Risk and Subtypes of Stroke Following New-Onset Postoperative Atrial Fibrillation in Coronary Bypass Surgery: A Population-Based Cohort Study.

Background New-onset postoperative atrial fibrillation (POAF) develops in approximately one-third of patients undergoing cardiac surgery and is associated with a higher incidence of ischemic stroke and increased mortality. However, it remains unknown to what extent ischemic stroke events in patients with POAF are cardioembolic and whether anticoagulant therapy is indicated. We investigated the long-term risk and pathogenesis of postoperative stroke in patients undergoing coronary artery bypass grafting experiencing POAF. Methods and Results This was a register-based cohort study. Data from the WDHR (Western Denmark Heart Registry) were linked with the DNPR (Danish National Patient Register), the Danish National Prescription Register, and the Cause of Death Register. All stroke diagnoses were verified, and ischemic stroke cases were subclassified according to pathogenesis. Furthermore, investigations of all-cause mortality and the use of anticoagulation medicine for the individual patient were performed. A total of 7813 patients without a preoperative history of atrial fibrillation underwent isolated coronary artery bypass grafting between January 1, 2010, and December 31, 2018, in Western Denmark. POAF was registered in 2049 (26.2%) patients, and a postoperative ischemic stroke was registered in 195 (2.5%) of the patients. After adjustment, there was no difference in the risk of ischemic stroke (hazard ratio [HR], 1.08 [95% CI, 0.74-1.56]) or all-cause mortality (HR, 1.09 [95% CI, 0.98-1.23]) between patients who developed POAF and non-POAF patients. Although not statistically significant, patients with POAF had a higher incidence rate (IR; per 1000 patient-years) of cardioembolic stroke (IR, 1 [95% CI, 0.6-1.6] versus IR, 0.5 [95% CI, 0.3-0.8]), whereas non-POAF patients had a higher incidence rate of large-artery occlusion stroke (IR, 1.1 [95% CI, 0.8-1.5] versus IR, 0.7 [95% CI, 0.4-1.4]). Early initiation of anticoagulation medicine was not associated with a lower risk of ischemic stroke. However, patients with POAF were more likely to die of cardiovascular causes than non-POAF patients (P<0.001). Conclusions We found no difference in the adjusted risk of postoperative stroke or all-cause mortality in POAF versus non-POAF patients. Patients with POAF after coronary artery bypass grafting presented with a higher, although not significant, proportion of ischemic strokes of the cardioembolic type.

Elevated blood plasma levels of tissue factor-bearing extracellular vesicles in patients with atrial fibrillation.

BACKGROUND: The risk of thrombus formation in the left atrial appendage (LAA) in patients with atrial fibrillation (AF) may result from blood stasis, local endocardial changes, and/or changed blood composition. Extracellular vesicles (EVs), especially subtypes exposing tissue factor (TF), have procoagulant capacity. We hypothesized that blood concentrations of TF-bearing EVs and other procoagulant biomarkers are elevated in AF patients, particularly in the LAA lumen. METHODS: From 13 AF patients and 12 controls a venous blood sample was drawn prior to cardiac surgery. Intraoperatively, venous blood and blood directly from the LAA was drawn. Plasma levels of EVs, including TF- and cell type specific antigen-bearing EVs, were measured using a protein microarray platform. Plasma levels of TF, von Willebrand factor (vWF), cell free deoxyribonucleic acid (cf-DNA), procoagulant phospholipids (PPLs), and total submicron particles were also evaluated. RESULTS: Significantly higher EV levels, including a several-fold higher median level of TF-bearing EVs were measured in AF patients compared with controls. Median concentrations of TF and vWF were approximately 40% and 30% higher, respectively, in the AF group than in the control group, while no significant differences in levels of cf-DNA, PPLs, or total submicron particles were observed. No significant differences in levels of any of the measured analytes were observed between intraoperative venous and LAA samples. CONCLUSIONS: Increased plasma concentrations of TF in AF patients are accompanied and probably at least partly explained by increased levels of TF-bearing EVs, which may be mechanistically involved in increased thrombogenicity in AF patients.

