Effect of Prophylactic Amiodarone on Clinical and Economic Outcomes After Cardiothoracic Surgery: A Meta-Analysis

Prevention of Atrial Fibrillation After Cardiac Surgery: A Review of Literature and Comparison of Different Treatment Modalities

Atrial fibrillation is the most common arrhythmia to occur after cardiac surgery, with an incidence of 10% to 50%. It is associated with postoperative complications including increased risk of stroke, prolonged hospital stays and increased costs. Despite new insights into the mechanisms of atrial fibrillation, no specific etiologic factor has been identified as the sole perpetrator of the arrhythmia. Current evidence suggests that the pathophysiology of atrial fibrillation in general, as well as after cardiac surgery, is multifactorial. Studies have also shown that new-onset postoperative atrial fibrillation following cardiac surgery is associated with a higher risk of short-term and long-term mortality. Furthermore, it has been demonstrated that prophylactic medical therapy decreases the incidence of postoperative atrial fibrillation after cardiac surgery. Of note, the incidence of postoperative atrial fibrillation has not changed during the last decades despite the numerous preventive strategies and operative techniques proposed, although the perioperative and postoperative care of cardiac patients as such has improved.

Medical Therapy After CABG: the Known Knowns, the Known Unknowns, and the Unknown Unknowns

PURPOSE

Medical therapies play a central role in secondary prevention after surgical revascularization. While coronary artery bypass grafting is the most definitive treatment for ischemic heart disease, progression of atherosclerotic disease in native coronary arteries and bypass grafts result in recurrent adverse ischemic events. The aim of this review is to summarize the recent evidence regarding current therapies in secondary prevention of adverse cardiovascular outcomes after CABG and review the existing recommendations as they pertain to the CABG subpopulations.

RECENT FINDINGS

There are many pharmacologic interventions recommended for secondary prevention in patients after coronary artery bypass grafting. Most of these recommendations are based on secondary outcomes from trials which include but did not focus on surgical patients as a cohort. Even those designed with CABG in mind lack the technical and demographic scope to provide universal recommendations for all CABG patients.

CONCLUSION

Recommendations for medical therapy after surgical revascularization are chiefly based on large-scale randomized controlled trials and meta-analyses. Much of what is known about medical management after surgical revascularization results from trials comparing surgical to non-surgical approaches and important characteristics of the operative patients are omitted. These omissions create a group of patients who are relatively heterogenous making solid recommendations elusive. While advances in pharmacologic therapies are clearly adding to the armamentarium of options for secondary prevention, knowing what patients benefit most from each therapeutic option remains challenging and a personalized approach is still required.

Risk and protective factors for atrial fibrillation after cardiac surgery and valvular interventions: an umbrella review of meta-analyses

Objective

Postoperative atrial fibrillation (POAF) is a common complication affecting approximately one-third of patients after cardiac surgery and valvular interventions. This umbrella review systematically appraises the epidemiological credibility of published meta-analyses of both observational and randomised controlled trials (RCT) to assess the risk and protective factors of POAF.

Methods

Three databases were searched up to June 2021. According to established criteria, evidence of association was rated as convincing, highly suggestive, suggestive, weak or not significant concerning observational studies and as high, moderate, low or very low regarding RCTs.

Results

We identified 47 studies (reporting 61 associations), 13 referring to observational studies and 34 to RCTs. Only the transfemoral transcatheter aortic valve replacement (TAVR) approach was associated with the prevention of POAF and was supported by convincing evidence from meta-analyses of observational data. Two other associations provided highly suggestive evidence, including preoperative hypertension and neutrophil/lymphocyte ratio. Three associations between protective factors and POAF presented a high level of evidence in meta-analyses, including RCTs. These associations included atrial and biatrial pacing and performing a posterior pericardiotomy. Nineteen associations were supported by moderate evidence, including use of drugs such as amiodarone, b-blockers, glucocorticoids and statins and the performance of TAVR compared with surgical aortic valve replacement.

