A study of nearly 15,000 patients who underwent cardiac surgery found that chest bone infections—particularly mediastinitis—significantly increased the risk of mortality within 90 days. Milder infections such as deep incisional surgical-site infections were also associated with an elevated mortality risk.
Investigators analyzed outcomes from patients who underwent cardiopulmonary bypass surgery between 2006 and 2019. Among 14,850 patients, 3.6% (n = 542) developed deep sternal wound infections, 72% (n = 390) had deep incisional surgical-site infections (diSSI), and 28% (n = 152) had mediastinitis.
Patients with mediastinitis had the poorest outcomes. Ninety-day survival was 82% compared with 94% for diSSI and 95% among patients without deep infections (P < .001).
To reduce survival bias, the investigators conducted a landmark analysis that excluded patients who died within 28 days of surgery. In this refined group, both mediastinitis and diSSI were linked to higher mortality. Patients with mediastinitis were over six times more likely to die, and those with diSSI were more than four times as likely to die compared with patients without infection.
The infections differed in timing and microbiology. Mediastinitis typically developed 14 days postsurgery, whereas diSSI appeared around day 19 (P < .001). Staphylococcus aureus and Enterobacterales were more common in mediastinitis, while coagulase-negative staphylococci predominated in diSSI. Bloodstream infections were present in 46% of mediastinitis cases and 16% of diSSI cases.
All patients with deep sternal wound infections underwent surgical debridement, antibiotic therapy, and vacuum-assisted closure. Treatment protocols were consistent throughout the study period.
Other risk factors for 90-day mortality included age over 56 years, insulin-dependent diabetes, peripheral arterial disease, prior cardiac surgery, emergency procedures, end-stage renal disease, reduced ejection fraction (< 30%), and longer cardiopulmonary bypass duration.
The investigators concluded that mediastinitis and diSSI are distinct infection types with different pathogens, timing, and outcomes, and both should be monitored separately.
The investigators suggested that closer monitoring and prompt, aggressive treatment of both infection types may improve survival in patients undergoing cardiac surgery.
No conflicts of interest were declared.
Source: Surgery