The role of inflammation in atrial fibrillation following open heart surgery

Effect of Endothelial Adhesion Molecules on Atrial Fibrillation: A Systematic Review and Meta-analysis

Background: Endothelial adhesion molecules (EAMs), and more specifically vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), belong to a family of immunoglobulin-like molecules and are found to have increased expression in inflamed microvessels. Due to the growing evidence regarding EAM effects on cardiovascular diseases, we aimed to investigate the link between EAMs and atrial fibrillation (AF) to discover the efficacy of EAMs assessment as predictive markers in high-risk patients. Methods: We searched for articles published from January 1990 to April 2022. Two independent researchers selected studies that examined the relationship between VCAM-1 and ICAM-1 levels and AF. Study design, patient characteristics, VCAM-1 and ICAM-1 levels, and measurement methods were extracted from the selected articles. Results: Of 181 records, 22 studies were finally included in the systematic review. Meta-analyses showed a significant difference in serum levels of EAMs in patients with AF compared with patients with sinus rhythms (VCAM-1: mean difference [MD] 86.782, 95% CI 22.805-150.758, p=0.008; ICAM-1: MD 28.439 ng/mL, 95% CI 12.540-44.338, p<0.001). In subgroup analysis of persistent AF, the differences were still significant (VCAM-1: MD 98.046, 95% CI 26.582-169.510, p=0.007; ICAM-1: MD 25.091, 95% CI 12.952-37.230, p<0.001). We also found the mean ranges of VCAM-1 (95% CI 661.394-927.984 ng/mL) and ICAM-1 (95% CI 190.101-318.169 ng/mL) in patients with AF. Conclusion: This study suggests a positive association between serum levels of VCAM-1 and ICAM-1 with AF, but there is a need for further large-scale studies.

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.

A novel case of impaired C-reactive protein response following open-heart surgery: A case report and review of the literature

BACKGROUND

C-reactive protein (CRP) is expected to increase in response to a range of inflammatory stimuli such as infections or extensive tissue trauma.

CASE REPORT

We present a novel case of severely impaired CRP response following NSTEMI, influenza A infection and open-heart surgery in which serum CRP concentrations remained < 1 mg/L during an observational period of 28 days.

CONCLUSION

To our knowledge, no previous publications exists describing patients with a lack of CRP response following cardiothoracic surgery. We believe this to be a novel finding warranting further investigations regarding the etiology and prevalence of this phenomenon.

Vitamin D supplementation protects against reductions in plasma 25-hydroxyvitamin D induced by open-heart surgery: Assess-d trial

Low vitamin D (serum or plasma 25‐hydroxyvitamin D (25(OH)D)) is a global pandemic and associates with a greater prevalence in all‐cause and cardiovascular mortality and morbidity. Open‐heart surgery is a form of acute stress that decreases circulating 25(OH)D concentrations and exacerbates the preponderance of low vitamin D in a patient population already characterized by low levels. Although supplemental vitamin D increases 25(OH)D, it is unknown if supplemental vitamin D can overcome the decreases in circulating 25(OH)D induced by open‐heart surgery. We sought to identify if supplemental vitamin D protects against the acute decrease in plasma 25(OH)D propagated by open‐heart surgery during perioperative care. Participants undergoing open‐heart surgery were randomly assigned (double‐blind) to one of two groups: (a) vitamin D (n = 75; cholecalciferol, 50,000 IU/dose) or (b) placebo (n = 75). Participants received supplements on three separate occasions: orally the evening before surgery and either orally or per nasogastric tube on postoperative days 1 and 2. Plasma 25(OH)D concentrations were measured at baseline (the day before surgery and before the first supplement bolus), after surgery on postoperative days 1, 2, 3, and 4, at hospital discharge (5–8 days after surgery), and at an elective outpatient follow‐up visit at 6 months. Supplemental vitamin D abolished the acute decrease in 25(OH)D induced by open‐heart surgery during postoperative care. Moreover, plasma 25(OH)D gradually increased from baseline to day 3 and remained significantly increased thereafter but plateaued to discharge with supplemental vitamin D. We conclude that perioperative vitamin D supplementation protects against the immediate decrease in plasma 25(OH)D induced by open‐heart surgery.

ClinicalTrials.gov Identifier: NCT02460211.

