# Prolonged Systemic Inflammatory Response Syndrome Predicts Atrial Fibrillation After Cardiac Surgery

## TL;DR

Prolonged inflammation after heart surgery increases the risk of atrial fibrillation both shortly after surgery and in the long term.

## Contribution

This study identifies prolonged systemic inflammatory response syndrome as a predictor of postoperative atrial fibrillation in cardiac surgery patients.

## Key findings

- Prolonged SIRS occurred in 6.3% of patients after cardiac surgery.
- Prolonged SIRS was linked to a higher risk of postoperative atrial fibrillation during hospitalization and at 2 years post-discharge.
- Transfusion of packed red blood cells and elevated C-reactive protein levels were risk factors for prolonged SIRS.

## Abstract

Cardiac surgery and the use of cardiopulmonary bypass (CPB) lead to short-lasting postoperative inflammatory response and some patients fail to adapt to the stress leading to a prolonged systemic inflammatory response syndrome (SIRS). We aimed to identify the risk factors for prolonged SIRS and whether this may affect the onset of short- and long-term postoperative atrial fibrillation (AF) after adult cardiac surgery patients.

The CAREBANK biobank study consists of prospectively enrolled patients undergoing adult cardiac surgery from 2016 to 2021 with ongoing follow-up data. This substudy included patients operated on with or without the use of CPB.

Overall, 982 patients underwent cardiac surgery, 824 (84%) patients using CPB. Prolonged SIRS was observed in 62 (6.3%) patients. Transfusion of packed red blood cells (OR 1.9, 95%, confidence interval [CI] 1.1-3.5, P = .03), and the first postoperative day C-reactive protein level (OR 1.2, 95%, CI 1.0-1.3, per 10 units, P = .002) were associated with the development of prolonged SIRS in a multivariable analysis. Patients with prolonged SIRS had more adverse events during index hospitalization, mainly driven by the higher incidence of postoperative AF compared to non-SIRS patients (OR 2.4, 95%, CI, 1.4-4.0, P < .001). At 2 years, the incidence of post-discharge AF was higher compared with non-SIRS patients (hazard ratio 2.0, 95% CI, 1.1-3.6, P = .024).

A subset of cardiac surgery patients demonstrates impaired adaptation to the perioperative inflammatory response, placing them at increased risk for AF both early after surgery and following discharge.

NCT03444259

Postoperative atrial fibrillation (POAF) is a common, often transient phenomenon affecting one-third of patients undergoing cardiac surgery and may resolve within minutes to hours without intervention.