Atorvastatin Reduces the Incidence of Postoperative Atrial Fibrillation in Statin-Naive Patients Undergoing Isolated Heart Valve Surgery: A Double-Blind, Placebo-Controlled Randomized Trial

Preoperative statin therapy for adults undergoing cardiac surgery

BACKGROUND

Despite significant advances in surgical techniques and perioperative care, people undertaking cardiac surgery due to cardiovascular disease are more prone to the development of postoperative adverse events. Statins (5-hydroxy-3-methylglutaryl-co-enzyme A (HMG-CoA) reductase inhibitors) are well-known for their anti-inflammatory and antioxidant effects and are established for primary and secondary prevention of coronary artery disease. In addition, statins are thought to have clinical benefits in perioperative outcomes in people undergoing cardiac surgery. This review is an update of a review that was first published in 2012 and updated in 2015.

OBJECTIVES

To evaluate the benefits and harms of preoperative statin therapy in adults undergoing cardiac surgery compared to standard of care or placebo.

SEARCH METHODS

We performed a search of the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 9, 2023), Ovid MEDLINE (1980 to 14 September 2023), and Ovid Embase (1980 to 2023 (week 36)). We applied no language restrictions.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing any statin treatment before cardiac surgery, for any given duration and dose, versus no preoperative statin therapy (standard of care) or placebo. We excluded trials without a registered trial protocol and trials without approval by an institutional ethics committee.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology. Primary outcomes were short-term mortality and major adverse cardiovascular events. Secondary outcomes were myocardial infarction, atrial fibrillation, stroke, renal failure, length of intensive care unit (ICU) stay, length of hospital stay and adverse effects related to statin therapy. We reported effect measures as risk ratios (RRs) or mean differences (MDs) with corresponding 95% confidence intervals (CIs). We used the RoB 1 tool to assess the risk of bias in included trials, and GRADE to assess the certainty of the evidence.

MAIN RESULTS

We identified eight RCTs (five new to this review) including 5592 participants. Pooled analysis showed that statin treatment before surgery may result in little to no difference in the risk of postoperative short-term mortality (RR 1.36, 95% CI 0.72 to 2.59; I2 = 0%; 6 RCTs, 5260 participants; low-certainty evidence; note 2 RCTs reported 0 events in both groups so RR calculated from 4 RCTs with 5143 participants). We are very uncertain about the effect of statins on major adverse cardiovascular events (RR 0.93, 95% CI 0.77 to 1.13; 1 RCT, 2406 participants; very low-certainty evidence). Statins probably result in little to no difference in myocardial infarction (RR 0.88, 95% CI 0.73 to 1.06; I2 = 0%; 5 RCTs, 4645 participants; moderate-certainty evidence), may result in little to no difference in atrial fibrillation (RR 0.87, 95% CI 0.72 to 1.05; I2 = 60%; 8 RCTs, 5592 participants; low-certainty evidence), and may result in little to no difference in stroke (RR 1.47, 95% CI 0.90 to 2.40; I2 = 0%; 4 RCTs, 5143 participants; low-certainty evidence). We are very uncertain about the effect of statins on renal failure (RR 1.04, 95% CI 0.80 to 1.34; I2 = 57%; 4 RCTs, 4728 participants; very low-certainty evidence). Additionally, statins probably result in little to no difference in length of ICU stay (MD 1.40 hours, 95% CI -1.62 to 4.41; I2 = 43%; 3 RCTs, 4528 participants; moderate-certainty evidence) and overall hospital stay (MD -0.31 days, 95% CI -0.64 to 0.03; I2 = 84%; 5 RCTs, 4788 participants; moderate-certainty evidence). No study had any individual risk of bias domain classified as high. However, two studies were at high risk of bias overall given the classification of unclear risk of bias in three domains.

AUTHORS' CONCLUSIONS

In this updated Cochrane review, we found no evidence that statin use in the perioperative period of elective cardiac surgery was associated with any clinical benefit or worsening, when compared with placebo or standard of care. Compared with placebo or standard of care, statin use probably results in little to no difference in MIs, length of ICU stay and overall hospital stay; and may make little to no difference to mortality, atrial fibrillation and stroke. We are very uncertain about the effects of statins on major harmful cardiac events and renal failure. The certainty of the evidence validating this finding varied from moderate to very low, depending on the outcome. Future trials should focus on assessing the impact of statin therapy on mortality and major adverse cardiovascular events.

