Predictors and impact of atrial fibrillation after isolated coronary artery bypass grafting

Sex, Atrial Fibrillation, and Long-Term Mortality After Cardiac Surgery

Importance

There are limited data on the association of sex with the incidence of postoperative atrial fibrillation (poAF) and subsequent long-term mortality after cardiac surgery.

Objective

To evaluate whether the incidence of poAF and associated long-term mortality after cardiac surgery differ by sex.

Design, Setting, and Participants

This retrospective cohort study was conducted at 2 tertiary care centers in Massachusetts from January 1, 2002, until October 1, 2016, with follow-up until December 1, 2022. Adult (aged >20 years) women and men undergoing coronary artery bypass graft surgery, aortic valve surgery, mitral valve surgery, and combined procedures with cardiopulmonary bypass were examined using medical records. Patients who had data on poAF were included in data analyses.

Exposures

Sex and poAF.

Main Outcomes and Measures

Primary outcomes were the incidence of poAF and all-cause mortality. poAF was defined as any atrial fibrillation detected on electrocardiogram (EKG) during the index hospitalization in patients presenting for surgery in normal sinus rhythm. Data on poAF were obtained from EKG reports and supplemented by information from the Society of Thoracic Surgeons Adult Cardiac Surgery Database. All-cause mortality was assessed via hospital records. The hypotheses were formulated prior to data analysis.

Results

Among 21 568 patients with poAF data (mean [SD] age, 66.5 [12.4] years), 2694 of 6601 women (40.8%) and 5805 of 14 967 men (38.8%) developed poAF. In a multivariable logistic regression model, women had lower risk of poAF (odds ratio [OR], 0.85; 95% CI, 0.79-0.91; P < .001). During the follow-up study period, 1294 women (50.4%) and 2376 men (48.9%) in the poAF group as well as 1273 women (49.6%) and 2484 men (51.1%) in the non-poAF group died. Cox proportional hazards analysis found that the association between poAF and mortality was significantly moderated (ie, effect modified) by sex. Compared with same-sex individuals without poAF, men with poAF had a 17% higher mortality hazard (hazard ratio [HR], 1.17; 95% CI, 1.11-1.25; P < .001), and women with poAF had a 31% higher mortality hazard (HR, 1.31; 95% CI, 1.21-1.42; P < .001).

Conclusions and Relevance

In this retrospective cohort study of 21 568 patients who underwent cardiac surgery, women were less likely to develop poAF than men when controlling for other relevant characteristics; however, women who did develop poAF had a higher risk of long-term mortality than men who developed poAF. This observed elevated risk calls for a tailored approach to perioperative care in women undergoing cardiac surgery.

Postoperative Atrial Fibrillation Following Off-Pump Coronary Artery Bypass Graft Surgery: Elderly Versus Young Patients

Background Atrial fibrillation (AF) is one of the common rhythm disturbances that occur after coronary artery bypass graft (CABG) surgery. Postoperative atrial fibrillation (POAF) can lead to thromboembolic events, hemodynamic instability, and prolonged hospital stay, affecting morbidity and influencing short and long-term outcomes after CABG. Methodology This prospective comparative study was conducted between May 2018 and April 2020. This study aimed to compare the prevalence of POAF following off-pump coronary artery bypass graft surgery (OPCAB) between elderly and young patients. Additionally, we aimed to determine the risk factors associated with POAF following OPCAB in the elderly compared to young patients. Patients aged ≥65 years were considered elderly, and those aged <65 years were considered young. A total of 120 patients (60 in the elderly group and 60 in the young group) were included in this study and evaluated to correlate the preoperative and intraoperative risk factors with postoperative outcomes during the hospital stay. Results The prevalence of POAF following OPCAB in the elderly was significantly higher compared to young patients (48.3% vs. 20%,p = 0.002). The elderly group also had a significantly longer intensive care unit stay (p = 0.001) and hospital stay (p = 0.001). In an unadjusted logistic regression model, age (odds ratio (OR) = 3.74, 95% confidence interval (CI) = 1.66-8.41, p = 0.001), preoperative plasma B-type natriuretic peptide (OR = 1.01, 95% CI = 1.00-1.01, p = 0.001), and left atrial diameter (OR = 1.10, 95% CI = 1.03-1.17, p = 0.001) were significantly associated with POAF. However, in an adjusted logistic regression model, age was found to be an independent predictor (OR = 1.31, 95% CI = 1.14-1.52, p < 0.0001) of POAF following OPCAB. Although stroke developed in the elderly (p >0.05), no mortality was observed postoperatively. Conclusions The prevalence of POAF following OPCAB in the elderly is higher than in young patients. Advancing age is an independent predictor of POAF following OPCAB.

Prevalence of Postoperative Atrial Fibrillation Following Off-Pump Coronary Artery Bypass Graft Surgery in Elderly Patients

Background Atrial fibrillation (AF) is one of the frequent complications following coronary artery bypass surgery. Postoperative atrial fibrillation (POAF) can lead to thromboembolic events and prolong hospital stays. We aimed to determine the prevalence of POAF following off-pump coronary artery bypass surgery (OPCAB) in the elderly population.  Materials and Methods  This cross-sectional study was carried out between May 2018 to April 2020. Elderly patients (age ≥65 years) admitted for isolated elective OPCAB were eligible for the study. A total of 60 elderly patients were evaluated based on the preoperative and intraoperative risk factors and postoperative outcomes during the hospital stay. Results The mean age was 67.83±4.06 years, and the prevalence of POAF in elderly adults was 48.3%. The mean number of grafts was 3.20±0.73, and ICU stays at 3.43±1.61 days. The mean duration of the hospital stays was 10.03±2.12 days. Although stroke developed in 1.7% of post-CABG patients, no mortality was observed postoperatively. Conclusion  POAF is one of the commonly encountered complications following OPCAB. Though OPCAB is a superior revascularization procedure, preoperative planning and attention are especially needed in the elderly to reduce the prevalence of POAF.