Perioperative Biomarkers Predicting Postoperative Atrial Fibrillation Risk After Coronary Artery Bypass Grafting: A Narrative Review

Postoperative atrial fibrillation (POAF) after cardiac surgery remains a highly prevalent and costly condition that negatively impacts patient quality of life and survival. Numerous retrospective studies, meta-analysis, and review papers have been reported identifying POAF risk based on patients' risk factors and clinical biomarkers. In this narrative review, the authors report significant variations among selected pre- and perioperative biomarkers used to predict POAF incidence in patients without a history of atrial fibrillation (AF). POAF prediction based on B-type natriuretic peptide, N-terminal pro B-type natriuretic peptide, C-reactive protein, interleukin-6, creatinine, and plasminogen activator inhibitor-1 differs significantly among different studies, thereby limiting their clinical utility to predict POAF risk with high accuracy. Conversely, soluble vascular endothelial cells adhesion molecule-1, soluble CD40 ligand, Galectin-3, and aldosterone show promise for better POAF prediction. However, the current datasets for these selected biomarkers are not of sufficient size to validate the broad clinical application specifically for patients with no prior history of AF.

Effect of epicardial application of amiodarone-releasing hydrogel on heart rate in an animal model

BACKGROUND

The purpose of the experiment was to study the safety of local epicardial use of the hydrogel with amiodarone, as well as the influence of its different dosages on the heart rate of mongrel rabbits.

METHODS

The epicardial application of the hydrogel material with amiodarone was performed in 46 rabbits. Rabbits were divided into 5 groups: Group No. 1-dose of amiodarone in the hydrogel 1 mg, Group No. 2-dose 3 mg; Group No. 3-dose 6 mg; Group No. 4-hydrogel without amiodarone; Group No. 5-amiodarone intravenously, 60 mg.

RESULTS

The application of hydrogel with amiodarone is not accompanied by a systemic inflammatory reaction. In group No. 2, there was a significant reduction in the heart rate (before surgery: 158±16, after: 130±11, (P<0,001), without any disturbances to the conduction system of the heart functioning. With an increase in amiodarone concentration (Group No. 3), significant atrial and atrioventricular (AV) conduction defects (up to 70%) were noted; when the dosage of amiodarone (Group No. 1) was reduced, there was no influence on the heart rate reduction. The hydrogel without amiodarone has no effect on the conductive system.

CONCLUSIONS

The method of local epicardial delivery of amiodarone in the form of a hydrogel material is safe. The hydrogel with amiodarone is effective for the heart rate reduction (according to the experiment on animals), compared to the control group and the group with intravenous drug administration. The optimal dosage of amiodarone in the hydrogel is 3 mg.

Association of Preoperative Platelet-to-Lymphocyte Ratio with Atrial Fibrillation after Coronary Artery Bypass Graft Surgery

OBJECTIVE

The aim of this study was to investigate the association between platelet-to-lymphocyte ratio (PLR) and atrial fibrillation (AF) after coronary artery bypass graft (CABG) surgery.

SUBJECTS AND METHODS

A total of 125 patients were retrospectively analyzed. AF was diagnosed using standard clinical criteria, and PLR was calculated as the ratio of the platelets to lymphocytes, obtained from the blood samples that were taken in the fasting state before CABG surgery. The association of different variables with postoperative AF and PLR was calculated using univariate and multivariate analysis. The receiver operating characteristics curve was used to determine the sensitivity and specificity of PLR and the optimal cutoff value for predicting post-CABG AF.

RESULTS

Of the 125 patients, 50 with AF (mean age: 67.0 ± 9.5 years, 38 males and 12 females) and 75 patients without AF (mean age: 61.1 ± 9.1 years, 58 males and 17 females) were identified, and the difference in the mean age was statistically significant (p = 0.01). PLR was also significantly higher in those with AF (152.8 ± 82.2) than those without AF (118.2 ± 32.9) (p = 0.012). Univariate analysis showed that age and PLR were associated with AF after CABG surgery (p < 0.001 and p = 0.005, respectively). Using a multivariate logistic regression model with the backward elimination method, age and PLR remained as independent predictors of AF after CABG surgery (p < 0.001 and p = 0.005, respectively). PLR levels >119.3 predicted postoperative AF with 64% sensitivity and 56% specificity (AUC: 0.634, p = 0.012).

CONCLUSION

In this study, age and PLR level were independent predictors of AF after CABG surgery. Patients with an elevated preoperative PLR were at higher risk of AF after CABG surgery.

