Inflammation, oxidative stress and postoperative atrial fibrillation in cardiac surgery

Increased risk of atrial fibrillation in patients with psoriasis: A meta-analysis of observational studies

BACKGROUND

Several epidemiological studies have shown that psoriasis increases the risk of developing atrial fibrillation but evidence of this is still scarce.

AIMS

Our objective was to systematically review, synthesise and critique the epidemiological studies that provided information about the relationship between psoriasis and atrial fibrillation risk.

METHODS

We searched through PubMed, EMBASE and the bibliographies for articles published between 1 January 2000, and 1 November 2017, that reported on the association between psoriasis and atrial fibrillation. All abstracts, full-text articles and sources were reviewed with duplicate data excluded. Summary relative risks (RRs) with 95% CI were pooled using a random effects model.

RESULTS

We identified 252 articles, of these eight unique abstracts underwent full-text review. We finally selected six out of these eight studies comprising 11,187 atrial fibrillation patients. The overall pooled relative risk (RR) of atrial fibrillation was 1.39 (95% CI: 1.257-1.523, P < 0.0001) with significant heterogeneity (I2 = 80.316, Q = 45.723, τ2 = 0.017, P < 0.0001) for the random effects model. In subgroup analysis, the greater risk was found in studies from North America, RR 1.482 (95% CI: 1.119-1.964, P < 0.05), whereas a moderate risk was observed in studies from Europe RR 1.43 (95% CI: 1.269-1.628, P < 0.0001).

LIMITATIONS

We were only able to include six studies with 11,178 atrial fibrillation patients, because only a few such studies have been published.

CONCLUSION

Our results showed that psoriasis is significantly associated with an increased risk of developing atrial fibrillation. Therefore, physicians should monitor patient's physical condition on a timely basis.

Dose-dependent scavenging activity of the ultra-short-acting β1-blocker landiolol against specific free radicals

Landiolol, a highly cardioselective ultra-short-acting β1-blocker, prevents perioperative atrial fibrillation associated with systemic inflammation and oxidative stress. We evaluated the direct scavenging activity of landiolol against multiple free radical species. Nine free radical species (hydroxyl, superoxide anion, ascorbyl, tert-butyl peroxyl, tert-butoxyl, singlet oxygen, 2,2-diphenyl-1-picrylhydrazyl, nitric oxide, and tyrosyl radicals) were directly quantified using an X-band ESR spectrometer with the spin-trapping method. IC50 and reaction rate constants were estimated from the dose-response curve for each free radical. Landiolol scavenged six of the free radical species examined: hydroxyl radical (IC50 = 0.76 mM, k landiolol = 1.4 × 10‍10 M‍-1 s‍-1, p<0.001), superoxide anion (58 mM, 2.1 M‍-1 s‍-1, p = 0.044), tert-butoxyl radical (4.3 mM, k landiolol/k CYPMPO = 0.77, p<0.001), ascorbyl free radical (0.31 mM, p<0.001), singlet oxygen (0.69 mM, k landiolol/k 4-OH ‍TEMP = 2.9, p<0.001), and nitric oxide (15 mM, 1.7 × 10 M‍-1 s‍-1, p<0.001). This study is the first to report that landiolol dose-dependently scavenges multiple free radical species with different reaction rate constants. These results indicate the potential clinical application of landiolol as an antioxidative and anti-inflammatory agent in addition to its present clinical use as an anti-arrhythmic agent.

A novel predictive model for new-onset atrial fibrillation in patients after isolated cardiac valve surgery

Background

Postoperative atrial fibrillation (POAF) is a severe complication after cardiac surgery and is associated with an increased risk of ischemic stroke and mortality. The main aim of this study was to identify the independent predictors associated with POAF after isolated valve operation and to develop a risk prediction model.

Methods

This retrospective observational study involved patients without previous AF who underwent isolated valve surgery from November 2018 to October 2021. Patients were stratified into two groups according to the development of new-onset POAF. Baseline characteristics and perioperative data were collected from the two groups of patients. Univariate and multivariate logistic regression analyses were applied to identify independent risk factors for the occurrence of POAF, and the results of the multivariate analysis were used to create a predictive nomogram.

Results

A total of 422 patients were included in the study, of which 163 (38.6%) developed POAF. The Multivariate logistic regression analysis indicated that cardiac function (odds ratio [OR] = 2.881, 95% confidence interval [CI] = 1.595–5.206; P &lt; 0.001), Left atrial diameter index (OR = 1.071, 95%CI = 1.028–1.117; P = 0.001), Operative time (OR = 1.532, 95%CI = 1.095–2.141; P = 0.013), Neutrophil count (OR = 1.042, 95%CI = 1.006–1.08; P = 0.021) and the magnitude of fever (OR = 3.414, 95%CI = 2.454–4.751; P &lt; 0.001) were independent predictors of POAF. The above Variables were incorporated, and a nomogram was successfully constructed with a C-index of 0.810. The area under the receiver operating characteristic curve was 0.817.

Conclusion

Cardiac function, left atrial diameter index, operative time, neutrophil count, and fever were independent predictors of POAF in patients with isolated valve surgery. Establishing a nomogram model based on the above predictors helps predict the risk of POAF and may have potential clinical utility in preventive interventions.

Intravenous landiolol for the prevention of atrial fibrillation after aortic root, ascending aorta, and aortic arch surgery: A propensity score-matched analysis

Objective

Postoperative atrial fibrillation (POAF) after cardiac surgery is associated with increased mortality. The efficacy of landiolol hydrochloride for POAF prevention after coronary artery bypass grafting procedure and valve surgery has been reported. However, little evidence is available on its role in POAF prevention after aortic root, ascending aorta, and aortic arch surgery. This study aimed to determine the association between intravenous landiolol and the incidence of POAF after these aortic surgeries.

Methods

We included 358 consecutive adult patients without preoperative atrial fibrillation who underwent aortic root, ascending aorta, and aortic arch surgery between January 1, 2011, and December 31, 2018, at our institution. The therapeutic influence of landiolol in preventing POAF was estimated by propensity score-matched analysis (n = 222). The primary end point was the incidence of POAF within 72 hours after surgery. The secondary end points included adverse clinical events such as 30-day mortality and symptomatic cerebral infarction.

Results

The median age of the cohort was 72 years, 68.5% were men, and 46.4% received postoperative oral or transdermal β-blockers. After minimizing differences in patient background by propensity score matching, the incidence of POAF in the landiolol group was significantly lower than that in the reference group (18.9% vs 38.7%; P = .002). Landiolol use was associated with reduced incidence of POAF (odds ratio, 0.39; 95% CI, 0.21 to −0.72; P = .003). There were no significant differences in secondary end points.

Conclusions

Intravenous landiolol was associated with a lower incidence of POAF after aortic root, ascending aorta, and aortic arch surgery.

Vitamin C supplementation attenuates oxidative stress and improves erythrocyte deformability in cardiac surgery with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) depletes endogenous Vitamin C and generates oxidative stress in cardiac surgery. This study aimed to clarify whether Vitamin C supplementation reduces oxidant production and improves erythrocyte deformability in cardiac surgery with CPB. In a randomized and controlled design, 30 eligible patients undergoing cardiac surgery with hypothermic CPB were equally assigned to the Vitamin C group and control group. Subjects of the Vitamin C group and control group received an intravenous infusion of Vitamin C 20 mg·kg^-1 and a placebo during rewarming period of CPB, respectively. We measured the plasma level of reactive oxygen species (ROS) and phosphorylation levels of non-muscle myosin IIA (NMIIA) in erythrocyte membrane, as an index of erythrocyte deformability, before and after CPB. Vitamin C supplementation attenuated the surge in plasma ROS after CPB, mean 1.661 ± standard deviation 0.801 folds in the Vitamin C group and 2.743 ± 1.802 in the control group. The tyrosine phosphorylation level of NMIIA after CPB was upregulated in the Vitamin C group compared to the control group, 2.159 ± 0.887 folds and 1.384 ± 0.445 (P = 0.0237). In addition, the phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and focal adhesion kinase (FAK) in erythrocytes was concurrently enhanced in the Vitamin C group after CPB. The phosphorylation level of endothelial nitric oxide synthase in erythrocytes was significantly increased in the Vitamin C group (1.734 ± 0.371 folds) compared to control group (1.102 ± 0.249; P = 0.0061). Patients receiving Vitamin C had lower intraoperative blood loss and higher systemic vascular resistance after CPB compared to controls. Vitamin C supplementation attenuates oxidative stress and improves erythrocyte deformability via VASP/FAK signaling pathway in erythrocytes during CPB.

