Influence of anterior periaortic fat pad excision on incidence of postoperative atrial fibrillation

OBJECTIVE: In humans, the existence of an anterior periaortic fat pad (AFP) containing parasympathetic ganglia has been described in the aortopulmonary window. Changes in the autonomic nervous system (ANS) tone can lead to postoperative atrial fibrillation (POAF). The AFP is usually removed during coronary bypass grafting (CABG) to fully expose the aortic root. The purpose of this study was to evaluate the influence of AFP removal during CABG on the ANS tone, incidence of POAF, hospital stay, and in-hospital morbidity and mortality. METHODS: A total of 215 patients were randomized in this prospective, double-blind trial to either removal (n=107) or maintenance (n=108) of the AFP during their first CABG. All patients underwent continuous telemetry monitoring after surgery. They underwent at least 1-h Holter monitoring on the second postoperative day. Heart rate variability measurements of both time-domain and frequency-domain analysis were included. POAF was defined as AF for more than 5min or causing hemodynamic instability. RESULTS: The mean age was nearly 58 years, and 76% were male. There was no difference in the incidence of POAF between the retained and removed AFP groups (19.3% vs 17%, respectively; P=0.664, odds ratio=1.16). Mean heart rate and heart rate variability parameters, in-hospital stay, and postoperative morbidity and mortality were similar in both groups. CONCLUSIONS: Removal of the AFP during CABG has no significant effect on the incidence of POAF, ANS tone, and postoperative morbidity or mortality.