Conclusions

Our study provides evidence confirming the protective role of amiodarone, b-blockers, atrial pacing and posterior pericardiotomy against POAF as well as highlights the risk of untreated hypertension. Further research is needed to assess the potential role of statins, glucocorticoids and colchicine in the prevention of POAF.

PROSPERO registration number

CRD42021268268.

New-Onset Atrial Fibrillation in Adult Patients After Cardiac Surgery

Purpose of Review

An overview of recent literature regarding pathophysiology, risk factors, prophylaxis, and treatment of new-onset atrial fibrillation (AF) in post-cardiac surgical patients.

Recent Findings

AF is the most frequent adverse event after cardiac surgery with significant associated morbidity, mortality, and financial cost. Its causes are multifactorial, and models to stratify patients into risk categories are progressing but a consistent, evidence-based system has not yet been developed. Pharmacologic and surgical interventions to prevent and treat this complication have been an area of ongoing research and recent societal guidelines reflect this.

Summary

Inconsistencies remain surrounding how to best identify higher-risk AF patients, which interventions should be used to prevent and treat AF, and which patient groups should receive these interventions. The evidence for these available strategies and their place in contemporary guidelines are summarized.

Cardiology: Post-Cardiothoracic Surgery Atrial Fibrillation: A Review of Preventive Strategies

Objective:

To review the available literature addressing preventive strategies of post-cardiothoracic surgery atrial fibrillation (post-CTS atrial fibrillation).

Data Sources:

Pertinent articles related to the etiology, risk factors, and preventive strategies were identified through a MEDLINE search (1966–March 2007) using the MeSH terms atrial fibrillation, cardiothoracic surgery, cardiac surgery, etiology, neurohormonal, sympathetic, volume, fluid, inflammation, risk factors, operative, pacing, β-adrenergic blockers, amiodarone, sotalol, calcium-channel blockers, magnesium, HMG-CoA reductase inhibitors, statins, fatty acids, PUFA, steroids, and nonsteroidal antiinflammatory drugs.

Study Selection and Data Extraction:

Articles evaluated were limited to human studies, published in the English language, with a Jadad score greater than 3. References of identified articles were reviewed for additional pertinent articles.

Data Synthesis:

Post-CTS atrial fibrillation most commonly occurs on the second or third postoperative day, with an incidence of 20–50%. Etiology theories include neurohormonal activation, volume overload, and inflammation. Studies examining nonpharmacologic therapies have shown that maintenance of the anterior epicardial fat pad is not a viable prophylactic strategy. Biatrial cardiac pacing, especially in combination with amiodarone, is a viable preventive option. Withdrawal of preoperative β-blockers places patients at higher risk for atrial fibrillation; these drugs should be continued postoperatively. Evidence exists supporting the use of amiodarone, sotalol, and magnesium in addition to β-blockers. Since most of these strategies work by attenuating neurohormonal activation, adverse events, including hypotension and bradycardia, are of concern. Adding agents with antiinflammatory properties, including hydroxymethylglutaryl coenzyme A reductase inhibitors or corticosteroids, may prove to be of benefit. Additional studies using novel therapies are needed in addition to established preventive strategies.

Conclusions:

Available evidence supports the continuation of preoperative β-blockers, as well as prophylactic amiodarone, sotalol, and magnesium. Other novel therapies, mostly targeting inflammation, are under investigation and may provide additional strategies.

