New-onset postoperative atrial fibrillation impact on 5-year clinical outcomes and costs

Objective: The impact of new-onset postoperative atrial fibrillation (POAF) following coronary artery bypass grafting (CABG) surgery on long-term clinical outcomes and costs is not known. This subanalysis of the Veterans Affairs “Randomized On/Off Bypass Follow-up Study” compared 5-year outcomes and costs between patients with and without POAF. Methods: Of the 2203 veterans in the study, 100 with pre-CABG atrial fibrillation (93) or missing data (7) were excluded (4.8%). Unadjusted and risk-adjusted outcomes were compared between new-onset POAF (n = 551) and patients without POAF (n = 1552). Five-year clinical outcomes included mortality, major adverse cardiovascular events (MACE, comprising mortality, repeat revascularization, and myocardial infarction), MACE subcomponents, stroke, and costs. A stringent P value of ≤.01 was required to identify statistical significance. Results: Patients with POAF were older and had more complex comorbidities. Unadjusted 5-year all-cause mortality was 16.3% POAF versus 11.9% no-POAF, P = .008. Unadjusted cardiac-mortality was 7.4% versus 4.8%, P = .022. There were no differences between groups in any other unadjusted outcomes including MACE or stroke. After risk adjustment, there were no significant differences between groups in 5-year all-cause mortality (POAF odds ratio, 1.19; 99% confidence interval, 0.81-1.75) or cardiac mortality (odds ratio, 1.51, 99% confidence interval, 0.88-2.60). Adjusted first-year post-CABG costs were $15,300 greater for patients with POAF, but 2- through 5-year costs were similar. Conclusions: No 5-year risk-adjusted outcome differences were found between patients with and without POAF after CABG. Although first-year costs were greater in patients with POAF, this difference did not persist in subsequent years.