Response to the Letter on “Risks of New-Onset Atrial Fibrillation after Coronary Artery Bypass Grafting”

Dear Editor,

We appreciate the opportunity to respond to the letter by Guvenc et al. [1] regarding our article, “Predictive Value of Age, Creatinine, and Ejection Fraction I and II Scores for Postoperative Atrial Fibrillation in Isolated On-Pump Coronary Artery Bypass Grafting Surgery: A Multicenter Retrospective Study” [2]. We are grateful for their interest in our work and their insightful comments, which allow us to further elaborate on the study’s methodology and findings.

First, we acknowledge the concern regarding the potential variability in perioperative treatment methods across different centers. While it is true that variations in perioperative management may influence clinical outcomes. We sought to minimize these effects by using standard data collection protocols across participating centers and ensuring that essential preoperative, intraoperative and postoperative variables were routinely collected from medical records using predetermined criteria to improve consistency and reliability. In addition, all centers involved in our study adhere to national and international guidelines for coronary artery bypass grafting and perioperative management, ensuring a degree of uniformity in treatment regimens [3].

Regarding the classification of urgent and emergency cases, we confirm that emergency cases were defined as patients requiring immediate surgery due to life-threatening conditions such as severe coronary artery lesions or perforation of a coronary artery during percutaneous coronary intervention, whereas urgent cases included patients requiring surgery within 24–48 h due to unstable angina or evolving myocardial infarction. These classifications were consistently applied across all participating centers following established definitions used in cardiac surgery literature. While we included patients with emergent conditions requiring immediate surgery, we excluded those with preoperative hemodynamic instability to reduce the confounding effects and ensure a more homogeneous study population. Hemodynamic instability was defined as patients who required inotropic support and/or intra-aortic balloon pump use, distinguishing them from emergent patients who remained hemodynamically stable at the time of surgery.

We appreciate the discussion on cardiopulmonary bypass (CPB) methods, including the impact of prime solution strategies on microcirculatory perfusion and its potential effects on postoperative atrial fibrillation (PoAF). While we acknowledge the role of CPB management in influencing outcomes, the retrospective nature of our study limited our ability to control all specific intraoperative techniques used at each center. However, all centers adhered to standard CPB protocols.

The concern regarding the relatively low preoperative beta-blocker and statin usage rates is well noted. While higher adherence to preoperative beta-blocker therapy is recommended for reducing PoAF risk [3, 4], real-world data indicate that patient-related factors, including contraindications and physician discretion, influence medication use. Our study reflects actual clinical practice, and the statistical analysis in the study accounted for these variations by including beta-blocker and statin use as variables, ensuring that their potential influence on PoAF incidence was considered when interpreting the results.

With respect to the management of PoAF, we agree that treatment strategies, including intravenous beta-blockers, amiodarone, and cardioversion are critical. However, our study primarily focused on PoAF prediction rather than its management. Future studies evaluating the relationship between specific treatment strategies and PoAF outcomes could provide further insights into optimizing postoperative care.

We appreciate the point raised regarding postoperative stroke as a predictor of PoAF. While stroke can be both a cause and consequence of PoAF [5], our multivariate analysis identified postoperative stroke as an independent predictor, consistent with prior literature suggesting interplay between cerebrovascular events and cardiac arrhythmias [6]. Stroke may disrupt the autonomic nervous system [7], which is hypothesized to have a role in causing cardiac arrhythmia, most often atrial fibrillation [8]. We acknowledge the need for further studies to delineate this relationship more comprehensively.