Atrial Fibrillation, Neurocognitive Decline and Gene Expression After Cardiopulmonary Bypass

OBJECTIVE

Atrial fibrillation and neurocognitive decline are common complications after cardiopulmonary bypass. By utilizing genomic microarrays we investigate whether gene expression is associated with postoperative atrial fibrillation and neurocognitive decline.

METHODS

Twenty one cardiac surgery patients were prospectively matched and underwent neurocognitive assessments pre-operatively and four days postoperatively. The whole blood collected in the pre-cardiopulmonary bypass, 6 hours after-cardiopulmonary bypass, and on the 4^th postoperative day was hybridized to Affymetrix Gene Chip U133 Plus 2.0 Microarrays. Gene expression in patients who developed postoperative atrial fibrillation and neurocognitive decline (n=6; POAF+NCD) was compared with gene expression in patients with postoperative atrial fibrillation and normal cognitive function (n=5; POAF+NORM) and patients with sinus rhythm and normal cognitive function (n=10; SR+NORM). Regulated genes were identified using JMP Genomics 4.0 with a false discovery rate of 0.05 and fold change of >1.5 or <-1.5.

RESULTS

Eleven patients developed postoperative atrial fibrillation. Six of these also developed neurocognitive decline. Of the 12 patients with sinus rhythm, only 2 developed neurocognitive decline. POAF+NCD patients had unique regulation of 17 named genes preoperatively, 60 named genes six hours after cardiopulmonary bypass, and 34 named genes four days postoperatively (P<0.05) compared with normal patients. Pathway analysis demonstrated that these genes are involved in cell death, inflammation, cardiac remodeling and nervous system function.

CONCLUSION

Patients who developed postoperative atrial fibrillation and neurocognitive decline after cardiopulmonary bypass may have differential genomic responses compared to normal patients and patients with only postoperative atrial fibrillation, suggesting common pathophysiology for these conditions. Further exploration of these genes may provide insight into the etiology and improvements of these morbid outcomes.

Postoperative atrial fibrillation: role of inflammatory biomarkers and use of colchicine for its prevention

Postoperative atrial fibrillation (POAF) is the most common complication following cardiac surgery, occurring in up to 65% of cardiac surgical patients. It is a condition associated with increased morbidity, increased length of hospital stay, and increased health care costs. One of the many potential causes of POAF is postsurgical inflammation, as demonstrated by increased levels of inflammatory biomarkers such as C-reactive protein and interleukin-6. Although still a subject of debate, the role of these inflammatory markers in the pathogenesis of POAF remains under vigorous investigation. Several antiinflammatory drugs have demonstrated promising results in prevention of POAF, including nonsteroidal antiinflammatory drugs, glucocorticoids, and statins. Colchicine is one of the oldest medications used in modern medicine, typically for the treatment and prevention of gout. New evidence has recently surfaced that colchicine may also be useful in the prevention of POAF. In recent studies, colchicine has demonstrated both safety and efficacy in the prevention of POAF. Several new studies are currently being initiated that may further elucidate colchicine's role in the prevention of POAF.

Inflammation in new-onset atrial fibrillation after cardiac surgery: a systematic review

BACKGROUND

Postoperative new-onset atrial fibrillation (PNAF) is the most common complication following cardiac surgery. The pathogenesis of PNAF is multifactorial. The concept of the postoperative inflammatory response, as a potential underlying mechanism has been extensively studied. This review aims to provide a comprehensive summary of literature relevant to the association between the inflammatory response following cardiac surgery and PNAF.

DESIGN

MEDLINE, EMBASE and the Cochrane Central Register were systematically reviewed by two independent investigators for studies published between January 1980 and May 2012, in which an association between serum markers of inflammation and PNAF was evaluated, or the effect of drugs with anti-inflammatory properties on the risk of PNAF.

RESULTS

Sixty-three studies met selection criteria (39 observational and 24 randomized studies) including 27,363 patients. The mean incidence of PNAF after cardiac surgery was 25·5%. Elevated levels of various inflammatory mediators were associated with PNAF, and the most consistent association was found between white blood cell count and PNAF. Of the drugs with anti-inflammatory properties, statins gave the best protective effect against PNAF, followed by anti-oxidants, steroids and colchicine. Nonsteroidal anti-inflammatory drugs did not prevent PNAF significantly.

CONCLUSION

The postoperative inflammation response may play a role in the pathogenesis of PNAF. However, of the inflammation biomarkers, only elevated white blood cell count reliably predicts PNAF. Pre- and perioperative use of statins and several other drugs with anti-inflammatory properties reduce the incidence of PNAF.