Statin and Postcardiac Surgery Atrial Fibrillation Prevention: A Systematic Review and Meta-Analysis

ABSTRACT

Postoperative atrial fibrillation (POAF) is a frequently reported postcardiac surgery complication leading to increased in-hospital and long-term mortality rates. Many randomized controlled trials (RCTs) have recently suggested using statins to protect against POAF. Therefore, we performed a systematic literature search and meta-analysis in electronic databases for eligible studies published between January 2006 and January 2022. The principal inclusion criteria were as follows: RCTs' study design, statin-naive patients, total study participants ≥50 units, and statin pretreatment started no more than 21 days before cardiac surgery. In the primary analysis, statin pretreatment reduced the incidence of POAF compared with placebo. Analyzing different molecules, atorvastatin was associated with lower incidence of POAF but rosuvastatin was not. We therefore performed a sensitivity analysis excluding RCTs affected by important risk of biases. Thus, studies whose participants were ≥199 were those eligible for the secondary analysis. No statistically significant difference between statin pretreatment and placebo (OR 0.87; 95% CI: 0.71-1.07, P = 0.18) as well as for atorvastatin (OR 0.88; 95% CI: 0.61-1.28; P = 0.48; I 2 = 84%) and rosuvastatin (OR 0.87; 95% CI: 0.68-1.12, P = 0.29) was observed. To conclude, statin pretreatment before cardiac surgery is not associated with a significant reduction in POAF occurrence.

[Elevation of C-reactive protein early after cardiopulmonary bypass surgery is associated with occurrence of postoperative atrial fibrillation]

OBJECTIVE

To explore the association between postoperative C-reactive protein (CRP) levels and the occurrence of postoperative atrial fibrillation in patients undergoing cardiopulmonary bypass surgery.

METHODS

We retrospectively analyzed the data of 550 patients undergoing cardiopulmonary bypass surgery in our hospital from September, 2018 to May, 2021, and after screening against the exclusion criteria, 363 patients were selected for further analysis. Univariate analysis was used to analyze the correlation of age and early postoperative CRP level with the occurrence of postoperative atrial fibrillation, and Chi-square test was used to explore the correlation of gender, disease type, and comorbidity with postoperative atrial fibrillation followed by multivariate analysis of the data using a binary logistic regression model.

RESULTS

The 363 patients enrolled in this study included 247 with valvular disease, 42 with aortic dissection, 37 with coronary heart disease, and 37 with congenital heart disease, with a median postoperative CRP level of 88.65 mg/L and a median age of 57 years (range 5-77 years). Postoperative atrial fibrillation occurred in 101 (27.82%) of the patients, who were subsequently divided into atrial fibrillation group and sinus group. Univariate and multivariate correlation analyses showed that early postoperative elevation of CRP level was an important factor contributing to the occurrence of postoperative atrial fibrillation.

CONCLUSION

Early postoperative elevation of CRP level is associated with the occurrence of atrial fibrillation following cardiopulmonary bypass surgery.

Long-term outcomes of postoperative atrial fibrillation following non cardiac surgery: A systematic review and metanalysis

BACKGROUND

New-onset atrial fibrillation (AF) in non-cardiac postoperative setting is common and is associated with a high risk of in-hospital mortality and morbidity. The long-term risks of stroke, mortality and AF recurrence rate in patients with postoperative AF (POAF) are unclear.

METHODS

We performed a systematic literature review in electronic databases from inception to March 5th, 2020 of studies reporting the incidence of stroke, mortality and AF recurrence in patients with POAF. We confined our analysis to studies with a cohort of at least 150 patients with POAF and with a median follow-up of 12 months as a minimum. Odds Ratios (OR) were pooled using a random-effects model.

