Short- and long-term mortality after deep sternal wound infection following cardiac surgery: experiences from SWEDEHEART.

Abstract

Objectives: Deep sternal wound infection (DSWI) is a serious complication after open-heart surgery. We investigated the association between DSWI and short- and long-term all-cause mortality in a large well-defined nationwide population.

Methods: A retrospective, nationwide cohort study, which included 114676 consecutive patients who underwent coronary artery bypass grafting (CABG) and/or valve surgery from 1997 to 2015 in Sweden. Short- and long-term mortality was compared between DSWI patients and non-DSWI patients using propensity score inverse probability weighting adjustment based on patient characteristics and comorbidities. Median follow-up was 8.0 years (range 0-18.9).

Results: Altogether, 1516 patients (1.3%) developed DSWI, most commonly in patients undergoing combined CABG and valve surgery (2.1%). DSWI patients were older and had more disease burden than non-DSWI patients. The unadjusted cumulative mortality was higher in the DSWI group compared with the non-DSWI group at 90 days (7.9% vs 3.0%, P < 0.001) and at 1 year (12.8% vs 4.5%, P < 0.001). The adjusted absolute difference in risk of death was 2.3% [95% confidence interval (CI): 0.8-3.9] at 90 days and 4.7% (95% CI: 2.6-6.7) at 1 year. DSWI was independently associated with 90-day [adjusted relative risk (aRR) 1.89 (95% CI: 1.38-2.59)], 1-year [aRR 2.13 (95% CI: 1.68-2.71)] and long-term all-cause mortality [adjusted hazard ratio 1.56 (95% CI: 1.30-1.88)].

Conclusions: Both short- and long-term mortality risks are higher in DSWI patients compared to non-DSWI patients. These results stress the importance of preventing these infections and careful postoperative monitoring of DSWI patients.

Keywords: Cardiac surgery; Deep sternal wound infection; Incidence; Mediastinitis; Mortality.