Association between serum albumin levels and paroxysmal atrial fibrillation by gender in a Chinese population: a case–control study

Background

Hypoalbuminemia is linked to the emergence of cardiovascular events. However, there is an unclear association between serum albumin (ALB) and gender in paroxysmal AF patients. This retrospective study aimed to explore the association between ALB levels and paroxysmal AF by gender in a Chinese population.

Methods

This study included patients with paroxysmal AF who were hospitalized consecutively in China from January 2019 to September 2021. Controls with sinus rhythm and without paroxysmal AF were matched (2:1) to cases by gender and age. Pearson correlation analysis was used to study the correlation between ALB and blood lipid profiles, multivariate regression models were performed to investigate the association between ALB and paroxysmal AF.

Results

There were 305 patients with paroxysmal AF and 610 patients with controls included in this study. Low ALB in male with AF patients were significantly associated with paroxysmal AF (OR = 0.889, 95% CI 0.832–0.950). ALB was positively correlated with triglyceride (TG) (r = 0.212, p < 0.001), total cholesterol (TC) (r = 0.381, p = 0.002), low-density lipoprotein cholesterol (LDL-C) (r = 0.263, p < 0.001), and high-density lipoprotein cholesterol (HDL-C) (r = 0.329, p < 0.001).

Conclusion

Low ALB in male patients is significantly associated with paroxysmal AF in a Chinese population. Monitoring for hypoalbuminemia in men might help reduce the incidence of paroxysmal AF.

Trimethylamine N-oxide facilitates the progression of atrial fibrillation in rats with type 2 diabetes by aggravating cardiac inflammation and connexin remodeling

Diabetes is an independent risk factor for atrial fibrillation (AF). This study aimed to elucidate the pathophysiology of diabetes-related AF from the perspective of the gut microbial metabolite trimethylamine N-oxide (TMAO). In the present study, male rats received either a normal diet to serve as the control group or a high-fat diet/streptozotocin to induce type 2 diabetes mellitus. Then, diabetic rats were divided into two groups based on the presence or absence of 3,3-dimethyl-1-butanol (DMB, a specific TMAO inhibitor) in drinking water: the diabetic cardiomyopathy (DCM) group and the DCM + DMB group. Eight weeks later, compared with control rats, rats in the DCM group exhibited gut microbiota dysbiosis and systemic TMAO elevation. The inflammatory cytokines IL-1β, IL-6, and TNF-α were markedly increased in the atria of rats in the DCM group. Downregulated expression of connexin 40 and lateralized distribution of connexin 43 were also observed in the atria of DCM rats. AF inducibility was significantly higher in DCM rats than in control rats. Furthermore, DMB treatment effectively ameliorated atrial inflammation and connexin remodeling while markedly reducing plasma TMAO levels. DMB treatment also decreased the vulnerability of diabetic rats to AF. In conclusion, TMAO might promote atrial inflammation and connexin remodeling in the development of diabetes, which may play a key role in mediating diabetes-related AF.

Pathology-related changes in cardiac energy metabolites, inflammatory response and reperfusion injury following cardioplegic arrest in patients undergoing open-heart surgery

Introduction

Changes in cardiac metabolites in adult patients undergoing open-heart surgery using ischemic cardioplegic arrest have largely been reported for non-ventricular tissue or diseased left ventricular tissue, with few studies attempting to assess such changes in both ventricular chambers. It is also unknown whether such changes are altered in different pathologies or linked to the degree of reperfusion injury and inflammatory response. The aim of the present work was to address these issues by monitoring myocardial metabolites in both ventricles and to establish whether these changes are linked to reperfusion injury and inflammatory/stress response in patients undergoing surgery using cold blood cardioplegia for either coronary artery bypass graft (CABG, n = 25) or aortic valve replacement (AVR, n = 16).

Methods

Ventricular biopsies from both left (LV) and right (RV) ventricles were collected before ischemic cardioplegic arrest and 20 min after reperfusion. The biopsies were processed for measuring selected metabolites (adenine nucleotides, purines, and amino acids) using HPLC. Blood markers of cardiac injury (Troponin I, cTnI), inflammation (IL- 6, IL-8, Il-10, and TNFα, measured using Multiplex) and oxidative stress (Myeloperoxidase, MPO) were measured pre- and up to 72 hours post-operatively.

Results

The CABG group had a significantly shorter ischemic cardioplegic arrest time (38.6 ± 2.3 min) compared to AVR group (63.0 ± 4.9 min, p = 2 x 10-6). Cardiac injury (cTnI release) was similar for both CABG and AVR groups. The inflammatory markers IL-6 and Il-8 were significantly higher in CABG patients compared to AVR patients. Metabolic markers of cardiac ischemic stress were relatively and significantly more altered in the LV of CABG patients. Comparing diabetic and non-diabetic CABG patients shows that only the RV of diabetic patients sustained major ischemic stress during reperfusion and that diabetic patients had a significantly higher inflammatory response.

Discussion

CABG patients sustain relatively more ischemic stress, systemic inflammatory response and similar injury and oxidative stress compared to AVR patients despite having significantly shorter cross-clamp time. The higher inflammatory response in CABG patients appears to be at least partly driven by a higher incidence of diabetes amongst CABG patients. In addition to pathology, the use of cold blood cardioplegic arrest may underlie these differences.

Pericardial Effusion Provoking Atrial Fibrillation After Cardiac Surgery: JACC Review Topic of the Week

Postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery. Patients who develop POAF are more likely to experience adverse outcomes, including increased rates of death, stroke, heart failure, and hospitalizations, and higher hospital costs. Understanding the mechanisms underlying POAF is important to improve patients' outcome and optimize health systems' efficiency. Beyond classic pathogenic hypotheses, emerging evidence suggests that postoperative pericardial effusion and localized pericardial inflammation may trigger POAF. This hypothesis is supported by data from nonhuman animal models and a growing body of evidence showing that reducing postoperative pericardial effusion might reduce POAF incidence. In this review, we summarize the classic pathophysiology theories of POAF following cardiac surgery and discuss new etiologic mechanisms with a specific focus on the role of pericardial effusion and inflammation.

The association between the prognostic nutritional index and 28-day mortality among atrial fibrillation patients in China over 80 years of age

BACKGROUNDS AND AIMS

The most prevalent form of cardiac rhythm abnormality among older populations is atrial fibrillation (AF). The prognostic nutritional index (PNI) is a reliable predictor of mortality in various diseases. The association between the PNI and mortality among AF patients over 80 years remains uncleared.

METHODS AND RESULTS

A retrospective assessment of AF cases admitted to a single cardiovascular disease unit in China between January 2015 and June 2020 was performed. The PNI at admission was defined as 10 × serum albumin (g/dL) + 0.005 × total lymphocyte count (per mm³). The association between PNI and cardiovascular disease (CVD)-related or all-cause mortality within 28 days was assessed via multivariable Cox regression. The analysis included 1141 patients. The CVD-related and all-cause mortality rates were 3.3% and 8.7%. Kaplan-Meier analyses revealed that cases with lower PNI tertiles exhibited higher all-cause mortality (T1: 7.6%; T2: 6.1%; T3: 2.4%, P < 0.001) or CVD mortality (T1: 6.3%; T2: 2.9%; T3: 0.8%, P < 0.001). After adjusting for potential confounders, continuous PNI was negatively related to the hazard of all-cause mortality (HR 0.92, 95% CI 0.89, 0.96) and CVD-related mortality (HR 0.90, 95% CI 0.84, 0.95). Compared to the T1 group, patients with a higher PNI exhibited a lower risk of all-cause mortality (P for trend 0.003) and CVD-related mortality (P for trend 0.005). Among most subgroups, CVD-related and all-cause mortality decreased with elevating PNI values.

CONCLUSIONS

PNI is significantly negatively correlated with CVD-related and all-cause mortality among AF cases over 80 years.