Novel Use of Ranolazine as an Antiarrhythmic Agent in Atrial Fibrillation

Objective: To review the limitations of current antiarrhythmic drugs in atrial fibrillation (AF) and discuss the rationale and clinical trials supporting the use of ranolazine in AF. Data Sources: MEDLINE was searched from 1980 to September 2016 using the terms ranolazine, atrial fibrillation, coronary artery bypass grafting, and valve surgery. Study Selection and Data Extraction: English-language studies and reviews assessing antiarrhythmic drugs, including ranolazine, were incorporated. Data Synthesis: The use of ranolazine monotherapy has been evaluated in 2 clinical trials. In the RAFFAELLO trial, higher doses of ranolazine showed a trend toward lower AF recurrence versus placebo ( P = 0.053), but further evidence is needed to support its use as a sole therapeutic agent. Ranolazine has shown utility in a limited number of studies as an adjunctive agent, which is critical for those in whom standard therapy is inadequate or the adverse event profile precludes optimized standard therapy. In the HARMONY trial, ranolazine 750 mg and dronedarone 225 mg twice daily reduced the AF burden by 59.1% from baseline ( P = 0.008 vs placebo). In a trial by Koskinas and colleagues, patients receiving ranolazine 1500 mg once and intravenous amiodarone had a higher conversion rate than those receiving amiodarone alone ( P = 0.024). There are also promising studies for the prevention and treatment of post–cardiothoracic surgery AF, which require further investigation. Conclusions: Ranolazine’s pharmacological properties and available evidence suggest potential for its use in AF.

Postoperative Critical Care of the Adult Cardiac Surgical Patient. Part I: Routine Postoperative Care

OBJECTIVES

Cardiac surgery, including coronary artery bypass, cardiac valve, and aortic procedures, is among the most common surgical procedures performed in the United States. Successful outcomes after cardiac surgery depend on optimum postoperative critical care. The cardiac intensivist must have a comprehensive understanding of cardiopulmonary physiology and the sequelae of cardiopulmonary bypass. In this concise review, targeted at intensivists and surgeons, we discuss the routine management of the postoperative cardiac surgical patient.

DATA SOURCE AND SYNTHESIS

Narrative review of relevant English-language peer-reviewed medical literature.

CONCLUSIONS

Critical care of the cardiac surgical patient is a complex and dynamic endeavor. Adequate fluid resuscitation, appropriate inotropic support, attention to rewarming, and ventilator management are key components. Patient safety is enhanced by experienced personnel, a structured handover between the operating room and ICU teams, and appropriate transfusion strategies.

A multistudy analysis investigating systematic differences in cardiovascular trial results between Europe and Asia

OBJECTIVE

To assess whether there are differences in the results of cardiovascular trials between Europe and Asia using data from an extensive collection of randomised controlled trials.

STUDY DESIGN AND SETTING

All meta-analyses containing randomised controlled trials (RCT's) for the treatment or prevention of cardiovascular diseases were searched for in The Cochrane Library (2000-2008) and MEDLINE (2005-2008). Analysis was then conducted within and over each meta-analysis which satisfied given criteria. Separate estimates of treatment effect were calculated for Europe and Asia in each meta-analysis and then compared. Estimates of a common inter-continental difference over all meta-analyses were also calculated and meta-regression was performed. This was performed for both fatal and non-fatal end points.

RESULTS

The literature search identified 59 meta-analyses that satisfied the inclusion criteria. After exclusion, the number of meta-analyses reporting greater effect sizes in Asia than in Europe was significantly more than would be expected by chance (fatal 12/14, p=0.013; non-fatal 23/32, p=0.020).

CONCLUSIONS

This study provides some evidence that for cardiovascular interventions treatment effect estimation differs between Europe and Asia, with respect to both fatal and non-fatal end points.

Are cardiovascular trial results systematically different between North America and Europe? A study based on intra-meta-analysis comparisons

BACKGROUND

It is often assumed that differences in the efficacy of treatments between countries (or regions) will be neither negligible nor minor and therefore cannot be overlooked when assessing the potential benefit of treatments in one country (or region) on the basis of trials conducted in another country (or region).

AIM

To assess differences in the results of cardiovascular trials between Europe and North America on the basis of data from an extensive collection of trials.

