Effect of Angiotensin-Converting Enzyme Inhibitors or Angiotensin Receptor Blockers on the Frequency of Post-Cardiothoracic Surgery Atrial Fibrillation

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.

Atrial Fibrillation after Rheumatic Heart Valve Surgery: Incidence, Predictors, and Outcomes

BACKGROUND

 Atrial fibrillation after cardiac surgery (AFACS) impacts 10 to 65% of patients. AFACS is associated with stroke and other systemic embolic manifestations.

METHODS

 Patients at our hospital who underwent rheumatic valve surgery procedures including aortic valve replacement (AVR), mitral valve replacement (MVR), AVR with coronary artery bypass grafting (CABG), MVR with CABG, or AVR and MVR with/without CABG were included in this study in the period from 2002 to 2017.

RESULTS

 In total, 346 patients were included in the current analysis, with a mean age of 51.6 ± 16.1 years, and 51% were males. AFACS was documented in 102 patients (29.9%) .: Univariate predictors of AFACS included age, gender, body mass index (BMI), operation type, left ventricular ejection fraction (EF), left atrial (LA) diameter, previous history of AF, use of aldosterone antagonists more than a month before surgery, use of diuretics more than a month before surgery, length of ICU stay, total length of stay, cross-clamp time more than 90 minutes, pump time more than 120 minutes, postoperative acute kidney injury, left ventricular dimensions.By multivariate analysis, only age (p = 0.028, AOR = 10.6), male gender (p = 0.021, AOR = 3.4), type of surgery (p = 0.034, AOR = 7.12), history of AF (p = 0.018, AOR = : 2.32), BMI (p < 0.001, AOR = 3.91), EF before surgery (p ≤ 0.001, AOR = 3.91), and LA diameter (p = 0.0051, AOR = 18.23) were independent predictors of AFACS.

CONCLUSION

 This study identifies risk factors associated with the development of atrial fibrillation after rheumatic valve heart surgery. Older patients, male gender, type of surgery, preoperative AF, BMI, EF before surgery, and LA diameter are independent predictors of AF after cardiac valve surgery.

Pharmacological strategies for prevention of postoperative atrial fibrillation

Atrial fibrillation (AF) complicating cardiac surgery continues to be a major problem that increases the postoperative risk of stroke, myocardial infarction, heart failure and costs and can affect long-term survival. The incidence of AF after surgery has not significantly changed over the last two decades, despite improvement in medical and surgical techniques. The mechanism and pathophysiology underlying postoperative AF (PoAF) is incompletely understood and results from a combination of acute and chronic factors, superimposed on an underlying abnormal atrial substrate with increased interstitial fibrosis. Several anti-arrhythmic and non-anti-arrhythmic medications have been used for the prevention of PoAF, but the effectiveness of these strategies has been limited due to a poor understanding of the basis for the increased susceptibility of the atria to AF in the postoperative setting. In this review, we summarize the pathophysiology underlying the development of PoAF and evidence behind pharmacological approaches used for its prevention in the postoperative setting.

Clinical update on the management of atrial fibrillation

Atrial fibrillation (AF) is a cardiac arrhythmia associated with significant morbidity and mortality, affecting more than 3 million people in the United States and 1-2% of the population worldwide. Its estimated prevalence is expected to double within the next 50 years. During the past decade, there have been significant advances in the treatment of AF. Studies have demonstrated that a rate control strategy, with a target resting heart rate between 80 and 100 beats/minute, is recommended over rhythm control in the vast majority of patients. The CHA2 DS2 ≥ (congestive heart failure, hypertension, age ≥ 65 yrs, diabetes mellitus, stroke or transient ischemic attack, vascular disease, female gender) scoring system is a potentially useful stroke risk stratification tool that incorporates additional risk factors to the commonly used CHADS2 (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke transient ischemic attack) scoring tool. Similarly, a convenient scheme, termed HAS-BLED (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly, drugs/alcohol concomitantly), to assess bleeding risk has emerged that may be useful in select patients. Furthermore, new antithrombotic strategies have been developed as potential alternatives to warfarin, including dual-antiplatelet therapy with clopidogrel plus aspirin and the development of new oral anticoagulants such as dabigatran, rivaroxaban, and apixaban. Vernakalant has emerged as another potential option for pharmacologic conversion of AF, whereas recent trials have better defined the role of dronedarone in the maintenance of sinus rhythm. Finally, catheter ablation represents another alternative to manage AF, whereas upstream therapy with inhibitors of the renin-angiotensin-aldosterone system, statins, and polyunsaturated fatty acids could potentially prevent the occurrence of AF. Despite substantial progress in the management of AF, significant uncertainty surrounds the optimal treatment of this condition.