Fatty Acid Composition in Various Types of Cardiac Adipose Tissues and Its Relation to the Fatty Acid Content of Atrial Tissue.

Diet, with its content of various types of fatty acids (FAs), is of great importance for cellular function. Adipose tissue (AT) serves as a storage for dietary FAs, but after appropriate activation it may also offer important biological properties, e.g., by releasing adipokines and cytokines to the surrounding milieu. Such effects may depend on the diet and type of FA involved. Similarly, the composition of FAs in the heart is also likely to be important for cardiac function. We investigated samples of epicardial adipose tissue (EAT), pericardial adipose tissue (PAT), subcutaneous adipose tissue (SCAT), and tissue from the right atrial appendage to compare the FA compositions in patients undergoing elective cardiac surgery. Minor differences among AT compartments were found, while the comparison of atrial tissue and EAT showed major differences in saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and n-3 and n-6 polyunsaturated fatty acids (PUFAs). These findings may be of importance for understanding biological availability, dietary effects, and the effects of FAs on the heart.

Elimination of Mycobacterium chimaera in a heater cooler device used during on-pump cardiothoracic surgery.

Since 2014, several infections with non-tuberculous mycobacteria (NTM) belonging to the species Mycobacterium ( M.) chimaera have been associated with the use of heater-cooler devices during on-pump cardiothoracic surgery both in European countries and the United States of America. Infections have been detected after surgery, with a delay of a few months and up to five years. Bacterial contamination of heater-cooler devices has also been described without any associated infections. In many centres, it has been a challenging task to eliminate NTM from the heater-cooler devices in order to reduce the risk to patients. In this case-report, we describe how we managed to achieve negative cultures for M. chimaera by changing the cleaning procedure of the Sorin Group Heater-Cooler System with three tanks.

Preoperative Electrocardiogram Score for Predicting New-Onset Postoperative Atrial Fibrillation in Patients Undergoing Cardiac Surgery.

OBJECTIVE: To investigate if electrocardiogram (ECG) markers from routine preoperative ECGs can be used in combination with clinical data to predict new-onset postoperative atrial fibrillation (POAF) following cardiac surgery. DESIGN: Retrospective observational case-control study. SETTING: Single-center university hospital. PARTICIPANTS: One hundred consecutive adult patients (50 POAF, 50 without POAF) who underwent coronary artery bypass grafting, valve surgery, or combinations. INTERVENTIONS: Retrospective review of medical records and registration of POAF. MEASUREMENTS AND MAIN RESULTS: Clinical data and demographics were retrieved from the Western Denmark Heart Registry and patient records. Paper tracings of preoperative ECGs were collected from patient records, and ECG measurements were read by two independent readers blinded to outcome. A subset of four clinical variables (age, gender, body mass index, and type of surgery) were selected to form a multivariate clinical prediction model for POAF and five ECG variables (QRS duration, PR interval, P-wave duration, left atrial enlargement, and left ventricular hypertrophy) were used in a multivariate ECG model. Adding ECG variables to the clinical prediction model significantly improved the area under the receiver operating characteristic curve from 0.54 to 0.67 (with cross-validation). The best predictive model for POAF was a combined clinical and ECG model with the following four variables: age, PR-interval, QRS duration, and left atrial enlargement. CONCLUSION: ECG markers obtained from a routine preoperative ECG may be helpful in predicting new-onset POAF in patients undergoing cardiac surgery.

Marine n-3 fatty acids are incorporated into atrial tissue but do not correlate with postoperative atrial fibrillation in cardiac surgery.