METHODS

A systematic search was conducted of Medline (from the year 2005 to 2008) and the Cochrane Library (from 2000 to 2008) for all meta-analyses of randomized controlled trials aimed at treating and preventing cardiovascular disease. Within each meta-analysis that satisfied given criteria, trial results were compared between Europe and North America with respect to a fatal and/or non-fatal endpoint by forming separate estimates of treatment efficacy for each of these continents.

RESULTS

The literature search found 59 meta-analyses that satisfied all the inclusion criteria. For most meta-analyses, it was the case that relative to the control, the intervention was more favoured in trials conducted in Europe than in North America with regard to both fatal endpoints (28 out of 43 meta-analyses) and non-fatal endpoints (28 out of 40 meta-analyses). However, it was only with regard to non-fatal endpoints that this imbalance turned out to be statistically significant at the 5% level (P=0.017). Also, the lack of statistically significant differences in trial results between Europe and North America within individual meta-analyses meant that it was not possible to determine for which types of intervention these intercontinental differences are likely to be more pronounced than others.

CONCLUSION

There is some evidence to support the theory that, relative to controls, interventions are more favoured in cardiovascular trials conducted in Europe than in North America, when treatment efficacy is measured in terms of a non-fatal endpoint. However, the overall support for systematic differences in cardiovascular trial results between Europe and North America is weak, which may be surprising given the amount of data collected.

Examining the safety of amiodarone

INTRODUCTION

Amiodarone is the most widely used antiarrhythmic agent, with demonstrated effectiveness against all the spectrum of cardiac tachyarrhythmias. The risk of adverse effects acts as a limiting factor to its utilization especially in the long term. This article systematically reviews the published evidence on amiodarone versus placebo to examine its safety as an antiarrhythmic drug.

AREAS COVERED

Authors collected data on adverse effects reported in 49 randomized placebo-controlled trials with amiodarone. Adverse effects were classified according to the organ/system involved. Pooled estimates of the number needed to treat (NNT) and to harm (NNH) versus placebo were calculated.

EXPERT OPINION

Amiodarone is effective for both the acute conversion of atrial fibrillation (AF) (11 trials, NNT = 4 at 24 h; p = 0.003) and the prevention of postoperative AF (18 trials, NNT = 8; p < 0.001), although with an increased risk of bradycardia, hypotension, nausea or phlebitis (pooled NNH = 4; p < 0.001). Amiodarone administration for the maintenance of sinus rhythm has a favorable net clinical benefit (pooled NNT = 3; p < 0.001 versus pooled NNH for either thyroid toxicity, gastrointestinal discomfort, skin toxicity or eye toxicity = 11; p < 0.001). Treatment with amiodarone for the prophylaxis of sudden cardiac death has less favorable net clinical benefit (15 trials, NNT = 38; p < 0.001 versus NNH for either thyroid toxicity, hepatic toxicity, pulmonary toxicity or bradycardia = 14; p < 0.001). Amiodarone treatment in this setting should be used in only selected cases.

Patterns of management of atrial fibrillation complicating coronary artery bypass grafting: Results from the PRoject of Ex-vivo Vein graft ENgineering via Transfection IV (PREVENT-IV) Trial

BACKGROUND

Current practice related to the management of atrial fibrillation (AF) complicating coronary artery bypass grafting (CABG) is uncertain.

METHODS

We examined management of post-CABG AF in the PREVENT-IV trial, and we explored patterns of use of postoperative rhythm versus rate control and anticoagulation for AF by geographic region and type of site. We also compared outcomes of patients who developed post-CABG AF (663) with those who did not (2,131).

RESULTS

The incidence of AF was 24%. Post-CABG AF was treated with a rhythm control strategy in 81% of patients and with warfarin in 23% of patients. Although there were significant variations across sites in the management of post-CABG AF, patterns of use of postoperative rhythm versus rate control and anticoagulation did not differ by geographic region or by whether or not the enrolling site was an academic institution. Mortality was higher in patients with post-CABG AF than patients without AF at 30 days (1.5% vs 0.7%, P = .01) but not at 3 years (6.9% vs 4.9%, P = .41). There was a trend toward a higher risk of mortality or stroke at 30 days in patients with AF (2.4% vs 1.9%, P = .08).

