Sex-Specific Differences in New-Onset Afib Post-CABG

CABG surgery
CABG surgery
Patients with new-onset atrial fibrillation after CABG experience higher rates of morbidity and poor long-term survival outcomes compared to women.

Men who experience new-onset atrial fibrillation (AF) after undergoing coronary artery bypass graft surgery (CABG) have worse outcomes and poorer long-term survival compared to women, according to research published in Circulation: Cardiovascular Quality Outcomes.

Researchers conducted a large, multi-center observational study of more than 11,000 consecutive patients without a history of AF who underwent isolated CABG between January 2002 and December 2012. The primary outcome measures were the adjusted incidence of new-onset, in-hospital post-CABG AF and adjusted time, in hours, from the conclusion of CABG surgery to the first AF episode.

A total of 11,236 patients (8214 men; 3022 women) were included in the analysis. Unadjusted incidence of post-CABG was 30.2% in men and 27.4% in women (overall: 29.5%). Between 2002 and 2010, rates of new-onset post-CABG AF significantly decreased in both men and women (P =.007), and were lower in women for all years. Overall, women’s risk-adjusted odds of developing post-CABG AF were significantly lower than men’s (odds ratio [OR]: 0.75; 95% confidence interval [CI], 0.64-0.89).

During their hospital stay, men on average had a statistically significantly greater risk for developing new-onset post-CABG AF compared to women (hazard ratio [HR]: 1.16; 95% CI, 1.06-1.28). Results were similar on a year-by-year basis. At 48 hours, women had a 77% probability of being AF free, compared to a 72% probability for men (P <.001).

In patients who experienced ≥1 episode of AF, the adjusted mean duration of the first AF episode was significantly shorter in women compared to men (mean: 6.3 hours; 95% CI, 4.4-7.9 vs mean: 9.0 hours; 95% CI, 8.1-10.1, respectively; mean difference: -3.1; 95% CI, -5.1 to -1.2).

Similarly, adjusted mean duration of patients’ longest AF episode was also significantly shorter in women compared to men (mean: 9 hours; 95% CI, 7-12 vs mean: 14 hours; 95% CI, 13-15, respectively; mean difference: -4.6 hours; 95% CI, -7.3 to -2.0).

Finally, adjusted median total time in AF was also significantly lower in women compared to men (median: 19 hours; 95% CI, 18-21 vs median: 22 hours; 95% CI, 20-24; median difference: -2.4 hours; 95% CI, -2.5 to -2.3, P <.0001).

The researchers noted that the study results are consistent with other studies that identified male sex as post-CABG AF risk factor; no previous studies exist to compare the results of AF episode duration in women vs men.

“Future research should investigate how the differences in incidence and duration of post-CABG AF observed here between women and men play out in terms of long-term outcomes,” the researchers concluded. “Although it is well established that post-CABG AF is associated with poorer long-term survival, it is not yet known that the magnitude of this association is consistent across sex.”

Disclosures: The researchers reported no conflicts of interest.


Filardo G, Ailawadi G, Pollock BD, et al. Sex differences in the epidemiology of new-onset in-hospital post-coronary artery bypass graft surgery atrial fibrillation. Circ Cardiovasc Qual Outcomes. 2016 Oct 18. doi: 10.1161/circoutcomes.116.003023 [Epub ahead of print].