Background

Postoperative atrial fibrillation (AF) occurs in 20-30% of patients after coronary artery bypass grafting (CABG). Blood cardioplegia possesses several beneficial effects such as less haemodilution, reduced cardiac oedema and need for transfusion. However, it has not been fully clarified whether the use of warm blood cardioplegia compared to Histidine-tryptophan-ketoglutarate (HTK) can reduce the risk of post-operative atrial fibrillation. Our aim was to analyse differences in early postoperative outcome after CABG in patients without previous history of atrial fibrillation to further define the influence of cardioplegia type on atrial fibrillation.

Methods

Patients undergoing CABG in elective or emergency setting at our department between January 2010 and November 2021 were included in this study. Patients received either warm blood cardioplegia or HTK. Descriptive analyses were used to analyse preoperative, intraoperative, and postoperative data. Univariate analysis identified risk factors for the onset of AF. Median follow-up time was 195 days (147; 204). Results

Overall, 3731 patients were included of whom 2743 received HTK, while 990 received warm blood cardioplegia. Cardioplegia amount was 1430±454ml and 32±101ml respectively. AF occurred in 318 (11.6%) patients after HTK and in 106 (10.7%) patients after warm cardioplegia, while AF at discharge persisted in 105 (3.8%) and 41 (4.1%) patients respectively. Univariate analysis identified several risk factors for new onset of AF such as renal failure (OR 1.248; p<.001), perioperative infarction (OR 2.146; p=.034) and bleeding (OR 2.003; p<.001). Cardioplegia type did not influence the onset of AF but the onset of AF correlated with a worse prognosis with a 180-day survival of 98.7±0.2 vs. 90±0.2% (log rank p<.001).  

Conclusion

The use of warm blood cardioplegia compared with HTK did not reduce the incidence of postoperative atrial fibrillation in our cohort. The onset of postoperative atrial fibrillation after CABG was negatively associated with early and mid-term outcome. Our study confirms already known risk factors predisposing postoperative AF and identified an associated risk for renal failure and postoperative bleeding.