Primary Prevention of Atrial Fibrillation where are we in 2012?

Drugs to alter or delay myocardial remodelling associated with heart failure, hypertension, or inflammation in the post-operative setting, may prevent the development of atrial fibrillation. Current experimental and clinical evidences support specific treatments for defined patient population (i.e. ACE-inhibitors and ARB for chronic heart failure and hypertension expecially with LV hypertrophy; statins, corticosteroids and possibly colchicine after cardiac surgery).

Upstream therapies for management of atrial fibrillation: review of clinical evidence and implications for European Society of Cardiology guidelines. Part I: primary prevention

Atrial fibrillation (AF) is associated with significant morbidity and mortality. It is also a progressive disease secondary to continuous structural remodelling of the atria due to AF itself, to changes associated with ageing, and to deterioration of underlying heart disease. Current management aims at preventing the recurrence of AF and its consequences (secondary prevention) and includes risk assessment and prevention of stroke, ventricular rate control, and rhythm control therapies including antiarrhythmic drugs and catheter or surgical ablation. The concept of primary prevention of AF with interventions targeting the development of substrate and modifying risk factors for AF has emerged as a result of recent experiments that suggested novel targets for mechanism-based therapies. Upstream therapy refers to the use of non-antiarrhythmic drugs that modify the atrial substrate- or target-specific mechanisms of AF to prevent the occurrence or recurrence of the arrhythmia. Such agents include angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), statins, n-3 (ω-3) polyunsaturated fatty acids, and possibly corticosteroids. Animal experiments have compellingly demonstrated the protective effect of these agents against electrical and structural atrial remodelling in association with AF. The key targets of upstream therapy are structural changes in the atria, such as fibrosis, hypertrophy, inflammation, and oxidative stress, but direct and indirect effects on atrial ion channels, gap junctions, and calcium handling are also applied. Although there have been no formal randomized controlled studies (RCTs) in the primary prevention setting, retrospective analyses and reports from the studies in which AF was a pre-specified secondary endpoint have shown a sustained reduction in new-onset AF with ACEIs and ARBs in patients with significant underlying heart disease (e.g. left ventricular dysfunction and hypertrophy), and in the incidence of AF after cardiac surgery in patients treated with statins. In the secondary prevention setting, the results with upstream therapies are significantly less encouraging. Although the results of hypothesis-generating small clinical studies or retrospective analyses in selected patient categories have been positive, larger prospective RCTs have yielded controversial, mostly negative, results. Notably, the controversy exists on whether upstream therapy may impact mortality and major non-fatal cardiovascular events in patients with AF. This has been addressed in retrospective analyses and large prospective RCTs, but the results remain inconclusive pending further reports. This review provides a contemporary evidence-based insight into the role of upstream therapies in primary (Part I) and secondary (Part II) prevention of AF.

Review: Beyond the Guidelines: New and Novel Agents for the Prevention of Atrial Fibrillation After Cardiothoracic Surgery

Postoperative atrial fibrillation (POAF), a common complication of cardiac surgery, can increase the morbidity and mortality, as well as the costs of the surgery being preformed. Guidelines recommend the use of β-blockers, amiodarone, or sotalol to decrease the risk of experiencing POAF. However, none of these agents fully protect the patient from POAF, thus newer agents are needed to be used in combination with them. Many different agents have been studied to fit this role and may be grouped into 2 categories: agents with antiarrhythmic activity such as magnesium and polyunsaturated fatty acids and agents with anti-inflammatory activity such as statins and free radical scavengers. Most of these novel agents have been studied in a wide variety of trials; however, some clearly have more effect than others. Although none of these newer agents have the data required to make blanket recommendations for use at this point, given the safety profile and low costs of some, many continue to be evaluated in randomized-controlled trials.