Postoperative Atrial Fibrillation Reduced by Intraoperative and Postoperative Cell Saver System in Coronary Artery Bypass Graft Surgery

OBJECTIVE

Postoperative atrial fibrillation is commonly seen after cardiac surgery. One of the contributing factors is mediastinal shed blood and inflammation. Cell salvage techniques can reduce allogenic blood transfusion and reduce inflammation. The aim of this study was to investigate the reduction of postoperative atrial fibrillation by using the cell-salvage system.

METHODS

Patients who underwent isolated coronary artery bypass graft surgery (n = 498) were analyzed retrospectively in 2 groups. Postoperative atrial fibrillation group (n = 75) and non-postoperative atrial fibrillation group (n = 423). Preoperative and postoperative demographic and clini- cal data were compared between the 2 groups, respectively. Postoperative atrial fibrillation and possible contributing factors were analyzed with multinomial logistic regression analysis.

RESULTS

In the postoperative atrial fibrillation group, the patients' age and European System for Cardiac Operative Risk Evaluation (Euroscore) were higher than in the non-postoperative atrial fibrillation group (P = .001 and P = .003, respectively). Postoperative intensive care unit stay and hospital stay were longer in the postoperative atrial fibrillation group than in the non-postoperative atrial fibrillation group (P = .001 and P = .046, respectively). There were no statistical differences in mortality between groups. The incidence of postoperative atrial fibrillation decreased with the use of cell saver system and low Euroscore.

CONCLUSION

The use of a cell salvage device intraoperatively and during the early postoperative period can decrease the incidence of postop- erative atrial fibrillation group.

Elevated Blood Urea Nitrogen to Serum Albumin Ratio Is an Adverse Prognostic Predictor for Patients Undergoing Cardiac Surgery

Background

Elevated blood urea nitrogen (BUN) and reduced albumin have been prominently correlated with unfavorable outcomes in patients with cardiovascular diseases. However, whether combination BUN and albumin levels could predict the adverse outcomes of cardiac surgery patients remains to be confirmed. Here, we investigated the prognostic effect of the preoperative BUN to serum albumin ratio (BAR) in cardiac surgery patients.

Methods

Data were obtained from the Medical Information Mart for Intensive Care (MIMIC) III and eICU databases and classified into a training cohort and validation cohort. The BAR (mg/g) was calculated by initial BUN (mg/dl)/serum albumin (g/dl). The primary outcome was in-hospital mortality. Secondary outcomes were 1-year mortality, prolonged length at intensive care unit, and duration of hospital stay. The associations of BAR with outcomes were explored by multivariate regression analysis and subgroup analyses. Then, C statistics were performed to assess the added prognostic impact of BAR beyond a baseline risk model.

Results

Patients with in-hospital death had significantly higher levels of BAR. Multivariate regression analysis identified BAR, as a categorical or continuous variable, as an independent factor for adverse outcomes of cardiac surgery (all p < 0.05). Subgroup analyses demonstrated a significant relationship between elevated BAR and in-hospital mortality in different subclasses. The addition of BAR to a baseline model provided additional prognostic information benefits for assessing primary outcome. Results were concordant in the external validation cohort.

Conclusions

Increased preoperative BAR is a potent predictor of unfavorable outcomes in patients undergoing cardiac surgery.

The effects of vitamin D supplementation on postoperative atrial fibrillation after coronary artery bypass grafting in patients with vitamin D deficiency

INTRODUCTION

Postoperative atrial fibrillation (POAF) as a common complication of coronary artery bypass grafting (CABG) surgery is associated with increased mortality and morbidity rates. Vitamin D deficiency increases the prevalence of POAF; however, the effects of vitamin D supplementation on the incidence of POAF have not yet been completely elucidated.

METHODS

In this prospective, open-label, randomized clinical trial the level of 25-hydroxy vitamin D (25(OH) D) was measured in patients undergoing CABG surgery. Patients with vitamin D insufficiency (defined as 25(OH) D level < 30 ng/ml) were included and randomly assigned to control group to receive either the general standard of care (Group A) or to study group to receive the general standard of care plus oral vitamin D₃ , 600,000 IU 5 days before surgery (Group B). The primary outcome of our study was the occurrence of POAF during the first 5 days after CABG surgery.

RESULTS

Totally, 93 patients in group B and 103 patients in group A completed the study. The occurrence of POAF was significantly lower in group B as compared to group A (9.68% vs. 20.39%, p = .038). The length of intensive care unit (ICU) stay and hospital stay were reduced in group B patients (2.21 vs. 3.86 days, p < .001 and 7.40 vs. 9.58 days, p = .022, respectively).

CONCLUSION

Our study demonstrated that vitamin D supplementation reduces the incidence of POAF, duration of ICU, and hospital stay following CABG surgery.

A Genotype-Phenotype Analysis of Glutathione Peroxidase 4 in Human Atrial Myocardium and Its Association with Postoperative Atrial Fibrillation

Heterogeneity in the incidence of postoperative atrial fibrillation (POAF) following heart surgery implies that underlying genetic and/or physiological factors impart a higher risk of this complication to certain patients. Glutathione peroxidase-4 (GPx4) is a vital selenoenzyme responsible for neutralizing lipid peroxides, mediators of oxidative stress known to contribute to postoperative arrhythmogenesis. Here, we sought to determine whether GPX4 single nucleotide variants are associated with POAF, and whether any of these variants are linked with altered GPX4 enzyme content or activity in myocardial tissue. Sequencing analysis was performed across the GPX4 coding region within chromosome 19 from a cohort of patients (N = 189) undergoing elective coronary artery bypass graft (−/+ valve) surgery. GPx4 enzyme content and activity were also analyzed in matching samples of atrial myocardium from these patients. Incidence of POAF was 25% in this cohort. Five GPX4 variants were associated with POAF risk (permutated p ≤ 0.05), and eight variants associated with altered myocardial GPx4 content and activity (p < 0.05). One of these variants (rs713041) is a well-known modifier of cardiovascular disease risk. Collectively, these findings suggest GPX4 variants are potential risk modifiers and/or predictors of POAF. Moreover, they illustrate a genotype−phenotype link with this selenoenzyme, which will inform future mechanistic studies.

[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.

Intravenous Arginine Administration Attenuates the Inflammatory Response and Improves Metabolic Profiles in Diet-Induced Obese Mice after Sleeve Gastrectomy

Sleeve gastrectomy (SG) is a bariatric surgery that can effectively reduce weight and improve obesity-associated comorbidities. However, surgical stress intensifies inflammation and imbalanced metabolic profiles. Arginine (Arg) is a nutrient with immunomodulatory and anti-inflammatory properties. This study evaluated the short-term effects of Arg administration on adipocyte inflammation and metabolic alterations in obese mice after SG. Mice were assigned to normal and high-fat diet (HFD) groups. After 16 weeks, the HFD group were divided to sham (SH), SG with saline (SS), or Arg (SA) groups. SS and SA groups were postoperatively injected with saline or Arg via the tail vein and sacrificed at day 1 or 3 after the SG, respectively. Results showed that obesity caused elevated plasma glucose and leptin levels. The SG operation enhanced the expression of inflammatory cytokines and macrophage infiltration in adipose tissues, whereas hepatocyte gene expressions associated with lipid β-oxidation were downregulated. Arg treatment reversed the expressions of β-oxidation-associated genes and reduced lipid peroxide production in the liver. Additionally, adipose tissue expressions of inflammatory chemokines were reduced, while the M2 macrophage marker increased after surgery. The findings suggest that postoperative Arg administration elicited more balanced hepatic lipid metabolism, polarized macrophages toward the anti-inflammatory type, and attenuated adipocyte inflammation shortly after SG.

Clinical factors associated with arrhythmia and short-term prognosis following mitral valve repair: a retrospective cohort study

BACKGROUND

Postoperative arrhythmia (POA) is one of the common and serious postoperative complications. This retrospective study was conducted to investigate the clinical factors associated with POA and its short-term prognosis following mitral valve repair.

METHODS

A total of 618 patients receiving mitral valve repair between January 2015 and November 2020 in our hospital were included in this retrospective study, including 318 males and 300 females and aged 53.9±9.3 years. The patients were grouped into arrhythmia and non-arrhythmia groups and investigated for risk factors associated with the prognosis of POA using multivariate logistic regression based on their clinical data.

