New-Onset Atrial Fibrillation After Cardiac Surgery: Pathophysiology, Prophylaxis, and Treatment

Development and validation a nomogram for predicting new-onset postoperative atrial fibrillation following pulmonary resection

BACKGROUND

The new-onset postoperative atrial fibrillation (NOPAF) following pulmonary resection is a common clinical concern. The aim of this study was to construct a nomogram to intuitively predict the risk of NOPAF and offered protective treatments.

METHODS

Patients who underwent pulmonary resection between January 2018 and December 2020 were consecutively enrolled. Forward stepwise multivariable logistic regression analyses were used to screen independent predictors, and a derived nomogram model was built. The model performance was evaluated in terms of calibration, discrimination and clinical utility and validated with bootstrap resampling.

RESULTS

A total of 3583 patients who met the research criteria were recruited for this study. The incidence of NOPAF was 1.507% (54/3583). A nomogram, composed of five independent predictors, namely age, admission heart rate, extent of resection, laterality, percent maximum ventilation volume per minute (%MVV), was constructed. The concordance index (C-index) was 0.811. The nomogram showed substantial discriminative ability, with an area under the receiver operating characteristic curve of 0.811 (95% CI 0.758-0.864). Moreover, the model shows prominent calibration performance and higher net clinical benefits.

CONCLUSION

We developed a novel nomogram that can predict the risk of NOPAF following pulmonary resection, which may assist clinicians predict the individual probability of NOPAF and perform available prophylaxis. By using bootstrap resampling for validation, the optimal discrimination and calibration were demonstrated, indicating that the nomogram may have clinical practicality.

Investigate the relationship between obstructive sleep apnea and cardiac arrhythmia after CABG surgery

BACKGROUND AND OBJECTIVE

Heart rhythm disorder is one of the most common problems after coronary artery bypass graft surgery. Various factors, such as the history of sleep apnoea before the operation, may aggravate the occurrence of this disorder. The present study was conducted to determine the relationship between sleep apnoea before surgery and heart rhythm disorder after surgery in patients undergoing coronary Artery Bypass Grafting in 2019.

METHODS

This analytical cross-sectional study was conducted on 192 patients who were selected by sequential sampling. The research tool included demographic information, a checklist of heart rhythm disorders, and the Berlin sleep apnoea questionnaire. Descriptive statistics and the Chi-square test, Fisher's exact test, Mann-Whitney's U-test, and logistic regression were used to analyze the data.

RESULTS

A total of 71.35% of the samples were male, and the mean age of the participants was 57.8 ± 7.5 years. Also, 46.0% of the samples had sleep pane and 21.35% had rhythm disorder. The most frequent heart rhythm disorder in patients with obstructive sleep apnoea was atrial fibrillation. There was a significant relationship between the occurrence of rhythm disorder and a history of smoking (P = 0.021), and the regression model showed that a history of smoking is the only variable related to the occurrence of rhythm disorder after coronary Artery Bypass Grafting (P = 0.005, CI 95%: 6.566-1.386, OR = 3.017).

CONCLUSIONS

The results showed that there is no statistically significant relationship between sleep apnea and rhythm disorder after coronary artery bypass surgery.

Atrial Fibrillation after Descending Aorta Repair: Occurrence, Risk Factors, and Impact on Outcomes

BACKGROUND

 As risks of repairing the descending thoracic and thoracoabdominal aorta diminish, common complications that may prolong hospital stay, or actually increase risk, require attention. One such complication is postoperative atrial fibrillation (AF). Therefore, we characterized prevalence of, risk factors for, and effects of postoperative atrial fibrillation (PoAF) after descending and thoracoabdominal aorta repair.

METHODS

 From January 2000 to January 2011, 696 patients underwent open descending or thoracoabdominal aorta repair at Cleveland Clinic. Operations approached via median sternotomy (n = 178) and patients treated preoperatively for arrhythmias (32 amiodarone, 9 paced) or in AF on preoperative electrocardiogram (n = 14) were excluded, leaving 463. Logistic regression analysis identified risk factors for PoAF. Temporal relation of PoAF with postoperative morbidities was determined, and outcomes following PoAF were compared between propensity-matched pairs.

RESULTS

 New-onset PoAF occurred in 101 patients (22%) at a median 68 hours of postincision. Risk factors included older age (p = 0.002) and history of remote AF (p = 0.0004) but not operative details, such as pericardiotomy for cardiac cannulation. Hypoperfusion and neurologic complications tended to precede PoAF, whereas sepsis, respiratory failure, and dialysis followed. Among 94 propensity-matched patient pairs, those developing PoAF were more likely to experience hypoperfusion (p = 0.006), respiratory failure (p = 0.009), dialysis (p = 0.04), paralysis (p < 0.0001), longer intensive care unit stay (median 7 vs. 5 d, p = 0.02), and longer postoperative hospital stay (median 15 vs. 13 d, p = 0.004). However, hospital death was similar (6/94 PoAF [6.4%] vs. 7/94 no PoAF [7.4%], p = 0.8).

CONCLUSION

 PoAF after descending thoracic aorta surgery is relatively common and a part of a constellation of other serious complications prolonging postoperative recovery. While PoAF was associated with adverse events, it did not impact postoperative cost and mortality. Descending thoracic aorta surgery is by itself comorbid enough, which is likely why PoAF does not have a more significant effect on postoperative recovery and cost.