RESULTS

Qualitative analysis included 8 studies (7 observational cohort studies and 1 randomized controlled trial) enrolling 3,718,587 patients. Six studies underwent metanalysis comprising 17,684 postoperative patients with POAF and 2,169,248 postoperative patients without POAF. The development of POAF conferred a four-fold increased risk of stroke in the long-term [OR 4.05; 95% confidence interval (CI) 2.91-5.62]. Mortality in the two studies reporting long-term data was higher in patients with POAF compared to those without POAF (OR 3.59; CI 95% 2.84-4.53). Data about recurrence were too heterogeneous to undergo metanalysis.

CONCLUSIONS

POAF is associated with a greater risk of stroke and mortality over the long-term period. Studies focusing on AF recurrence are needed to address the perception of POAF as a benign transient entity. The increased mortality risk following POAF should encourage systematic detection and prevention of this arrhythmia.

Statin Therapy in Post-Operative Atrial Fibrillation: Focus on the Anti-Inflammatory Effects

BACKGROUND

Atrial fibrillation (AF) occurring after cardiac surgery, post-operative AF (POAF), is a serious and common complication of this treatment. POAF may be life-threatening and the available preventive strategies are insufficient or are associated with significantly increased risk of adverse effects, especially in long-term use. Therefore, more appropriate treatment strategies are needed.

METHODS

In this paper, the efficacy, safety, and other aspects of using statins in the prevention of POAF focusing on their anti-inflammatory effects are reviewed.

RESULTS

Recent studies have suggested that inflammation has a significant role in POAF, from the first AF episode to its serious complications including stroke and peripheral embolism. On the other hand, statins, the most widely used medications in cardiovascular patients, have pleiotropic effects, including anti-inflammatory properties. Therefore, they may potentially be effective in POAF prevention. Statins, especially atorvastatin, appear to be an effective option for primary prevention of POAF, especially in patients who had coronary artery bypass grafting (CABG), a cardiac surgery treatment associated with inflammation in the heart muscle. However, several large studies, particularly with rosuvastatin, did not confirm the beneficial effect of statins on POAF. One large clinical trial reported higher risk of acute kidney injury (AKI) following high-dose rosuvastatin in Chinese population. In this study, rosuvastatin reduced the level of C-reactive protein (CRP) but did not reduce the rate of POAF.

CONCLUSION

Further studies are required to find the most effective statin regimen for POAF prevention with the least safety concern and the highest health benefits.

Dexmedetomidine Improves Lung Function by Promoting Inflammation Resolution in Patients Undergoing Totally Thoracoscopic Cardiac Surgery

Objective

Totally thoracoscopic cardiac surgery under cardiopulmonary bypass combined with one-lung ventilation has been identified as the trend in cardiac surgery. The aim of this study was to examine the effects of the selective α ₂ adrenergic receptor agonist dexmedetomidine on the pulmonary function of patients who underwent mitral valve surgery using the totally thoracoscopic technique.

Methods

Fifty-seven patients who underwent thoracoscopic mitral valve surgery between July 2019 and December 2019 were selected. The patients were randomly divided into the control (Con) group (n = 28) and the dexmedetomidine (DEX) group (n = 29) using the random number table method. Arterial blood gas analyses were performed, and the oxygenation (PaO₂/FiO₂) and respiratory indexes (P(A-a)O/PaO₂) were calculated 5 min after tracheal intubation (T1), 2 h after operation (T2), 6 h after operation (T3), and 24 h after operation (T4). Moreover, the serum cytokines interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and intercellular adhesion molecule-1 (ICAM-1) were detected using the enzyme-linked immunosorbent method at all time points. Chest radiography was performed 24 h after surgery. Peripheral blood samples were collected before and after the operation for a complete hemogram. Additionally, the procalcitonin concentration was measured and recorded when the patients were transported to the intensive care unit (ICU). The postoperative extubation time, length of ICU stay, and pulmonary infection rate were also recorded.

Results

Inflammatory reaction after surgery was evident. However, the inflammatory cytokines IL-6, TNF-α, and ICAM-1 in the DEX group were lower than those in the Con group after surgery (T2 to T4; P < 0.05). Neutrophil counts and procalcitonin concentration were higher in the Con group than in the DEX group (P < 0.05). In addition, in the DEX group, pulmonary exudation on chest radiography was lower, and pulmonary function, as shown by an increase in oxidation index and decrease in the respiratory index, improved after surgery (P < 0.05). Moreover, the duration of mechanical ventilation in the Con group was 3.4 h longer than that in the DEX group.