CONCLUSION

Although a rhythm control strategy was used in most of the patients in this trial and the overall rate of use of warfarin was low, the significance of these findings is uncertain because of the lack of data from randomized clinical trials. The substantial variations in the management of post-CABG AF across sites are likely because of definitive data on the most effective therapies, highlighting the need for clinical trials on rate versus rhythm control and on anticoagulation for AF in this setting.

Impact of amiodarone on the ability of anterior fat pad retention to prevent postcoronary arterial bypass grafting atrial fibrillation incidence: a substudy of the AFIST III (Atrial Fibrillation Suppression Trial III)

BACKGROUND

In the AFIST III (Atrial Fibrillation Suppressions Trial III), anterior fat pad (AFP) retention did not decrease the incidence of postoperative atrial fibrillation (POAF), but prophylaxis with amiodarone did. In order to examine the inter-relationship between amiodarone with AFP retention on POAF, we performed a planned subgroup analysis of AFIST III.

METHODS

Coronary artery bypass graft (CABG) patients were randomized to AFP maintenance or removal with prophylactic amiodarone used via the discretion of the caregiver. Patients were categorized into four groups: AFP retention alone, AFP retention plus amiodarone, AFP removal alone and AFP removal plus amiodarone. Multivariate logistic regression was used to calculate adjusted odds ratios with 95% confidence intervals for development of POAF.

RESULTS

Amiodarone was used in 28% of the 178 patients (mean age = 66 +/- 10, 80% male, 5% previous atrial fibrillation) undergoing CABG surgery. The overall POAF occurrence rate, regardless of subgroup designation was 35.4%. On multivariate logistic regression, amiodarone plus AFP retention was associated with an 81% reduction in the odds of the patient developing POAF (p = 0.015). Amiodarone prophylaxis without AFP retention was associated with a 68% reduction (p = 0.040).

CONCLUSION

Amiodarone prophylaxis with or without AFP retention is an independent negative predictor of POAF. Combining amiodarone with AFP retention may provide a synergistic effect in the prevention of POAF. Further studies are needed to validate the results of this study.

The Changing Face of Postoperative Atrial Fibrillation Prevention

Atrial fibrillation is the most common postoperative arrhythmia with significant consequences on patient health. Postoperative atrial fibrillation (POAF) complicates up to 8% of all noncardiac surgeries, between 3% and 30% of noncardiac thoracic surgeries, and between 16% and 46% of cardiac surgeries. POAF has been associated with increased morbidity, mortality, and longer, more costly hospital stays. The risk of POAF after cardiac and noncardiac surgery may be affected by several epidemiologic and intraoperative factors, as well as by the presence of preexisting cardiovascular and pulmonary disorders. POAF is typically a transient, reversible phenomenon that may develop in patients who possess an electrophysiologic substrate for the arrhythmia that is present before or as a result of surgery. Numerous studies support the efficacy of beta-blockers in POAF prevention; they are currently the most common medication used in POAF prophylaxis. Perioperative amiodarone, sotalol, nondihydropyridine calcium channel blockers, and magnesium sulfate have been associated with a reduction in the occurrence of POAF. Biatrial pacing is a nonpharmacologic method that has been associated with a reduced risk of POAF. Additionally, recent studies have demonstrated that hydroxymethylglutaryl-CoA reductase inhibitors may decrease the risk of POAF. Finally, based on recent evidence that angiotensin converting enzyme inhibitors and angiotensin receptor blockers reduce the risk of permanent atrial fibrillation, these medications may also hold promise in POAF prophylaxis. However, there is a need for further large-scale investigations that incorporate standard methodologies and diagnostic criteria, which have been lacking in past trials.

