Sex Differences in Postoperative Atrial Fibrillation and Posterior Left Pericardiotomy: Sub-Analysis of the PALACS Trial.

BACKGROUND: This post hoc analysis of the Posterior Left Pericardiotomy for the Prevention of AtriaL Fibrillation After Cardiac Surgery (PALACS) trial examined the association between sex and postoperative atrial fibrillation (POAF) characteristics following cardiac surgery.

METHODS: In PALACS, patients undergoing cardiac surgery were randomized to posterior left pericardiotomy or no intervention. This analysis stratified participants by sex, evaluating differences in POAF incidence, duration, burden, postoperative in-hospital length of stay, and pericardial effusions.

RESULT: All 420 PALACS patients were included, consisting of 24%(102/420) female patients. POAF occurred in 22%(22/102) of females and 25%(81/318) of males (p=0.51). Female sex was associated with a lower POAF risk (adjusted Odds Ratio [OR] 0.47, 95% Confidence Interval [CI]:0.24-0.87, p=0.02). Posterior left pericardiotomy reduced the risk of POAF (adjusted OR 0.46 95%CI:0.28-0.76, p=0.003), without difference by sex (pinteraction=0.59). No sex differences were observed in POAF duration or burden. Female patients had longer postoperative in-hospital length of stay (median 7[Interquartile Range (IQR) 5,8] days versus 6[IQR 5,7] days, p=0.005); however, sex was not independently associated with hospitalization length (adjusted β 1,079, 95%CI: -448-2,605, p=0.17). Pericardial effusion incidence and size did not differ by sex. Moderate (>10 mm) posterolateral pericardial effusion was associated with higher POAF incidence (adjusted OR 2.98, 95%CI:1.07-8.16, p=0.03), without sex difference (pinteraction=0.61).

CONCLUSION: In PALACS, female patients had lower adjusted risk of POAF; however, the clinical course of POAF was similar between sexes. Posterior left pericardiotomy reduced POAF incidence without evidence of sex-specific heterogeneity.