RESULTS

POA was observed in 314 (50.8%) patients and atrial fibrillation (AF) was the most frequent (43.3%) type of POA. Compared with non-arrhythmia patients, arrhythmia patients had significantly longer time to use vasoactive drug use, longer intensive care unit (ICU) stay and longer hospital stay. In addition, the incidence of postoperative heart failure was significantly higher (P<0.05). Logistic regression analysis showed that preoperative arrhythmia [odds ratio (OR) =9.17; 95% confident interval (CI): 4.49-18.10], postoperative pain (OR =4.70; 95% CI: 1.55-6.12) and postoperative hypoxemia (OR =3.25; 95% CI: 1.04-6.28) were independently associated with POA.

CONCLUSIONS

This study demonstrates that the incidence of arrhythmia is relatively high after mitral valve repair and is associated with preoperative arrhythmia, postoperative pain and postoperative hypoxemia.

Mechanisms Underlying Antiarrhythmic Properties of Cardioprotective Agents Impacting Inflammation and Oxidative Stress

The prevention of cardiac life-threatening ventricular fibrillation and stroke-provoking atrial fibrillation remains a serious global clinical issue, with ongoing need for novel approaches. Numerous experimental and clinical studies suggest that oxidative stress and inflammation are deleterious to cardiovascular health, and can increase heart susceptibility to arrhythmias. It is quite interesting, however, that various cardio-protective compounds with antiarrhythmic properties are potent anti-oxidative and anti-inflammatory agents. These most likely target the pro-arrhythmia primary mechanisms. This review and literature-based analysis presents a realistic view of antiarrhythmic efficacy and the molecular mechanisms of current pharmaceuticals in clinical use. These include the sodium-glucose cotransporter-2 inhibitors used in diabetes treatment, statins in dyslipidemia and naturally protective omega-3 fatty acids. This approach supports the hypothesis that prevention or attenuation of oxidative and inflammatory stress can abolish pro-arrhythmic factors and the development of an arrhythmia substrate. This could prove a powerful tool of reducing cardiac arrhythmia burden.

Strain Echocardiography to Predict Postoperative Atrial Fibrillation

Postoperative atrial fibrillation (POAF) complicates 15% to 40% of cardiovascular surgeries. Its incidence progressively increases with aging, reaching 50% in octogenarians. This arrhythmia is usually transient but it increases the risk of embolic stroke, prolonged hospital stay, and cardiovascular mortality. Though many pathophysiological mechanisms are known, POAF prediction is still a hot topic of discussion. Doppler echocardiogram and, lately, strain echocardiography have shown significant capacity to predict POAF. Alterations in oxidative stress, calcium handling, mitochondrial dysfunction, inflammation, fibrosis, and tissue aging are among the mechanisms that predispose patients to the perfect "atrial storm". Manifestations of these mechanisms have been related to enlarged atria and impaired function, which can be detected prior to surgery. Specific alterations in the atrial reservoir and pump function, as well as atrial dyssynchrony determined by echocardiographic atrial strain, can predict POAF and help to shed light on which patients could benefit from preventive therapy.

Contribution of oxidative stress in the mechanisms of postoperative complications and multiple organ dysfunction syndrome

BACKGROUND

The extent of the damage following surgery has been subject of study for several years. Numerous surgical complications can impact postoperative quality of life of patients and even can cause mortality. Although these complications are generally due to multifactorial mechanisms, oxidative stress plays a key pathophysiological role. Moreover, oxidative stress could be an unavoidable effect derived even from the surgical procedure itself.

METHODS

A systematic review was performed following an electronic search of Pubmed and ScienceDirect databases. Keywords such as sepsis, oxidative stress, organ dysfunction, antioxidants, outcomes in postoperative complications, among others, were used. Review articles were preferably used between the years 2015 onwards, not excluding older ones.

RESULTS

The vast majority point to the role of oxidative stress in generating greater damage and worse prognosis in postoperative patients without the necessary care and precautions, taking importance on the use of antioxidants to prevent this problem.

DISCUSSIONS

Oxidative stress represents a common final pathway related to pathological processes such as inflammation or ischemia-reperfusion, among others. The expression of greater severity of these complications can result in multiple organ dysfunction or sepsis. The aim of this study was to present an update of the role of oxidative stress on surgical postoperative complications.

The Impact of Aorto-Mitral Angle on New-Onset Atrial Arrhythmia after Mitral Valve Repair in Patients with Mitral Regurgitation

In this study, we hypothesized that post-operative aorto-mitral angle might be associated to the occurrence of post-operative atrial arrhythmia (AA), including atrial fibrillation and atrial tachycardia, after mitral valve repair in patients with mitral regurgitation (MR). Thus, this present study aims to determine the effects of post-operative aorto-mitral angle on new-onset AA after mitral valve repair with mitral annuloplasty for the treatment of MR.In total, 172 patients without any history of AA underwent mitral valve repair with mitral annuloplasty in our institution between 2008 and 2017. Patient information, including medical records and echocardiographic data, were retrospectively studied.As per our findings, AA occurred in 15 (8.7%) patients during the follow-up period (median, 35.7 months; range, 0.5-132 months). The patients with AA were noted to have a longer cardiopulmonary bypass time and a smaller aorto-mitral angle at post-operative TTE than the others (119 ± 6° versus 125 ± 10°, P = 0.003). No significant difference was noted in the degree of post-operative residual MR or functional MS between the groups. In a multivariate Cox proportional hazards analysis, the longer cardiopulmonary bypass time and the smaller post-operative aorto-mitral angle were independent predictors of the occurrence of AA during the follow-up period (odds ratio per 10 minutes 1.11; 95% CI 1.02-1.22, P = 0.019: odds ratio 0.91; 95% CI 0.85-0.98, P = 0.012).A small aorto-mitral angle at post-operative TTE was determined to be a predictor of new-onset AA after a mitral valve repair for treating MR.

A double-blind randomised controlled trial on the effect of Tocovid, a tocotrienol-rich capsule on postoperative atrial fibrillation at the National Heart Institute, Kuala Lumpur: an interim blinded analysis

INTRODUCTION

Post-operative atrial fibrillation (POAF) is associated with poorer outcomes, increased resource utilisation, morbidity and mortality. Its pathogenesis is initiated by systemic inflammation and oxidative stress. It is hypothesised that a potent antioxidant and anti-inflammatory agent such as tocotrienol, an isomer of Vitamin E, could reduce or prevent POAF.

AIMS

The aim of this study is to determine whether a potent antioxidative and anti-inflammatory agent, Tocovid, a tocotrienol-rich capsule, could reduce the incidence of POAF and affect the mortality and morbidity as well as the duration of ICU, HDU and hospital stay.

METHODS

This study was planned as a prospective, randomised, controlled trial with parallel groups. The control group received placebo containing palm superolein while the treatment group received Tocovid capsules. We investigated the incidence of POAF, the length of hospital stay after surgery and the health-related quality of life.

RESULTS

Recruitment commenced in January 2019 but the preliminary results were unblinded as the study is still ongoing. Two-hundred and two patients have been recruited out of a target sample size of 250 as of January 2021. About 75% have completed the study and 6.4% were either lost during follow-up or withdrew; 4% of participants died. The mean age group was 61.44 ± 7.30 years with no statistical difference between the groups, with males having a preponderance for AF. The incidence of POAF was 24.36% and the mean time for developing POAF was 55.38 ± 29.9 h post-CABG. Obesity was not a predictive factor. No statistically significant difference was observed when comparing left atrial size, NYHA class, ejection fraction and the premorbid history. The mean cross-clamp time was 71 ± 34 min and the mean bypass time was 95 ± 46 min, with no difference between groups. There was a threefold increase in death among patients with POAF (p = 0.008) and an increase in the duration of ICU stay (p = 0.01), the total duration of hospital stay (p = 0.04) and reintubation (p = 0.045).

CONCLUSION

A relatively low incidence rate of POAF was noted although the study is still ongoing. It remains to be seen if our prophylactic intervention using Tocovid would effectively reduce the incidence of POAF. Clinical Registration Number: US National Library of Medicine. Clinical Trials - NCT03807037. Registered on 16th January 2019. Link: https://clinicaltrials.gov/ct2/show/NCT03807037.