OBJECTIVES: Postoperative new-onset atrial fibrillation (POAF) in cardiac surgery is associated with increased morbidity and mortality. Because n-3 polyunsaturated fatty acids (n-3 PUFA) have an antiarrhythmic effect, we hypothesized that a high content of marine n-3 PUFA in the atrial wall was associated with a reduced risk of POAF. DESIGN: Venous blood and tissue from the right atrial appendage were obtained from 50 patients undergoing elective cardiac surgery. We determined the content of marine n-3 PUFA in atrial tissue and in plasma phospholipids using gas chromatography. RESULTS: The mean age of the patients (results available from 49 patients) was 66.0±10.4years, and 22, 14, 10 and 3 patients underwent coronary artery bypass surgery, valve, combined or other cardiac surgery, respectively. Eighteen patients (36.7%) developed POAF. Concentrations of n-3 PUFA in the atrial wall and in plasma phospholipids did not predict the development of POAF, but there were significant correlations between marine n-3 PUFA in atrial tissue and plasma. CONCLUSION: Levels of marine n-3 PUFA in the atrial wall was not associated with the risk of POAF following cardiac surgery, despite significant correlations of marine n-3 PUFA in the atrium and in plasma phospholipids.

Longevity and admission to nursing home according to age after isolated coronary artery bypass surgery: a nationwide cohort study.

OBJECTIVES: Data on nursing home admission in patient's ≥80 years after isolated coronary artery bypass grafting (CABG) are scarce. The purpose of this study was to evaluate longevity and subsequent admission to a nursing home stratified by age in a nationwide CABG cohort. METHODS: All patients who underwent isolated CABG from 1996 to 2012 in Denmark were identified through nationwide registers. The cumulative incidence of admission to a nursing home after CABG was estimated. A Cox regression model was constructed to identify predictors for living in a nursing home 1 year after CABG. Kaplan-Meier estimates were used for survival analysis. Subanalysis on home care usage was performed in the period 2008-2012. RESULTS: A total of 38 487 patients were included. The median age was 65.4 ± 9.5 years (1455 > 80 years) and 80% were males. The 30-day mortality rate was 2.8%, increasing with age (1.2% in patients <60 years and 7.8% in patients ≥80 years). The mortality rate at 1 year was 2.2% among patients aged <60 and 14.1% among patients ≥80 years. At the 1-year follow-up, 4.2% of patients <60 years, 7.9% of patients 60-70 years, 14.4% of patients 70-74 years, 18.5% of patients 75-79 years and 29.1% of patients ≥80 years had received home care. The proportion of patients admitted to a nursing home at 1, 5 and 10 years after CABG was 0.1, 0.4 and 1.0% (<60 years), and 1.4, 7.5 and 16.8% (≥80 years), respectively. Main predictors for living in a nursing home 1 year postoperatively were: age ≥80 years [hazard ratio (HR) 17.8, 95% confidence interval (CI) 7.4-42.8], female sex (HR 1.7, 95% CI 1.1-2.6), previous heart failure (HR 1.6, 95% CI 1.0-2.4), previous myocardial infarction (HR 2.0, 95% CI 1.3-3.2) and previous stroke (HR 3.3, 95% CI 2.1-4.9). Neither urgent nor emergency surgeries were significant predictors for living in a nursing home 1 year postoperatively. CONCLUSIONS: The majority of all patients selected for CABG surgery in Denmark between 1996-2012, including the elderly, were able to live independently at home without the need of home care for many years after CABG. The risk of nursing home admission was small and dependent on the patient's age, sex and preoperative comorbidities.

Age-dependent trends in postoperative mortality and preoperative comorbidity in isolated coronary artery bypass surgery: a nationwide study.