Amiodarone Prophylaxis: Impact on Atrial Fibrillation and Outcomes after Cardiac Surgery

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the United States, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on prevention and treatment—if they keep current with developments in drug therapy.

Amiodarone Prophylaxis for Atrial Fibrillation After Cardiac Surgery: Meta-Analysis of Dose Response and Timing of Initiation

STUDY OBJECTIVE

To investigate a possible dose-response relationship between amiodarone and reduction in incidence of postoperative atrial fibrillation, and to determine whether pre- or postoperative initiation of amiodarone is superior.

DESIGN

Meta-analysis of randomized controlled trials.

DATA SOURCE

MEDLINE and EMBASE databases and the Cochrane Central Register of Controlled Trials for English-language reports published between 1966 and December 2005.

MEASUREMENTS AND MAIN RESULTS

Of 23 identified randomized controlled trials of amiodarone prophylaxis of postoperative atrial fibrillation, 14 were included in the final analysis. These studies enrolled a total of 2864 patients. For each study, the total administered amiodarone dose--categorized as low (< 3000 mg), medium (3000-5000 mg), or high (> 5000 mg)--and preoperative versus postoperative initiation were aggregated by using meta-analytic techniques. The incidence of postoperative atrial fibrillation was significantly reduced by amiodarone compared with placebo (p<0.001). Although the odds of developing atrial fibrillation appeared to be somewhat higher in the low-dose group, no significant differences were noted in the odds ratios (ORs) of developing atrial fibrillation among the low-, medium-, and high-dose groups: OR 0.58, 95% confidence interval (CI) 0.44-0.77; OR 0.45, 95% CI 0.30-0.69; and OR 0.44, 95% CI 0.33-0.58; respectively (p=0.238). In addition, the ORs for atrial fibrillation development associated with preoperative and postoperative initiation of amiodarone were not significantly different (OR 0.50, 95% CI 0.39-0.63; and OR 0.48, 95% CI 0.37-0.63; respectively, p=0.862).

CONCLUSION

Total amiodarone doses of 3000 mg or higher may be more effective than lower doses in reducing the rate of postoperative atrial fibrillation after cardiac surgery. Preoperative initiation of amiodarone appears to be unnecessary. These findings require confirmation in prospective, randomized trials.

Prophylactic Amiodarone for Prevention of Atrial Fibrillation After Cardiac Surgery: A Meta-Analysis

Amiodarone has been proposed to decrease atrial fibrillation after cardiac surgery. The literature was systematically reviewed for randomized trials comparing amiodarone with control for prevention of atrial fibrillation. Data were extracted on study characteristics, quality, and incidence of atrial fibrillation, cardiovascular outcomes, and length of hospitalization. Nineteen trials were included. Amiodarone reduced the odds ratio of atrial fibrillation (0.50; 95% confidence interval [CI]: 0.43 to 0.59, p < 0.0001), ventricular tachyarrhythmias (0.39; 95% CI: 0.26 to 0.58, p < 0.0001), and strokes (0.53; 95% CI: 0.30 to 0.92, p = 0.02). Amiodarone reduced hospital stay (0.6 days; 95% CI: 0.4 to 0.8, p < 0.0001). Amiodarone decreased atrial fibrillation, reduced perioperative ventricular tachyarrhythmias and strokes, and reduced duration of hospitalization. The current evidence supports recommending the routine use of perioperative amiodarone for cardiac surgery.

Cost-effectiveness of amiodarone for prophylaxis of atrial fibrillation after cardiothoracic surgery

STUDY OBJECTIVE

To determine whether prophylactic amiodarone, dosed according to Atrial Fibrillation Suppression Trial (AFIST) I and II regimens, is a cost-effective strategy for prevention of postoperative atrial fibrillation.

DESIGN

Cost-effectiveness analysis of retrospective cohort study.

SETTING

Urban, academic hospital.

