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Published on: February 26, 2013
Postcoronary Artery Bypass Graft Atrial Fibrillation Event Count and Survival: Differences by Sex
Giovanni Filardo1, Benjamin D Pollock2, Briget da Graca3
1Department of Epidemiology, Baylor Scott & White Health, Dallas, Texas; The Heart Hospital Baylor Plano, Plano, Texas; Robbins Institute for Health Policy & Leadership, Baylor University, Waco, Texas.
Insights
Experiencing two or more new-onset atrial fibrillation (AF) episodes after coronary artery bypass graft surgery (CABG) increases long-term mortality risk for both men and women. Women with two AF events faced the highest risk, while men
Area of Science:
- Cardiology
- Cardiac Surgery
- Electrophysiology
Background:
- New-onset atrial fibrillation (AF) following coronary artery bypass graft surgery (CABG) is linked to adverse outcomes.
- Limited data exist on how AF characteristics, such as event frequency, impact long-term mortality after CABG.
- Investigating sex-specific effects of post-CABG AF event frequency is crucial for understanding mortality risk.
Purpose of the Study:
- To examine the association between the number of post-CABG AF events and long-term mortality risk.
- To determine if this association is modified by sex.
Main Methods:
- Utilized Society of Thoracic Surgeons (STS) data for 9203 isolated-CABG patients (2002-2010).
- Supplemented STS data with in-hospital AF detection via continuous electrocardiogram monitoring and long-term survival data.
- Employed propensity-adjusted Cox regression to analyze the effect of AF event number on survival, testing for sex-based effect modification.
Main Results:
- AF occurred in 29.4% of women and 32.3% of men (P < .001).
- Two or more post-CABG AF events significantly increased 5-year mortality risk, independent of AF duration (P < .001).
- Mortality risk differed significantly by sex (P < .001): women with two AF episodes had the highest HR (2.98), followed by women and men with four or more events (HR=2.76 and HR=2.73, respectively). A single AF episode showed no increased mortality risk.
Conclusions:
- Multiple post-CABG AF episodes elevate 5-year mortality risk in both sexes, irrespective of total AF duration.
- While men's mortality risk increased with more AF events, women's risk peaked at two events.
- Further research is needed to elucidate the biological or treatment-related factors underlying these sex-specific differences in mortality risk.
Background:
New-onset atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG) is associated with poor outcomes, but data on the effects of its characteristics are lacking and conflicting. We examined the effect number of post-CABG AF events has on long-term mortality risk, and whether this is sex dependent.
Methods:
Routinely collected Society of Thoracic Surgeons (STS) data were supplemented with details on new-onset post-CABG AF (detected in-hospital by continuous electrocardiogram/telemetry monitoring) and long-term survival for 9203 consecutive patients with isolated-CABG (2002-2010). With the use of Cox regression, we determined the propensity-adjusted (STS-recognized risk factors) effect of number of AF events on survival, testing for effect modification by sex and controlling for AF duration.
Results:
AF occurred in 739 women (29.4%) and 2157 men (32.3%) (P < .001). Adjusted results showed 2 or more AF events significantly (P < .001) increased 5-year mortality risk, independently of total AF duration. However, mortality risk differed between the sexes (P < .001): women with 2 AF episodes had the greatest increase (hazard ratio [HR] = 2.98; 95% confidence interval [CI], 1.43-4.83; versus women without AF), followed by women and men with 4 or more AF events (HR = 2.76 [95% CI, 1.27-4.55] and HR = 2.73 [95% CI, 2.30-3.19], respectively). A single post-CABG AF episode was not associated with increased mortality risk.
Conclusions:
Both men and women who experienced 2 or more post-CABG AF episodes showed increased risk of 5-year mortality, independent of total AF duration. Although men's risk increased as the number of AF events increased, women's risk peaked at 2 AF events. Future research needs to determine whether this divergence stems from differences in treatment/management or underlying biology.