OBJECTIVES: An increasing number of octogenarians are being subjected to coronary artery bypass grafting (CABG). The purpose of this study was to examine age-dependent trends in postoperative mortality and preoperative comorbidity over time following CABG. METHODS: All patients who underwent isolated CABG surgery between January 1996 and December 2012 in Denmark were included. Patients were identified through nationwide administrative registers. Age was categorized into five different groups and time into three periods to see if mortality and preoperative comorbidity had changed over time. Predictors of 30-day mortality were analysed in a multivariable Cox proportional-hazard models and survival at 1 and 5 years was estimated by Kaplan-Meier curves. RESULTS: A total of 38 830 patients were included; the median age was 65.4 ± 9.5 years, increasing over time to 66.6 ± 9.5 years. Males comprised 80%. The number of octogenarians was 1488 (4%). The median survival was 14.7 years (60-69 years), 10.7 years (70-74 years), 8.9 years (75-79 years) and 7.2 years (≥80 years). The 30-day mortality rate was 3%, increasing with age (1% in patients <60 years, 8% in octogenarians). The long-term mortality rate at 1 and 5 years was 2 and 7% (age <60 years) and 14 and 36% (age >80 years), respectively. The proportion of patients >75 years increased from 10 to 20% during the study period as well as the proportion of patients undergoing urgent or emergency surgery. The burden of comorbidities increased over time, e.g. congestive heart failure 13-17%, diabetes 12-21%, stroke 9-11%, in all age groups. Age and emergency surgery were the main predictors of 30-day mortality: age >80 years [hazard ratio (HR): 5.75, 95% confidence interval (CI): 4.41-7.50], emergency surgery (HR: 5.23, 95% CI: 4.38-6.25). CONCLUSION: Patients are getting older at the time of surgery and have a heavier burden of comorbidities than before. The proportion of patients undergoing urgent or emergency surgery increased with age and over time. Despite this, the 30-day mortality decreased over time and long-term survival increased, except in octogenarians where it was stable. Octogenarians had substantially higher 30-day mortality compared with younger patients but surgery can be performed with acceptable risks and good long-term outcomes.

Early chest tube removal following cardiac surgery is associated with pleural and/or pericardial effusions requiring invasive treatment.

OBJECTIVES: Different opinions exist as to when chest tube removal should be performed following cardiac surgery. The aim of this study was to compare early chest tube removal with removal of the tubes in the morning day 1 postoperatively. Primary combined end point was the risk of postoperative accumulation of fluid in the pericardial and/or pleural cavities requiring invasive treatment. METHODS: A retrospective observational cohort study was performed among patients undergoing coronary artery bypass grafting (CABG) and/or conventional valve surgery between July 2010 and June 2013. Patients in whom chest tube output was <150 ml around midnight during the last 4 h were included in the study. These patients were divided into two groups: Group 1 had their chest tubes removed around midnight on the day of surgery, whereas Group 2 kept their tubes until next morning. Using Poisson regression, we estimated crude and adjusted relative risks (RRs) for developing postoperative pleural and/or pericardial effusion within 14 days requiring interventional treatment. RESULTS: A total of 1232 patients underwent CABG, conventional valve or combined surgery during the study period. Of these, 782 patients fulfilled the criteria for early chest tube removal, which was performed in 385 of the patients. A total of 76 patients in Group 1 (20%) and 51 patients in Group 2 (13%) developed postoperative pleural and/or pericardial effusions requiring invasive treatment (P = 0.011). A positive association between early chest tube removal and the development of pleural and/or pericardial effusions was seen [crude RR: 1.54 (95% CI: 1.11-2.13); adjusted RR: 1.70 (95% CI: 1.24-2.33)]. The association became stronger investigating pleural effusions alone (adjusted RR = 1.77; 95% CI: 1.27-2.46), whereas the association with pericardial effusions was less clear. CONCLUSIONS: Removal of all chest tubes around midnight on the day of surgery is associated with an increased risk of postoperative pleural and/or pericardial effusions requiring invasive treatment even if chest tube output during the last 4 h is <150 ml compared with removal of the tubes next morning.

Statin initiation and acute kidney injury following elective cardiovascular surgery: a population cohort study in Denmark†.

OBJECTIVES: Acute kidney injury (AKI) is a serious complication of cardiac surgery. Statins may prevent post-surgical AKI, yet methodological concerns about existing studies raise questions about the magnitude of a protective effect. We sought to determine the effect of initiating a statin prior to elective cardiac surgery on post-surgical AKI in a regional Danish surgical cohort. METHODS: We identified adults who underwent cardiac surgery during 2006-11 using the Western Denmark Heart Registry. Presurgical medication use, pre- and post-surgical serum creatinine (sCr) measures, and other patient characteristics were obtained from Danish population-based registries. Post-surgical AKI was assessed using sCr measures within 5 days of surgery. The adjusted risk ratio (RR) of AKI and 95% confidence interval (CI) were estimated for patients who initiated a statin within 100 days prior to surgery compared with patients without prior statin use; long-term statin users were excluded to reduce healthy-user bias. Subanalyses were stratified by surgery type: coronary artery bypass grafting (CABG) and non-CABG surgeries. RESULTS: We identified 1929 CABG and 1775 non-CABG patients. AKI occurred in 25% of CABG and 28% of non-CABG surgeries, and in 29% of the non-users and 21% of the statin initiators. Half of CABG patients and 9% of non-CABG patients initiated a statin prior to surgery. The adjusted RRs for the effect of statin initiation on AKI were as follows: all surgeries combined, RR = 0.86 (95% CI: 0.74, 0.98); CABG, RR = 0.88 (0.74, 1.05); non-CABG RR = 0.87 (0.68, 1.11). CONCLUSIONS: Presurgical statin initiation is associated with a reduction in AKI risk after cardiac surgery.