Prevention of postoperative atrial fibrillation: novel and safe strategy based on the modulation of the antioxidant system

Postoperative atrial fibrillation (AF) is the most common arrhythmia following cardiac surgery with extracorporeal circulation. The pathogenesis of postoperative AF is multifactorial. Oxidative stress, caused by the unavoidable ischemia-reperfusion event occurring in this setting, is a major contributory factor. Reactive oxygen species (ROS)-derived effects could result in lipid peroxidation, protein carbonylation, or DNA oxidation of cardiac tissue, thus leading to functional and structural myocardial remodeling. The vulnerability of myocardial tissue to the oxidative challenge is also dependent on the activity of the antioxidant system. High ROS levels, overwhelming this system, should result in deleterious cellular effects, such as the induction of necrosis, apoptosis, or autophagy. Nevertheless, tissue exposure to low to moderate ROS levels could trigger a survival response with a trend to reinforce the antioxidant defense system. Administration of n-3 polyunsaturated fatty acids (PUFA), known to involve a moderate ROS production, is consistent with a diminished vulnerability to the development of postoperative AF. Accordingly, supplementation of n-3 PUFA successfully reduced the incidence of postoperative AF after coronary bypass grafting. This response is due to an up-regulation of antioxidant enzymes, as shown in experimental models. In turn, non-enzymatic antioxidant reinforcement through vitamin C administration prior to cardiac surgery has also reduced the postoperative AF incidence. Therefore, it should be expected that a mixed therapy result in an improvement of the cardioprotective effect by modulating both components of the antioxidant system. We present novel available evidence supporting the hypothesis of an effective prevention of postoperative AF including a two-step therapeutic strategy: n-3 PUFA followed by vitamin C supplementation to patients scheduled for cardiac surgery with extracorporeal circulation. The present study should encourage the design of clinical trials aimed to test the efficacy of this strategy to offer new therapeutic opportunities to patients challenged by ischemia-reperfusion events not solely in heart, but also in other organs such as kidney or liver in transplantation surgeries.

Usefulness of statins pretreatment for the prevention of postoperative atrial fibrillation in patients undergoing cardiac surgery

BACKGROUND

postoperative atrial fibrillation (AF) remains the most common arrhythmic complication following cardiac surgery. We performed a meta-analysis based on all currently available randomized controlled trials (RCTs) to confirm the hypothesis that statins pretreatment may lower the risk of postoperative AF in patients undergoing cardiac surgery.

METHODS AND RESULTS

the published literature was scanned by formal searches of electronic databases up through August 2010. RCTs were eligible for inclusion if they compared preoperative statins treatment versus control in patients scheduled for cardiac surgery and had the data of postoperative AF reported. Prespecified criteria were met by eight RCTs involving 841 patients. During the follow-up period, 80 of 422 patients (19.0%) in the statins pretreatment group developed postoperative AF, significantly less than 149 of 419 (35.6%) patients assigned to the control group ( P < 0.001). Postoperative hospital stay was significantly shortened in patients pretreated with statins compared with the control ( P < 0.01).

CONCLUSIONS

this meta-analysis supports the effectiveness of statins pretreatment on reducing the incidence of postoperative AF in patients undergoing cardiac surgery.

Systemic vascular cell adhesion molecule-1 predicts the occurrence of post-operative atrial fibrillation

BACKGROUND

Post-operative atrial fibrillation occurs in 30% of patients after on-pump heart surgery and is associated to elevated inflammatory markers. We have evaluated if the systemic biomarkers of inflammation and endothelial damage, vascular cell adhesion molecule-1 (VCAM-1) and soluble thrombomodulin may help in identifying patients prone to development of post-operative atrial fibrillation.

METHODS

One hundred and forty-four patients in sinus rhythm submitted to elective coronary artery bypass surgery. Systemic inflammatory, oxidative stress and endothelial damage markers were measured at baseline and 72 h after surgery. During the procedure, a sample of the right atrial appendage was obtained for histochemistry. Electrocardiogram was monitored for 72 h after surgery for event adjudication.

RESULTS

22% of the patients developed post-operative atrial fibrillation. Baseline systemic inflammatory markers did not differ between patients with or without post-operative atrial fibrillation. However, baseline plasma VCAM-1 and thrombomodulin levels were significantly higher in patients who developed post-operative atrial fibrillation. After adjustment for age, gender, comorbidities and concurrent medication, circulating VCAM-1 remained as an independent predictor for post-operative atrial fibrillation development. No association was observed between systemic plasma VCAM-1 and VCAM-1 tissue expression in the right atrial appendage.