Prediction of postoperative atrial fibrillation with the systemic immune-inflammation index in patients undergoing cardiac surgery using cardiopulmonary bypass: a retrospective, single-center study

The systemic immune-inflammation index (SII, platelet count × neutrophil-lymphocyte ratio) is a novel parameter for systemic inflammation. Cardiopulmonary bypass (CPB) is associated with systemic inflammatory responses. This retrospective study aimed to determine whether SII could predict postoperative atrial fibrillation (POAF) after cardiac surgery using CPB. Patients who underwent cardiac surgery using CPB between January 2020 and July 2021 were included. The primary outcome was POAF incidence within 7 days. Receiver-operating characteristic (ROC) curve analysis was used to evaluate SII ability in predicting POAF. Multivariable analysis was used to estimate the independent association between SII and POAF development. The study included 212 patients, and 90 (43%) developed POAF. The preoperative SII cutoff of 545 × 109/L predicted a poor outcome with 71% sensitivity and 81% specificity. The area under the ROC curve was 0.80 (95% confidence interval [CI] 0.73-0.86). Multivariable analysis showed that SII ≥ 545 × 109/L was associated with the development of POAF (odds ratio 10.2; 95% CI 5.1-20.2, P < 0.001). SII predicted POAF with a curve of 0.91 (95% CI 0.82-1.00) in patients with coronary artery bypass grafting (CABG); the corresponding value in patients without CABG was 0.75 (95% CI 0.67-0.83). Preoperative SII may be a useful prognostic biomarker for POAF in patients undergoing cardiac surgery using CPB. Moreover, preoperative SII may play an important role in predicting POAF in patients undergoing CABG.

Left Volume Atrial Index and P-wave Dispersion as Predictors of Postoperative Atrial Fibrillation After Coronary Artery Bypass Graft: A Retrospective Cohort Study

Preoperative left atrial remodeling as Postoperative atrial fibrillation (POAF) predisposing factors could be measured by left atrial volume index (LAVI) and P-wave dispersion. This study aimed to assess P-wave dispersion and LAVI as preoperative predictors of POAF among patients who underwent Coronary Artery Bypass Graft (CABG). An analytical retrospective cohort study was performed on patients who underwent CABG. The P-wave dispersion and POAF were evaluated based on documented ECG results. LAVI size was collected from echocardiographic reports. Hazard ratios of P-wave dispersion and LAVI for POAF were analyzed using Cox proportional hazard model. A total of 42 subjects (57 ± 1 years) were included in this study. POAF occurred in 28.6% of patients at a median of 2 days after CABG. P-wave dispersion was significantly longer in patients in whom AF was developed (53.03 ± 3.82 ms vs 44.01 ± 1.98ms, p:0.028), while LAVI difference was not significant. The Cox proportional hazard model showed a significant association between P-wave dispersion and risk of POAF (HR 1.05, CI95%, 1.001-1.103; P = 0.048). There was no association between LAVI and risk of POAF (HR 1.003, CI 95%, 0.965-1.044; P = 0.864). P-wave dispersion is a predictor of POAF in patients who underwent CABG. Risk stratification using P-wave dispersion enables clinicians to identify high-risk patients before CABG surgery.

Complications and Their Association with Mortality Following Emergency Gastrointestinal Surgery-an Observational Study

PURPOSE

Emergency gastrointestinal surgery is followed by a high risk of major complications and death. This study aimed to investigate which complications showed the strongest association with death following emergency surgery for gastrointestinal obstruction or perforation.

METHODS

We retrospectively included adults who had undergone emergency gastrointestinal surgery for radiologically verified obstruction or perforation at three Danish hospitals between 2014 and 2015. The exposure variables comprised 16 predefined Clavien-Dindo-graded complications. Cox regression with delayed entry was used to analyze the association of these complications with 90-day mortality. We adjusted for hospital, age, American Society of Anesthesiologists classification, pre-operative Sepsis-2 score, cardiac comorbidity, renal comorbidity, hypertension, active cancer, bowel obstruction or perforation, and the surgical procedure. Subgroup analyses were done for patients with gastrointestinal obstruction or perforation.

RESULTS

Of the 349 included patients, 281 (80.5%) experienced at least one complication. The risk of death was 20.6% (14) for patients with no complications and varied between 21 and 57% for patients with complications. Renal impairment (hazard ratio (HR): 6.8 (95%CI: 3.7-12.4)), arterial thromboembolic events (HR 4.8 (2.3-9.9)), and atrial fibrillation (HR 4.4 (2.8-6.8)) showed the strongest association with 90-day mortality. Atrial fibrillation was the only complication significantly associated with death in patients with gastrointestinal obstruction as well as perforation.

CONCLUSION

This study of patients undergoing emergency gastrointestinal surgery revealed that renal impairment, arterial thromboembolic events, and atrial fibrillation had the strongest association with death. Atrial fibrillation may serve as an in-situ marker of patients needing escalation of care.

Nomogram predicts atrial fibrillation after coronary artery bypass grafting

Objective

Using the nomogram to intuitively predict atrial fibrillation after coronary artery bypass grafting. Identify high-risk patients with atrial fibrillation and provide preoperative protective therapy.

Methods

A total of 397 patients that underwent coronary artery bypass grafting were consecutively enrolled. Independent predictors of patients were analyzed by multivariate logistic regression. Two nomograms were constructed to predict postoperative atrial fibrillation.