A Prediction Rule Including Interleukin-6 in Pericardial Drainage Improves Prediction of New-Onset Atrial Fibrillation After Coronary Artery Bypass Grafting

OBJECTIVE

To test the hypothesis that a prediction rule including levels of interleukin-6 in pericardial drainage (pdIL-6) would improve the discrimination in classifying patients undergoing coronary artery bypass grafting (CABG) into different postoperative atrial fibrillation (POAF) risk levels.

DESIGN

Prospective cohort study.

SETTING

A university-affiliated tertiary hospital.

PARTICIPANTS

Patients undergoing CABG.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We prospectively recruited patients who underwent CABG into derivation and validation cohorts. The independent predictors were identified in the derivation cohort using multiple logistic regression and tested in the validation cohort. The performance of the predictive model was tested using area under the receiver operating characteristic curve (AUC) in both cohorts. A prediction rule was created by assigning points to each predictor. Patients were classified in various risk levels according to their total risk scores. We enrolled 302 and 207 patients in the derivation and validation cohorts, respectively. Multiple logistic regression analysis identified six predictors: age ≥61 y, left atrial diameter ≥49 mm, right atrial diameter ≥45 mm, number of grafts ≥3, and serum uric acid ≥226 µmol/L and pdIL-6 levels ≥166 ng/mL at postoperative 12 h. The AUC of the model was 0.78 and 0.77 for the derivation and validation cohort, respectively, which was greatly increased by adding pdIL-6. Patients were stratified into low-risk, moderate-risk and high-risk groups.

CONCLUSIONS

A POAF prediction rule including pdIL-6 had good performance for stratifying CABG patients into various risk groups for POAF. The inclusion of pdIL-6 resulted in clinically meaningful improvement in risk prediction.

The Blinding Period Following Ablation Therapy for Atrial Fibrillation: Proarrhythmic and Antiarrhythmic Pathophysiological Mechanisms

Atrial fibrillation (AF) causes heart failure, ischemic strokes, and poor quality of life. The number of patients with AF is estimated to increase to 18 million in Europe in 2050. Pharmacological therapy does not cure AF in all patients. Ablative pulmonary vein isolation is recommended for patients with drug-resistant symptomatic paroxysmal AF but is successful in only about 60%. In patients in whom ablative therapy is successful on the long term, recurrence of AF may occur in the first weeks to months after pulmonary vein ablation. The early recurrence (or delayed cure) of AF is not understood but forms the basis for the generally accepted 3-month blinding (or blanking) period after ablation therapy, which is not included in the evaluation of the eventual success rate of the procedures. The underlying pathophysiological processes responsible for early recurrence and the delayed cure are unknown. The implicit assumption of the blinding period is that the AF mechanism in this period is different from the ablation-targeted AF mechanism (ectopy from the pulmonary veins). In this review, we evaluate the temporary and long-lasting pro- and antiarrhythmic effects of each of the pathophysiological processes and interventions (necrosis, ischemia, oxidative stress, edema, inflammation, autonomic nervous activity, tissue repair, mechanical remodeling, and use of antiarrhythmic drugs) occurring in the blinding period that can modulate AF mechanisms. We propose that stretch-reducing ablation scar is a permanent antiarrhythmic mechanism that develops during the blinding period and is the reason for delayed cure.

Impact of Minimally Invasive Esophagectomy in Post-Operative Atrial Fibrillation and Long-Term Mortality in Patients Among Esophageal Cancer

Aims:

Postoperative Atrial fibrillation (POAF) after esophagectomy may prolong stay in intensive care and increase risk of perioperative complications. A minimally invasive approach is becoming the preferred option for esophagectomy, yet its implications for POAF risk remains unclear. The association between POAF and minimally invasive esophagectomy (MIE) was examined in this study.

Methods:

We used a dataset of 575 patients who underwent esophagectomy. Multivariate logistic regression analysis was performed to examine the association between MIE and POAF. A cox proportional hazards model was applied to assess the long-term mortality (MIE vs open esophagectomy, OE).

Results:

Of the 575 patients with esophageal cancer, 62 developed POAF. MIE was negatively associated with the occurrence of POAF (Odds ratio: 0.163, 95%CI: 0.033-0.801). No significant difference was observed in long-term mortality (Odds ratio: 2.144, 95%CI: 0.963-4.775).

Conclusions:

MIE may reduced the incidence of POAF without compromising the survival of patients with esophageal cancer. Moreover, the specific mechanism of MIE providing this possible advantage needs to be determined by larger prospective cohort studies with specific biomarker information from laboratory tests.

Machine Learning Outperforms Existing Clinical Scoring Tools in the Prediction of Postoperative Atrial Fibrillation During Intensive Care Unit Admission After Cardiac Surgery

OBJECTIVE(S)

Using the Medical Information Mart for Intensive Care III (MIMIC-III) database, we compared the performance of machine learning (ML) to the to the established gold standard scoring tool (POAF Score) in predicting postoperative atrial fibrillation (POAF) during intensive care unit (ICU) admission after cardiac surgery.

METHODS

Random forest classifier (RF), decision tree classifier (DT), logistic regression (LR), K neighbours classifier (KNN), support vector machine (SVM), and gradient boosted machine (GBM) were compared to the POAF Score. Cross-validation was used to assess the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of ML models. POAF Score performance confidence intervals were generated using 1,000 bootstraps. Risk profiles for GBM were generated using Shapley additive values.

RESULTS

A total of 6,349 ICU admissions encompassing 6,040 patients were included. POAF occurred in 1,364 of the 6,349 admissions (21.5%). For predicting POAF during ICU admission after cardiac surgery, GBM, LR, RF, KNN, SVM and DT achieved an AUC of 0.74 (0.71-0.77), 0.73 (0.71-0.75), 0.72 (0.69-0.75), 0.68 (0.67-0.69), 0.67 (0.66-0.68) and 0.59 (0.55-0.63) respectively. The POAF Score AUC was 0.63 (0.62-0.64). Shapley additive values analysis of GBM generated patient level explanations for each prediction.

CONCLUSION

Machine learning models based on readily available preoperative data can outperform clinical scoring tools for predicting POAF during ICU admission after cardiac surgery. Explanatory models are shown to have potential in personalising POAF risk profiles for patients by illustrating probabilistic input variable contributions. Future research is required to evaluate the clinical utility and safety of implementing ML-driven tools for POAF prediction.

Novel Combined Antioxidant Strategy against Hypertension, Acute Myocardial Infarction and Postoperative Atrial Fibrillation

Reactive oxygen species (ROS) play a physiological role in the modulation of several functions of the vascular wall; however, increased ROS have detrimental effects. Hence, oxidative stress has pathophysiological impacts on the control of the vascular tone and cardiac functions. Recent experimental studies reported the involvement of increased ROS in the mechanism of hypertension, as this disorder associates with increased production of pro-oxidants and decreased bioavailability of antioxidants. In addition, increased ROS exposure is found in ischemia-reperfusion, occurring in acute myocardial infarction and cardiac surgery with extracorporeal circulation, among other settings. Although these effects cause major heart damage, at present, there is no available treatment. Therefore, it should be expected that antioxidants counteract the oxidative processes, thereby being suitable against cardiovascular disease. Nevertheless, although numerous experimental studies agree with this notion, interventional trials have provided mixed results. A better knowledge of ROS modulation and their specific interaction with the molecular targets should contribute to the development of novel multitarget antioxidant effective therapeutic strategies. The complex multifactorial nature of hypertension, acute myocardial infarction, and postoperative atrial fibrillation needs a multitarget antioxidant strategy, which may give rise to additive or synergic protective effects to achieve optimal cardioprotection.

Atrial Fibrillation after Cardiac Surgery-To Infinity and Beyond!

No Abstract

Comparison of Del Nido Cardioplegia and Blood Cardioplegia in Terms of Development of Postoperative Atrial Fibrillation in Patients Undergoing Isolated Coronary Artery Bypass Grafting

Objective

Del Nido cardioplegia (DNC) has been used in pediatric cardiac surgery for many years with a single dose application and its usage in adult cardiac surgery has been increasing in recent years, with results being published. In this study, we aimed to investigate the effect of DNC on the development of postoperative atrial fibrillation (PoAF).

