projects on SAP early diagnosis and guidance on antibiotic therapy.