Increased interleukin-6 after cardiac surgery predicts infection

Area of Science:

• Cardiovascular Surgery
• Infectious Diseases
• Immunology

Background:

• Early detection of infection post-cardiac surgery is crucial for patient outcomes.
• Conventional markers like C-reactive protein and white blood cell counts are insufficient to differentiate infection from systemic inflammatory response syndrome (SIRS) after cardiopulmonary bypass (CPB).
• CPB triggers a systemic release of pro- and anti-inflammatory cytokines, including IL-6.

Purpose of the Study:

• To evaluate the predictive value of specific cytokines (TNF-alpha, IL-6, IL-10) for post-cardiac surgery infections.
• To assess if these cytokine levels can distinguish infection from SIRS in patients undergoing CPB.

Main Methods:

• Prospective study including 46 patients with impaired left ventricular ejection fraction (<60%) undergoing cardiac surgery.
• Plasma samples collected pre-operatively and at multiple time points post-surgery (ICU admission, days 1, 3, 7).
• Infection diagnosed using Centers for Disease Control and Prevention criteria.

Main Results:

• Thirteen patients developed post-operative infections.
• Significantly elevated levels of Interleukin-6 (IL-6) and Interleukin-10 (IL-10) were observed on postoperative day 3 in patients who developed infection.
• Elevated blood glucose immediately after surgery was also noted in infected patients.
• Tumor necrosis factor-alpha, leukocytes, and C-reactive protein did not show significant increases in infected patients.

Conclusions:

• Elevated Interleukin-6 (IL-6) levels on postoperative day 3 are predictive of infection following cardiac surgery in patients with compromised left ventricular function.
• IL-6 shows potential as an early diagnostic marker for post-cardiac surgery infections, outperforming traditional inflammatory markers.