Methods

In this retrospective observational comparative study, 255 patients who underwent isolated on-pump coronary artery bypass grafting, between January 2019 and November 2019, were enrolled. The patients were divided into two groups: DNC (n=132) and blood cardioplegia (BC) (n=123). Intraoperative and postoperative data were evaluated and compared in terms of the development of PoAF.

Results

We found that the development of PoAF and the length of hospital stay remain significantly higher in the BC group (P=0.044, P<0.001, respectively). In addition, the aortic cross-clamp time and the cardioplegia volume delivered were significantly lower in the DNC group (P=0.042, P<0.001, respectively). In multivariate logistic regression analysis, only higher cardioplegia volume was determined as an independent predictor for PoAF development (OR 1.001; 95% CI 1.000-1.001; P=0.033). We did not found difference between groups in terms of troponin T, inotropic drug support, need for intraaortic balloon pump and mortality.

Conclusion

This study showed that DNC can be used safely in adult coronary bypass surgery and PoAF development effect is reduced.

EuroScore and IL-6 predict the course in ICU after cardiac surgery

BACKGROUND

Despite modern advances in intensive care medicine and surgical techniques, mortality rates in cardiac surgical patients are still about 3%. Considerable efforts were made to predict morbidity and mortality after cardiac surgery. In this study, we analysed the predictive properties of EuroScore and IL-6 for mortality in ICU, prolonged postoperative mechanical ventilation, and prolonged stay in ICU.

METHODS

We enrolled 2972 patients undergoing cardiac surgery. The patients either underwent aortic valve surgery (AV), mitral valve surgery (MV), coronary artery bypass grafting (CABG), and combined operations of aortic valve and coronary artery bypass grafting (AV + CABG) or of mitral and tricuspid valve (MV + TV). Different laboratory and clinical parameters were analysed.

RESULTS

EuroScore as well as IL-6 were associated with increased mortality after cardiac surgery. Furthermore, a higher EuroScore and elevated levels of IL-6 were predictors for prolonged mechanical ventilation and a longer stay in ICU. Especially, highly significant elevated IL-6 levels and an increased EuroScore showed a strong association. Statistics suggested superiority when both parameters were combined in a single model.

CONCLUSION

Our results suggest that EuroScore and IL-6 are helpful in predicting the course in ICU after cardiac surgery, and therefore, the use of intensive care resources. Especially, the combination of highly elevated levels of IL-6 and EuroScore may prove to be excellent predictors for an unfortunate postoperative course in ICU.

Effects of upper limb ischemia-reperfusion on regional oxidative stress during aortic surgery with moderate hypothermia

INTRODUCTION

This study aims to evaluate the effect of acute, iatrogenic right arm ischemia and reperfusion (I/R) due to right axillary cannulation on regional oxidative stress using tissue perfusion markers such as central venous oxygen saturation, lactate, the difference between central venous and arterial CO₂ pressure, near-infrared spectroscopy (NIRS) measurements, and biomarkers like sialic acid, malondialdehyde, advanced oxidative protein products in aortic surgery with moderate hypothermia.

METHODS

Adult patients undergoing ascending aorta repair with antegrade cerebral perfusion via the axillary artery participated. Blood samples were collected from the internal jugular vein, right arm cubital vein, and left arm cubital vein, and analysis was performed at intraoperative time points.

RESULTS

Right-arm venous oxygen saturation levels are significantly lower than left arm and central venous, as expected in iatrogenic ischemia. Right arm lactate levels are significantly higher. Somatic right arm NIRS values are significantly lower than somatic left arm. There are no significant differences for biomarkers throughout the time points.

CONCLUSIONS

We have concluded that well-known markers reflect the results of ischemia-reperfusion more rapidly, and are more valuable than novel biomarkers. NIRS is a promising monitor in terms of providing information about tissue oxygenation. Oxidative stress biomarkers do not change quickly enough to give useful information in a short enough period of time; moreover, their costs are high and laboratory studies take time. Although axillary cannulation is controlled limb ischemia, the local effects of I/R did not completely normalize at the end of the surgery, and this regional I/R did not affect the global body organism.

Cardiac Connexin-43 Hemichannels and Pannexin1 Channels: Provocative Antiarrhythmic Targets

Cardiac connexin-43 (Cx43) creates gap junction channels (GJCs) at intercellular contacts and hemi-channels (HCs) at the peri-junctional plasma membrane and sarcolemmal caveolae/rafts compartments. GJCs are fundamental for the direct cardiac cell-to-cell transmission of electrical and molecular signals which ensures synchronous myocardial contraction. The HCs and structurally similar pannexin1 (Panx1) channels are active in stressful conditions. These channels are essential for paracrine and autocrine communication through the release of ions and signaling molecules to the extracellular environment, or for uptake from it. The HCs and Panx1 channel-opening profoundly affects intracellular ionic homeostasis and redox status and facilitates via purinergic signaling pro-inflammatory and pro-fibrotic processes. These conditions promote cardiac arrhythmogenesis due to the impairment of the GJCs and selective ion channel function. Crosstalk between GJCs and HCs/Panx1 channels could be crucial in the development of arrhythmogenic substrates, including fibrosis. Despite the knowledge gap in the regulation of these channels, current evidence indicates that HCs and Panx1 channel activation can enhance the risk of cardiac arrhythmias. It is extremely challenging to target HCs and Panx1 channels by inhibitory agents to hamper development of cardiac rhythm disorders. Progress in this field may contribute to novel therapeutic approaches for patients prone to develop atrial or ventricular fibrillation.

Postoperative Atrial Fibrillation After Cardiac Surgery: A Meta-Analysis

BACKGROUND

Postoperative atrial fibrillation (POAF) is common after cardiac surgery and linked to poorer short-term and long-term outcomes; however, conflicting evidence exists on stroke risk and how the index procedure affects outcomes. This study aims to provide a comprehensive review of the published outcomes of POAF after cardiac surgery, examined as a whole and by index procedure.

METHODS

A systematic review of POAF after cardiac surgery was conducted. Outcomes related to POAF were analyzed in a meta-analysis, and aggregate survival data were derived to examine long-term survival.

RESULTS

Sixty-one studies with 239,018 patients were identified, the majority (78.7%) undergoing coronary surgery. POAF occurred in 25.5% of patients and was associated with significantly higher rates of early mortality and stroke (odds ratio [OR], 1.74; P < .001; and OR, 2.21, P < .001, respectively) along with longer intensive care and overall hospital length of stay (mean difference 0.8 days, P = .008; and mean difference 2.8 days, P < .001, respectively). After a median of 6.6 years (range, 0.5-20 years), mortality and stroke remained significantly higher for those with POAF (OR, 1.57, P < .001; and OR, 1.81, P = .001). Pooled hazard ratio for long-term mortality was significantly higher for patients who underwent coronary surgery compared with isolated valve surgery.

CONCLUSIONS

POAF is common after cardiac surgery and is associated with significantly higher rates of both short-term and long-term stroke and mortality as well as increased hospital stay. Differences in hazard for long-term survival may be due to the underlying pathophysiological risk factors for POAF, which differ by surgical procedure.

Systematic review of pre-clinical therapies for post-operative atrial fibrillation

BACKGROUND

Post-operative atrial fibrillation (POAF) is a frequent cardiothoracic surgery complication that increases hospital stay, mortality and costs. Despite decades of research, there has been no systematic overview and meta-analysis of preclinical therapies for POAF in animal models.

METHODS

We performed a systematic search of MEDLINE and EMBASE from their inception through September 2020 to determine the effect of preclinical POAF therapies on primary efficacy outcomes using a prospectively registered protocol (CRD42019155649). Bias was assessed using the SYRCLE tool and CAMARADES checklist.

RESULTS

Within the 26 studies that fulfilled our inclusion criteria, we identified 4 prevention strategies including biological (n = 5), dietary (n = 2), substrate modification (n = 2), and pharmacological (n = 17) interventions targeting atrial substrate, cellular electrophysiology or inflammation. Only one study altered more than 1 pathophysiological mechanism. 73% comprised multiple doses of systemic therapies. Large animal models were used in 81% of the studies. Preclinical therapies altogether attenuated atrial fibrosis (SMD -2.09; 95% confidence interval [CI] -2.95 to -1.22; p < 0.00001; I2 = 47%), AF inducibility (RR 0.40; 95% CI 0.21 to 0.79; p = 0.008; I2 = 39%), and AF duration (SMD -2.19; 95% CI -3.05 to -1.32; p < 0.00001; I2 = 50%). However, all the criteria needed to evaluate the risk of bias was unclear for many outcomes and only few interventions were independently validated by more than 1 research group.

