Abstract 2555: New-onset Postoperative Atrial Fibrillation is an Early Predictive Marker of Late AF and Long-term Mortality Following Cardiac Surgery: A Comprehensive Population-based Study
Introduction Atrial fibrillation (AF) remains a frequent and serious early complication of cardiac surgery. Although the incidence and clinical determinants of new-onset early postoperative AF (POAF) have been described, data on its long-term consequences are lacking. We hypothesized that early POAF after cardiac surgery, which reflects underlying cardiovascular pathology, is a marker for the development of late AF.
Methods We conducted a study of all Olmsted County, MN residents who underwent CABG and/or valve surgery from January 1, 2000 to December 31, 2005 to examine the rates and long-term prognostic implications of POAF (AF ≤30 days of surgery). Patients were followed up to the last clinical visit, repeat cardiac surgery or death for first documentation of AF after 30 days of surgery (mean 4.4±2.5 years). Only patients who were free of any history of preoperative AF, pacemaker, congenital heart disease were analyzed (n=618).
Results The incidence of POAF was 36.9% (n=228). 8-year survival from late AF was 48.8% for patient with POAF and 86.9% for POAF-free patients; p<0.001. The unadjusted HR was 6.1, 95% CI [3.95–9.32]; p<0.001). The average time from surgery to late AF was 2.5±2.3 years. After excluding 30-day deaths, 8-year survival rates for patients with vs without POAF were 59.6% and 77.8%, respectively; p<0.001. In multivariate Cox regression analysis, after adjusting for age, gender, clinical and surgical risk factors, independent predictors of late AF were early POAF (HR=5.13, 95% CI [3.1– 8.5]; p<0.001), combined CABG and valve surgery (HR=2.95, 95% CI [1.76 – 4.96]; p<0.001), renal dysfunction (creat >2), (HR=2.59, 95% CI [1.15–5.85]; p=0.02), and early POAF duration. The risk of late AF increased by 8-fold in patients with POAF duration ≥3 days compared to those without POAF and by 2-fold vs those of lesser duration; HR=8.16, 95% CI [4.57–14.57]; p<0.001) and HR=2.23 (95% CI: [1.34 –3.72]; p=0.002), respectively.
Conclusions Early new-onset POAF, including its duration, is a strong and independent marker for the establishment of late AF and is associated with increased long-term mortality. Our findings suggest that an aggressive therapeutic approach for patients who develop early POAF following cardiac surgery is paramount.