Postoperative Infectious Pneumonia in Cardiothoracic Surgery: A Systematic Review and Meta-Analysis

Background Postoperative infectious pneumonia (PIP) is a common and serious complication following cardiothoracic surgery, including coronary artery bypass grafting (CABG), valve interventions, and thoracic oncologic procedures. It is associated with increased morbidity, prolonged intensive care unit (ICU) stay, and healthcare burden. Methods We performed a systematic review and meta-analysis according to PRISMA 2020 guidelines. Studies published between January 2021 and December 2023 were identified from PubMed, Embase, and Scopus. Eligible studies reported the incidence and/or perioperative risk factors for PIP with odds ratios (ORs) and 95% confidence intervals (CIs). A random-effects model was used for pooled estimates. Study quality was assessed using the Newcastle-Ottawa Scale. The review was prospectively registered in PROSPERO 2025 CRD 420251057914. Available from https://www.crd.york.ac.uk/PROSPERO/view/CRD420251057914. Results Six high-quality cohort studies involving 4,392 patients were included. The pooled incidence of PIP was 14.8% (95% CI, 10.6%–19.2%). Incidence was highest after thoracic oncologic surgery (17.2%), followed by valve surgery (15.8%) and CABG (13.5%). Significant risk factors included prolonged mechanical ventilation >48 hours (OR: 3.46), age >70 years (OR: 2.71), chronic obstructive pulmonary disease (OR: 2.95), cardiopulmonary bypass time >120 minutes (OR: 2.63), and left ventricular ejection fraction <40% (OR: 2.38). Heterogeneity was moderate (I² = 46%) with no publication bias. Conclusions PIP remains a major postoperative concern. Identification of key risk factors enables targeted preventive strategies—early extubation, pulmonary optimization, and standardized care pathways—to reduce PIP incidence and improve outcomes.