Results

The incidence of postoperative atrial fibrillation in this study was 29% (115/397). Multivariate Logistic showed that Age, Operative Time > 4 h, Left Atrial Diameter > 40 mm, Mean Arterial Pressure, Body Mass Index > 23 kg/m², Insulins, and Statins were independently associated with atrial fibrillation after isolated coronary artery bypass grafting. The nomogram of postoperative atrial fibrillation in patients was constructed using total predictor variables (AUC = 0.727, 95% CI 0.673–0.781). The model was internally validated (AUC = 0.701) by K-fold Cross-validation resampling (K = 5, Times = 400). To make an early intervention, the intraoperative information of the patients was excluded. Only 6 variables before surgery were used to establish the brief nomogram to predict postoperative atrial fibrillation (AUC = 0.707, 95% CI 0.651–0.764). The brief model was internally validated (AUC = 0.683) by resampling with K-fold Cross-validation resampling.

Conclusions

These two nomograms could be used to predict patients at high risk for atrial fibrillation after isolated coronary artery bypass grafting.

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.

Atrial fibrillation following coronary artery bypass graft: Where do we stand?

Atrial fibrillation (AF) is the most common atrial arrhythmia following coronary artery bypass graft (CABG). Its prevalence is 15-45% and is associated with poor long-term prognosis. Risk factors can be patient-related, intraoperative, and/or postoperative. Therapeutic and preventive strategies have been developed to curtail AF burden. Cardioversion is recommended for unstable or symptomatic patients and rate control if asymptomatic. Anticoagulation is challenging with risk of thromboembolism and bleeding. However, patients should be anticoagulated after cardioversion or if AF persists >48 h and risk factors of stroke exist. A minimum of 4 weeks is recommended but longer duration should be considered in patients at high risk of stroke irrespective of recurrence of AF.

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.

Colchicine Use and Risks of Stroke Recurrence in Acute Non-Cardiogenic Ischemic Stroke Patients: A Population-Based Cohort Study

Background: The objective is to study whether the cardiovascular protective effects of colchicines could be applied to non-cardiogenic ischemic stroke (IS) patients. Patients and Methods: Non-cardiogenic IS patients were identified from the National Health Insurance Research Database. Eligible patients were divided into chronic and non-chronic use categories based on their long-term status of colchicine use. The non-chronic use category was subdivided into (1) non-user and (2) new user groups while the chronic use category was divided into (3) former user and (4) long-term user groups according to the patient's recent status of colchicine use. Inverse probability of treatment weights for propensity scores was used to balance the baseline characteristics. The primary outcome was recurrent IS, which was compared within the non-chronic use and chronic use categories. Results: In the non-chronic use category, the number of patients was 355,498 and 912 in the non-user and new user groups, respectively. In the chronic use category, the number of patients was 4737 and 4354 in the former user and long-term user groups, respectively. In the non-chronic use category, patients in the new user group had a marginally lower risk of recurrent IS at 6-months (subdistribution hazard ratio [SHR], 0.95; 95% confidence interval [CI], 0.94-0.97) and 2-years (SHR, 0.92; 95% CI, 0.91-0.93) follow up. In the chronic use category, patients in the long-term user group also had a marginally lower risk of recurrent IS at 6-months (SHR, 0.87; 95% CI, 0.86-0.88) and 2-years (SHR, 0.87; 95% CI, 0.86-0.88) follow up. The effect of colchicine on the reduced risk of recurrent IS was more favorable in patients who also used statins. Conclusions: Recent colchicine use in acute non-cardiogenic IS patients is associated with marginal fewer incidences of recurrent IS. Patients with concurrent statin use may have more profound protective effects.

Early pharmacologic conversion of atrial fibrillation after off-pump coronary artery bypass grafting

Background

The aim of this study was to evaluate the efficacy of early amiodarone-based pharmacological cardioversion for postoperative atrial fibrillation (POAF) following off-pump coronary bypass grafting (OPCAB).

Methods

A total of 507 patients who underwent OPCAB between 2015 and 2017 were categorized into POAF (n=94) and no-POAF (n=413) groups. Patients in the POAF group were treated according to the following institutional protocol: 150 mg loading dose of intravenous amiodarone, followed by oral administration with sequential maintenance doses at 600, 400, and 200 mg per day. If sinus rhythm was restored before discharge, patients were discharged without amiodarone or anticoagulants, except for dual antiplatelets.

Results

Before discharge at index hospitalization, 97.8% of POAF patients had restored sinus rhythm. Independent risk factors for POAF were age, unstable angina, prior percutaneous transluminal coronary angioplasty, and left atrial diameter. The mean follow-up duration was 41.1±12.8 months. Freedom from overall mortality and composite events, including mortality, major bleeding requiring admission and cerebrovascular events, were similar between the 2 groups. Results were consistent after propensity-score matching.

Conclusions

Amiodarone-based rapid pharmacological cardioversion of POAF resulted in a high sinus rhythm conversion rate (97.9%). Rate of late adverse cardiovascular events including stroke, were low even without anticoagulation. As optimal treatment and anticoagulation guidelines for POAF after OPCAB have not yet been established, amiodarone-based treatment protocols may be considered as a useful option.

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

Remote Heart Rhythm Monitoring by Photoplethysmography-Based Smartphone Technology After Cardiac Surgery: Prospective Observational Study

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery, yet the precise incidence and significance of arrhythmias after discharge home need to be better defined. Photoplethysmography (PPG)-based smartphone apps are promising tools to enable early detection and follow-up of arrhythmias.

OBJECTIVE

By using a PPG-based smartphone app, we aimed to gain more insight into the prevalence of AF and other rhythm-related complications upon discharge home after cardiac surgery and evaluate the implementation of this app into routine clinical care.

METHODS

In this prospective, single-center trial, patients recovering from cardiac surgery were asked to register their heart rhythm 3 times daily using a Food and Drug Administration-approved PPG-based app, for either 30 or 60 days after discharge home. Patients with permanent AF or a permanent pacemaker were excluded.

