Immature Granulocytes: A Risk Factor of Infection after Cardiac Surgery

Area of Science:

• Immunology
• Clinical Cytometry
• Surgical Complications

Background:

• Cardiac surgery with cardiopulmonary bypass (CPB) causes significant leukocyte subset changes, similar to sepsis.
• Immature granulocytes (IGs) increase post-CPB and in sepsis.
• Secondary infections are a major risk following CPB surgery.

Purpose of the Study:

• To investigate if multicolor flow cytometry (FCM) assessment of leukocyte subsets can identify patients at high risk of infectious complications after open-heart surgery.
• To evaluate the association between specific leukocyte subsets and the development of secondary infections.

Main Methods:

• A single-center observational pilot study involving 59 patients undergoing open-heart surgery under CPB.
• Blood samples collected preoperatively and immediately postoperatively.
• Analysis of 26 leukocyte subsets using three antibody combinations (5-10 colors) via FCM.
• Recording of secondary infections during hospital stay.

Main Results:

• Postoperative lymphopenia (NK and T-cells) and increased IGs and monocytes were observed.
• Patients developing secondary infections had significantly higher immediate postoperative IG levels (6.6 vs. 3.8 G/L, P = 0.01).
• A significant increase in IGs post-surgery was strongly associated with infectious complications (46% vs. 5%, P < 0.001).

Conclusions:

• Postoperative increase in immature granulocytes (IGs) is linked to postoperative organ failure.
• Elevated postoperative IGs show promise for early identification of patients at risk for infectious complications after CPB.
• Flow cytometry assessment of IGs can aid clinicians in managing post-cardiac surgery infections.