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

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/mm (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.