Duration of Postoperative Atrial Fibrillation After Cardiac Surgery Is Associated With Worsened Long-Term Survival

Abstract

Background: Studies of the effects of postoperative atrial fibrillation (poAF) on long-term survival are conflicting, likely because of comorbidities that occur with poAF and the patient populations studied. Furthermore, the effects of poAF duration on long-term survival are poorly understood.

Methods: We utilized a prospectively collected database on outcomes of cardiac surgery at a large tertiary care institution between August 2001 and December 2010 with survival follow-up through June 2015 to analyze long-term survival of patients with poAF. In addition, we identified patient- and procedure-related variables associated with poAF, and estimated overall comorbidity burden using the Elixhauser comorbidity index. Survival was compared between patients with poAF (n = 513) and a propensity score matched control cohort, both for all patients and separately for subgroups of patients with poAF lasting less than 2 days (n = 218) and patients with prolonged poAF (n = 265).

Results: Patients with poAF were older and had a higher burden of comorbidities. Survival was significantly worse for patients with poAF than for the matched control group (hazard ratio 1.43, 95% confidence interval: 1.11 to 1.86). That was driven by decreased survival among patients with prolonged poAF (hazard ratio 1.97, 95% confidence interval: 1.37 to 2.80), whereas survival of patients with poAF for less than 2 days was not significantly different from that of matched controls (hazard ratio 0.91, 95% confidence interval: 0.60 to 1.39).

Conclusions: After close matching based on comorbidity burden, prolonged poAF is still associated with decreased survival. Therefore, vigilance is warranted in monitoring and treating patients with prolonged poAF after cardiac surgery.

Fig 1

Long-term survival of patients having postoperative atrial fibrillation (poAF [dotted line]) and patients not having poAF (No poAF [solid line]). The p value reflects the log odds test of difference in overall survival.

Fig 2

Long-term survival of patients having postoperative atrial fibrillation (poAF [dotted line]) and a propensity score matched control group (No poAF [solid line]). The p value reflects the Klein test of difference in overall survival between each patient with poAF and their PSM control patient.

Fig 3

Long-term survival of patients with postoperative atrial fibrillation (poAF [dotted lines]) of different duration compared with propensity score matched patients without poAF (No poAF [solid lines]). (A) Although there was no change in survival between patients with poAF of less than 2 days’ duration and their matched patients, (B) there was a significantly worse survival for patients with poAF of more than 2 days’ duration or present at discharge compared with matched patients without poAF. The p value reflects the Klein test of difference in overall survival between each patient with poAF and the propensity score matched control patient.