RESULTS

We included 24 patients (mean age 60.2 years, SD 12 years; 15/23, 65% male) who underwent coronary artery bypass grafting and/or valve surgery. During hospitalization, 39% (9/23) experienced postoperative AF. After discharge, the PPG app reported AF or atrial flutter in 5 patients. While the app notified flutter in 1 patient, this was a false positive, as electrocardiogram revealed a 2nd-degree, 2:1 atrioventricular block necessitating a permanent pacemaker. AF was confirmed in 4 patients (4/23, 17%) and interestingly, was associated with an underlying postoperative complication in 2 participants (pneumonia n=1, pericardial tamponade n=1). A significant increase in the proportion of measurements indicating sinus rhythm was observed when comparing the first to the second month of follow-up (P<.001). In the second month of follow-up, compliance was significantly lower with 2.2 (SD 0.7) measurements per day versus 3.0 (SD 0.8) measurements per day in the first month (P=.002). The majority of participants (17/23, 74%), as well as the surveyed primary care physicians, experienced positive value by using the app as they felt more involved in the postoperative rehabilitation.

CONCLUSIONS

Implementation of smartphone-based PPG technology enables detection of AF and other rhythm-related complications after cardiac surgery. An association between AF detection and an underlying complication was found in 2 patients. Therefore, smartphone-based PPG technology may supplement rehabilitation after cardiac surgery by acting as a sentinel for underlying complications, rhythm-related or otherwise.

Anticoagulation management of postoperative atrial fibrillation after cardiac surgery: A systematic review

BACKGROUND

Postoperative atrial fibrillation (POAF) often complicates cardiac surgery and is associated with increased mortality and risk of thromboembolism. However, the optimal oral anticoagulation (OAC) strategy is uncertain. We performed a systematic review to examine the OAC practice patterns and efficacy in these circumstances.

METHODS

MEDLINE and EMBASE were searched from 2000 to 2019 using the search terms cardiac surgical procedures, cardiac surgery, postoperative complications, atrial fibrillation, atrial flutter, and terms for anticoagulants. Collected data included anticoagulation patterns (time of initiation, type, and duration) and outcomes (stroke, bleeding, and mortality).

RESULTS

From 763 records, 4 prospective and 13 retrospective studies were included totaling 44,908 patients with 8929 (19.9%) who developed POAF. Anticoagulation rates ranged from 4% to 43% (mean 21% overall). Sixteen studies used warfarin, 3 nonvitamin K OAC (NOAC), and 2 both. Four studies reported the use of bridging unfractionated or low-molecular-weight heparin. Concomitant antiplatelet therapy was reported in half the studies, ranging from 80% to 99%. OAC use was associated with lower risk of thromboembolic events in two retrospective studies (including a national Danish cohort with 2108 patients with POAF). Patients discharged on warfarin experienced reduced mortality in a large, single center, retrospective analysis, but no association was observed in the Danish cohort.

CONCLUSION

There is wide practice variation in the uptake, timing of initiation, duration, and choice of OAC for POAF following cardiac surgery. The evidence is largely retrospective and insufficient to assess the efficacy of different OAC strategies. Further studies are warranted to guide clinical practice.

Volatile and Intravenous Anesthetics for Brain Protection in Cardiac Surgery: Does the Choice of Anesthesia Matter?

Postoperative neurologic complications have a significant effect on morbidity, mortality, and long-term disability in patients undergoing cardiac surgery. The etiology of brain injury in patients undergoing cardiac surgery is multifactorial and remains unclear. There are several perioperative causative factors for neurologic complications, including microembolization, hypoperfusion, and systemic inflammatory response syndrome. Despite technologic advances and the development of new anesthetic drugs, there remains a high rate of postoperative neurologic complications. Moreover, despite the strong evidence that volatile anesthesia exerts cardioprotective effects in patients undergoing cardiac surgery, the neuroprotective effects of volatile agents remain unclear. Several studies have reported an association of using volatile anesthetics with improvement of biochemical markers of brain injury and postoperative neurocognitive function. However, there is a need for additional studies to define the optimal anesthetic drug for protecting the brain in patients undergoing cardiac surgery.

Mechanisms, Prevention, and Treatment of Atrial Fibrillation After Cardiac Surgery: A Narrative Review

New onset of postoperative atrial fibrillation (AF) generally is recognized as a frequent and debilitating complication after cardiac surgery, contributing to a considerable health- care cost. Extensive research has been conducted to study the underlying mechanisms and risk factors of AF in the perioperative period. Many options have been suggested to lower the incidence, and the concurrent cost in health resources. This review attempts to synthesize the large body of existing literature on AF, as well as expand and illustrate the available knowledge on its management strategies. The latter incorporates recent developments in the anesthesthetic approach as well as in the pharmacologic arsenal. In addition, the current review provides a tool for understanding the pathophysiology of AF and for reducing the occurrence after cardiac surgery. By using it, clinicians can manage patients with AF in the perioperative period of cardiac surgery and minimize the relatively high economic cost that accompanies it.