CONCLUSION

Treatments with therapies targeting atrial substrate, cellular electrophysiology or inflammation reduced POAF in preclinical animal models compared to controls. Improving the quality of outcome reporting, independently validating promising approaches and targeting complimentary drivers of POAF are promising means to improve the clinical translation of novel therapies for this highly prevalent and clinically meaningful disease.

Intravenous Glutamine Administration Improves Glucose Tolerance and Attenuates the Inflammatory Response in Diet-Induced Obese Mice after Sleeve Gastrectomy

Obesity is a health problem associated with many metabolic disorders. Weight reduction can effectively alleviate obesity-associated complications. Sleeve gastrectomy is a commonly used bariatric surgery and is considered safe and effective for improving outcomes. Glutamine (GLN) is an amino acid with anti-oxidative and anti-inflammatory properties. This study used a mouse model of sleeve gastrectomy to investigate the impacts of intravenous GLN administration on glucose tolerance and adipocyte inflammation short-term after surgery. C57BL6 male mice were divided into normal control (NC) and high-fat diet groups. The high-fat diet provided 60% of energy from fat for 10 weeks to induce obesity. Mice fed the high-fat diet were then assigned to a sham (SH) or sleeve gastrectomy with saline (S) or GLN (G) groups. The S group was intravenously injected with saline, while the G group was administered GLN (0.75 g/kg body weight) via a tail vein postoperatively. Mice in the experimental groups were sacrificed on day 1 or 3 after the surgery. Results showed that obesity resulted in fat accumulation, elevated glucose levels, and adipokines production. Sleeve gastrectomy aggravated expressions of inflammatory cytokine and macrophage infiltration markers, cluster of differentiation 68 (CD68), epidermal growth factor-like module-containing mucin-like hormone receptor-like 1 (EMR-1), and macrophage chemoattractant protein-1, in adipose tissues. Treatment of obese mice with GLN downregulated hepatic proteomic profiles associated with the gluconeogenesis pathway and improved glucose tolerance. Moreover, macrophage infiltration and adipose tissue inflammation were attenuated after the sleeve gastrectomy. These findings imply that postoperative intravenous GLN administration may improve glucose tolerance and attenuate inflammation shortly after the bariatric surgery in subjects with obesity.

The role of exogenous Fibrinogen in cardiac surgery: stop bleeding or induce cardiovascular disease

The surgical treatment contributes to broad variety of cardiovascular diseases (CVD). Due to many involved factors in preoperative bleeding, it is almost difficult to perform better Haemostatic approach. Fibrinogen is a major blood glycoprotein and a coagulation factor which decreases postoperative bleeding. It has a potential role in platelet activation and bleeding inhibition; it may reflect the inflammatory responses and be related to the endothelial dysfunction. Fibrinogen can act as a pro-inflammatory element via increasing some inflammatory markers including IL-6, tumor necrosis factor-α (TNF-α), monocyte chemo attractant protein (MCP-1), macrophage inflammatory protein-1 (MIP-1a and b), matrix metalloproteinase (MMP-1 and MMP-9) and Toll-like Receptors (TLRs); through activation of these factors, fibrinogen may induce some inflammatory mechanisms such as focal adhesion kinase (FAK), mitogen-activated protein kinases (MAPK) and nuclear factor κB (NF-κB) pathways. It may cause endothelial dysfunction by increasing P and E-selection, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) levels which activate MAPK and NF-κB pathways. This factor is also associated with increased exocytosed von Willebrand factor (vWF) as well as activation of Rho-GTPase mechanism. All of these data demonstrate the dual role of fibrinogen in cardiac surgeries, bleeding inhibition and CVD. Therefore, identifying the CVD factors is helpful for designing preventive strategies and alternative drugs.

Blood-based 8-hydroxy-2'-deoxyguanosine level: A potential diagnostic biomarker for atrial fibrillation

BACKGROUND

Recent research findings have revealed a key role of oxidative DNA damage in the pathogenesis of atrial fibrillation (AF). Therefore, the circulating oxidative DNA damage marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) may represent a biomarker for staging AF and identifying patients at risk for AF recurrence and postoperative atrial fibrillation (POAF) after treatment.

OBJECTIVE

The purpose of this study was to investigate whether serum levels of 8-OHdG correlate with the stage of AF, recurrence after AF treatment, and onset of POAF after cardiac surgery.

METHODS

In this prospective observational study, 8-OHdG levels were detected by enzyme-linked immunosorbent assay in human serum samples. Blood samples were collected from control patients without AF history; patients with paroxysmal AF and persistent AF undergoing electrical cardioversion or pulmonary vein isolation (PVI); and patients with sinus rhythm (SR) undergoing cardiac surgery. AF recurrence was determined during 12-month follow-up. Univariate and multivariate analyses were used to identify changes in 8-OHdG levels between the groups.

RESULTS

Compared to the control group, 8-OHdG levels in the patient groups gradually and significantly increased during arrhythmia progression. 8-OHdG levels in AF patients showing AF recurrence after PVI treatment were significantly increased compared to patients without AF recurrence. Moreover, in SR patients undergoing cardiac surgery, 8-OHdG levels were significantly elevated in those showing POAF compared to patients without POAF.

CONCLUSION

8-OHdG level may represent a potential diagnostic biomarker for AF staging as well as for predicting AF recurrence and POAF after treatment.

Association between cardioplegia and postoperative atrial fibrillation in coronary surgery

OBJECTIVE

The aim of this multicenter study was to evaluated whether cold or warm cardioplegia are associated with postoperative atrial fibrillation (POAF) and the prognostic role of the latter on early stroke and neurological mortality.

METHOD

This was a retrospective analysis of prospective collected data from 9 cardiac centers in Italy and the United States including patients undergoing surgery between 2010 and 2018. From the 9 institutional databases, 17,231 patients underwent isolated CABG on-pump, using either warm cardioplegia (n = 7730) or cold cardioplegia (n = 9501); among the latter group blood and crystalloid cardioplegia were used in 691 and 8810 patients, respectively. After matching, two pairs of 4162 patients (overall cohort 8324) were analyzed.

RESULTS

In matched population, the rate of POAF was 18% (1472 cases), 15% (608) in warm group versus 21% (864) in cold group (p < 0.001). Multivariable analysis confirmed that cold cardioplegia was associated with higher rate of POAF, along with age, hypercholesterolemia, LVEF, reoperation, preoperative IABP, previous stroke, cardiopulmonary and cross-clamp. Moreover, cold cardioplegia as well as POAF increased the rate of postoperative stroke as well as early mortality and neurological mortality Propensity-weighted cohort included 11,830 (70%) patients out of 17,231. After adjustment, both cold blood and cold crystalloid cardioplegia negatively influenced POAF, stroke and neurological mortality.

CONCLUSIONS

Warm cardioplegia may reduce the rate of POAF in CABG patients with respect to cold cardioplegia, either blood or crystalloid. This has a prognostic impact on postoperative stroke and neurological mortality.

The role of surgery type in postoperative atrial fibrillation and in-hospital mortality in esophageal cancer patients with preserved left ventricular ejection fraction

BACKGROUND

Postoperative atrial fibrillation (POAF) is one of the most common complications of esophagectomy, which may extend the inpatient hospital stay. Minimally invasive esophagectomy (MIE) has been increasingly used in clinical practice; however, its POAF risk and short-term mortality remain unclear. This study aimed to examine the POAF risk and in-hospital mortality rate between patients receiving MIE and open esophagectomy (OE).

METHODS

Esophageal cancer patients who underwent MIE or OE from a retrospective cohort study were evaluated. A multivariate logistic regression model was built to assess the associations between esophagectomy (MIE vs. OE) and various outcomes (POAF, in-hospital mortality). Covariates included age, sex, body mass index, neoadjuvant therapy, tumor stage, surgery incision type, comorbidities, cardia conditions, peri-operative medication, and complications.

