Is the Preoperative Administration of Amiodarone or Metoprolol More Effective in Reducing Atrial Fibrillation: After Coronary Bypass Surgery?

Atrial Fibrillation After Coronary Artery Bypass Grafting and Its Relationship with Hospital Complications in São Paulo State

INTRODUCTION

Atrial fibrillation is the main complication in the postoperative period of cardiovascular surgery. Its genesis is multifactorial, so its rapid identification to mitigate the associated risks is essential.

OBJECTIVE

To evaluate the incidence of atrial fibrillation in patients undergoing coronary artery bypass grafting (CABG) and its relationship with other complications in our setting.

METHODS

This is a multicenter, observational study involving patients undergoing isolated CABG between 2017 and 2019 with data from the Registro Paulista de Cirurgia Cardiovascular (or REPLICCAR II). Variables were prospectively collected in REDCap following the definitions given by version 2.73 of the Society of Thoracic Surgeons Adult Cardiac Surgery Database. Data were collected with prior authorization from the local ethics committee and analyses performed in R software.

RESULTS

A total of 3,803 patients were included, of these 605 had postoperative atrial fibrillation (POAF). In order to adjust the groups, propensity score matching was used. Such analyses resulted in 605 patients in each group (without POAF vs. with POAF). Among patients with POAF, the mean age was 67.56 years, with a prevalence of males (73.6%, 445 patients). Patients belonging to the group with POAF had a mortality rate of 9.26% (P=0.007), longer ventilation time (P<0.001), pneumonia (P<0.001), and sepsis (P<0.001). In multiple analysis, acute renal dysfunction (P=0.032) and longer intensive care unit stay (P<0,001) were associated with the presence of POAF.

CONCLUSION

POAF in CABG is associated with longer intensive care unit and hospital stay, as well as renal dysfunction, pneumonia, and in-hospital mortality.

Navigating the Incidence of Postoperative Arrhythmia and Hospitalization Length: The Role of Amiodarone and Other Antiarrhythmics in Prophylaxis

Antiarrhythmic drugs play a pivotal role in managing and preventing arrhythmias. Amiodarone, classified as a class III antiarrhythmic, has been used prophylactically to effectively prevent atrial fibrillation postoperatively in cardiac surgeries. However, there is a lack of consensus on the use of amiodarone and other antiarrhythmic drugs as prophylaxis to reduce the occurrence of all types of postoperative arrhythmias in cardiac and non-cardiac surgeries. A comprehensive PubMed query yielded 614 relevant papers, of which 52 clinical trials were analyzed. The data collection included the class of antiarrhythmics, timing or method of drug administration, surgery type, type of arrhythmia and its incidence, and hospitalization length. Statistical analyses focused on prophylactic antiarrhythmics and their respective reductions in postoperative arrhythmias and hospitalization length. Prophylactic amiodarone alone compared to placebo demonstrated a significant reduction in postoperative arrhythmia incidence in cardiac and non-cardiac surgeries (24.01%, p<0.0001), and it was the only treatment group to significantly reduce hospitalization length versus placebo (p = 0.0441). Prophylactic use of class 4 antiarrhythmics versus placebo also demonstrated a significant reduction in postoperative arrhythmia incidence (28.01%, p<0.0001), and while there was no significant statistical reduction compared to amiodarone (4%, p=0.9941), a lack of abundant data provides a case for further research on the prophylactic use of class 4 antiarrhythmics for this indication. Amiodarone prophylaxis remains a prime cornerstone of therapy in reducing postoperative arrhythmia incidence and hospitalization length. Emerging data suggests a need for a broader exploration of alternative antiarrhythmic agents and combination therapies, particularly class 4 antiarrhythmics, in both cardiac and non-cardiac surgeries. This meta-analysis depicts the effectiveness of amiodarone, among other antiarrhythmics, in postoperative arrhythmia incidence and hospitalization length reduction in cardiac and non-cardiac surgeries.

Prevention of postoperative atrial fibrillation in cardiac surgery: a quality improvement project

PURPOSE

Postoperative atrial fibrillation (POAF) has an incidence of 20-60% in cardiac surgery. The Society of Cardiovascular Anesthesiologists and the European Association of Cardiothoracic Anaesthesiology Practice Advisory have recommended postoperative beta blockers and amiodarone for the prevention of POAF. By employing quality improvement (QI) strategies, we sought to increase the use of these agents and to reduce the incidence of POAF among our patients undergoing cardiac surgery.

