New-onset atrial fibrillation after CABG significantly increases the risk of death and stroke in left main patients

Gregg Stone

New data from the EXCEL trial, which found that percutaneous coronary intervention (PCI) was non-inferior to coronary artery bypass grafting (CABG) at three years in patients with left main disease, indicate that CABG patients have a significantly increased risk of new-onset atrial fibrillation than do PCI patients. Furthermore, these data show that patients with new-onset atrial fibrillation have a significantly increased of death and stroke at both at 30 days and at three years.

Writing in the Journal of the American College of Cardiology, Ioanna Kosmidou (Clinical Trials Center, Cardiovascular Research Foundation, New York, USA) and others report that new-onset atrial fibrillation is a “common complication” after CABG and that preoperative atrial fibrillation is a predictor of long-term mortality and morbidity after CABG for left main disease. However, they add that the effect of new-onset atrial fibrillation on outcomes following either CABG or PCI in patients with left main disease is unknown. Therefore, they reviewed data from EXCEL—Evaluation of Xience vs. coronary artery bypass surgery for effectiveness of left main revascularisation—to determine the predictors, incidence, and outcomes of new-onset atrial fibrillation in patients with left main disease undergoing either PCI or CABG.

Of 1,905 patients in the EXCEL study overall, 1,812 did not have atrial fibrillation at baseline. Of these, 893 underwent CABG and 919 underwent PCI. Kosmidou et al comment: “New-onset atrial fibrillation developed at a mean of 2.7±2.5 days after revascularisation in 162 patients (8.9%), including 161 of 893 (18%) CABG-treated patients and one of 919 (0.1%) PCI-treated patients (p<0.0001).” They note that by the time of hospital discharge, the atrial fibrillation had resolved in 85.8% of patients (including those who had undergone cardioversion).

At 30 days, the risk for the composite outcome of death, myocardial infarction, or stroke was significantly higher in patients with new-onset atrial fibrillation than those without. The risk of this endpoint was also significantly increased at three years in patients with new-onset atrial fibrillation: 19.3% vs. 12.8% for patients with new-onset atrial fibrillation (p=0.02). According to the authors, the increased risk of cardiovascular death associated with new-onset atrial fibrillation was driven by stroke-related and heart failure related death.

A multivariate analysis showed that older age, greater body mass index (BMI), and reduced left ventricular ejection fraction (LVEF) were all independent predictors of new-onset atrial fibrillation in patients undergoing CABG. However, Kosmidou et al observe that the C-statistics for the correlations between these risk factors and new-onset atrial fibrillation were modest and they comment: “Many patients who may benefit from CABG have these characteristics.”

The authors suggest that while the increased periprocedural risk of new-onset atrial fibrillation should be recognised in patients with the aforementioned risk factors, they should not be seen as a barrier to performing CABG. “Rather than avoiding CABG in these patients, effective preoperative and preoperative measures (prophylactic beta-blockers or amiodarone) should be considered to prevent the post-surgical occurrence of new-onset atrial fibrillation,” they write.

Study investigator Gregg Stone (Clinical Trials Center, Cardiovascular Research Foundation, New York, USA) told Cardiovascular News: ““These data demonstrate that the markedly increased risk of atrial fibrillation after CABG compared to PCI should be one of the issues that are discussed with the patient and taken into account when deciding upon the optimal revascularization therapy for complex coronary artery disease. Further studies are essential to examine whether more intensive surveillance to detect AF and recurrent arrhythmias after CABG and more aggressive therapies when atrial fibrillation occurs, including anticoagulation, left atrial appendage occlusion, and ablation may improve outcomes after CABG in patients with postoperative atrial fibrillation.”


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