Conclusion

Dexmedetomidine has a protective effect on pulmonary function in patients undergoing mitral valve surgery using a totally video-assisted thoracoscopic technique, which may be related to a reduction in the concentration of inflammatory cytokines in the early perioperative period.

Preoperative Statin Therapy for Atrial Fibrillation and Renal Failure after Cardiac Surgery

BACKGROUND

Performing cardiac surgery in patients with cardiovascular risk factors incorporates a steady risk for the development of postoperative complications. Perioperative statin intake was associated with an improvement of perioperative outcomes in these patients. However, the European Association for Cardio-Thoracic Surgery guidelines regarding the perioperative statin treatment were changed recently due to large studies reporting about relevant adverse effects related to statin therapy.

METHODS

All relevant databases were searched including the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and the metaRegister of Controlled Trials. Various registries were screened (National Research Register, the ClinicalTrials.gov, and gray literature) with search on online conference indices of relevant scientific meetings. No language restrictions were applied.

RESULTS

We identified 10 randomized controlled studies summarizing 3,468 participants undergoing various kinds of cardiac surgical procedures. All included studies presented with marked differences regarding study design. Pooled analysis indicated that statin pretreatment was associated with a formally reduced incidence of postoperative atrial fibrillation (AF) (odds ratio [OR] 0.63, 95% confidence interval [CI] 0.39-1.00; p = 0.05) but with an increased incidence of renal failure (OR 1.20, 95% CI 1.01-1.44; p = 0.04) compared with control. Substantial heterogeneity was observed among studies reporting about AF.

CONCLUSION

Current but sparse evidence reveals that statin pretreatment is associated with a higher rate of postoperative renal failure compared with control therapy but is ineffective to substantially reduce postoperative AF. Given the relevant heterogeneity among included studies, statin pretreatment cannot be generally recommended.

Postoperative Atrial Fibrillation Following Cardiac Surgery: From Pathogenesis to Potential Therapies

Postoperative atrial fibrillation (POAF) is a major complication after cardiac surgery which can lead to high rates of morbidity and mortality, an enhanced length of hospital stay, and an increased cost of care. POAF is postulated to be a multifactorial phenomenon; however, some major pathogeneses have been proposed, including inflammatory pathways, oxidative stress, and autonomic dysfunction. Genetic studies also showed that inflammatory pathways, beta-1 adrenoreceptor variants, G protein-coupled receptor kinase 5 gene variants, and non-coding single-nucleotide polymorphisms in the 4q25 chromosomal locus are involved in this phenomenon. Moreover, several predisposing factors lead to the development of POAF, consisting of pre-, intra-, and postoperative contributors. The main predisposing factors comprise age, prior history of major cardiovascular risk factors, and ischemia-reperfusion injury during surgery. The management of POAF is based on the usual therapies used for non-surgical AF, including medications for either rate control or rhythm control in hemodynamically unstable patients. The perioperative administration of β-blockers and some antiarrhythmic agents has been recommended in major international guidelines. In addition, upstream therapies consisting of colchicine, magnesium, statins, and antioxidants have attenuated the incidence of POAF; however, some uncomfortable side effects developed in large randomized trials. The use of anticoagulation has also resulted in less mortality in patients with POAF at higher risk of thromboembolic events. Despite these recommendations, the actual regimen for the prevention of POAF remains controversial. In this review, we highlight the pathogenesis, predisposing factors, and potential therapeutic options for the management of patients at risk for or with POAF following cardiac surgery.

Could Short-Term Perioperative High-Dose Atorvastatin Offer Antiarrhythmic and Cardio-Protective Effects in Rheumatic Valve Replacement Surgery?

OBJECTIVES

To evaluate the role of prophylactic high-dose atorvastatin for prevention of postoperative atrial fibrillation (POAF), inflammatory response attenuation, and myocardial protection after valve replacement cardiac surgery.

DESIGN

Randomized controlled trial.