METHODS

This single-centre QI initiative followed the traditional Plan, Do, Study, Act (PDSA) cycle scientific methodology. A POAF risk score was developed to categorize all patients undergoing cardiac surgery as either normal or elevated risk. Risk stratification was incorporated into a preprinted prescribing guide, which recommended postoperative beta blockade for all patients and a postoperative amiodarone protocol for patients with elevated risk starting on postoperative day one (POD1). A longitudinal audit of all patients undergoing cardiac surgery was conducted over 11 months to track the use of prophylactic medications and the incidence of POAF.

RESULTS

Five hundred and sixty patients undergoing surgery were included in the QI initiative from 1 December 2020 to 1 November 2021. The baseline rate of POAF across all surgical subtypes was 39% (198/560). The use of prophylactic amiodarone in high-risk patients increased from 13% (1/8) at the start of the project to 41% (48/116) at the end of the audit period. The percentage of patients receiving a beta blocker on POD1 did fluctuate, but remained essentially unchanged throughout the audit (34.8% in December 2020 vs 46.7% in October 2021). After 11 months, the overall incidence of POAF was 29% (24.9% relative reduction). Notable reductions in the incidence of POAF were observed in more complex surgical subtypes by the end of the audit, including multiple valve replacement (89% vs 56%), aortic repair (50% vs 33%), and mitral valve surgery (45% vs 33%).

CONCLUSIONS

This single-centre QI intervention increased the use of prophylactic amiodarone by 28% for patients at elevated risk of POAF, with no change in the early postoperative initiation of beta blockers (46.7% of patients by POD1). There was a notable reduction in the incidence of POAF in patients at elevated risk undergoing surgery.

Combination prophylactic amiodarone with beta-blockers versus beta-blockers in atrial fibrillation after cardiac surgery: A systematic-review and meta-analysis

BACKGROUND

Guideline recommendations regarding the preferred preventive measures for postoperative atrial fibrillation (POAF) are unclear, nor have we found any review articles addressing the combination of amiodarone and beta-blockers for the prevention of POAF.

OBJECTIVES

To investigate the efficacy and safety of combination beta-blockers and amiodarone in the prevention of POAF while also comparing the use of amiodarone and beta-blockers individually.

METHODS

We used Pubmed as the primary resource. POAF incidence was the primary outcome of this study. The secondary outcomes were hospital length of stay (LOS), ICU LOS, treatment-related drug discontinuation (TRDD), and mortality. The random-effects model assessed all pooled outcomes with 95% confidence intervals. Statistical significance was set at p≤0.05.

RESULTS

The amiodarone subgroup of POAF incidence saw a Risk Ratio (RR) of 0.81 [0.63, 1.06], p=0.12, while the combination subgroup resulted in a RR of 0.63 [0.49, 0.80], p <0.001. TRDD for the amiodarone subgroup resulted in a RR of 0.68 [0.25, 1.82], p=0.44, while the combination subgroup saw a RR of 0.84 [0.57, 1.23], p=0.36. For mortality, the amiodarone subgroup resulted in a RR of 0.97 [0.48, 1.98], p=0.93, while the combination subgroup resulted in a RR of 1.04 [0.27, 4.05], p=0.96. Both hospital and ICU LOS saw no significant difference between treatment arms for both the combination subgroup and amiodarone alone. Except for the incidence of postoperative atrial fibrillation (POAF) in the combination prophylaxis group, most of the measured outcomes did not meet the optimized information size (OIS) that was estimated.

CONCLUSION

Combination prophylaxis with amiodarone and beta-blockers significantly lowered risks of POAF incidence in comparison to beta-blockers alone while also having comparative mortality and TRDD outcomes.

Demographic and clinical predictors of post-operative atrial fibrillation in cardio-surgical patients

AIMS

Post-operative atrial fibrillation is defined as an episode of atrial fibrillation that occurs 1-5 days after a surgical procedure in patients without a previous history of atrial fibrillation. Multiple factors such as demographics, cardiac surgical, endogenous, or mental health may relate to post-operative atrial fibrillation.The aim of this study was to identify multivariable high-risk factors for post-operative atrial fibrillation and to propose a risk-assessment tool.

