Surgical ablation of atrial fibrillation: a protocol for a systematic review and meta-analysis of randomised controlled trials

Prophylactic ablation during cardiac surgery in patients without atrial fibrillation: a systematic review and meta-analysis of randomized trials

OBJECTIVES

Atrial fibrillation is the most common complication of cardiac surgery and occurs frequently in patients without a history of the arrhythmia. We conducted a systematic review and meta-analysis of randomized controlled trials to assess whether prophylactic ablation during cardiac surgery in patients without a history of atrial fibrillation prevents atrial fibrillation.

METHODS

We searched CENTRAL, MEDLINE and Embase from inception to August 2024. We included randomized trials of adults without a history of atrial fibrillation undergoing cardiac surgery. The intervention of interest was ablation during surgery. We pooled data using random-effects models. The primary outcome was new-onset early postoperative atrial fibrillation within 30 days following surgery. The key secondary outcome was incident clinical atrial fibrillation at follow-up (minimum 6 months). We assessed risk of bias using the Cochrane Collaboration's risk of bias tool v.2 and evidence quality using Grading of Recommendations, Assessment, Development and Evaluation (GRADE).

RESULTS

We included 7 trials (n = 687). The intervention was pulmonary vein isolation in 6 trials and ganglion plexi ablation in 1. Patients who received prophylactic ablation were less likely to have early postoperative atrial fibrillation (21% vs 37%, risk ratio [RR] 0.5, 95% confidence interval 0.3-0.8, I2 = 64%) and incident clinical atrial fibrillation at longest follow-up (range 6 months-2 years; 3% vs 10%, RR 0.3, 95% confidence interval 0.2-0.7, I2 = 0%). The quality of evidence was low.

CONCLUSIONS

Prophylactic ablation during cardiac surgery may prevent atrial fibrillation in patients without a history of the arrhythmia. A definitive randomized trial is needed to confirm effects and safety.

Perioperative and mid-term outcomes of mitral valve surgery with and without concomitant surgical ablation for atrial fibrillation: a retrospective analysis

OBJECTIVES

We retrospectively analysed perioperative and mid-term outcomes for patients undergoing mitral valve surgery with and without atrial fibrillation.

METHODS

Patients who underwent mitral valve surgery between January 2018 and February 2023 were included and categorized into 3 groups: 'No AF' (no documented atrial fibrillation), 'AF no SA' (atrial fibrillation without surgical ablation) and 'AF and SA' (atrial fibrillation with concomitant surgical ablation). Groups were compared for perioperative and mid-term outcomes, including mortality, stroke, bleeding and pacemaker implantation. A P-value <0.05 was considered statistically significant.

RESULTS

Of the 400 patients included, preoperative atrial fibrillation was present in 43%. Mean follow-up was 1.8 (standard deviation: 1.1) years. The patients who underwent surgical ablation for atrial fibrillation exhibited similar overall outcomes compared to patients without preoperative atrial fibrillation. Patients with untreated atrial fibrillation showed higher mortality ('No AF': 2.2% versus 'AF no SA': 8.3% versus 'AF and SA': 3.2%; P-value 0.027) and increased postoperative pacemaker implantation rates ('No AF': 5.7% versus 'AF no SA': 15.6% versus 'AF and SA': 7.9%, P-value: 0.011). In a composite analysis of adverse events (Mortality, Bleeding, Stroke), the highest incidence was observed in patients with untreated atrial fibrillation, while patients with treated atrial fibrillation had similar outcomes as those without preoperative documented atrial fibrillation ('No AF': 9.6% versus 'AF no SA': 20.2% versus 'AF and SA' 3: 9.5%, P-value: 0.018).

CONCLUSIONS

Concomitant surgical ablation should be considered in mitral valve surgery for atrial fibrillation, as it leads to similar mid-term outcomes compared to patients without preoperative documented atrial fibrillation.