PATIENTS

A total of 2046 patients who underwent cardiothoracic surgery between February 1, 1998, and October 31, 2003. Of these patients, 186 received amiodarone and 1860 served as controls.

MEASUREMENTS AND MAIN RESULTS

Each patient who received prophylactic amiodarone using the AFIST I or II dosing strategies was matched for age, sex, history of valvular surgery, history of atrial fibrillation, beta-blocker intolerance, and receipt of preoperative digoxin therapy with 10 patients who did not receive prophylactic amiodarone. Occurrence of postoperative atrial fibrillation, total hospital costs, and both intensive care unit (ICU) and total hospital length of stay (LOS) were compared between groups. Nonparametric bootstrapping was conducted to examine study results as part of a quadrant analysis and to calculate confidence intervals for the incremental cost-effectiveness ratio. The ICU and total hospital LOS, and total costs for patients with and without postoperative atrial fibrillation were also compared. Fewer patients receiving prophylactic amiodarone developed postoperative atrial fibrillation compared with controls (23.1% vs 29.9%, p=0.05). Total hospital costs for the amiodarone group were 28% less than those for the control group (24,131 US dollars +/- 26,539 vs 33,518 US dollars +/- 40,892, p=0.002). Approximately 98% of the time, patients receiving amiodarone prophylaxis fell into the quadrant that showed superior efficacy and lower total costs. Patients who developed postoperative atrial fibrillation, compared with those who did not, regardless of amiodarone prophylaxis, had a longer mean +/- SD stay in the ICU (6.9 +/- 17.1 vs 3.7 +/- 7.9 days, p<0.001), a longer mean total hospital LOS (14.8 +/- 18.8 vs 10.2 +/- 10.4 days, p+/-0.001), and higher mean total hospital costs (41,574 US dollars +/- 54,721 vs 28,968 US dollars +/- 31,046, p<0.001).

CONCLUSION

Prophylactic amiodarone was shown to reduce the occurrence of postoperative atrial fibrillation as well as total hospital costs in patients undergoing cardiothoracic surgery. In patients who developed postoperative atrial fibrillation, both ICU and total hospital LOS as well as total hospital costs were increased.

Safety of amiodarone in the prevention of postoperative atrial fibrillation: A meta-analysis

PURPOSE

A meta-analysis was conducted to assess the safety of amiodarone in the prevention of postoperative atrial fibrillation.

METHODS

A search of the medical literature was conducted to identify randomized controlled trials of prophylactic amiodarone use in cardiothoracic surgery. Studies were independently reviewed by three investigators and selected for inclusion if they met the following three criteria: (1) randomized controlled trial of amiodarone versus placebo or routine treatment, (2) patients underwent coronary artery bypass graft or valvular surgery, and (3) reported data on the frequency of at least one of the following safety endpoints: bradycardia, hypotension, heart block, nausea, cerebral vascular accident, myocardial infarction, and death. Both random- and fixed-effects models were used to determine any significant associations between amiodarone and safety endpoints.

RESULTS

Eighteen trials were analyzed. A total of 3408 patients were enrolled in these trials (1736 received amiodarone and 1672 received placebo). Amiodarone increased the odds of developing bradycardia (odds ratio [OR], 1.70; 95% confidence interval [CI], 1.05-2.74) and hypotension (OR, 1.62; 95% CI, 1.04-2.54). The administration of i.v. amiodarone, an average daily dose exceeding 1 g, and postoperative amiodarone administration were each associated with a greater likelihood of hemodynamic adverse effects. Amiodarone did not appear to affect other safety endpoints.

CONCLUSION

Meta-analysis showed amiodarone to be associated with an increased risk of developing bradycardia and hypotension when used for the prophylaxis of postoperative atrial fibrillation. The greatest risk in the occurrence of these adverse events arose when using regimens containing i.v. amiodarone, initiating prophylaxis during the postoperative period, and using regimens with average daily doses exceeding 1 g.