METHODS AND RESULTS

A cross-sectional observational study was conducted in a University Hospital of Greece. Predictor variables examined demographic and clinical variables, anxiety, depression, health-related quality of life, frailty, perioperative mortality (European System for Cardiac Operative Risk Evaluation II), and 10-year survival/mortality risk (Charlson Comorbidity Index score). The outcome variable was post-operative atrial fibrillation. Multivariable analysis was assessed to identify predictors of post-operative atrial fibrillation.Ninety-one patients were included in our sample. Post-operative atrial fibrillation was diagnosed in 44 (48.4%). Factors associated with post-operative atrial fibrillation are the following: age group of 66-75 years [OR 5.78, 95% confidence interval (CI) 1.37-24.34], Charlson Comorbidity Index score (OR 1.42, 95% CI 1.07-1.89), and hours of mechanical ventilation (OR 1.03, 95% CI 1.00-1.06). The Charlson Comorbidity Index score was identified as an independent predictor of post-operative atrial fibrillation (exp: 1.412, 95% CI: 1.017-1.961).

CONCLUSION

Patients with post-operative atrial fibrillation had a higher Charlson Comorbidity Index score. The Charlson Comorbidity Index was identified as an independent clinical predictor of post-operative atrial fibrillation. The risk-assessment tool proposed includes age, Charlson Comorbidity Index score, and hours of mechanical ventilation. Future studies are needed to establish such an assessment.

Mechanisms, Prevention, and Treatment of Atrial Fibrillation After Cardiac Surgery: A Narrative Review

New onset of postoperative atrial fibrillation (AF) generally is recognized as a frequent and debilitating complication after cardiac surgery, contributing to a considerable health- care cost. Extensive research has been conducted to study the underlying mechanisms and risk factors of AF in the perioperative period. Many options have been suggested to lower the incidence, and the concurrent cost in health resources. This review attempts to synthesize the large body of existing literature on AF, as well as expand and illustrate the available knowledge on its management strategies. The latter incorporates recent developments in the anesthesthetic approach as well as in the pharmacologic arsenal. In addition, the current review provides a tool for understanding the pathophysiology of AF and for reducing the occurrence after cardiac surgery. By using it, clinicians can manage patients with AF in the perioperative period of cardiac surgery and minimize the relatively high economic cost that accompanies it.

Metoprolol for prophylaxis of postoperative atrial fibrillation in cardiac surgery patients: systematic review and meta-analysis

PURPOSE

Postoperative atrial fibrillation (POAF) is a potentially lethal and morbid complication after open heart surgery. This systematic review and meta-analysis aimed to investigate metoprolol compared with other treatments for prophylaxis against POAF.

METHODS

We searched CENTRAL, MEDLINE, EMBASE and trial registries for randomised controlled trials that evaluated metoprolol for preventing the occurrence of POAF after surgery against other treatments or placebo. Random-effects model was used for estimating the risk ratios (RRs) and mean differences with 95% CIs.

RESULTS

Nine trials involving 1570 patients showed metoprolol reduced POAF compared with placebo (416 patients; RR 0.46, 95% CI 0.33 to 0.66; I²=21%; risk difference (RD) -0.19, 95% CI -0.28 to -0.10). However, metoprolol increased the risk of POAF compared with carvedilol (159 patients; RR 1.59, 95% CI 1.20 to 2.12; I²=4%; RD 0.13, 95% CI 0.06 to 0.20). There was no difference when compared with sotalol or amiodarone. The occurrence of cardiovascular conditions after drugs administration or death between the groups was not different. The overall quality of evidence was moderate to high. Subgroup analysis and funnel plot were not performed.

CONCLUSIONS

Metoprolol is effective in preventing POAF compared with placebo and showed no difference with class III antiarrhythmic drugs. Death and thromboembolism are associated with open heart surgery, but not significant in relation to the use of metoprolol.

PROSPERO REGISTRATION NUMBER

CRD42019131585.

[Atrial Fibrillation After Coronary Artery Bypass Surgery: Risk Factors, Prevention and Treatment]

This review focuses on the issue of atrial fibrillation (AF) following coronary bypass surgery in patients with ischemic heart disease. Risk factors of this complication are discussed in detail. The authors addressed the effect of diabetes mellitus on development of postoperative AF. Data on current methods for prevention and treatment of AF are provided.