Atrial fibrillation and inflammation

Atrial fibrillation (AF) is the most common clinical arrhythmia. Recent investigations have suggested that inflammation might have a role in the pathophysiology of AF. In this review, the association between inflammation and AF, and the effects of several agents that have anti-inflammatory actions, such as statins, polyunsaturated fatty acids, corticosteroids and angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, have been investigated.

Preoperative angiotensin-blocking drug therapy is not associated with atrial fibrillation after cardiac surgery

BACKGROUND

Preoperative use of angiotensin-blocking drug therapy (ABDT) with angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers and its link to occurrence of postoperative atrial fibrillation (POAF), a common marker of poor outcomes after cardiac surgery, remain controversial.

METHODS

From 1997 to 2003, 10,552 patients underwent coronary artery bypass grafting with or without valve surgery. To adjust for differences of clinical characteristics between patients who received ABDT within 24 hours before surgery compared with those who did not, propensity score analyses were conducted.

RESULTS

Angiotensin-blocking drug therapy was prescribed in 4,795 (45%) before surgery, of which 1,725 (36%) developed POAF before discharge versus 1,908 (33%) of 5,757 patients who did not receive ABDT (unadjusted odds ratio 1.13, 95% CI 1.05-1.25, P < .01). In 6,744 propensity score-matched patients with well-balanced comorbidity profiles, ABDT was not associated with POAF (odds ratio 1.05, CI 0.95-1.16, P = .38). Stratified analysis within quintiles of propensity score and propensity-adjusted logistic multivariable regression confirmed these findings.

CONCLUSIONS

In this large observational study, we found no evidence of an association between preoperative angiotensin blockade and the occurrence of POAF. Adequately powered randomized studies are needed to clarify the best strategy of perioperative ABDT in patients with and without guideline-based indications.

Adjuvant therapy for atrial fibrillation

Atrial fibrillation (AF) is the most common heart rhythm disorder, with increasing prevalence in the aging US population and affecting more than 2.3 million people. Current approaches for managing AF are rate- or rhythm-control strategies, both using anti-thrombotic therapy to prevent thromboembolism. While great advances have been made in understanding the pathophysiology of AF, few new strategies have shown promise in prevention or treatment of AF. Recent data suggest that non-antiarrhythmic medication may be useful in modifying the substrate that allows AF precipitation and perpetuation. This article reviews the data on the role of these agents in the prevention and management of AF as an adjunct to standard therapy.

Association between the use of non-antiarrhythmic drugs and postoperative atrial fibrillation

PURPOSE

To evaluate the association between statins, N-acetylcysteine (NAC) and angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) and postoperative atrial fibrillation (AF).

METHODS

A total of 590 patients undergoing coronary artery bypass and/or valve surgery were studied. An AF episode lasting >5 min during hospitalization was accepted as endpoint.

RESULTS

AF rate was 18% (n=106). Multivariable positive predictors of AF included age ≥ 65, left atrial diameter ≥ 45 mm, cross clamp time; negative predictors included use of left internal mammarian artery, NAC, and ACEIs or ARBs.

CONCLUSIONS

ACEIs or ARBs and NAC is associated with low incidence of postoperative AF, however, this association was not found with statin or combined use these agents.

Atrial fibrillation following cardiac surgery: clinical features and preventative strategies

Atrial fibrillation (AF) is a common complication of cardiac surgery, with an increasing incidence. Post-operative AF results in many complications and increased healthcare resources. Despite substantial interest in the prediction and prevention of post-operative AF, as well as guidelines for the management of this common arrhythmia, there is still some uncertainty about appropriate risk stratification and management. The aim of this review article is to provide an overview of clinical predictive features for the development of AF following cardiac surgery and suitable preventive measures, using both antiarrhythmic and non-antiarrhythmic strategies.

Association between perioperative NSAID use and post-cardiothoracic surgery atrial fibrillation, blood transfusions, and cardiovascular outcomes: a nested cohort study from the AF Suppression Trials (AFIST) I, II and III

BACKGROUND

Nonsteroidal anti-inflammatory drug (NSAID) use may reduce the incidence of post-cardiothoracic surgery (CTS) atrial fibrillation (AF). The cerebrovascular and cardiovascular safety of using NSAIDs for post-CTS AF has not been determined.