Prediction model for postoperative atrial fibrillation in non-cardiac surgery using machine learning

Some patients with postoperative atrial fibrillation (POAF) after non-cardiac surgery need treatment, and a predictive model for these patients is clinically useful. Here, we developed a predictive model for POAF in non-cardiac surgery based on machine learning techniques. In a total of 201,864 patients who underwent non-cardiac surgery between January 2011 and June 2019 at our institution, 5,725 (2.8%) were treated for POAF. We used machine learning with an extreme gradient boosting algorithm to evaluate the effects of variables on POAF. Using the top five variables from this algorithm, we generated a predictive model for POAF and conducted an external validation. The top five variables selected for the POAF model were age, lung operation, operation duration, history of coronary artery disease, and hypertension. The optimal threshold of probability in this model was estimated to be 0.1, and the area under the receiver operating characteristic (AUROC) curve was 0.80 with a 95% confidence interval of 0.78-0.81. Accuracy of the model using the estimated threshold was 0.95, with sensitivity and specificity values of 0.28 and 0.97, respectively. In an external validation, the AUROC was 0.80 (0.78-0.81). The working predictive model for POAF requiring treatment in non-cardiac surgery based on machine learning techniques is provided online (https://sjshin.shinyapps.io/afib_predictor_0913/). The model needs further verification among other populations.

Atrial fibrillation after cardiac surgery: A systematic review and meta-analysis

OBJECTIVE

New-onset postoperative atrial fibrillation (POAF) after cardiac surgery is common, with rates up to 60%. POAF has been associated with early and late stroke, but its association with other cardiovascular outcomes is less known. The objective was to perform a meta-analysis of the studies reporting the association of POAF with perioperative and long-term outcomes in patients with cardiac surgery.

METHODS

We performed a systematic review and a meta-analysis of studies that presented outcomes for cardiac surgery on the basis of the presence or absence of POAF. MEDLINE, EMBASE, and the Cochrane Library were assessed; 57 studies (246,340 patients) were selected. Perioperative mortality was the primary outcome. Inverse variance method and random model were performed. Leave-one-out analysis, subgroup analyses, and metaregression were conducted.

RESULTS

POAF was associated with perioperative mortality (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.58-2.33), perioperative stroke (OR, 2.17; 95% CI, 1.90-2.49), perioperative myocardial infarction (OR, 1.28; 95% CI, 1.06-1.54), perioperative acute renal failure (OR, 2.74; 95% CI, 2.42-3.11), hospital (standardized mean difference, 0.80; 95% CI, 0.53-1.07) and intensive care unit stay (standardized mean difference, 0.55; 95% CI, 0.24-0.86), long-term mortality (incidence rate ratio [IRR], 1.54; 95% CI, 1.40-1.69), long-term stroke (IRR, 1.33; 95% CI, 1.21-1.46), and longstanding persistent atrial fibrillation (IRR, 4.73; 95% CI, 3.36-6.66).

CONCLUSIONS

The results suggest that POAF after cardiac surgery is associated with an increased occurrence of most short- and long-term cardiovascular adverse events. However, the causality of this association remains to be established.

Predicting atrial fibrillation after cardiac surgery: a scoping review of associated factors and systematic review of existing prediction models

INTRODUCTION

Postoperative atrial fibrillation (POAF) is common after cardiac surgery and associated with increased hospital length of stay, patient morbidity and mortality. We aimed to identify factors associated with POAF and evaluate the accuracy of available POAF prediction models.

METHODS

We screened articles from Ovid MEDLINE® and PubMed Central® (PMC) and included studies that evaluated risk factors associated with POAF or studies that designed or validated POAF prediction models. We only included studies in cardiac surgical patients with sample size n ⩾ 50 and a POAF outcome group ⩾20. We summarised factors that were associated with POAF and assessed prediction model performance by reviewing reported calibration and discriminative ability.

RESULTS

We reviewed 232 studies. Of these, 142 fulfilled the inclusion criteria. Age was frequently found to be associated with POAF, while most other variables showed contradictory findings, or were assessed in few studies. Overall, 15 studies specifically developed and/or validated 12 prediction models. Of these, all showed poor discrimination or absent calibration in predicting POAF in externally validated cohorts.

CONCLUSIONS

Except for age, reporting of factors associated with POAF is inconsistent and often contradictory. Prediction models have low discrimination, missing calibration statistics, are at risk of bias and show limited clinical applicability. This suggests the need for studies that prospectively collect AF relevant data in large cohorts and then proceed to validate findings in external data sets.

Preoperative left atrial volume index may be associated with postoperative atrial fibrillation in non-cardiac surgery

BACKGROUND

Postoperative atrial fibrillation (POAF) is related to mortality after non-cardiac surgery. Left atrial volume index (LAVI) is known to be associated with prognosis and development of atrial fibrillation, but it has not been fully investigated in patients undergoing non-cardiac surgery.

MATERIALS AND METHODS

A total of 203,787 consecutive adult patients underwent non-cardiac surgery at our institution between January 2011 and June 2019. After identifying those with available LAVI estimated during preoperative echocardiography, we divided them into those with LAVI higher and lower than 34 mL/m2. The primary outcome was incidence of POAF.

RESULTS

A total of 83,097 patients were enrolled in this study. The study patients were divided into the low (57,838 [69.6%]) and high (25,259 [30.4%]) LAVI groups. After an adjustment, higher LAVI was associated with increased incidence of POAF (5.1% vs. 8.1%; odds ratio [OR], 1.33; 95% confidence interval [CI], 1.25-1.41; p < 0.001). In 24,549 pairs of propensity-score-matched population, the result was similar (6.2% vs. 7.9%; OR, 1.30; 95% CI, 1.21-1.39; p < 0.001). The estimated threshold of LAVI associated with POAF was 36.4 mL/m2 with an area under the curve of 0.571. Subgroup analysis in non-thoracic and thoracic surgery showed that the association between preoperative LAVI and POAF significantly interacted with diastolic dysfunction (p for interaction < 0.001), and the observed association was valid in patients without diastolic dysfunction.

CONCLUSION

Preoperative LAVI was shown to be associated with POAF in non-cardiac surgery. Our result needs verification in further studies.

The impact of obesity on early postoperative atrial fibrillation burden

BACKGROUND

Obesity has been linked to the development of postoperative atrial fibrillation. This study is aimed at investigating the role of body mass index in the evolution of de novo, early postoperative atrial fibrillation by assessing differences between obese and nonobese patients undergoing cardiac surgery.