Preoperative β-Blockers as a Coronary Surgery Quality Metric: The Lack of Evidence of Efficacy

BACKGROUND

Two quality measures used in public reporting and value-based payment programs require β-blockers be administered less than 24 hours before isolated coronary artery bypass graft surgery to prevent atrial fibrillation and mortality. Questions have arisen about continued use of these measures.

METHODS

We conducted a systematic search for randomized controlled trials (RCTs) examining the impact of preoperative β-blockers on atrial fibrillation or mortality after isolated coronary artery bypass graft surgery to determine what evidence of efficacy supports the measures.

RESULTS

We identified 11 RCTs. All continued β-blockers postoperatively, making it unfeasible to separate the benefits of preoperative vs postoperative administration. Meta-analysis was precluded by methodologic variation in β-blocker utilized, timing and dosage, and supplemental and comparison treatments. Of the eight comparisons of β-blockers/β-blocker plus digoxin versus placebo (n = 826 patients), six showed significant reductions in atrial fibrillation/supraventricular arrhythmias. Of the three comparisons (n = 444) of β-blockers versus amiodarone, two found no significant difference in atrial fibrillation; the third showed significantly lower incidence with amiodarone. One RCT compared β-blocker plus amiodarone versus each of those drugs separately; the combination reduced atrial fibrillation significantly better than the β-blocker alone, but not amiodarone alone. Seven RCTs reported short-term mortality, but this outcome was too rare and the sample sizes too small to provide any meaningful comparisons.

CONCLUSIONS

Existing RCT evidence does not support the structure of quality measures that require β-blocker administration specifically within 24 hours before coronary artery bypass graft surgery to prevent postoperative atrial fibrillation or short-term mortality. Quality measures should be revised to align with the evidence, and further studies conducted to determine optimal timing and method of prophylaxis.

Posterior Left pericardiotomy for the prevention of postoperative Atrial fibrillation after Cardiac Surgery (PALACS): study protocol for a randomized controlled trial

BACKGROUND

Postoperative atrial fibrillation (POAF) is a common complication following cardiac surgery. POAF is associated with increased morbidity and hospital costs. We herein describe the protocol for a randomized controlled trial to determine if performing a posterior left pericardiotomy prevents POAF after cardiac surgery.

METHODS/DESIGN

All patients submitted to cardiac surgery at our institution will be screened for inclusion into the study. The study will consist of two parallel arms with random allocation between groups to either receive a posterior left pericardiotomy or serve as a control. Masking will be done in a single-blinded fashion to the patient. Patients will be continuously monitored postoperatively for the occurrence of atrial fibrillation until discharge. At the follow-up clinic visit (15-30 days after surgery), the primary endpoint (atrial fibrillation) and other secondary endpoints, such as pleural or pericardial effusion, will be assessed. A total sample size of 350 subjects will be recruited.

DISCUSSION

POAF is associated with increased morbidity, prolonged hospital stay, and increased costs after cardiac surgery. Several strategies aimed at reducing the incidence of POAF have been investigated, including beta-blockers, amiodarone, and statins, all with suboptimal results. Posterior left pericardiotomy has been associated with a reduction of POAF in previous series. However, these studies had limited sample sizes and suboptimal methodology, so that the efficacy of posterior pericardiotomy in preventing POAF remains to be definitively proven. Our randomized trial aims to determine the effect of a posterior left pericardiotomy on the incidence of POAF.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT02875405 , protocol record 1502015867. Registered on July 2016.

Efficacy of amiodarone and lidocaine for preventing ventricular fibrillation after aortic cross-clamp release in open heart surgery: a meta-analysis of randomized controlled trials

OBJECTIVE

The relative preventative efficacy of amiodarone and lidocaine for ventricular fibrillation (VF) after release of an aortic cross-clamp (ACC) during open heart surgery has not been determined. This meta-analysis was designed to systematically evaluate the influence of amiodarone, lidocaine, or placebo on the incidence of VF after ACC.

METHODS

Prospective randomized controlled trials (RCTs) that compared the VF-preventative effects of amiodarone with lidocaine, or amiodarone or lidocaine with placebo were included. PubMed, EMBASE, and the Cochrane Library were searched for relevant RCTs. Fixed or randomized effect models were applied according to the heterogeneity of the data from the selected studies.

