Objectives: The aim of the present study was to investigate the association between systemic inflammatory response index (SIRI) and the occurrence of postoperative atrial fibrillation (POAF) in patients undergoing coronary artery bypass grafting (CABG).

Patients and methods: Between September 2022 and July 2024, a total of 276 consecutive patients (189 males, 87 females; mean age: 62.6±7.3; range, 49 to 79 years) who underwent elective isolated CABG were included in this study. Clinical data and electrocardiograms of the patients were obtained. Based on the rhythm status during hospitalization after surgery, the patients were divided into two groups with POAF rhythm (n=78) and normal sinus rhythm (n=198). The SIRI index value was obtained based on the product of the number of neutrophils per monocyte divided by the lymphocyte count immediately before surgery.

Results: The mean value of preoperative SIRI in the group with POAF was 6.8±1.1, while it was 3.2±0.8 in the non-POAF group, indicating a significant difference (p=0.008). According to the receiver operating characteristic (curve analysis, a SIRI higher than 5.5 could predict POAF with a sensitivity of 79.2% and a specificity of 66.8%. Along with increased SIRI, advanced age, history of hypertension and smoking, as well as reduced left ventricular ejection fraction were other predictors of POAF.

Conclusion: Assessing preoperative SIRI index can predict the occurrence of POAF in CABG patients with acceptable sensitivity and specificity values.