J. B. Grau1,2, C. K. Johnson1, C. E. Kuschner1, G. Ferrari1,2, R. E. Shaw1 1Valley Heart And Vascular Institute,Cardiothoracic Surgery,Ridgewood, NJ, USA 2University Of Pennsylvania,Surgery,Philadelphia, PA, USA
Introduction:
Post-operative atrial fibrillation (AF) after coronary artery bypass grafting (CABG) occurs frequently, affecting 20-35% of CABG patients. Post-CABG AF can result in longer hospital stay, and has been shown to decrease survival at 10 years. This study assesses survival and major adverse cardiovascular events (MACE) at 20 years in patients with new-onset post-operative AF after CABG.
Methods:
Patients undergoing CABG between 1994 and 2014 at the Valley Hospital were assessed and matched by surgical approach. In the resulting population of 1856 patients, 363 developed new-onset post-operative AF. Logistic regression was used to determine the significant factors associated with the development of post-op AF. Patients were followed for a mean of 12 ± 5 years (ranging 1 to 21.4 years). A univariate Kaplan Meier analysis was used to compare long-term survival and MACE in patients with and without new-onset Post-op AF. A multivariate Cox Proportional Hazards Regression analysis was used to determine which factors were independently associated with decreased survival.
Results:
Overall 363 patients (19.6%) developed AF post CABG. Logistical regression demonstrated that male gender, increased age, prior cerebrovascular accidents and on-pump CABG were associated with the development of post-op AF. Follow-up MACE in the 1856 patients included 30-day mortality (17 pts, 0.9%), late death (513 pts, 27.6%) late myocardial infarction (76 pts, 4.1%), late PCI (210 pts, 11.3%) repeat CABG (14 pts, 0.8%), any repeat revascularization (219 pts, 11.8%), any stroke (78 pts, 4.2%) and cerebrovascular accident (34 pts, 1.8%). Kaplan Meier analysis showed that patients with post op AF had poorer long-term survival (Log Rank Test p<0.0001) and increased occurrence of MACE (Log Rank Test p<0.0001). Multivariate Cox Proportional Hazards Regression showed that LVEF<35%, Increased age, diabetes, CHF, Active smoking, and History of Renal failure were independently associated with increased MACE and decreased survival. Presence of On-pump CABG, presence of cardiogenic shock, and use of LIMA-SVG over BIMA were independently solely associated with increased mortality. Presence of atrial fibrillation post CABG was independently associated with reduced survival (Adj HR: 1.440; 95%CI: 1.179-1.757; p<0.0001) and increased occurrence of MACE (Adj HR: 1.297; 95CI: 1.094-1.537; p=0.003).
Conclusion:
Our study demonstrates that new-onset AF after CABG is associated with poorer survival and increased MACE at 20 years follow-up. Unfortunately, we have no tools to know how many of the patients that developed AF actually had subclinical symptoms prior to CABG. It is unclear whether CABG causes AF or uncovers an underlying subset of patients conducive to poor outcomes, where AF is just an additional factor. This data suggests that AF is a marker of pathology that deserves close surveillance, not only in the post-operative period, but also in the long term follow up.