CONCLUSIONS

In patients undergoing coronary artery bypass surgery, elevated VCAM-1 levels predict a higher risk for post-operative atrial fibrillation. Plasma VCAM-1 elevation is not related to its expression in the right atria, suggesting that systemic endothelial damage rather than local changes pre-exist in patients who develop the arrhythmia.

New-onset atrial fibrillation predicts long-term mortality after coronary artery bypass graft

OBJECTIVES

We sought to investigate the association between new-onset atrial fibrillation after coronary artery bypass graft (CABG) (post-operative atrial fibrillation [POAF]) and long-term mortality in patients with no history of atrial fibrillation.

BACKGROUND

POAF predicts longer hospital stay and greater post-operative mortality.

METHODS

A total of 16,169 consecutive patients with no history of AF who underwent isolated CABG at our institution between January 1, 1996, and December 31, 2007, were included in the study. All-cause mortality data were obtained from Social Security Administration death records. A multivariable Cox proportional hazards regression model was constructed to determine the independent impact of new-onset POAF on long-term survival after adjusting for several covariates. The covariates included age, sex, race, pre-operative risk factors (ejection fraction, New York Heart Association functional class, history of myocardial infarction, index myocardial infarction, stroke, chronic obstructive pulmonary disease, peripheral arterial disease, smoking, diabetes, renal failure, hypertension, dyslipidemia, creatinine level, dialysis, redo surgery, elective versus emergent CABG, any valvular disorder) and post-operative adverse events (stroke, myocardial infarction, acute respiratory distress syndrome, and renal failure), and discharge cardiac medications known to affect survival in patients with coronary disease.

RESULTS

New-onset AF occurred in 2,985 (18.5%) patients undergoing CABG. POAF independently predicted long-term mortality (hazard ratio: 1.21; 95% confidence interval: 1.12 to 1.32) during a mean follow-up of 6 years (range 0 to 12.5 years). This association remained true after excluding from the analysis those patients who died in-hospital after surgery (hazard ratio: 1.21; 95% confidence interval: 1.11 to 1.32). Patients with POAF discharged on warfarin experienced reduced mortality during follow-up.

CONCLUSIONS

In this large cohort of patients, POAF predicted long-term mortality. Warfarin anticoagulation may improve survival in POAF.

Leukocyte-Aprotinin Atrial Fibrillation Study (LAFFS): Impact of Aprotinin and Leukofiltration on Atrial Fibrillation, Renal Insufficiency and Encephalopathy Post-Cardiopulmonary Bypass

Purpose: Atrial fibrillation remains the leading postoperative complication following cardiopulmonary bypass. A randomized trial was undertaken to evaluate the effectiveness of leukocyte filtration and aprotinin, applied separately and in combination, on the incidence of post-operative atrial fibrillation. A secondary component of the study was the impact of these adjunct interventions on post-surgical renal and neurological dysfunction. Methods: A total of 1,220 patients undergoing primary isolated coronary artery bypass grafting were randomly assigned to one of four treatment groups. The control group (305 patients) received standard cardiopulmonary bypass with moderately hypothermic (34ºC) cardioplegic arrest. In the filtration group (310 patients) leukocyte reducing filters were incorporated into the bypass circuit and deployed strategically. The aprotinin group (285 patients) received full Hammersmith dose aprotinin. The combination therapy group (320 patients) received both aprotinin and leukocyte filtration. Results: The incidences of atrial fibrillation were 25% in the control group, 16% in the filtration group, 19% in the aprotinin group and 10% in the combination therapy group (P < 0.001). Renal dysfunction was detected in 3% of the control group, 2% of the filtration group, 8% of the aprotinin group, and 5% of the combination group (P < 0.005). Neurological dysfunction occurred in 2% of the control group, 2% of the filtration group, 1% of the aprotinin group, and 2% of the combination group (P = n.s.). Conclusions: Combination therapy with aprotinin and leukocyte filtration markedly reduced atrial fibrillation post-cardiopulmonary bypass, and was more effective than the individual treatments. Aprotinin treatment increased the incidence of renal dysfunction, and the addition of leukocyte filtration partially mitigated this detrimental effect of aprotinin. Thus, strategic leukocyte filtration augments aprotinin's anti-arrhythmic effects while suppressing its nephrotoxic sequelae.