Deep sternal wound infection after cardiac surgery: A combination of 2 distinct infection types, deep incisional surgical-site infection and mediastinitis: Results of a retrospective study

Abstract

Introduction: Deep sternal wound infection after cardiac surgery remains a serious complication associated with a poor prognosis. Deep sternal wound infection is classified by the Centers for Disease Control and Prevention as deep incisional surgical site-infection and mediastinitis. This study aims to describe the incidence, perioperative characteristics, and outcomes of deep sternal wound infection on the basis of clinical presentations.

Methods: This monocentric retrospective study included all consecutive patients who underwent cardiac surgery with cardiopulmonary bypass between 2006 and 2019 in a tertiary teaching hospital. The primary outcome was 90-day mortality, and the main secondary outcome was a landmark analysis of 90-day mortality, excluding patients who died within the first 28 days.

Results: Among the 14,850 patients included in this study, deep sternal wound infection occurred in 542 (3.6%) patients: 390 (72%) presented with deep incisional surgical site-infection and 152 (28%) presented mediastinitis. Patients with deep sternal wound infection had a lower 90-day survival than patients without deep sternal wound infection; in particular, patients with mediastinitis had the lowest survival rate compared to deep incisional surgical site-infection- and deep sternal wound infection -free patients (82% vs 94% vs 95%, respectively; both comparisons P < .001), and mediastinitis was an independent risk factor for 90-day mortality. No difference in 90-day survival was observed between patients without deep sternal wound infection and patients with deep incisional surgical site-infection (P = .378). However, in the landmark analysis, both deep incisional surgical site-infection and mediastinitis were associated with lower survival compared with patients without deep sternal wound infection and were independent risk factors for mortality.

Conclusion: Deep incisional surgical site-infection and mediastinitis exhibited distinct incidences, bacterial characteristics, and prognoses, with mediastinitis being associated with the poorest prognosis. However, when the competing risk of death was considered, deep incisional surgical-site infection diSSI also emerged as an independent risk factor for 90-day mortality.