Characterisation of Ventricular Nucleotide Metabolism and Clinical Predictors Associated with the Onset of Atrial Fibrillation Following Cardiac Surgery

TL;DR

This study explores how changes in heart cell energy levels and surgical factors like age and procedure time relate to the risk of developing atrial fibrillation after heart surgery.

Contribution

The study identifies ventricular nucleotide metabolism changes and clinical predictors for postoperative atrial fibrillation following cardiac surgery.

Findings

Patients who developed AF had longer cross-clamp times during CABG and AVR surgeries.

CABG patients with AF showed significant drops in ATP/ADP and ATP/AMP ratios post-reperfusion.

Age and cross-clamp time were the most significant clinical predictors of AF development.

Abstract

Introduction: Postoperative atrial fibrillation (POAF) is a common complication after heart surgery, adversely impacting clinical outcomes and healthcare costs. Little is known about the dynamics of nucleotide metabolism associated with the development of POAF at a ventricular level. We conducted a post hoc trial analysis to investigate the changes in ventricular adenine nucleotides and the clinical predictors associated with the development of AF. Methods: Using data from a randomised trial, we analysed ATP/ADP, ATP/AMP, and energy charges in left and right ventricular biopsies of patients who developed AF compared to non-AF patients. A logistic regression model was used to understand the predictors associated with the development of atrial fibrillation in this cohort. Results: We analysed adenine nucleotide levels available in 88 patients who underwent coronary artery bypass grafting (CABG) (n = 65) and aortic valve replacement (AVR) (n = 23), out of which 27 (31%) developed a new onset of AF. Seventeen (43.4%) patients in the CABG group and ten (26.15%) in the AVR group developed AF. The patients who developed postoperative AF had longer cross-clamp times for CABG (p = 0.013) and AVR (p = 0.002). The most significant predictors for AF development were age (p = 0.003) and cross-clamp time (p = 0.012). In patients undergoing CABG who developed AF, we found a significant drop in post-reperfusion ATP/ADP and ATP/AMP ratios compared to pre-reperfusion. This was not significant for the patients who underwent AVR. Furthermore, the patients who underwent CABG and developed AF had higher pre- and post-reperfusion ATP/ADP ratios and energy charges than non-AF patients, suggesting a higher reserve of cardiac nucleotides. Conclusions: The development of postoperative atrial fibrillation is associated with intraoperative changes in the ventricular adenine nucleotide metabolism of patients undergoing CABG. In the clinical analysis, age and cross-clamp time were significant predictors of AF development.

Figures