METHODS

Patients with early de novo postoperative atrial fibrillation were included. Continuous cardiac rhythms were recorded during the first 5 postoperative days in obese (N = 67, 66 ± 9 years; 51 [76%] male) and nonobese (N = 89, 69 ± 9; 75 [84%] male) patients without a history of atrial fibrillation undergoing cardiac surgery. Postoperative atrial fibrillation burden was defined as the ratio between total duration of all atrial fibrillation episodes and total recording time (atrial fibrillation burden, %).

RESULTS

A total of 1191 (median: 5/patient) postoperative atrial fibrillation episodes were identified in the obese group compared with 1218 (median: 4/patient) in the nonobese group. The median duration and number of prolonged (>60 minutes) postoperative atrial fibrillation episodes were higher in obese patients (250 vs 145 minutes, P = .003, and median of 2 vs 1 episode, P = .031). Obesity was associated with a larger early postoperative atrial fibrillation burden (obese patients: median, 7%; interquartile range, 2.5-19.7 vs nonobese patients: median, 3.2%; interquartile range, 0.5-8.8, P = .001) mainly on the third postoperative day (P = .021).

CONCLUSIONS

Obesity predisposes to a larger number of prolonged atrial fibrillation episodes in the early postoperative period after cardiac surgery for coronary artery disease or valvular heart disease. The higher atrial fibrillation burden in the early postoperative period occurred particularly on the third day. Future studies will determine whether obesity prevention may play a key role in reducing the incidence of postoperative atrial fibrillation in patients undergoing cardiac surgery.

Prophylactic amiodarone vs dronedarone for prevention of perioperative arrhythmias in offpump coronary artery bypass grafting: A pilot randomized controlled trial

The aim of this study was to compare the effects of prophylactic dronedarone and amiodarone in prevention of arrhythmias during and following off-pump coronary artery bypass grafting (OPCAB). This randomized, controlled, double-blinded, parallel-group study was carried out on 36 adult male patients aged 30-70 years, with modified Parsonnet score 0-10 undergoing offpump coronary artery bypass grafting. After obtaining approval from the institutional ethics committee and informed consent, the patients were randomly allocated to two equal groups (n=18). In one group, patients were given inj. amiodarone 3mg/kg in 100ml of normal saline prior to skin incision intravenously over 20 minutes. In the second group patients received tablet dronedarone 400mg orally twice daily, commencing three days prior to the date of surgery. Patients in the amiodarone group received placebo tablet while patients in the dronedarone group received placebo infusion for the sake of blinding. The frequency and profile of arrhythmias intraoperatively and 24 hours postoperatively were studied. Intraoperative arrhythmias occurred in 50% of patients receiving amiodarone and 16.67% of patients receiving dronedarone. Maximum ventricular rate during atrial fibrillation was significantly lower in the dronedarone group (121 beats per min) than in the amiodarone group (168 beats per min). The study concludes that dronedarone appears to be at least as effective as amiodarone in prophylaxis of intraoperative and postoperative arrhythmias in patients undergoing OPCAB, with a better control of ventricular response.

Clinical significance and risk factors for new onset and recurring atrial fibrillation following cardiac surgery - a retrospective data analysis

Background

Although mortality after cardiac surgery has significantly decreased in the last decade, patients still experience clinically relevant postoperative complications. Among others, atrial fibrillation (AF) is a common consequence of cardiac surgery, which is associated with prolonged hospitalization and increased mortality.

Methods

We retrospectively analyzed data from patients who underwent coronary artery bypass grafting, valve surgery or a combination of both at the University Hospital Muenster between April 2014 and July 2015. We evaluated the incidence of new onset and intermittent/permanent AF (patients with pre- and postoperative AF). Furthermore, we investigated the impact of postoperative AF on clinical outcomes and evaluated potential risk factors.

Results

In total, 999 patients were included in the analysis. New onset AF occurred in 24.9% of the patients and the incidence of intermittent/permanent AF was 59.5%. Both types of postoperative AF were associated with prolonged ICU length of stay (median increase approx. 2 days) and duration of mechanical ventilation (median increase 1 h). Additionally, new onset AF patients had a higher rate of dialysis and hospital mortality and more positive fluid balance on the day of surgery and postoperative days 1 and 2. In a multiple logistic regression model, advanced age (odds ratio (OR) = 1.448 per decade increase, p < 0.0001), a combination of CABG and valve surgery (OR = 1.711, p = 0.047), higher C-reactive protein (OR = 1.06 per unit increase, p < 0.0001) and creatinine plasma concentration (OR = 1.287 per unit increase, p = 0.032) significantly predicted new onset AF. Higher Horowitz index values were associated with a reduced risk (OR = 0.996 per unit increase, p = 0.012). In a separate model, higher plasma creatinine concentration (OR = 2.125 per unit increase, p = 0.022) was a significant risk factor for intermittent/permanent AF whereas higher plasma phosphate concentration (OR = 0.522 per unit increase, p = 0.003) indicated reduced occurrence of this arrhythmia.

Conclusions

New onset and intermittent/permanent AF are associated with adverse clinical outcomes of elective cardiac surgery patients. Different risk factors implicated in postoperative AF suggest different mechanisms might be involved in its pathogenesis. Customized clinical management protocols seem to be warranted for a higher success rate of prevention and treatment of postoperative AF.

Electronic supplementary material

The online version of this article (10.1186/s12871-017-0455-7) contains supplementary material, which is available to authorized users.