RESULTS

Of the 484 patients with esophageal cancer, 63 received MIE. A total of 53 patients developed POAF. Compared to patients receiving OE, MIE patients had 81% reduced odds of POAF (adjusted odds ratio [aOR] 0.185, 95% CI 0.039-0.887, P = 0.035). No statistically significant association was found for in-hospital mortality (aOR 0.709, 95% CI 0.114-4.409, P = 0.712).

CONCLUSIONS

MIE is associated with a lower risk of POAF, compared to traditional surgery. No significant short-term survival benefit was found for MIE.

Adverse remodeling in atrial fibrillation following isolated aortic valve replacement surgery

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia with adverse clinical outcomes. Aortic valve replacement (AVR) is one of the most frequently performed cardiac surgeries, although there is scarce evidence on arrhythmic outcomes. We aimed to evaluate AF during the first year post- isolated aortic valve replacement surgery and its clinical, analytical, and echocardiographic predictors.

METHODS

Severe aortic stenosis patients with no prior atrial fibrillation submitted to isolated aortic valve replacement surgery were included in our study, of which 316 remained in sinus rhythm and 24 developed AF. We performed logistic regression searching for AF predictors and a longitudinal comparison between pre and post-operative echocardiographic data.

RESULTS

Postoperative AF (POAF), diabetes, and follow-up indexed Left Atrium Diameter (iLAD) were significantly higher in the group of patients developing AF. POAF and iLAD were independent AF predictors at follow-up. No differences between groups were found regarding baseline and follow-up echocardiographic data except for indexed Left Ventricle End-diastolic Diameter (LVED), which failed to decrease after surgery in the AF group.

CONCLUSIONS

POAF and iLAD independently predicted AF at 1 year following isolated AVR surgery in aortic stenosis patients with no AF history. iLVED did not decrease significantly at follow-up in AF patients, possibly reflecting adverse ventricular remodeling.

Insight into atrial fibrillation through analysis of the coding transcriptome in humans

Atrial fibrillation is the most common sustained cardiac arrhythmia in humans, and its prevalence continues to increase because of the aging of the world population. Much still needs to be learned about the molecular pathways involved in the development and the persistence of the disease. Analysis of the transcriptome of cardiac tissue has provided valuable insight into diverse aspects of atrial remodeling, in particular concerning electrical remodeling-related to ion channels-and structural remodeling identified by dysregulation of processes linked to inflammation, fibrosis, oxidative stress, and thrombogenesis. The huge amount of data produced by these studies now represents a valuable source for the identification of novel potential therapeutic targets. In addition, the shift from cardiac tissue to peripheral blood as a substrate for transcriptome analysis revealed this strategy as a promising tool for improved diagnosis and therefore better patient care.

Path to precision: prevention of post-operative atrial fibrillation

Development of post-operative atrial fibrillation (POAF) following open-heart surgery is a significant clinical and economic burden. Despite advancements in medical therapies, the incidence of POAF remains elevated at 25-40%. Early work focused on detecting arrhythmias from electrocardiograms as well as identifying pre-operative risk factors from medical records. However, further progress has been stagnant, and a deeper understanding of pathogenesis and significant influences is warranted. With the advent of more complex machine learning (ML) algorithms and high-throughput sequencing, we have an unprecedented ability to capture and predict POAF in real-time. Integration of multimodal heterogeneous data and application of ML can generate a paradigm shift for diagnosis and treatment. This will require a concerted effort to consolidate and streamline real-time data. Herein, we will review the current literature and emerging opportunities aimed at predictive targets and new insights into the mechanisms underlying long-term sequelae of POAF.

C-reactive protein after coronary artery bypass graft surgery and its relationship with postoperative atrial fibrillation

Aims

Postoperative atrial fibrillation (POAF), a common complication following coronary artery bypass graft (CABG) surgery, is associated with increased morbidity and mortality. Inflammation may be an important factor for the pathogenesis of POAF, and increased preoperative levels of C-reactive protein (CRP) are associated with the development of POAF. However, the relationship between postoperative CRP and POAF is less well established.

Methods and results

Patients undergoing first-time isolated CABG surgery (1 January 2000–31 December 2016) were identified using the Eastern Danish Heart Surgery Database and nationwide administrative registries. Patients with no history of atrial fibrillation and with available CRP measurements from postoperative day (POD) 4 were included. The study population was divided into quartiles based on CRP. The association between CRP levels and the odds of developing POAF was investigated using multivariable logistic regression analysis. We included 6711 patients. The CRP intervals on POD 4 for the CRP groups (lowest to highest) were ≤90, &gt;90 to ≤127, &gt;127 to ≤175, and &gt;175 mg/L, respectively. Patients in the highest CRP group were older and more often men compared with patients in the lowest CRP group [median age 67 years (P25–P75: 61–73) and 84.7% men vs. median age 64 years (P25–P75: 56–70) and 77.9% men]. In the lowest and highest CRP groups, 25% and 35% developed POAF, respectively. In adjusted analysis, the highest CRP group, compared with the lowest CRP group, was associated with greater odds of developing POAF (odds ratio 1.31; 95% confidence interval 1.12–1.54).

Conclusion

Increased postoperative CRP levels after CABG surgery was associated with the development of POAF.

Interleukin-6 Receptor Asp358 A>C Polymorphism Is Associated With Postoperative Atrial Fibrillation

BACKGROUND

This study examined the associations of single-nucleotide polymorphisms in the interleukin-6 receptor gene (Asp358 A>C) and the interleukin-6 promoter (-174G>C and -597G>A) with interleukin-6 levels and postoperative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG).

METHODS

The study enrolled 371 Chinese Han patients who were undergoing CABG. Serum interleukin-6 levels were measured preoperatively and at 6, 12, and 18 hours postoperatively. Genotypes for the 3 polymorphisms were determined.

RESULTS

Overall, POAF developed in 30.2% of patients. The CC genotype and C allele frequencies for the interleukin-6 receptor Asp358 A>C polymorphism were significantly higher in patients with POAF than in patients without POAF (P = .003), and the interleukin-6 levels were significantly higher in patients with the CC genotype compared with A allele carriers at 6, 12, and 18 hours in the overall cohort and at 12 and 18 hours in the POAF subgroup, but there were no significant differences in the non-POAF subgroup. However, the allele and genotype frequencies of the interleukin-6 -174G>C and -597G>A polymorphisms were similar among groups, and there were no differences in interleukin-6 levels at any time point between the C/A allele carriers and the patients with GG genotypes. Univariate analysis showed that the CC genotype for interleukin-6 receptor Asp358 A>C, age, and history of cerebrovascular disease were associated with POAF. Multivariable regression showed that the CC genotype was independently related to the development of POAF (odds ratio, 2.01; 95% confidence interval: 1.15 to 3.52; P = .014).

CONCLUSIONS

The interleukin-6 receptor Asp358 A>C polymorphism may contribute to genetic susceptibility to POAF after CABG.

Role of Oxidative Stress in the Genesis of Ventricular Arrhythmias

Ventricular arrhythmias, mainly lethal arrhythmias, such as ventricular tachycardia and fibrillation, may lead to sudden cardiac death. These are triggered as a result of cardiac injury due to chronic ischemia, acute myocardial infarction and various stressful conditions associated with increased levels of circulating catecholamines and angiotensin II. Several mechanisms have been proposed to underlie electrical instability of the heart promoting ventricular arrhythmias; however, oxidative stress which adversely affects ion homeostasis due to changes in the ion channel structure and function, seems to play a critical role in eliciting different types of ventricular arrhythmias. Prevention or mitigation of the severity of ventricular arrhythmias due to antioxidants has been indicated as the fundamental contribution in the field of preventive cardiology; however, novel interventions have to be developed for greater effectiveness and specificity in attenuating the adverse effects of oxidative stress. In this review, we have attempted to discuss proarrhythmic effects of oxidative stress differing in time and concentration dependence and highlight a molecular and cellular concept how it alters cardiac cell automaticity and conduction velocity sensitizing the probability of ventricular arrhythmias with resultant sudden cardiac death due to ischemic heart disease and other stressful situations. It is concluded that pharmacological approaches targeting multiple mechanisms besides oxidative stress might be more effective in the treatment of ventricular arrhythmias than current antiarrhythmic therapy.