Rationale and Design of the Randomized Controlled Trial of New Oral Anticoagulants vs. Warfarin for post Cardiac Surgery Atrial Fibrillation: The NEW-AF Trial

: New onset atrial fibrillation commonly occurs following cardiac surgery and is associated with increased rates of stroke and mortality. In non-surgical patients with atrial fibrillation, novel oral anticoagulants (NOACs) have been shown to confer equivalent benefits for stroke prevention with less bleeding risk and less tedious monitoring requirements compared with Warfarin. However, NOACs have yet to be adopted widely in cardiac surgery patients. The NEW-AF study has been designed as a pragmatic, prospective, randomized controlled trial that will compare financial, convenience and safety outcomes for patients with new onset atrial fibrillation after cardiac surgery who are treated with NOACs versus Warfarin. Study results may contribute to optimizing the options for stroke prophylaxis in cardiac surgery patients and catalyze more widespread application of NOAC therapy in this patient population. The trial is registered with clinicaltrials.gov under registration number NCT03702582Rationale and Design of the Randomized Controlled Trial of New Oral Anticoagulants vs. Warfarin for post Cardiac Surgery Atrial Fibrillation: The NEW-AF Trial.

Botulinum Toxin-Chitosan Nanoparticles Prevent Arrhythmia in Experimental Rat Models

Several experimental studies have recently demonstrated that temporary autonomic block using botulinum toxin (BoNT/A1) might be a novel option for the treatment of atrial fibrillation. However, the assessment of antiarrhythmic properties of BoNT has so far been limited, relying exclusively on vagal stimulation and rapid atrial pacing models. The present study examined the antiarrhythmic effect of specially formulated BoNT/A1-chitosan nanoparticles (BTN) in calcium chloride-, barium chloride- and electrically induced arrhythmia rat models. BTN enhanced the effect of BoNT/A1. Subepicardial injection of BTN resulted in a significant antiarrhythmic effect in investigated rat models. BTN formulation antagonizes arrhythmia induced by the activation of Ca, K and Na channels.

Sex-related difference in outcomes after aortic root replacement

PURPOSE

Poorer short-term outcomes have been described for females after cardiovascular surgery. We examined the influence of sex on the outcomes after aortic root replacement (ARR).

METHODS

Medical records of 848 patients (females, n = 159/848, 19%) who underwent ARR at our center from 2005 to 2018 were retrospectively reviewed. Sex differences of the following outcomes were analyzed: the primary end point (in-hospital mortality or stro111ke), secondary end point (new requirement for permanent pacemaker), and long-term survival (median follow-up 21.4 months [interquartile range,1.3-60.0]).

RESULTS

Females were significantly older (61.3 vs 58.7 [male]) with higher rates of pre-existing cerebrovascular disease (14% [22/159] vs 7% [52/689]) and previous valve intervention (20% [32/159] vs 13% [89/689]) but less myocardial infarction [1%(1/159) vs 7%(48/689)]. The surgical indication was different (aneurysm 75% [120/159] vs 87% [602/689], dissection 13% [21/159] vs 6% [41/689]; P < .01]). Females had larger average aneurysm size after controlling for body size (P ≤ .001). There was no sex difference in in-hospital mortality (3% [5/159] vs 2% [16/689]) or stroke (4% [7/159] vs 4% [29/689]). Multivariable logistic regression indicated that female sex was not an independent predictor of combined in-hospital stroke or death (odds ratio [OR], 0.59; 95% confidence interval [CI], 0.28-1.25), confirmed by propensity score analysis. There was no difference in long-term survival (5-year survival, 90.96% vs 93.03%; P = .44). Females had higher incidence of permanent pacemaker requirement [11% (18/159) vs 6% (39/689), P = .03] and female sex was an independent predictor of permanent pacemaker requirement (OR, 2.01; 95% CI, 1.085-3.724; P = .03).

CONCLUSIONS

While female patients have different baseline characteristics and indication for ARR, they are not exposed to an increased risk of in-hospital mortality or stroke. However, females experience increased incidence of permanent pacemaker requirement.

The use of neutrophil lymphocyte ratio to predict complications post cardiac surgery

Background

Cardiac surgery remains the gold standard treatment for select cohorts of patients with coronary artery and valvular heart diseases. It induces an acute systemic inflammatory response due to cardiopulmonary bypass (CPB), myocardial arrest, and surgical trauma. There is growing evidence that increased inflammation leads to greater complications and poorer outcomes for patients post cardiac surgery. Neutrophil/lymphocyte ratio (NLR) is a promising marker of inflammation. This study assessed if NLR could predict postoperative atrial fibrillation and acute kidney injury after cardiac surgery.

Methods

A retrospective review of patients undergoing first-time on-pump cardiac surgery was performed. Postoperative atrial fibrillation and acute kidney injury within 7 days of surgery was recorded. Preoperative, day 1, and day 2 NLR were recorded. Potential confounders such as age, sex, comorbidities, and operative factors were included in univariate analysis. Backwards stepwise multivariate regression analysis was performed to identify independent predictors of these complications.

Results

Nine hundred and six patients were included for analysis. Higher preoperative NLR was significantly associated with postoperative atrial fibrillation. Day 1 and day 2 NLR were associated with postoperative atrial fibrillation in analyses including all patients. Older age, male gender, preexisting atrial arrhythmias, and higher EuroSCORE II also had a significant association. Diabetes mellitus was protective for postoperative arrhythmias. Preoperative NLR was not significantly associated with acute kidney injury. Day 2 NLR, older age, higher EuroSCORE II, and longer CPB time were independently associated with acute kidney injury post cardiac surgery.

Conclusions

Higher preoperative and postoperative NLRs are associated with higher rates of complications post cardiac surgery.

New-Onset Atrial Fibrillation in Adult Patients After Cardiac Surgery

Purpose of Review

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

Recent Findings

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

Summary

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

Coronary artery bypass graft surgery complications: A review for emergency clinicians

INTRODUCTION

Coronary artery bypass graft (CABG) surgery remains a high-risk procedure, and many patients require emergency department (ED) management for complications after surgery.