Incidence and predictors of atrial fibrillation after coronary artery bypass surgery: detection by event loop recorder monitoring from a contemporary multicentre cohort

Background Atrial fibrillation (AF) is a frequent complication after cardiac surgery. We explored the incidence and predictors of post-operative AF at 30-day follow-up in an unselected multi-centre cohort of patients undergoing elective coronary artery bypass grafting (CABG) in contemporary practice. Methods and results We enrolled 740 consecutive patients scheduled for elective CABG with or without valve surgery. Cardiac rhythm was continuously monitored for 15 days after surgery by an ambulatory event loop recorder. Clinical follow-up for the occurrence of arrhythmias was performed for the next 15 days by office visits. The primary end point was the incidence of AF at 30-day follow-up. Mean age was 56.5 ± 8.9 years; 69.5% were males; 80% had diabetes. All patients completed 30-day follow-up. At the end of 30 days, AF occurred in 77 patients (10.4%). Most episodes (47 out of 77 episodes, 61%) of AF occurred during post-operative day 2. Episodes of AF were very rare after the first 5 post-operative days (3 out of 77 episodes, 3.9%). Multivariable regression analysis identified the following independent predictors of AF at 30-day follow-up: the lack of beta blocker use (hazard ratio 0.37, 95% confidence interval 0.21-0.64, P < 0.001), and the preoperative left atrial volume index (hazard Ratio 2.21, 95% confidence interval 1.79-2.74, P < 0.001). Conclusions In patients undergoing elective CABG, the incidence of post-operative AF at 30-day follow-up is rather low; the lack of beta blocker use in the perioperative period, and the preoperative left atrial volume index independently predicted the occurrence of AF at 30 days.

Preoperative Antihypertensive Medication in Relation to Postoperative Atrial Fibrillation in Patients Undergoing Cardiac Surgery: A Meta-Analysis

Background. We undertake a systematic review and meta-analysis to evaluate the effect of preoperative hypertension and preoperative antihypertensive medication to postoperative atrial fibrillation (POAF) in patients undergoing cardiac surgery. Methods. We searched PubMed, Embase, and Cochrane Library (from inception to March 2016) for eligible studies. The outcomes were the effects of preoperative hypertension, preoperative calcium antagonists regimen, preoperative ACE inhibitors regimen, and preoperative beta blocking agents regimen with POAF. We calculated pooled risk ratios (OR) and 95% CIs using random- or fixed-effects models. Results. Twenty-five trials involving 130087 patients were listed. Meta-analysis showed that the number of preoperative hypertension patients in POAF group was significantly higher (P < 0.05), while we found that there are no significant differences between two groups in Asia patients by subgroup analysis, which is in contrast to other outcomes. Compared with the Non-POAF group, the number of patients who used calcium antagonists and ACE inhibitors preoperatively in POAF group was significantly higher (P < 0.05). And we found that there were no significant differences between two groups of preoperative beta blocking agents used (P = 0.08). Conclusions. Preoperative hypertension and preoperative antihypertensive medication in patients undergoing cardiac operations seem to be associated with higher risk of POAF.

Comparison of the effects of bepridil and aprindine for the prevention of atrial fibrillation after cardiac and aortic surgery: A prospective randomized study

BACKGROUND

Approximately one-third of the patients undergoing cardiovascular surgery reportedly experience paroxysmal atrial fibrillation (AF) during the postoperative period. However, the usefulness of antiarrhythmic drugs for preventing postoperative AF recurrence in the Japanese population has not been extensively studied.

METHODS

From a total of 118 patients who developed postoperative paroxysmal AF between April 2009 and March 2011, 72 patients (45 men, mean age 68±8 years) requiring treatment for postoperative AF due to symptoms lasting ≥30 min were enrolled to prospectively investigate the efficacy of oral bepridil (100 mg/day, n=37) or aprindine (40 mg/day, n=35).

RESULT

The AF recurrence-free survival rates at 1, 3, 7, and 14 days were 100%, 94%, 57%, and 49%, respectively, in the aprindine group, and 100%, 97%, 86%, and 76%, respectively, in the bepridil group (P=0.028, aprindine vs. bepridil).

CONCLUSION

Bepridil, at a fixed dose of 100 mg/day, was considered to be more effective than a routine dose of aprindine for the prevention of postoperative AF recurrence.

Preventive strategies for atrial fibrillation after cardiac surgery in Nordic countries

BACKGROUND AND AIMS

Atrial fibrillation is a common arrhythmia after cardiac surgery. It increases morbidity, length of hospital stay, and costs of operative treatment. Beta-blockers, sotalol, amiodarone, corticosteroids, and biatrial pacing have been shown to be efficient in the prevention of postoperative atrial fibrillation. The aim of this study was to find out how widely different prophylactic strategies for postoperative atrial fibrillation are used in Scandinavian countries.

MATERIAL AND METHODS

An online link for a questionnaire was emailed to (214) cardiac surgeons in Finland, Sweden, Norway, Denmark, and Estonia to assess the use of prophylactic methods for postoperative atrial fibrillation.

RESULTS

A total of 97 surgeons responded to the survey. Oral beta-blockers were routinely used for atrial fibrillation prophylaxis by 62% of responders. The main reasons for nonuse of beta-blockers were that responders were unconvinced of the evidence of benefit or they preferred some alternative prophylaxis. Intravenous beta-blockers were used frequently by 6% of responders. Amiodarone was used for prophylaxis by 18% of responders. Nonusers were unconvinced of its efficacy, were afraid of its complications, or found its use too cumbersome. Other prophylactic atrial fibrillation strategies that were used are as follows: sotalol by 2%, magnesium by 17%, corticosteroids by 1%, and atrial pacing by 11% of respondents.

CONCLUSIONS

There is still widely varying implementation of strategies for atrial fibrillation prophylaxis among Scandinavian cardiac surgeons. Lack of confidence in the efficacy of these approaches is the main rationale for nonimplementation.

Role of magnesium in cardiovascular diseases

Magnesium, the fourth most abundant cation in the human body, is involved in several essential physiological, biochemical, and cellular processes regulating cardiovascular function. It plays a critical role in modulating vascular smooth muscle tone, endothelial cell function, and myocardial excitability and is thus central to the pathogenesis of several cardiovascular disorders such as hypertension, atherosclerosis, coronary artery disease, congestive heart failure, and cardiac arrhythmias. This review discusses the vasodilatory, anti-inflammatory, anti-ischemic, and antiarrhythmic properties of magnesium and its current role in the prevention and treatment of cardiovascular disorders.