SETTING

Assiut University Hospitals.

PARTICIPANTS

Sixty-four adult patients undergoing cardiac valve replacement surgery.

INTERVENTIONS

The participants were equally divided into 2 groups. Group S received 80 mg of atorvastatin (oral tablets), 12 and 2 hours preoperatively, and on the 2nd, 3rd, 4th, and 5th postoperative days. Control group C received placebo at the same time periods.

MEASUREMENTS

The incidence of POAF, postoperative white blood cell count, serum C-reactive protein, interleukin 6, and troponin I.

MAIN RESULTS

Group S patients showed a lower incidence of POAF compared with the placebo group (p = 0.031). The white blood cell count showed significant reductions in group S compared with group C on the second, third, fourth, and fifth postoperative days. The C-reactive protein level showed significant reductions on the third, fourth, and fifth postoperative days in group S compared with group C (p = 0.001, 0.001, and 0.001, respectively). The serum level of interleukin 6 showed a significant reduction on the fifth postoperative day in group S compared with group C (p = 0.001). There was no significant difference between the 2 groups regarding the troponin I level and inotropic score.

CONCLUSION

Prophylactic use of high dose atorvastatin can decrease the incidence of POAF and attenuate the inflammatory process in adult patients undergoing isolated rheumatic cardiac valve replacement surgery.

Redox State in Atrial Fibrillation Pathogenesis and Relevant Therapeutic Approaches

BACKGROUND

Myocardial redox state is a critical determinant of atrial biology, regulating cardiomyocyte apoptosis, ion channel function, and cardiac hypertrophy/fibrosis and function. Nevertheless, it remains unclear whether the targeting of atrial redox state is a rational therapeutic strategy for atrial fibrillation prevention.

OBJECTIVE

To review the role of atrial redox state and anti-oxidant therapies in atrial fibrillation.

METHOD

Published literature in Medline was searched for experimental and clinical evidence linking myocardial redox state with atrial fibrillation pathogenesis as well as studies looking into the role of redoxtargeting therapies in the prevention of atrial fibrillation.

RESULTS

Data from animal models have shown that altered myocardial nitroso-redox balance and NADPH oxidases activity are causally involved in the pathogenesis of atrial fibrillation. Similarly experimental animal data supports that increased reactive oxygen / nitrogen species formation in the atrial tissue is associated with altered electrophysiological properties of atrial myocytes and electrical remodeling, favoring atrial fibrillation development. In humans, randomized clinical studies using redox-related therapeutic approaches (e.g. statins or antioxidant agents) have not documented any benefits in the prevention of atrial fibrillation development (mainly post-operative atrial fibrillation risk).

CONCLUSION

Despite strong experimental and translational data supporting the role of atrial redox state in atrial fibrillation pathogenesis, such mechanistic evidence has not been translated to clinical benefits in atrial fibrillation risk in randomized clinical studies using redox-related therapies.

Perioperative statin therapy in cardiac and non-cardiac surgery: a systematic review and meta-analysis of randomized controlled trials

Background

The effects of perioperative statin therapy on clinical outcome after cardiac or non-cardiac surgery are controversial. We aimed to assess the association between perioperative statin therapy and postoperative outcome.

Methods

Electronic databases were searched up to May 1, 2018, for randomized controlled trials of perioperative statin therapy versus placebo or no treatment in adult cardiac or non-cardiac surgery. Postoperative outcomes were: myocardial infarction, stroke, acute kidney injury (AKI), and mortality. We calculated risk ratio (RR) or odds ratio (OR) and 95% confidence interval (CI) using fixed-effects meta-analyses. We performed meta-regression and subgroup analyses to assess the possible influence of statin therapy regimen on clinical outcomes and trial sequential analysis to evaluate the risk of random errors and futility.