RESULTS

We included eight RCTs in the analysis. Pooled results suggested that the preventative effects of amiodarone and lidocaine were comparable (relative risk (RR)=1.12, 95% confidence interval (CI): 0.70 to 1.80, P=0.63), but both were superior to the placebo (amiodarone, RR=0.71, 95% CI: 0.51 to 1.00, P=0.05; lidocaine, RR=0.63, 95% CI: 0.46 to 0.88, P=0.006). The percentage of patients requiring electric defibrillation counter shocks (DCSs) did not differ significantly among patients administered amiodarone (RR=0.21, 95% CI: 0.04 to 1.19, P=0.08), lidocaine (RR=2.44, 95% CI: 0.13 to 44.02, P=0.55), or the placebo (RR=0.56, 95% CI: 0.25 to 1.25, P=0.16).

CONCLUSIONS

Amiodarone and lidocaine are comparably effective in preventing VF after ACC, but the percentage of patients who subsequently require DCSs does not differ among those administered amiodarone, lidocaine, or placebo.

Evaluation of amiodarone versus metoprolol in treating atrial fibrillation after coronary artery bypass grafting

Introduction

Atrial fibrillation (AF) is the most common arrhythmia affecting patients in open heart ICU after coronary artery bypass grafting (CABG). Most cardiac surgery textbooks recommend beta blockers as the drug of choice for treating such a condition while many experienced physicians and a number of anesthesiology references offer amiodarone as the drug of choice. Therefore, because of insufficient evidence and the aforementioned controversy, we decided to conduct a study evaluating these two antiarrhythmic medicines.

Methods

This is a double-blind, randomized, clinical trial performed on patients admitted for CABG at Amir al Momenin hospital in Arak province, Iran, who developed new onset AF after surgery. Based on the type of medication used, these patients were randomly divided into two groups: amiodarone (A) group and metoprolol (M) group. Each group consisted of 73 cases. All data were analyzed via SPSS 19.

Results

Among the results achieved in this study, amiodarone was successful in treating AF in 55 patients (73%), while metoprolol achieved normal rhythm in treating AF in 69 patients (92%). With a p-value of 0.04, it seems that metoprolol is more effective in treating AF.

Conclusion

Metoprolol seems to be a most efficacious medication for post-CABG AF (p-value = 0.004).

Predictors of new-onset atrial fibrillation in elderly patients with coronary artery disease after coronary artery bypass graft

OBJECTIVE

To identify the factors associated with the development of postoperative atrial fibrillation (POAF) after coronary artery bypass graft (CABG) in elderly patients with coronary artery disease (CAD).

METHODS

A total of 81 patients with CAD who underwent CABG were enrolled in the study. Patients were divided into two groups: Group 1, without postoperative atrial fibrillation (59 patients, 74.6% men, mean age 65.8 ± 4.0 years); Group 2, with early new-onset atrial fibrillation after CABG (22 patients, 90.9% men, mean age 67.7 ± 5.4 years). Interleukin (IL)-6, IL-8, IL-10, C-reactive protein (CRP), fibrinogen, superoxide dismutase (SOD), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and troponin I were studied.

RESULTS

During the observation period, atrial fibrillation occurred in 27.2% cases, an average of 4.9 ± 3.8 days after surgery. In group 2, the left atrium (LA) dimension was larger than in group 1 (43.9 ± 3.4 mm vs. 37.6 ± 3.9 mm, P < 0.001). Patients with POAF had significantly higher IL-6 (72.7 ± 60.8 pg/mL vs. 38.0 ± 34.6 pg/mL, P = 0.04), IL-8 (11.9 ± 6.0 pg/mL vs. 7.7 ± 5.4 pg/mL, P = 0.01) and SOD (2462.0 ± 2029.3 units/g vs. 1515.0 ± 1292.9 units/g, P = 0.04) compared with group without POAF. The multivariate analysis showed that the odds ratio (OR) for POAF development in patients with left atrium more than 39 mm was 2.1 [95% confidence interval (CI): 1.2-3.8, P = 0.0004], IL-6 levels more than 65.18 pg/mL-1.4 (95% CI: 1.1-2.7, P = 0.009), IL-8 levels more than 9.67 pg/mL-1.2 (95% CI: 1.1-3.7, P = 0.009), SOD more than 2948 units/g-1.1 (95% CI: 1.01-2.9, P = 0.04).

CONCLUSIONS

In our study, the independent predictors of postoperative atrial fibrillation after CABG in elderly patients were left atrium dimension and the increased postoperative concentration of IL-6, IL-8 and superoxide dismutase.