Derivation and validation of an early diagnostic score for mediastinitis after cardiothoracic surgery

Abstract

Objectives: The aim of this study was to elaborate on and validate a score for the early diagnosis of mediastinitis after cardiothoracic surgery. Methods: Between 2007 and 2017, patients who experienced thoracic surgical-site infection after cardiothoracic surgery were enrolled. Laboratory, clinical, and chest CT findings were retrospectively analyzed. Patients were followed up until hospital discharge or intra-hospital death. Univariate and multivariate regression analyses were performed. Results: 950 surgical-site infections were found and analyzed (131 mediastinitis, 819 superficial/deep infections). Of the 131 mediastinitis episodes, 88% required surgical thoracic debridement,Staphylococcus aureus was identified in 43%, and overall mortality was 42%. The following variables were related to mediastinitis diagnosis: sternal diastasis (OR = 2.5; 95% confidence interval [95%CI]: 1.2–5.3; P = 0.012), bilateral pleural effusion (OR = 1.9; 95%CI: 1.0–3.6; P = 0.04), leukocyte count ≥14,000cells/mm3 (OR = 2.5; 95%CI: 1.3–4.7; P = 0.006), male sex (OR = 2; 95%CI: 1.11–4; P = 0.022), and positive blood culture (OR = 3.0; 95%CI: 1.6–5.6; P = 0.001). The score predicted with reasonable accuracy mediastinitis in the derivation cohort (AUC-ROC, 0.7476) and the validation cohort (AUC-ROC, 0.7149). Groups with high (31%) and low (5%) risk of mediastinitis were identified. Conclusions: An early diagnostic score in patients with surgical-site infection after cardiothoracic surgery identified groups with a low and high risk for mediastinitis. Keywords: Mediastinitis, Diagnosis, Surgical site infections