Preoperative tissue Doppler imaging-derived atrial conduction time can predict postoperative atrial fibrillation in patients undergoing aortic valve replacement for aortic valve stenosis

BACKGROUND

Postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery and may result in stroke or heart failure and poor prognosis. This study aimed to evaluate a novel index of total atrial conduction time derived from the P-wave onset (lead II) to the peak A' wave on tissue Doppler imaging (PA-TDI duration). The PA-TDI duration was compared with previously reported predictors of POAF, and the optimal cutoff value of PA-DTI was calculated in patients undergoing aortic valve replacement (AVR) for AV stenosis (AS). METHODS AND RESULTS: We enrolled 63 patients undergoing isolated AVR. They underwent transthoracic echocardiography with TDI preoperatively and were monitored postoperatively with continuous electrocardiographic telemetry for 7 days. The hospital stay was significantly longer in the 41 patients with POAF than in the 22 without POAF (33.8±19.7 vs. 24.1±8.1 days, P=0.03). Multivariate analysis revealed that PA-TDI duration (odds ratio [OR], 1.07; 95% confidence interval [CI], 1.02-1.13; P=0.0072) and age (OR, 1.14; CI, 1.03-1.28; P=0.016) were significant independent predictors of POAF. Receiver-operating characteristic curve analysis showed the optimal cutoff values of PA-TDI duration and age were 147.3 ms and 74 years, respectively.

CONCLUSIONS

The PA-TDI duration was an independent predictor of POAF after AVR for AS. Patients with PA-TDI duration >147 ms should be considered high risk and treated appropriately to improve outcomes.

Blood transfusion and the risk of atrial fibrillation after cardiac surgery

BACKGROUND

Red blood cell transfusion (Tx) induces a proinflammatory state. Inflammatory mediators are associated with an increased risk of postoperative atrial fibrillation (AF). Therefore, in this study we determined the association between AF and Tx after isolated coronary artery bypass graft surgery (CABG).

METHOD

Between January 2008 and December 2010, a total of 879 patients underwent CABG. Of these, 815 (92.7%) had complete data extracted from our institution's Society of Thoracic Surgeons (STS) database. Predictors of AF development among four levels of Tx versus nontransfused patients were examined. Multivariable logistic regression and propensity score matching models were used.

RESULTS

The mean age was 65.8 years (±10.3), 77.4% were male, and 54.4% had an STS predicted risk score (mortality/morbidity) of ≥10%. A total of 564 (69.2%) had at least one unit of Tx. Adjusting for age, sex, time on pump, congestive heart failure, stroke, creatinine level (<1.5 mg per deciliter vs. ≥1.5), STS morbidity/mortality score, perioperative myocardial infarction (MI), cross-clamp time, medications, and hemoglobin level, the odds ratio (OR) of AF increased with increasing Tx (OR, 1.36; 95% confidence interval [CI], 1.11 to 1.68; p = 0.003). The odds of AF increased 61% with each increasing level of Tx (OR, 1.61; 95% CI, 1.15 to 2.26; p = 0.006, by propensity analysis).

CONCLUSIONS

Perioperative Tx may be associated with excess AF following CABG. This risk increases with increasing number of Tx.

Perioperative stroke: risk assessment, prevention and treatment

OPINION STATEMENT

Numerous risk factors for perioperative stroke have been identified and many are modifiable. Surgical patients with a history of cerebrovascular disease should be evaluated by a neurologist. Cardiac and cerebrovascular testing is critical in identifying patients at high risk for perioperative stroke. The identification and treatment of carotid disease in the context of upcoming surgery has been a source of controversy. Routine carotid revascularization performed with coronary artery bypass graft (CABG) surgery for incidentally discovered carotid stenosis is not recommended. Prior to aortic manipulation during CABG, epiaortic ultrasound should be performed to identify aortic atheromatous plaques. If possible, preoperative aspirin, beta blocker, statin, and angiotensin converting-enzyme (ACE) inhibitor therapy should be continued in the perioperative period. Patients who are prescribed anticoagulation at high risk of thromboembolism should receive bridging anticoagulation during the perioperative period. The identification and prevention of postoperative atrial fibrillation (AF) is central to stroke prevention. CABG patients should be initiated on beta blockade +/- amiodarone to prevent postoperative AF. Many practitioners have been traditionally nihilistic towards acute perioperative stroke treatment. Given the narrow therapeutic window of treatment options, candidacy is dependent on timely recognition. Intravenous and endovascular thrombolysis/therapies are viable options in selected patients under the guidance and expertise of a neurologist. This article will present the epidemiology of perioperative stroke, the pathophysiology, risk assessment and stratification for common surgeries. The article will additionally focus on treatment options including modifiable risk factor reduction and the perioperative management of medications.

Management of postoperative atrial fibrillation and subsequent outcomes in contemporary patients undergoing cardiac surgery: insights from the Society of Thoracic Surgeons CAPS-Care Atrial Fibrillation Registry

BACKGROUND

Postoperative atrial fibrillation (POAF) is a well-recognized complication of cardiac surgery; however, its management remains a challenge, and the implementation and outcomes of various strategies in clinical practice remain unclear.

HYPOTHESIS

We hypothesize that treatment for POAF is variable, and that it is associated with particular morbidity and mortality following cardiac surgery.

METHODS

We compared patient characteristics, operative procedures, postoperative management, and outcomes between patients with and without POAF following coronary artery bypass grafting (CABG) in the Society of Thoracic Surgeons multicenter Contemporary Analysis of Perioperative Cardiovascular Surgical Care (CAPS-Care) registry (2004-2005).

RESULTS

Of 2390 patients who underwent CABG, 676 (28%) had POAF. Compared with patients without POAF, those with POAF were older (median age 74 vs 71 years, P<0.0001) and more likely to have hypertension (86% vs 83%, P=0.04) and impaired renal function (median estimated glomerular filtration rate 56.9 vs 58.6 mL/min/1.73 m2, P=0.0001). A majority of patients with POAF were treated with amiodarone (77%) and β-blockers (68%); few (9.9%) underwent cardioversion. Patients with POAF were more likely to experience complications (57% vs 41%, P<0.0001), including acute limb ischemia (1.0% vs 0.4%, P=0.03), stroke (4.0% vs 1.9%, P=0.002), and reoperation (13% vs 7.9%, P<0.0001). Length of stay (median 8 days vs 6 days, P<0.0001), in-hospital mortality (6.8% vs 3.7%, P=0.001), and 30-day mortality (7.8 vs 3.9, P<0.0001) were all worse for patients with POAF. In adjusted analyses, POAF remained associated with increased length of stay following surgery (adjusted ratio of the mean: 1.27, 95% confidence interval: 1.2-1.34, P<0.0001).