Results

We included data from 35 RCTs involving 8200 patients. Perioperative statin therapy was associated with lower incidence of postoperative myocardial infarction in non-cardiac surgery (OR = 0.44 [95% CI 0.30–0.64], p < 0.0001), but not in cardiac surgery (OR = 0.93 [95% CI 0.70–1.24], p = 0.61) (p_subgroup = 0.002). Higher incidence of AKI was present in cardiac surgery patients receiving perioperative statins (RR = 1.15 [95% CI 1.00–1.31], p = 0.05), nonetheless not in non-cardiac surgery (RR = 1.52 [95% CI 0.71–3.26], p = 0.28) (p_subgroup = 0.47). No difference in postoperative stroke and mortality was present in either cardiac or non-cardiac surgery. However, low risk of bias trials performed in cardiac surgery showed a higher mortality with statins versus placebo (OR = 3.71 [95% CI 1.03–13.34], p = 0.04). Subgroup and meta-regression analyses failed to find possible relationships between length of statin regimens and clinical outcomes. Trial sequential analysis suggested no firm conclusions on the topic.

Conclusions

Perioperative statins appear to be protective against postoperative myocardial infarction in non-cardiac surgery and associated with higher AKI in cardiac surgery. Possible positive or even negative effects on mortality could not be excluded and merits further investigations. Currently, no randomized evidence supports the systematic administration of statins in surgical patients.

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0441-3) contains supplementary material, which is available to authorized users.

Perioperative statin administration with decreased risk of postoperative atrial fibrillation, but not acute kidney injury or myocardial infarction: A meta-analysis

A controversy effect of perioperative statin use for preventing postoperative atrial fibrillation (POAF) and acute kidney injury (AKI) after cardiac surgery still remains. We thus performed current systematic review and meta-analysis to comprehensively evaluate effects of statin in cardiac surgery. 22 RCTs involving 5243 patients were included. Meta-analysis of 18 randomized controlled trials with 3995 participants suggested that perioperative statin use could decrease the risk of POAF (relative risk [RR] 0.69, 95%CI 0.56 to 0.86, P = 0.001), with a moderate heterogeneity (I 2 = 65.7%, P H  < 0.001). And the beneficial effect was found only in patients receiving coronary artery bypass graft (CABG), but not in patients undergoing valve surgery. However, perioperative statin use was not associated with lower risks of AKI (RR 0.98, 95%CI 0.70 to 1.35, P = 0.884, I 2 = 33.9%, P H  = 0.157) or myocardial infarction (MI) (RR 0.84, 95%CI 0.58 to 1.23, P = 0.380, I 2 = 0%, P H  = 0.765), and even an increased trend of AKI was observed in patients with valve surgery. Perioperative statin use could decrease the inflammation response with no impact on clinical outcomes. In conclusion, perioperative statin use is useful in preventing POAF, particularly in patients with CABG, and ameliorate inflammation, while it has no effect on AKI and MI after cardiac surgery.

ScaI atrial natriuretic peptide gene polymorphisms and their possible association with postoperative atrial fibrillation - a preliminary report

INTRODUCTION

Atrial fibrillation (AF) is a frequently encountered complication after coronary artery bypass grafting (CABG), but its underlying mechanisms are still unclear. The natriuretic peptides have been reported as markers for predicting the occurrence of postoperative AF. This study evaluates whether the ScaI ANP gene polymorphisms predict the occurrence of postoperative AF.

MATERIAL AND METHODS

A prospective study of 203 consecutive patients with coronary artery disease undergoing elective CABG was undertaken for atrial natriuretic peptide (ANP) ScaI gene polymorphism. Several perioperative data were analysed. Postoperative AF was defined as lasting for at least 15 min, confirmed by 12-lead ECG and occurring within 6 postoperative days. The ScaI polymorphism of the ANP gene was determined by polymerase chain reaction (PCR). Size-dependent separation of the PCR products on a polyacrylamide gel was followed by staining with ethidium bromide.

RESULTS

The total frequency of AF was 19.7%. The frequencies of ScaI ANP gene polymorphisms were as follows: A1A1 4.90%, A1A2 59.60% and A2A2 35.46%. In order to assess the hypothesis that the A2 allele is a marker of increased risk of postoperative atrial fibrillation, the odds ratio (OR) was calculated: A2 vs. non-A2, OR = 0.98 (0.23-4.1), p = 0.97, which was not significant. The odds ratios for A2A2 and A1A1 were not significant either: A2A2 vs. non-A2A2, OR = 1.11 (0.54-2.29), p = 0.76, and A1A1 vs. non-A1A1, OR = 1.17 (0.23-5.92), p = 0.84.

