Atrial Fibrillation and Stroke Risk After Coronary Artery Bypass Grafting Surgery

Abstract

Background: The present multicentre study was aimed at determining the effect of preoperative atrial fibrillation (preop-AF) as stroke risk factor in coronary artery bypass graft surgery (CABG) during the perioperative period. Methods: Patients undergoing isolated CABG surgery were enrolled from 21 Spanish centers. Baseline variables related with perioperative stroke risk were recorded and analysed. The Northern New England Cardiovascular Disease Study Group (NNECVDSG) stroke risk schema was used to stratify stroke risk and compare predicted vs observed neurologic outcomes in this study. Results: 26347 patients were enrolled in the study. Prevalence of preop-AF was 4.2%, and was associated significantly with major cardiovascular comorbidities. The stroke rate was 1.38% (365 strokes), and it was slightly higher for patients with preop-AF vs non preop-AF, 1.82% vs 1.36%, p = 0.2. NNECVDSG schema showed good predictive ability calculating the area under the receiver operating characteristic curve (c-statistic 0.696; 95% CI 0.668 to 0.723). To investigate the associations of baseline preoperative variables with perioperative CABG-stroke a logistic regression model was performed. Preop-AF impact on perioperative stroke was lower that other variables. Preop-AF did not show an adverse impact in the quartiles groups according to NNECVDSG Stroke Risk Index. Conclusion: Risk of perioperative stroke in isolated CABG surgery patients is not significantly increased by preop-AF.

Keywords: Coronary Artery Bypass Grafting; Strial fibrillation; Stroke.

Figure 1.. Bar graph of percentage of preoperative atrial fibrillation (open bars) and perioperative stroke (filled bars) according to presence accumulative of preoperative stroke risk factors (age≥ 75 years-old, female, diabetes mellitus, renal failure, peripheral vascular disease, left ventricular ejection fraction < 40%, urgent and emergent surgery). Line represent tendency of progressive increase of the preoperative prevalence of the atrial fibrillation (y = 2.0914x – 0.4533; R² = 0.982).

Figure 2.. Prevalence of the preoperative atrial fibrillation by age (solid line) and its exponential line of tendency (y = 1.4131e0.1652x ; R² = 0.9493) in the cohort of 26347 isolated coronary artery bypass graft surgery. Dotted line showed prevalence atrial fibrillation in population-based study (data from Framingham study8).