CONCLUSIONS

Postoperative AF is common following CABG, and such patients continue to have higher rates of postoperative complications. Postoperative AF is significantly associated with increased length of stay following surgery.

Clinical and echocardiographic predicators of postoperative atrial fibrillation

BACKGROUND

Postoperative atrial fibrillation is the most common arrhythmia after coronary artery bypass grafting, with a reported incidence of 10% to 60%. Preoperative clinical and echocardiographic data, especially the atrial electromechanical interval, predict postoperative atrial fibrillation in elective coronary artery bypass patients.

METHODS

A prospective study evaluated preoperative clinical and echocardiographic data in 192 patients who underwent elective coronary artery bypass from 2010 to 2012.

RESULTS

18 (9.37%) patients developed postoperative atrial fibrillation. Compared to patients without postoperative atrial fibrillation, these 18 had significantly longer intensive care unit and hospital stays, they were significantly older (58.62 ± 10.02 vs. 53.22 ± 8.23 years; p = 0.02), with a larger left atrial volume (83.39 ± 8.31 vs. 55.47 ± 8.37 cm(3), p = 0.001), longer atrial electromechanical interval (133.67 ± 8.15 vs. 98.05 ± 6.71 ms p < 0.0001), and lower tissue Doppler imaging systolic velocity wave amplitude (6.6 ± 1 vs. 9.4 ± 2.2 cm·s(-1); p = 0.001); they also had a higher prevalence of hypertension (61.11% vs. 38.5%; p = 0.04). Using 115 ms as the cutoff value of atrial electromechanical interval enabled us to detect patients who developed postoperative atrial fibrillation with 100% sensitivity, 77% specificity, 78% positive predictive value, and 100% negative predictive value.

CONCLUSION

Older hypertensive patients are at higher risk of developing postoperative atrial fibrillation. Preoperative measurement of atrial electromechanical interval by tissue Doppler echocardiography is a useful predictor of postoperative atrial fibrillation in coronary artery bypass patients.

Off-pump coronary revascularization: A potential benefit for female patients?

Coronary artery disease is one of the leading causes of illness for both men and women. However, women are 3 times more likely to die for coronary artery disease as they are of breast cancer. There are an increasing prevalence of coronary artery disease in women and thus facing the need for surgical revascularization. It has long being accepted that women carry a high risk of coronary surgery than men. Many investigators have suggested that female itself is predictive of poor outcome after on pump coronary surgery. We thought to search the litlature to investigate whether women who undergo off-pump surgery receive any benefits compared with women undergoing on-pump surgery.

Predictors of postoperative atrial fibrillation after on-pump coronary artery bypass grafting: is duration of mechanical ventilation time a risk factor?

PURPOSE

This study aimed to establish the role of risk factors in the etiology of postoperative atrial fibrillation (AF) after coronary artery bypass grafting (CABG).

METHODS

Between September 2001 and March 2008, 1040 patients underwent isolated CABG at our clinic. Nine hundred and eleven of these patients did not have any AF(Non-AF Group) and the other one hundred and twenty-nine had AF (AF Group). A retrospective study was performed for patient, disease and treatment related factors and multivariate analysis was used to identify independent clinical predictors of postoperative AF.

RESULTS

Postoperative AF was identified in 129 (12.4%) of the patients, and those were significantly older and had significantly higher additive EuroSCORE score as compared with patients without AF. During the postoperative course, patients with postoperative AF also had significantly higher and prolonged (≥6 hours) mechanical ventilation time, longer and prolonged intensive care unit stay and longer hospital stay. Logistic regression analysis revealed that postoperative AF development ratio was 1.690 times higher when the ventilation time was over 6 hours (OR 1.690, 95% CI 1.092-2.615, p = 0.018); 1.240 times higher in the presence of elevated additive EuroSCORE score (OR 1.240, 95% CI1.109-1.385, p = 0.0001); 1.052 times higher in the presence of advanced age (OR 1.052,95% CI 1.031-1.0741, p = 0.0001).

CONCLUSION

Analysis of our data reveals that, patient's age, additive EuroSCORE score, and prolonged ventilation are predictors of postoperative AF. Identification of risk factors might lead to better prevention of this problem and its potential consequences. However, to support our investigation and obtain more reliable evidence, prospective randomized controlled trials are needed.

Preoperative hemoglobin A1c predicts atrial fibrillation after off-pump coronary bypass surgery

OBJECTIVE

Diabetes mellitus has been recognized as a risk factor for mortality and morbidity after coronary bypass grafting, but a significant association between diabetes mellitus and postoperative atrial fibrillation (AF) has not been found. Although a recent study demonstrated a potential link between preoperative hemoglobin A1c level and risk of postoperative AF, there has not been sufficient examination of this relationship. We aimed to investigate the association between preoperative hemoglobin A1c and AF after isolated off-pump coronary bypass grafting.

METHODS

Of 912 consecutive patients undergoing isolated coronary bypass surgery, 805 were retrospectively analyzed for AF after excluding the following 107 cases: emergency (n=81), chronic AF (n=18), and pacemaker rhythm (n=8). We performed a group analysis with hemoglobin A1c levels categorized into tertiles of the baseline distribution and a continuous analysis based on 1% increments in hemoglobin A1c levels. The cutoff points for the tertiles were as follows: lower, 3.8-5.6% (n=283); middle, 5.7-6.7% (n=282); upper, 6.8-11.4% (n=240).