CONCLUSIONS

ANP genotype did not predispose to the incidence of "new-onset" AF.

Atrial fibrillation after cardiac surgery: Prevention and management: The Australasian experience

Background

Atrial fibrillation (AF) after cardiac surgery is a major health problem that is associated with a significant financial burden. This paper aims to highlight this problem and review the current guidelines in the prevention and management of AF after cardiac surgery, providing our experience in the Australasian centers.

Methods

We conducted a literature review using mainly PubMed to compare the current practice with the available evidence. EMBASE and Cochrane library were also searched. We concurrently developed an online questionnaire to collect data from other Australasian centers regarding their approach to this problem.

Results

We identified 194 studies that were considered relevant to our research. We did not find any formal protocols published in the literature. From our Australasian experience; seven centers (58%) had a protocol for AF prophylaxis. The protocols included electrolytes replacement, use of amiodarone and/or β-blockers. Other strategies were occasionally used but were not part of a structured protocol.

Conclusion

The development of an integrated medical and surgical protocol for the prophylaxis of AF after cardiac surgery is an important aspect for the care of postoperative cardiac patients. Considerations of prophylactic strategies other than those routinely used should be included in the protocol. This area should receive considerable attention in order to reduce the postoperative complications and health costs.

The Use of Statins in the Treatment and Prevention of Atrial Fibrillation

The hydroxy-methyl-glutaryl-CoA reductase inhibitors (statins) are used extensively in the treatment of hyperlipidemia and in the primary and secondary prevention of cardiovascular and cerebrovascular diseases. Statins have also been demonstrated to confer secondary pleiotropic benefits in a variety of other disease processes, including a potential advantage in treating and preventing atrial fibrillation. These effects are primarily due to the up-regulation of endothelial nitric oxide synthase activity and a decrease in nicotinamide adenine dinucleotide phosphate oxidase production, which leads to downstream effects that improve the electromechanical function of atrial and myocardial tissue. The following serves as a focused and updated review of the published clinical data regarding the pleiotropic effects of statins in atrial fibrillation.

Perioperative statin therapy in cardiac surgery: a meta-analysis of randomized controlled trials

BACKGROUND

Several studies suggest beneficial effects of perioperative statin therapy on postoperative outcome after cardiac surgery. However, recent randomized controlled trials (RCTs) show potential detrimental effects. The objective of this systematic review is to examine the association between perioperative statin therapy and clinical outcomes in cardiac surgery patients.

METHODS

Electronic databases were searched up to 1 November 2016 for RCTs of preoperative statin therapy versus placebo or no treatment in adult cardiac surgery. Postoperative outcomes were acute kidney injury, atrial fibrillation, myocardial infarction, stroke, infections, and mortality. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using fixed-effects meta-analyses. Primary analysis was restricted to trials with low risk of bias according to Cochrane methodology, and sensitivity analyses examined whether the risk of bias of included studies was associated with different results. We performed trial sequential analysis (TSA) to test the strength of the results.

RESULTS

We included data from 23 RCTs involving 5102 patients. Meta-analysis of trials with low risk of bias showed that statin therapy was associated with an increase in acute kidney injury (314 of 1318 (23.82%) with statins versus 262 of 1319 (19.86%) with placebo; OR 1.26 (95%CI 1.05 to 1.52); p = 0.01); these results were supported by TSA. No difference in postoperative atrial fibrillation, myocardial infarction, stroke, infections, or mortality was present. On sensitivity analysis, statin therapy was associated with a slight increase in hospital mortality. Meta-analysis including also trials with high or unclear risk of bias showed no beneficial effects of statin therapy on any postoperative outcomes.

CONCLUSIONS

There is no evidence that statin therapy in the days prior to cardiac surgery is beneficial for patients' outcomes. Particularly, statins are not protective against postoperative atrial fibrillation, myocardial infarction, stroke, or infections. Statins are associated with a possible increased risk of acute kidney injury and a detrimental effect on hospital survival could not be excluded. Future RCTs should further evaluate the safety profile of this therapy in relation to patients' outcomes and assess the more appropriate time point for discontinuation of statins before cardiac surgery.