Statistical primer: individual patient data meta-analysis and meta-analytic approaches in case of non-proportional hazards

Individual patient data (IPD) meta-analyses build upon traditional (aggregate data) meta-analyses by collecting IPD from the individual studies rather than using aggregated summary data. Although both traditional and IPD meta-analyses produce a summary effect estimate, IPD meta-analyses allow for the analysis of data to be performed as a single dataset. This allows for standardization of exposure, outcomes, and analytic methods across individual studies. IPD meta-analyses also allow the utilization of statistical methods typically used in cohort studies, such as multivariable regression, survival analysis, propensity score matching, uniform subgroup and sensitivity analyses, better management of missing data, and incorporation of unpublished data. However, they are more time-intensive, costly, and subject to participation bias. A separate issue relates to the meta-analytic challenges when the proportional hazards assumption is violated. In these instances, alternative methods of reporting time-to-event estimates, such as restricted mean survival time should be used. This statistical primer summarizes key concepts in both scenarios and provides pertinent examples.

Trends in surgical ablation at the time of cardiac surgery among patients with atrial fibrillation

Background

The 2017 American Association for Thoracic Surgery (AATS) guidelines support surgical ablation in patients undergoing cardiac surgery with preoperative atrial fibrillation (AF) owing to a reduction in early mortality and improved overall safety. We explored practice patterns changes and outcomes in patients undergoing concomitant surgical ablation following the guideline change.

Methods

We identified 19,246 patients with preoperative AF who underwent cardiac surgery between 2016 and 2019 from the Florida and Maryland State Inpatient Databases. Rates of surgical ablation by procedure type were temporally trended across years. Secondary outcomes included complications, inpatient mortality, and hospital readmissions. Using multivariable logistic regression, we identified patient variables associated with concomitant surgical ablation.

Results

A total of 2738 patients (14.3%) with AF underwent a concomitant surgical ablation. The rate of surgical ablation increased from 2.1% to 17.4% (P < .001) from 2016 to 2017 but remained unchanged thereafter. Postoperative mortality was lower in the surgical ablation cohort (2.7% vs 3.7%; P = .006), although with a higher rate of pacemaker insertion (11.8% vs 7.2%; P < .0001). Patients with a high-risk Elixhauser score (odds ratio [OR], 0.83; 95% confidence interval [CI], 0.73-0.95), lower income (OR, 0.66; 95% CI, 0.57-0.75), or African American or Hispanic race/ethnicity (OR, 0.80; 95% CI, 0.67-0.96 and OR, 0.82; 95% CI, 0.71-0.96, respectively) had lower odds of undergoing concomitant surgical ablation.

Conclusions

Despite a class I-2a recommendation by the AATS, surgical ablation continues to be underutilized in clinical practice, especially in patients with high-risk comorbidities, with lower incomes, or from minority populations. Surgeons should be mindful of guideline-directed AF management in these vulnerable populations.

Overview of meta-analysis

Meta-analysis has been recognized as the best means to evaluate objectively and study the evidence for a particular issue. In order to give researchers a better understanding of the Meta process, we present an overall introduction to Meta-analysis in terms of comprehensive assessment of the literature, goals, advantages, main steps, and article structure.

Efficacy and safety of benralizumab for eosinophilic asthma: A systematic review and meta-analysis of randomized controlled trials

CONTEXT

Benralizumab is a humanized monoclonal antibody that targets the α chain of the IL-5 receptor (IL-5Rα) and is currently being assessed in clinical trials for asthma control.

OBJECTIVE

Our systematic review and meta-analysis intends to evaluate the therapeutic efficacy and safety of benralizumab in patients with eosinophilic asthma.

DATA SOURCES AND EXTRACTION

Literature searches of PubMed, Embase, and the Cochrane Library were performed to identify randomized controlled trials of benralizumab and clinic outcomes in asthmatics.

RESULTS

In total, 7 articles with 2,321 subjects met our inclusion criteria. From this pooled analysis, we found that benralizumab significantly reduces exacerbations (RR: 0.63, 95% CI: 0.52-0.76, p < 0.00001; I² = 52%, p = 0.06) compared to placebo in eosinophilic asthma. There was no statistical trend for improvement in forced expiratory volume in 1 second or asthma control indices such as Quality of Life Assessment (AQLQ) and Asthma Control Questionnaire score in benralizumab-treated patients. In addition, safety data indicated that benralizumab administration resulted no increasing incidence of adverse events and was well tolerated (RR: 1.00, 95% CI: 0.95-1.05, p = 0.96; I² = 40%, p = 0.13).

CONCLUSION

These results demonstrate the efficacy and safety of benralizumab for asthma patients with severe or uncontrolled symptoms and elevated eosinophils and provide support for benralizumab as an ideal option to treat asthma in this patient population.