OBJECTIVE

This narrative review provides an evidence-based summary of the current data for the emergency medicine evaluation and management of post-CABG surgery complications.

DISCUSSION

While there has been a recent decline in all cardiac revascularization procedures, there remains over 200,000 CABG surgeries performed in the United States annually, with up to 14% of these patients presenting to the ED within 30 days of discharge with post-operative complications. Risk factors for perioperative mortality and morbidity after CABG surgery can be divided into three categories: patient characteristics, clinician characteristics, and postoperative factors. Emergency physicians will be faced with several postoperative complications, including sternal wound infections, pneumonia, thromboembolic phenomena, graft failure, atrial fibrillation, pulmonary hypertension, pericardial effusion, strokes, renal injury, gastrointestinal insults, and hemodynamic instability. Critical patients should be evaluated in the resuscitation bay, and consultation with the primary surgical team is needed, which improves patient outcomes. This review provides several guiding principles for management of acute complications. Understanding these complications and an approach to the management of hemodynamic instability is essential to optimizing patient care.

CONCLUSIONS

Postoperative complications of CABG surgery can result in significant morbidity and mortality. Physicians must rapidly diagnose these conditions while evaluating for other diseases. Early surgical consultation is imperative, as is optimizing the patient's hemodynamics, including preload, heart rate, cardiac rhythm, contractility, and afterload.

Identification of new-onset atrial fibrillation after cardiac surgery in Vietnam. A feasibility study of a novel screening strategy in a limited-resource setting: study protocol

INTRODUCTION

Atrial fibrillation (AF) developing after cardiac surgery is the most common postoperative complication with an incidence up to 50%. The presence of postoperative AF is associated with significant morbidity, mortality and economic burden. However, in Vietnam, data on AF postcardiac surgery are limited, in part due to a shortage of screening equipment. This project aims to identify the incidence, risk factors and postoperative complications of new-onset postoperative AF after cardiac surgery, and the feasibility of introducing a novel screening strategy using the combination of two portable devices to detect AF.

METHODS AND ANALYSIS

This is a feasibility study examining patients who are (1) ≥18 years old; (2) undergoing coronary artery bypass graft and/or valve surgery and (3) in normal sinus rhythm prior to their operation. Patients with congenital heart disease, a prior history of AF or those who require a pacemaker after surgery will be excluded. All patients will be followed up for the duration of their hospitalisation. The screening strategy will include monitoring the continuous ECG tracing in the intensive care unit, and if AF is suspected, a 30 s lead-1 ECG will be recorded using the smartphone-based AliveCor Kardia Mobile. On the postoperative wards, blood pressure will be measured three times daily using a modified blood pressure device (Microlife BP200 Afib): and if AF is suspected a 30 s ECG will be recorded using the AliveCor Kardia Mobile. A 12-lead ECG may be ordered subsequently if clinically indicated. The primary outcome is the incidence of postoperative AF. Secondary outcomes include establishing the risk factors and complications associated with postoperative AF; and the barriers and facilitators of the screening strategy.

ETHICS AND DISSEMINATION

Ethics approval was granted by Scientific Board of Cardiovascular Centre, E Hospital on 28 September, 2017. Study results will be disseminated through local and international conferences and peer-reviewed publications.

Postoperative atrial fibrillation prediction following isolated surgical aortic valve replacement

Objective

Postoperative atrial fibrillation (POAF) is the most common complication following cardiac surgery, with increased risk of stroke and high mortality. Our aim was to identify patients at risk and to design a model that could predict POAF.

Methods

In this single center study, we evaluated 1191 patients requiring isolated surgical aortic valve replacement between January 2000 and June 2014. The patients were followed during the early postoperative period until discharge.

Results

AF occurred in 342 patients (28.71%). Six variables associated with high arrhythmic risk [advanced age, body mass index, tricuspid regurgitation, prolonged ventilation, longer intensive care unit stay, and dilated left atrium (LA; volume ≥35 ml/m²)] were selected to create a multivariate prediction model. This model predicted POAF in 64.7% of cases, with a moderate discriminative power (AUC=0.65; p=0.001; 95% CI, 0.571-0.771). We also developed the CHAID (Chi-square automatic interaction detection) model showing multilevel interactions among risk factors for POAF. Age had the greatest discriminative power, with patients aged >68 years at a higher risk for POAF. In low-risk patients, the subgroup with dilated LA (volume ≥40 ml) was more prone to develop POAF. For the intermediate-risk group, history of AF was the next deciding variable, whereas for the high-risk group, it was tricuspid regurgitation (at least moderate).

Conclusion

The multivariate logistic model has an acceptable predictive value. CHAID-derived model is a new tool that could be easily applied to identify patients requiring prophylactic regimens.

Preoperative P-wave duration as a predictor of atrial fibrillation after coronary artery bypass grafting: A prospective cohort study with meta-analysis

Objectives

Methods

Results

Conclusion

Can dexmedetomidine reduce atrial fibrillation after cardiac surgery? A systematic review and meta-analysis

Purpose

Cardiac surgery patients always present with atrial fibrillation (AF) after admission to the intensive care unit, leading to high mortality and lengthy hospitalization. Dexmedetomidine (DEX) is a popular medication used for sedation in the intensive care unit; however, whether it can reduce AF needs to be analyzed.