RESULTS

AF occurred in 159 patients (19.8%) after surgery. The median value (25th-75th percentile) of preoperative hemoglobin A1c was significantly lower in patients who developed AF than in those who did not (5.8 (5.4-6.3) vs 6.1 (5.5-7.2), p=0.01). The incidence of postoperative AF was 28.3% (80/283) in the lower tertile, 17.4% (49/282) in the middle tertile, and 12.5% (30/240) in the upper tertile (p for trend=0.01). The unadjusted odds ratio (95% confidence interval) for the association between hemoglobin A1c and postoperative AF was 0.70 (0.61-0.83) per 1% increase and 0.42 (0.29-0.70) for the upper versus the lower tertile. This association persisted after adjustment for the univariate predictors (0.74 (0.60-0.92) per 1% increase; 0.54 (0.31-0.90) for upper vs lower tertile) and the known risk factors (0.78 (0.63-0.95) per 1% increase; 0.55 (0.35-0.88) for upper vs lower tertile). The area under the receiver operator characteristic curve (95% confidence interval) for preoperative hemoglobin A1c as a predictor of postoperative AF was 0.70 (0.65-0.75) (p=0.01).

CONCLUSIONS

Preoperative hemoglobin A1c independently predicts the occurrence of AF after isolated off-pump coronary bypass grafting.

Left atrial expansion index for predicting atrial fibrillation and in-hospital mortality after coronary artery bypass graft surgery

BACKGROUND

Atrial fibrillation (AF), a common complication after coronary artery bypass graft surgery (CABG), is associated with prolonged hospital stay. This prospective study assessed the accuracy of left atrial parameters and additional preoperative characteristics for predicting post-CABG AF and in-hospital mortality.

METHODS

A total of 197 patients without hemodynamic-significant valvular problems, who received isolated CABG, were enrolled. Echocardiography was performed before CABG.

RESULTS

Compared with patients without post-CABG AF, those with post-CABG AF were older (71 vs 64 years, p<0.0001), had a higher incidence of CABG during index hospitalization of acute myocardial infarction and preoperative respiratory failure requiring ventilator support, lower left ventricular ejection fraction (0.41 vs 0.48, p<0.0001), lower left atrial expansion index (52.2% vs 93.3%, p<0.0001), and higher left ventricular filling pressure (24.2 vs 19.1 mm Hg, p<0.0001). Multivariate analysis of preoperative variables showed that independent predictors of AF included age (odds ratio [OR], 1.064; 95% confidence interval [CI], 1.022 to 1.107 per 1-year increase; p 0.002), maximal indexed left atrial volume (OR, 1.026; 95% CI, 1.002 to 1.051 per 1 mL/m2 increase; p 0.037) and left atrial expansion index (OR, 0.981; 95% CI, 0.962 to 0.998 per 1% increase; p 0.029). The left atrial expansion index was also significantly associated with in-hospital mortality (OR, 0.982; 95% CI, 0.951 to 0.996 per 1% increase; p 0.042). Incidence of post-CABG AF in patients with left atrial expansion index less than 120% progressively increased as left atrial expansion index decreased.

CONCLUSIONS

Left atrial expansion index independently predicts post-CABG AF and in-hospital mortality.

Postoperative atrial fibrillation

Postoperative atrial fibrillation (POAF) is common among surgical patients and associated with a worse outcome. Pathophysiology of POAF is not fully disclosed, and several perioperative factors could be involved. Direct cardiac stimulation from perioperative use of catecholamines or increased sympathetic outflow from volume loss/anaemia/pain may play a role. Metabolic alterations, such as hypo-/hyperglycaemia and electrolyte disturbances, may also contribute to POAF. Moreover, inflammation, both systemic and local, may play a role in its pathogenesis. Strategies to prevent POAF aim at reducing its incidence and ameliorate global outcome of surgical patients. Nonpharmacological prophylaxis includes an adequate control of postoperative pain, the use of thoracic epidural analgesia, optimization of perioperative oxygen delivery, and, possibly, modulation of surgery-associated inflammatory response with immunonutrition and antioxidants. Perioperative potassium and magnesium depletion should be corrected. The impact of those interventions on patients outcome needs to be further investigated.

Left-ventricular electromechanical delay is prolonged in patients with postoperative atrial fibrillation

OBJECTIVE

Although several risk factors for postoperative atrial fibrillation (AF) have been proposed, it remains the most common complication after cardiac surgery, even in low-risk patients. There is still no single reliable and reproducible parameter for predicting AF, and no standardized recommendation exists for this issue. Electromechanical delay (excitation-contraction coupling delay) is the time delay from the electrical activation to the actual systolic motion, and it reflects abnormality in calcium-handling proteins, which is considered one mechanism of postoperative AF. We hypothesized that left-ventricular electromechanical delay (LVEMD) is correlated to postoperative AF and serially examined it by echocardiography.

METHODS

We prospectively included 16 patients with relatively low risk for AF, who underwent cardiac surgery. The inclusion criteria were younger than 80 years, an ejection fraction greater than 45%, a left-atrial dimension less than 50mm, and a brain natriuretic peptide (BNP) value less than 250 pg ml⁻¹. Postoperative AF for 10 postoperative days was monitored by 24-h electrocardiogram. The LVEMD was assessed by pulse-wave tissue Doppler echocardiography before and 1, 3, and 7 days after the operation. Serum BNP, adrenalin, and noradrenalin levels were also examined at the same time.

RESULTS

Postoperative AF was detected in six (37.5%) patients. There was no significant difference in heart rate, QRS duration, and serum hormones between the non-AF (n = 10) and AF (n = 6) groups. Although the preoperative LVEMD was comparable, that on postoperative day 1 of the AF group was significantly longer than that of the non-AF group (in the septal wall, 174 ± 50 vs 101 ± 36 ms, p = 0.020; in the lateral wall, 195 ± 71 and 111 ± 37 ms, p = 0.029). A LVEMD on postoperative day 1 greater than 150 ms well predicted postoperative AF (sensitivity, 75% and 75%; specificity, 100% and 86%, in septal and lateral LVEMDs, respectively).

CONCLUSIONS

LVEMD is prolonged in patients with postoperative AF. This could be a new predicting parameter for AF in low-risk patients.