OBJECTIVE

To evaluate whether NSAIDs could reduce the incidence of post-CTS atrial fibrillation without increasing patients' risk of stroke or myocardial infarction (MI).

METHODS

Patients (n = 555) undergoing CTS from the Atrial Fibrillation Suppression Trials I, II and III were evaluated in this nested cohort study. Demographic, surgical and medication use characteristics were prospectively collected as part of the AFIST trials. Endpoints included post-CTS atrial fibrillation, stroke, MI and the need for red blood cell transfusion. Multivariable logistic regression was used to control for potential confounders and calculate adjusted odds ratios with 95% confidence intervals.

RESULTS

The population was 67.8 +/- 8.6 years old and 77.1% male with 127 (22.9%) patients receiving an NSAID postoperatively. Overall, 14.6% underwent valve surgery, 6.1% had prior AF, 12.6% had heart failure and 84.0% and 44.1% received postoperative beta-blockade and prophylactic amiodarone. NSAID use was associated with reductions in the adjusted odds of post-CTS atrial fibrillation (0.54 (0.32-0.90)) and the need for RBC transfusions (0.63 (0.41-0.97)). No elevation in the odds of developing stroke (1.10 (0.21-5.66)) or MI (1.70 (0.40-7.10)) was observed.

LIMITATIONS

Patients were not randomized to receive NSAIDs versus a control. We may not have had adequate power to evaluate stoke or MI in this analysis.

CONCLUSIONS

NSAIDs decreased the odds of developing post-CTS atrial fibrillation, further supporting the hypothesis of inflammation as a trigger for post-CTS atrial fibrillation. The need for RBC transfusions was also reduced with NSAID use. We may have been underpowered to evaluate stroke or MI incidence, but the qualitative elevations in these variables suggest more safety data is needed before NSAIDs can be routinely recommended.

Non-antiarrhythmic medications for atrial fibrillation: from bench to clinical practice

Many treatment modalities have been developed over the years for the management of atrial fibrillation (AF). While they are still considered the first line of treatment for suppression of AF, antiarrhythmics often lead to treatment failure, complications and undesired consequences. Pulmonary vein ablation is an invasive procedure which is not always curative. Recently, there have been a variety of studies reporting the potential antiarrhythmic effects of various nonantiarrhythmic agents. This paper aims to provide a comprehensive review of the findings reported thus far about the antiarrhythmic effects of agents which are not antiarrhythmic drugs themselves, but which have been found to offer promise in the prevention and treatment of AF.

Prevention of atrial fibrillation following cardiac surgery: basis for a novel therapeutic strategy based on non-hypoxic myocardial preconditioning

Atrial fibrillation is the most common complication of cardiac surgical procedures performed with cardiopulmonary bypass. It contributes to increased hospital length of stay and treatment costs. At present, preventive strategies offer only suboptimal benefits, despite improvements in anesthesia, surgical technique, and medical therapy. The pathogenesis of postoperative atrial fibrillation is considered to be multifactorial. However oxidative stress is a major contributory factor representing the unavoidable consequences of ischemia/reperfusion cycle occurring in this setting. Considerable evidence suggests the involvement of reactive oxygen species (ROS) in the pathogenic mechanism of this arrhythmia. Interestingly, the deleterious consequences of high ROS exposure, such as inflammation, cell death (apoptosis/necrosis) or fibrosis, may be abrogated by a myocardial preconditioning process caused by previous exposure to moderate ROS concentration known to trigger survival response mechanisms. The latter condition may be created by n-3 PUFA supplementation that could give rise to an adaptive response characterized by increased expression of myocardial antioxidant enzymes and/or anti-apoptotic pathways. In addition, a further reinforcement of myocardial antioxidant defenses could be obtained through vitamins C and E supplementation, an intervention also known to diminish enzymatic ROS production. Based on this paradigm, this review presents clinical and experimental evidence supporting the pathophysiological and molecular basis for a novel therapeutic approach aimed to diminish the incidence of postoperative atrial fibrillation through a non-hypoxic preconditioning plus a reinforcement of the antioxidant defense system in the myocardial tissue.