The aim of this study was to retrospectively investigate whether performing surgical atrial fibrillation (AF) ablation in conjunction with cardiac surgery (CS) increases the risk for postoperative permanent pacemaker (PPM) requirement. The 30-day risk for PPM requirement was analyzed in consecutive patients who underwent CS from January 2007 to August 27, 2013. Patients were divided into 3 groups: (1) those who underwent AF ablation concomitant with CS (AF ABL), (2) patients with any history of AF who underwent surgery who did not undergo ablation (AF NO ABL), and (3) those with no histories of AF who underwent surgery (NO AF). Logistic regression analysis was performed adjusting for age, gender, and surgery type. Of 13,453 CS patients, 353 (3%) were in the AF ABL group, 1,701 (12%) in the AF NO ABL group, and 11,399 (85%) in the NO AF group. A total of 7,651 patients (57%) underwent coronary artery bypass grafting, 4,384 (33%) underwent valve surgery, and 1,418 (10%) underwent coronary artery bypass grafting and valve surgery. The overall PPM risk was 1.6% (212 of 13,453); risk was 5.7% (20 of 353) in the AF ABL group, 3.1% (53 of 1,701) in the AF NO ABL group, and 1.2% (139 of 11,399) in the NO AF group. The unadjusted and adjusted odds of PPM were higher in the AF ABL and AF NO ABL groups than in the NO AF group (adjusted odds ratio [OR] 2.7, 95% confidence interval [CI] 1.7 to 4.4, and adjusted OR 1.7, 95% CI 1.2 to 2.4, respectively). The unadjusted OR comparing the AF ABL group and the AF NO ABL group was significant (unadjusted OR 1.9, 95% CI 1.9 to 3.2); however, the OR adjusted for surgery type, age, and gender showed a trend toward significance (adjusted OR 1.6, 95% CI 0.9 to 2.7). In conclusion, in this large cohort of patients who underwent CS, surgical AF ablation appeared to carry an increased risk for postoperative PPM implantation.
Atrial fibrillation (AF) occurs commonly in patients with structural heart disease requiring cardiac surgery (CS). For instance, 8.7% of patients referred for coronary artery bypass grafting (CABG), 19.2% of those referred for aortic valve surgery, and 29% of those who underwent mitral valve (MV) repair had histories of AF. Also, a review of the nationwide Society of Thoracic Surgeons database showed that 40.6% of patients with preoperative AF will undergo surgical AF ablation (S-AFA) at the time of CS. This proportion varies with the type of surgery; 61.5% of patients with AF who undergo MV surgery and 27.5% of patients with AF who undergo CABG will undergo concomitant AF ablation. The surgical ablation lesion set, and the inflammatory changes along with the mechanical consequences of the primary surgical procedure could adversely affect the conduction system. Few studies have suggested that concomitant S-AFA might increase the postoperative risk for permanent pacemaker (PPM) implantation. We sought to investigate whether S-AFA increases the risk for PPM implantation in patients who undergo CS.
Methods
A total of 13,453 patients who underwent CS at our institution from January 2007 and August 27, 2013, were retrospectively identified and enrolled. We divided patients into 3 groups: (1) those who underwent concomitant AF ablation along with CS (AF ABL), (2) those with any history of AF who underwent surgery who did not undergo ablation (AF NO ABL), and (3) those with no histories of AF who underwent surgery (NO AF). The primary end point was the risk for PPM implantation for any reason <30 days after surgery. Surgery type was divided into 3 categories: (1) isolated CABG, (2) isolated valve, and (3) CABG and valve.
Preoperative variables were compared among patients across the 3 different groups. One-way analysis of variance and chi-square tests were used to test for group differences in numeric and categorical variables, respectively ( Table 1 ). Incidence of PPM implantation was calculated among the different surgery types ( Table 2 ). Simple logistic regression models were built to identify individual variables that were associated with PPM requirement ( Table 3 ). To assess the impact of AF ablation on PPM requirement, a multivariate logistic regression model was constructed, taking into account surgery type, gender, and age, and adjusted odds ratios (ORs) along with 95% confidence intervals (CIs) were calculated for each pairwise comparison of groups. Finally, an interaction term was added to determine whether surgery type modifies the association between AF ablation and PPM requirement. All analyses were performed using SAS version 9.4 (SAS Institute Inc., Cary, North Carolina). All statistical tests were 2 sided and assessed at the 0.05 level of significance.
| Variable | All Patients (N=13453) | AF ABL (N=353) | AF NO ABL (N=1701) | NO AF (N=11399) | p-value |
|---|---|---|---|---|---|
| Age (years) | 63.4 ± 13.4 | 64.4 ±11.5 | 70.6 ± 12.6 | 62.3 ± 13.3 | <0.001 |
| Female | 4639 (34.5%) | 143 (40.5%) | 665 (39.1%) | 3831 (33.6%) | <0.001 |
| Ejection Fraction | 52.1 ± 13.0 | 51.4 ±12.2 | 49.9 ± 13.7 | 52.5 ± 12.9 | <0.001 |
| Coronary Bypass | 7651 (58.9%) | 58 (0.8%) | 505 (6.6%) | 7088 (92.6%) | <0.001 |
| Coronary Bypass+Valve Surgery | 1418 (10.5%) | 67 (19.0%) | 238 (14.0%) | 1113 (9.8%) | <0.001 |
| Valve Surgery | 4384 (32.6%) | 228 (5.2%) | 958 (21.9%) | 3198 (32.6%) | <0.001 |
| Hypertension | 11592 (86.2%) | 292 (82.7%) | 1522 (89.5%) | 9778 (85.8%) | <0.001 |
| Diabetes Mellitus | 4900 (36.4%) | 89 (25.2%) | 615 (36.2%) | 4196 (36.8%) | <0.001 |
| Length of Stay (days) | 8.0 ± 7.1 | 10.1 ± 9.4 | 10.3 ±8.3 | 7.6 ± 6.7 | <0.001 |
| 30 Day Pacemaker Implantation Rate | 212 (1.6%) | 20 (5.7%) | 53 (3.1%) | 139 (1.2%) | <0.001 |
| Surgery Type | 30-day PPM risk |
|---|---|
| Any Coronary Bypass (n=9069) | 1.0 % (n=88) |
| Coronary Bypass +valve (n=1418) | 3.9% (n=55) |
| Aortic Valve Surgery (n=3975) | 2.7% (n=108) |
| Mitral Valve Surgery (n=611) | 1.0% (n=6) |
| Multivalve Surgery (n=252) | 4.0% (n=10) |
| Variables | OR (95% CI) |
|---|---|
| Age | 1.01 (1.00, 1.02) |
| Female | 1.20 (0.91, 1.59) |
| Ejection Fraction | 1.00 (0.99, 1.01) |
| Procedure Type | |
| Valve vs Coronary Bypass | 6.72 (4.57, 9.88) |
| Coronary Bypass+Valve vs Coronary Bypass | 9.32 (6.03, 14.40) |
| Atrial Fibrillation Ablation vs. No Atrial Fibrillation | 4.87 (3.00, 7.87) |
| Atrial fibrillation No Ablation vs. No Atrial Fibrillation | 2.61 (1.89, 3.59) |
| Atrial Fibrillation Ablation vs. Atrial Fibrillation No Ablation | 1.87 (1.10, 3.17) |
| Hypertension | 0.57 (0.41, 0.80) |
| Diabetes Mellitus | 0.80 (0.60, 1.08) |
| Length of Stay (days) | 1.04 (1.03, 1.05) |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
