Cardiac surgery, especially when cardiopulmonary bypass (CPB) is used, can trigger a short postoperative inflammatory response, but some patients develop prolonged systemic inflammatory response syndrome (SIRS). This CAREBANK biobank substudy, published in Interdisciplinary Cardiovascular and Thoracic Surgery, examined risk factors for prolonged SIRS and its association with short- and long-term postoperative atrial fibrillation (AF).

The analysis included prospectively enrolled adults who underwent cardiac surgery between 2016 and 2021, with operations performed with or without CPB. Ongoing follow-up data were used to assess outcomes, including post-discharge AF.

Among 982 patients, 824 (84%) underwent surgery with CPB. Prolonged SIRS was observed in 62 patients (6.3%). Multivariable analysis identified transfusion of packed red blood cells (OR 1.9; 95% CI, 1.1-3.5; p = 0.03) and higher first-postoperative-day C-reactive protein (CRP) levels (OR 1.2 per 10-unit increase; 95% CI, 1.0-1.3; p = 0.002) as factors associated with prolonged SIRS.

Patients with prolonged SIRS had more adverse events during the index hospitalization, mainly driven by a higher incidence of postoperative AF than non-SIRS patients (OR 2.4; 95% CI, 1.4-4.0; p < 0.001). At 2 years, post-discharge AF incidence remained higher in the prolonged SIRS group (HR 2.0; 95% CI, 1.1-3.6; p = 0.024).

These findings suggest that prolonged SIRS was associated with a greater likelihood of AF both during hospitalization and after discharge following cardiac surgery. Further studies are needed to better define the underlying pathways and clinical implications.