Perspectives and challenges of antioxidant therapy for atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia associated with significant morbidity and mortality. The mechanisms underlying the pathogenesis of AF are poorly understood, although electrophysiological remodeling has been described as an important initiating step. There is growing evidence that oxidative stress is involved in the pathogenesis of AF. Many known triggers of oxidative stress, such as age, diabetes, smoking, and inflammation, are linked with an increased risk of arrhythmia. Numerous preclinical studies and clinical trials reported the importance of antioxidant therapy in the prevention of AF, using vitamins C and E, polyunsaturated fatty acids, statins, or nitric oxide donors. The aim of our work is to give a current overview and analysis of opportunities, challenges, and benefits of antioxidant therapy in AF.

Defining the role of perioperative statin treatment in patients after cardiac surgery: A meta-analysis and systematic review of 20 randomized controlled trials

BACKGROUND

Although statin use has been indicated to prevent atrial fibrillation in previous observational and experimental trials, the issue remains inadequately and insufficiently explored. We therefore performed this meta-analysis to evaluate the effects of perioperative statin therapy on complications and short-term prognosis following cardiac surgery.

METHODS

A search of the PubMed, EMBASE and the Cochrane database of controlled trials was performed from inception to June 2016 to identify relevant randomized controlled trials (RCTs). The primary endpoints included postoperative atrial fibrillation, acute kidney injury and all-cause mortality.

RESULTS

Twenty studies involving 4338 patients were included in the meta-analysis. Among the patients who underwent cardiac surgery, perioperative statin therapy was significantly associated with a decreased risk of postoperative atrial fibrillation (OR: 0.50; P=0.0004), particularly in the subgroup of patients who used atorvastatin and those who underwent isolated coronary artery bypass grafting (CABG) surgery. Moreover, perioperative statin use significantly decreased the length of hospital stay (weighted mean difference (WMD): -0.43; P=0.002). However, no reductions were observed in acute kidney injury, myocardial infarction, postoperative serum creatinine concentration or the length of intensive care unit (ICU) stay.

CONCLUSIONS

Perioperative statin therapy might be promising for the prevention of postoperative atrial fibrillation following cardiac surgery, especially for patients undergoing isolated CABG surgery or atorvastatin administration. Additionally, statin use can decrease the length of the hospital stay.

Statin Antiarrhythmic Effect on Atrial Fibrillation in Statin-Naive Patients Undergoing Cardiac Surgery: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Statin therapy has been thought to improve outcomes in cardiac surgeries. We aimed to determine the statin effects on the development of postoperative atrial fibrillation (AF), hospital length of stay (LOS), and inflammatory status in patients undergoing cardiac surgeries.

METHODS

A systematic literature search in databases was performed, until January 2015. Randomized clinical trial (RCT) studies evaluating statin effect on statin-naive patients with sinus rhythm undergoing cardiac surgeries were eligible to be analyzed.

RESULTS

Twelve RCTs involving 1116 patients, 559 receiving statin and 557 receiving control regimen, were analyzed. Postoperative AF occurred in 17.9% and 36.1% of patients in the statin and control groups, respectively. The statin therapy was associated with decreases in the postoperative AF (risk ratio [RR] 0.50, 95% confidence interval [CI] 0.41-0.61, P < .000010), hospital LOS (mean difference in days, RR -0.44, 95% CI -0.67 to -0.20, P = .0002), and postoperative C-reactive protein (CRP) compared with control (mean difference in mg/L, RR -12.37, 95% CI -23.87 to -0.87, P = .04). The beneficial effects on AF and CRP were more marked in patients receiving atorvastatin compared to other statins. Decrease in postoperative AF was greater in coronary artery bypass graft surgery compared to that in isolated valvular surgery.

CONCLUSION

Perioperative statin therapy in statin-naive patients with sinus rhythm undergoing cardiac surgeries was associated with decreases in the development of postoperative AF, the hospital LOS, and the CRP level. However, there were insufficient data to provide evidences regarding statin impacts in patients undergoing isolated valvular surgery.