Nationwide trends in incidence of deep sternal wound infection after cardiac surgery and its association with long-term mortality.

BACKGROUND

While early outcomes of deep sternal wound infection (DSWI) after cardiac surgery are well documented, its association with long-term mortality remains less clear. We aimed to investigate trends in DSWI incidence in a well-defined nationwide cohort and evaluate its association with long-term mortality.

MATERIALS AND

METHODS

This observational study investigated all DSWI patients after cardiac surgery via sternotomy at Landspitali University Hospital from 2001-2024, with incidence assessed across 4-year intervals. Incidence of DSWI was evaluated from 2001-2024, while survival analyses were restricted to patients operated between 2001-2017 to allow adequate long-term follow-up and ensure comparability with respect to the surgical era. Long-term survival was assessed using Kaplan-Meier graphs and a Cox regression model with time-splitting at 90 days and 5 years. Median follow-up was 9.2 [5.7-13.0] years, and survival analyses were truncated at 10 years to ensure comparable observation time between groups.

RESULTS

Out of 4596 patients who underwent cardiac surgery via median sternotomy, 53 (1.2%) developed DSWI. The incidence declined from 2.5% in 2001-2004 to 0% in 2021-2024 (p<0.001), with no DSWI cases identified after 2017. DSWI patients were older and had a higher comorbidity burden compared to the non-DSWI cohort. Patients in the DSWI group had an approximately twofold higher risk of mortality 5 to 10 years after surgery than the non-DSWI patients (aHR = 1.9, 95% CI=1.1-3.3).

CONCLUSIONS

Rates of DSWI after cardiac surgery in Iceland have significantly decreased over the last 24 years, with no cases diagnosed from 2018 to 2024. This decline is important since DSWI remains associated with increased health care costs, but more importantly, higher long-term mortality after cardiac surgery.