Decreased patency rates following endoscopic vein harvest in coronary artery bypass surgery.

OBJECTIVES: Endoscopic vein harvest has gained widespread use in coronary artery bypass surgery. However, potential negative mid- and long-term effects following endoscopic vein harvest have been described. We aimed to compare long-term clinical outcomes following endoscopic and open vein graft harvesting. DESIGN: This study was a clinical follow-up with additional computed tomographic coronary angiography among 126 first-time bypass patients originally included in a randomized study comparing early leg wound complications and cosmetic results. Deceased patients were retrospectively followed up. RESULTS: Follow-up was complete, but information on clinical endpoints was not available in all patients. A total of 111 patients were alive at follow-up. Median observation time was 6.3 (range: 0.2­9.1) years including three in-hospital deaths. Vein graft failure was significantly higher in the endoscopic vein harvest (EVH) group (13 of 31; 42%) compared with the open vein harvest (OVH) group (2 of 32, 6%) (P = 0.001). However, this difference was not reflected by differences in recurrence of angina (P = 0.44), myocardial infarction (P = 0.11), and all-cause mortality (P = 0.15). CONCLUSIONS: Using a median follow-up time of 6.3 years significantly more vein graft failures were identified following EVH compared with OVH without any differences in long-term clinical outcomes.

Economic evaluation of endoscopic versus open vein harvest for coronary artery bypass grafting.

BACKGROUND: A short saphenous vein segment is commonly used as a conduit for coronary artery bypass grafting, and clinicians must decide whether to obtain it by performing open (OVH) or endoscopic vein harvest (EVH). We conducted a health economic evaluation, using data on resource usage collected alongside a randomized controlled trial, to investigate whether EVH is cost-effective compared with OVH. METHODS: Analyses were performed in accordance with international guidelines for health economic evaluations. We constructed 3 cost-levels as the current literature is inconclusive as to which resource consumptions differ significantly between harvesting methods. Outcomes were measured as purulent infections avoided in the cost-effectiveness analysis and for the cost-utility analysis we estimated quality-adjusted life-years gained. Results were presented as incremental cost-effectiveness ratios: ie, the extra cost of obtaining one extra quality-adjusted life-year and the extra cost of avoiding one purulent infection. To handle uncertainties, we performed bias corrected bootstrap analyses on 5,000 resamples and constructed cost-effectiveness acceptability curves. RESULTS: The incremental cost-effectiveness ratio was $79,391/quality-adjusted life-year and $1,970/purulent infection avoided when costs and outcomes within 35 days postoperatively were compared. Within 35 days postoperatively, EVH was less than 1% cost-effective at a willingness-to-pay threshold of $50,000/quality-adjusted life-year. CONCLUSIONS: The EVH was not cost-effective within 35 days postoperatively. Future studies should investigate long-term cost effectiveness.

Precautions related to midline sternotomy in cardiac surgery: a review of mechanical stress factors leading to sternal complications.