Materials and methods

Three primary databases, Medline, Embase (Ovid SP) and the Cochrane Central Register of Controlled Trials (CENTRAL), were searched. All English language and randomized control designed clinical publications comparing DEX to control medicines for sedation after elective cardiac surgery were included. Two independent colleagues conducted the data extraction and quality assessments. The subgroup analysis was performed according to the medicine used, age, AF history, and whether previous beta-blocker premedication and cardiopulmonary bypass (CPB) were applied. The overall incidence of AF was analyzed.

Results

A total of 1,295 patients in nine studies met the selection criteria among 2,587 studies screened from the database. After quantitative synthesis, our results revealed that the DEX group was not associated with a decreased incidence of AF compared with the placebo (risk ratio [RR] 0.76, 95% CI 0.37, 1.55, P=0.44) and morphine groups (RR 0.86, 95% CI 0.56, 1.31, P=0.48). Subgroup analysis also indicated that the DEX vs propofol comparison exhibited no difference: 1) for patients of age >60 years (P=0.69) or ≤60 years (P=0.69); 2) under CPB surgery (P=0.45) or without CPB surgery (P=0.88); 3) with beta-blocker premedication (P=0.32) or without beta-blocker premedication (P=0.90); and 4) with AF history (RR 1.07, 95% CI 0.85, 1.36, P=0.57) or without AF history (P=0.30).

Conclusion

This meta-analysis revealed that DEX could not reduce the incidence of AF compared to control medicines following cardiac surgery. DEX may have an increased influence on AF occurrence if patients had a history of AF. However, cautious interpretation should be made due to high clinical heterogeneity.

Does dexmedetomidine have an antiarrhythmic effect on cardiac patients? A meta-analysis of randomized controlled trials

Background

Cardiac surgery patients often experience several types of tachyarrhythmias after admission to the intensive care unit (ICU), which increases mortality and morbidity. Dexmedetomidine (DEX) is a popular medicine used for sedation in the ICU, and its other pharmacological characteristics are gradually being uncovered.

Purpose

To determine whether DEX has an antiarrhythmic effect after cardiac surgery.

Methods

The three primary databases MEDLINE, Embase (OVID SP) and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched, and all English-language and randomized control-designed clinical publications comparing DEX to control medicines for sedation after elective cardiac surgery were included. Two colleagues independently extracted the data and performed other quality assessments. A subgroup analysis was performed according to the different medicines used and whether cardiopulmonary bypass (CPB) was applied. All tachyarrhythmias that occurred in the atria and ventricles were analyzed.

Results

A total of 1295 patients in 9 studies met the selection criteria among 2587 studies that were screened. After quantitative synthesis, our results revealed that the DEX group was associated with a lower incidence of ventricular arrhythmia (VA, OR 0.24, 95% CI 0.09–0.64, I² = 0%, P = 0.005) than the control group. Subgroup analysis did not reveal a significant difference between the DEX and propofol subgroups (OR 0.13, 95% CI 0.03–0.56, I² = 0%, P = 0.007). Additionally, no difference in the incidence of atrial fibrillation (AF) was observed regardless of the different control medicines (OR 0.82, 95% CI 0.60–1.10, I² = 25%, P = 0.19) or whether CPB was applied.

Conclusions

This meta-analysis revealed that DEX has an antiarrhythmic effect that decreases the incidence of VA compared to other drugs used for sedation following cardiac surgery. DEX may not have an effect on AF, but cautious interpretation should be exercised due to high heterogeneity.

Relationship between perioperative left atrial appendage doppler velocity estimates and new-onset atrial fibrillation in patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass

BACKGROUND

Literature search reveals that postoperative atrial fibrillation (POAF) occurs in 15%-40% of coronary artery bypass graft (CABG) patients. Although several risk models exist for predicting the development of POAF, few have studied left atrial appendage (LAA) velocity. We hypothesize that an association between LAA velocity and development of POAF exists.

DESIGN AND METHODS

Single institution university hospital prospective observational clinical study performed between May 2016 and November 2016 in 96 adult patients undergoing CABG surgery utilizing cardiopulmonary bypass (CPB). Transesophageal echocardiography was performed perioperatively to measure LAA velocity and left atrial (LA) size after anesthetic induction, post-CPB and during the postoperative period before extubation. Student's t-test was used for inter-group comparisons. Data are expressed as mean ± (standard deviation). The value of P < 0.05 was considered statistically significant.

RESULTS

A total of 95 patients (69 males and 26 females) completed the study and were included in the final analysis. Of these, 21 (22%) (15 males and 5 females) developed POAF. The patient group which developed POAF was compared with the group that did not develop POAF. On comparing mean age of patients in each group (59 years in patients with no POAF and 63.71 years in patients with POAF, P = 0.04). LA volume indexed in POAF group (34.13 ml/m2) compared with that in group with no POAF (34.82 ml/m2) resulted in P = 0.04. Mean LAA velocities (pre-CPB, post-CPB, postoperative Intensive Care Unit) in group with no POAF were 41.06, 56.33, and 60.44 cm/s, respectively, whereas in the other group with POAF the values were 39.68, 55.04, and 58.09 cm/s, respectively. No statistical significance was noted (P > 0.05). Comparison of comorbidities also did not yield any significant results (P > 0.05).

CONCLUSIONS

Decreasing LAA velocity does not appear to independently predict the development of POAF in patients undergoing CABG surgery with the use of CPB. There is, however, a positive correlation of POAF with age and LA volume.

Comparison of Two Central Venous Pressure Control Strategies to Prevent Atrial Fibrillation After Coronary Artery Bypass Grafting

BACKGROUND:

Atrial fibrillation (AF) takes place in 10-40% of patients undergoing coronary artery bypass grafting (CABG), and increases cardiovascular mortality. Enlargement of atrial chambers is associated with increased AF incidence, so patients with higher central venous pressure (CVP) are expected to have larger atrial distension, which increases AF incidence.