Contemporary management of atrial fibrillation: update on anticoagulation and invasive management strategies

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Its increasing prevalence, particularly among the elderly, renders it one of the most serious current medical epidemics. Several management questions confront the clinician treating a patient with AF: Should the condition be treated? Is the patient at risk of death or serious morbidity as a result of this diagnosis? If treatment is necessary, is rate control or rhythm control superior? Which patients need anticoagulation therapy, and for how long? This review of articles obtained by a search of the PubMed and MEDLINE databases presents the available evidence that can guide the clinician in answering these questions. After discussing the merits of available therapy, including medications aimed at controlling rate, rhythm, or both, we focus on the present status of ablative therapy for AF. Catheter ablation, particularly targeting the pulmonary veins, is being increasingly performed, although the precise indications for this approach and its effectiveness and safety are being actively investigated. We briefly discuss other invasive options that are less frequently used, such as pacemakers, defibrillators, left atrial appendage closure devices, and the surgical maze procedure.

Postoperative atrial fibrillation

Atrial fibrillation is a common arrhythmia that occurs after cardiac surgery. It is associated with an increase in morbidity, length of hospital stay and mortality. Patients who are at higher risk of postoperative atrial fibrillation should receive prophylactic treatment. Atrial fibrillation usually resolves spontaneously after heart rate is controlled; however, if patients are highly symptomatic or hemodynamically unstable, sinus rhythm should be restored by electrical or pharmacologic cardioversion.

Relation of obesity to atrial fibrillation after isolated coronary artery bypass grafting

The impact of obesity on risk of atrial fibrillation (AF) after coronary artery bypass grafting (CABG) is poorly understood. This study was performed to investigate the relation between body mass index (BMI; kilograms per square meter) or body surface area (BSA; square meters) and AF after CABG. Postoperative AF was assessed in a cohort of 7,027 consecutive patients without preoperative AF undergoing isolated CABG at Baylor University Medical Center from January 1, 1997 to December 31, 2006. Two propensity-adjusted models controlling for risk factors identified by the Society of Thoracic Surgeons and other clinical/nonclinical details were used. After adjustment, BMI and BSA (modeled using smoothing techniques to avoid categorization) were strongly associated (p <0.0001) with postoperative AF. Although evidence existed that gender was associated with AF (p <0.0001 and p = 0.1088 for BSA and BMI models, respectively), there was no indication that the effect of BMI or BSA on postoperative AF varied by gender. In conclusion, this study demonstrates that increased BMI and BSA are associated with a higher risk of AF after CABG and that risk for men is higher for the entire BSA spectrum and for extreme values of BMI.

Clinical review: treatment of new-onset atrial fibrillation in medical intensive care patients--a clinical framework

Atrial fibrillation occurs frequently in medical intensive care unit patients. Most intensivists tend to treat this rhythm disorder because they believe it is detrimental. Whether atrial fibrillation contributes to morbidity and/or mortality and whether atrial fibrillation is an epiphenomenon of severe disease, however, are not clear. As a consequence, it is unknown whether treatment of the arrhythmia affects the outcome. Furthermore, if treatment is deemed necessary, it is not known what the best treatment is. We developed a treatment protocol by searching for the best evidence. Because studies in medical intensive care unit patients are scarce, the evidence comes mainly from extrapolation of data derived from other patient groups. We propose a treatment strategy with magnesium infusion followed by amiodarone in case of failure. Although this strategy seems to be effective in both rhythm control and rate control, the mortality remained high. A randomised controlled trial in medical intensive care unit patients with placebo treatment in the control arm is therefore still defendable.

Postoperative complications of coronary artery bypass grafting surgery

Coronary artery bypass grafting (CABG) surgery continues to be an effective and well-used intervention for coronary artery disease. Older patients and those with sicker hearts will become the norm. In spite of increased risk for patients undergoing CABG, overall mortality rates have decreased. Nursing contributions to these improved outcomes cannot be overestimated. Continued understanding and appreciation of these complications will be necessary to effectively care for patients and create optimal outcomes.

Postoperative atrial fibrillation

Atrial fibrillation is a common arrhythmia after cardiac surgery. It is associated with an increase in morbidity, length of hospital stay, and mortality. Patients who are at higher risk of postoperative atrial fibrillation should receive prophylactic treatment. Atrial fibrillation usually resolves spontaneously after heart rate is controlled; however, if patients are highly symptomatic or hemodynamically unstable, sinus rhythm should be restored by electrical or pharmacologic cardioversion. Patients with atrial fibrillation of more than 48 hours should receive antithrombotic therapy for thromboembolism prevention.

Brain natriuretic peptide concentration in pericardial fluid is independently associated with atrial fibrillation after off-pump coronary artery bypass surgery

OBJECTIVES

Postoperative atrial fibrillation is associated with the increased incidence of morbidities and mortality. Predisposing determinants of atrial fibrillation development after off-pump coronary artery bypass grafting remain unclear. We hypothesized that pericardial fluid natriuretic peptide concentrations have a predictive value for developing postoperative atrial fibrillation in patients who have undergone off-pump coronary artery bypass grafting.

METHODS

We prospectively measured atrial natriuretic peptide and brain natriuretic peptide concentrations in plasma and pericardial fluid in 42 consecutive patients undergoing off-pump coronary artery bypass grafting, then continuously observed the occurrence of atrial fibrillation following off-pump coronary artery bypass grafting until the time of discharge.

RESULTS

Postoperative atrial fibrillation was documented in nine patients (21%, atrial fibrillation group), and not in 33 patients (no atrial fibrillation group). Between the groups, there was neither significant difference in plasma atrial natriuretic peptide concentrations nor in pericardial atrial natriuretic peptide concentrations. Plasma brain natriuretic peptide concentrations were comparable in both groups [56.2 (interquartile range 42.7-102.8) vs. 35.2 pg/ml (13.8-75.0), P=0.07]. Pericardial fluid brain natriuretic peptide concentrations were significantly higher in the atrial fibrillation group than in the no atrial fibrillation group [188.0 (124.8-411.0) vs. 39.3 pg/ml (10.0-88.4), P=0.0001]. In a multivariable logistic regression model, pericardial brain natriuretic peptide concentration was significantly associated with a higher risk of postoperative atrial fibrillation (odds ratio=3.0 every 50 pg/ml increase; 95% confidence interval, 1.1-8.6; P=0.04).

CONCLUSION

Our results suggested that pericardial fluid brain natriuretic peptide concentration is independently associated with the development of atrial fibrillation after off-pump coronary artery bypass grafting.