BACKGROUND: After midline sternotomy patients are instructed on activity precautions to avoid sternal wound complications. We questioned how restrictive these precautions must be, since they can lead to a postoperative decrease in quality of life. AIMS: To identify mechanical stress factors causing sternal instability and infection in order to create evidence based guidelines for activity following sternotomy. METHODS: Literature review. RESULTS: No evidence was found to support weight limitation regarding activity, as long as the upper arms are kept close to the body and activity is within a pain-free range. RECOMMENDATIONS: Avoid stretching both arms backwards at the same time (10 days); loaded activities should be done with the elbows close to the body (eight weeks); only move arms within a pain-free range; use leg rolling with counterweighing when getting in and out of bed; when coughing cross the arms in a "self-hugging" posture; supportive bra or vest is recommended when breast cup>or=D, body mass index>or=35 or frequent cough. CONCLUSION: This study provides insights into mechanical stress factors acting upon sternum and the overlying skin. RECOMMENDATIONS on activity precautions based on these finding have a patient supportive approach focusing on possibilities and not restrictions.

Transfusion practice in coronary artery bypass surgery in Denmark: a multicenter audit.

Transfusion rates in coronary artery bypass grafting (CABG) continue to vary substantially, although guidelines for allogeneic transfusion have been developed. In order to evaluate ongoing transfusion practices, we performed a multicenter audit in four Danish hospitals regarding the use of allogeneic blood products among patients undergoing first-time CABG. Data on patient characteristics, peri- and postoperative factors were retrieved from 600 patient records (150 records per hospital). Substantial differences were seen regarding preoperative intake of antiplatelet drugs, perioperative use of antifibrinolytic drugs, use of cardiopulmonary bypass (CPB), cross-clamp time, time on CPB, lowest hemoglobin during CPB, and number of distal anastomoses. The percentage of patients transfused with allogeneic red blood cells ranged from 30.0% to 64.2%. Several patients (12.1-42.7%) transfused with red blood cells were discharged with a hemoglobin concentration >7 mmol/l, indicating inappropriate transfusions. The relative risk of receiving an allogeneic blood transfusion was 2.1 (95% CI: 1.6-2.7) in the hospital with the highest transfusion rate, after adjustment for patient-, drug-, and procedure-related factors. Interesting differences in transfusion rates exists in Danish hospitals and these differences may reflect true variations in transfusion practices. Audits create a basis for educational efforts among surgeons and anesthesiologists to standardize transfusion practices.

Prophylactic tranexamic acid in elective, primary coronary artery bypass surgery using cardiopulmonary bypass.

OBJECTIVE: Perioperative use of tranexamic acid (TA), a synthetic antifibrinolytic drug, decreases perioperative blood loss, and the proportion of patients receiving blood transfusion in cardiac surgery, but the results may vary in different clinical settings. The primary objective of the present study was to determine the efficacy of TA to decrease chest tube drainage and the proportion of patients requiring perioperative allogeneic transfusions following primary, elective, on-pump coronary artery bypass grafting (CABG) in patients with a low baseline risk of postoperative bleeding. METHODS: In a double-blinded, prospective, placebo-controlled study, 46 patients were randomized into two groups. One group received TA 1.5 g as a bolus, followed by a constant infusion of 200 mg/h until 1.5 g. The other group received placebo (0.9% saline). Among exclusion criteria were treatment with acetylsalicylic acid, non-steroidal anti-inflammatory drugs or other platelet inhibitors within 7 days before surgery. RESULTS: Preoperative demographics, biochemical and surgical characteristics were comparable between groups. At 6 h postoperatively, there was a trend towards a greater blood loss (median and interquartile range) in the placebo group (710 and 460-950 ml) compared to the TA group (400 and 350-550 ml), but the difference did not reach statistical significance. Neither were transfusion rates and the amount of autotransfused shed mediastinal blood different between the groups postoperatively. Postoperative d-dimer concentrations were significantly higher in the placebo group compared to the TA group (P < 0.001) This difference could not be explained by differences in the amount of autotransfused shed mediastinal blood alone. Plasma concentrations of beta-thromboglobulin and platelet factor 4 were significantly increased postoperatively in both groups, but without any intergroup differences. Seven patients (15%), one in the TA group and six in the placebo group, were reoperated due to excessive bleeding. Surgical correctable bleeding was found in all except two patients from the placebo group. CONCLUSIONS: An antifibrinolytic effect following prophylactic use of TA in elective, primary CABG among patients with a low risk of postoperative bleeding, did not result in any significant decrease in postoperative bleeding compared to a placebo group.