OBJECTIVE:

To compare post-CABG AF incidence, following two CVP control strategies.

METHODS:

Interventional, randomized, controlled clinical study. The sample comprised 140 patients undergoing CABG between 2011 and 2015. They were randomized into two groups, G15 and G20, with CVP maintained ≤ 15 cmH2O and ≤ 20 cmH2O, respectively.

RESULTS:

70 patients were included in each group. The AF incidence in G15 was 8.57%, and in G20, 22.86%, with absolute risk reduction of 14.28%, and number needed to treat (NNT) of 7 (p = 0.03). Mortality (G15 = 5.71%; G20 = 11.42%; p = 0.07), hospital length of stay (G15 = 7.14 days; G20 = 8.21 days; p = 0.36), number of grafts (median: G15 = 3, G2 = 2; p = 0.22) and cardiopulmonary bypass use (G15 = 67.10%; G20 = 55.70%; p = 0.22) were statistically similar. Age (p = 0.04) and hospital length of stay (p = 0.001) were significantly higher in patients who developed AF in both groups.

CONCLUSION:

Keeping CVP low in the first 72 post-CABG hours reduces the relative risk of AF, and may be useful to prevent AF after CABG.

FUNDAMENTO:

A fibrilação atrial (FA) ocorre em 10-40% dos pacientes submetidos a cirurgia de revascularização miocárdica (RM), e eleva a mortalidade cardiovascular. Como o aumento dos átrios está associado ao aumento da incidência de FA, espera-se que pacientes com pressão venosa central (PVC) mais alta tenham maior distensão atrial, o que eleva a incidência dessa arritmia.

OBJETIVO:

Comparar a incidência de FA em pós-operatório de RM, seguindo duas estratégias de controle de PVC.

MÉTODOS:

Estudo clínico randomizado controlado intervencionista. A amostra foi composta por 140 pacientes submetidos a RM entre 2011 e 2015. Os pacientes foram randomizados em dois grupos, G15 e G20, mantidos com PVC máxima de 15 cmH2O e 20 cmH2O, respectivamente.

RESULTADOS:

Foram incluídos 70 pacientes em cada grupo. A incidência da arritmia em G15 foi de 8,57% e, no G20, de 22,86%, com redução de risco absoluto de 14,28% e número necessário para tratar (NNT) de 7 (p = 0,03). Mortalidade (G15 = 5,71%; G20 = 11,42%; p = 0,07), tempo de internamento (G15 = 7,14 dias; G20 = 8,21 dias; p = 0,36), número de enxertos (medianas: G15 = 3, G2 = 2; p = 0,22) e uso de circulação extracorpórea (G15 = 67,10%; G20 = 55,70%; p = 0,22) mostraram-se estatisticamente semelhantes. A idade (p = 0,04) e o tempo de internamento (p = 0,001) foram significativamente maiores nos pacientes que desenvolveram FA nos dois grupos.

CONCLUSÃO:

Manter a PVC com valores mais baixos nas primeiras 72h após a cirurgia de RM reduz o risco relativo de FA e pode ser uma ferramenta útil na prevenção da FA após RM.

Controversies in postoperative atrial fibrillation after noncardiothoracic surgery: clinical and research implications

Post operative atrial fibrillation after non-cardiothoracic surgery is an increasingly common problem. There is little high quality data to guide clinicians in risk prediction as well as short term and long term management. There appears to be a significant risk of recurrent atrial fibrillation and stroke but effective screening strategies have not been tested. In this commentary, we delineate various controversies in the management of post operative atrial fibrillation and briefly review the available evidence. Prospective studies in this clinically important area of cardiology should be encouraged.

Prevalence and Implications of Abnormal Respiratory Patterns in Cardiac Surgery: A Prospective Cohort Study

OBJECTIVE

To investigate the prevalence and impact of abnormal respiratory patterns in cardiac surgery patients.

DESIGN

Prospective cohort study.

SETTING

Tertiary hospital.

PARTICIPANTS

Patients scheduled for elective coronary artery bypass graft surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pulmonary function tests were performed in 454 patients before surgery. Abnormal respiratory patterns were defined as follows: obstructive (forced expiratory volume in 1 s [FEV₁]/forced vital capacity [FVC]<0.70), restrictive (FEV₁/FVC≥0.70 and FVC<80% of predicted), and mixed (FEV₁/FVC<0.70 and both FEV₁ and FVC<80% of predicted). Of the 31 patients with a history of chronic obstructive pulmonary disease, no abnormal respiratory pattern was confirmed in 5. Of the 423 patients without a history of lung disease, the authors newly identified 57 obstructive, 46 restrictive, and 4 mixed patterns. Therefore, lung disease was reclassified in 24.7% of cases. Independent predictors of obstructive pattern were age, male sex, history of smoking, and chronic obstructive pulmonary disease. Obstructive lung disease was associated with 16 hours or longer ventilation. A reduced FEV₁ was associated with a likelihood of atrial fibrillation (1-L decrement, odds ratio: 1.38, 95% confidence interval: 1.01-to-1.90, p = 0.04) and hospitalization time (regression coefficient: 1.23, 95% confidence interval: 0.54-to-1.91, p<0.001).

CONCLUSIONS

Abnormal respiratory patterns are common and often underdiagnosed in the cardiac surgery setting. Pulmonary function tests help reveal patients at risk of complications and may provide an opportunity for intervention.