Atrial Fibrillation After Bypass Surgery: Does the Arrhythmia or the Characteristics of the Patients Prolong Hospital Stay?

doi:10.1378/chest.113.6.1489

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Volume 113, Issue 6, June 1998, Pages 1489-1491

https://doi.org/10.1378/chest.113.6.1489 Get rights and content

Study objectives

The goal of this study was to determine whether prolonged hospital stay associated with atrial fibrillation or flutter (AF) after coronary artery bypass graft (CABG) surgery is attributable to the characteristics of patients who develop this arrhythmia or to the rhythm disturbance itself.

Design

An investigation was conducted through a prospective case series.

Setting

Patients were from a single urban teaching hospital.

Participants

Consecutive patients undergoing isolated CABG surgery between December 1994 and May 1996 were included in the study.

Interventions

No interventions were involved.

Results

Of 436 patients undergoing isolated CABG surgery, 101 (23%) developed AF. AF patients were older and more likely to have obstructive lung disease than patients without AF, but both patients with and without AF had similar left ventricular function and extent of coronary disease. ICU and hospital stays were longer in patients with AF. Multivariate analysis, adjusted for age, gender, and race, demonstrated that postoperative hospital stay was 9.2±5.3 days in patients with AF and 6.4±5.3 days in patients without AF (p<0.001).

Conclusions

Although AF is strongly associated with advanced age, most of the prolonged hospital stay appears to be attributable to the rhythm itself and not to patient characteristics.

Section snippets

MATERIALS AND METHODS

The study was conducted at Henry Ford Hospital between December 1994 and May 1996 and was approved by the Human Rights Committee (Institutional Review Board). All patients undergoing isolated CABG surgery were prospectively evaluated and screened for entry into a study examining management of AF after CABG surgery.⁷ Demographic and outcome data were prospectively obtained by a nurse coordinator or research fellow from the medical record concurrent with the patient's hospitalization and

RESULTS

A total of 436 consecutive patients underwent isolated CABG surgery during the study period and were included in the analysis. AF developed in 101 patients (23%). Characteristics of the groups with and without AF are compared in Table 1, showing that the members of the AF group were older. Postoperative outcomes are compared in Table 2. Hospital stay was prolonged in AF patients.

To determine the relative contributions of AF and other clinical features of patients to length of stay, the final

DISCUSSION

Twenty-three percent of patients undergoing isolated CABG surgery experienced clinically relevant AF; this percentage is in accord with that of other contemporary series.1, 2, 3^,⁶^,⁸ Characteristics of AF patients differed significantly from those of patients remaining in sinus rhythm in that AF patients were older, which is consistent with findings in previous reports.1, 2, 3 As previously described by others,² this study found an association with pulmonary disease; however, it is the first

ACKNOWLEDGMENT

We thank Drs. Gaetano Paone, Norman Silverman, and Charles Webb for their invaluable contributions and Gordon Jacobsen for statistical analyses.

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Preoperative B-Type Natriuretic Peptides to Predict Postoperative Atrial Fibrillation in Cardiac Surgery: A Systematic Review and Meta-Analysis
2024, Heart Lung and Circulation
Post-operative atrial fibrillation (AF) is the most common complication following cardiac surgery. There has been extensive exploration of clinical variables, imaging, and biomarkers to predict its occurrence after cardiac surgery. In this study, we examine the emerging biomarkers B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) to assess their pre-operative values and correlations with the occurrence of post-operative AF in patients undergoing cardiac surgery.
A comprehensive literature search was conducted using PubMed, EMBASE, MEDLINE via Ovid, ClinicalTrials.Gov, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL) to identify studies published until March 2023. The studies were included if they reported pre-operative BNP or NT-proBNP values and the development of post-operative AF in cardiac surgery patients. Subsequently, data were extracted, and a meta-analysis was performed using Review Manager 5.4 4 (The Cochrane Collaboration, 2020) and SPSS version 28 (IBM Corp, Armonk, NY, USA) to assess the difference between pre-operative BNP and NT-proBNP levels between patients with post-operative AF (AF group) and those without (No-AF group) using a random-effect model. Further analysis was performed in three subgroups: isolated coronary artery bypass grafting, isolated valve, and combined/mixed surgery group.
A total of 20 studies, including 9,079 participants were identified and included in the systematic review and meta-analysis. Pre-operative BNP levels were reported in 11 studies, and NT-proBNP levels were reported in 10 studies, of which one study reported both BNP and NT-proBNP levels. There is an overall significant difference between pre-operative levels of BNP (p=0.03, I²=95%) and NT-proBNP (p<0.001, I²=65%) when compared between AF and No-AF groups. Nonetheless, subgroup analysis showed there is no significant difference in pre-operative BNP levels, except in isolated valve surgery (p<0.001), whereas all subgroups showed significantly different pre-operative levels of NT-proBNP.
Elevated levels of both BNP and NT-proBNP were observed in patients who developed post-operative AF after undergoing cardiac surgery. In particular, pre-operative NT-proBNP levels were elevated in all patients irrespective of the type of surgical procedure, but elevated pre-operative BNP was only seen in valve surgery patients. These findings suggest the potential usefulness of NT-proBNP as a promising biomarker for predicting the occurrence of post-operative AF following cardiac surgery.
Maintenance of Serum Potassium Levels ≥3.6 mEq/L Versus ≥4.5 mEq/L After Isolated Elective Coronary Artery Bypass Grafting and the Incidence of New-Onset Atrial Fibrillation: Pilot and Feasibility Study Results
2022, Journal of Cardiothoracic and Vascular Anesthesia
Serum potassium levels frequently are maintained at high levels (≥4.5 mEq/L) to prevent atrial fibrillation after cardiac surgery (AFACS), with limited evidence. Before undertaking a noninferiority randomized controlled trial to investigate the noninferiority of maintaining levels ≥3.6 mEq/L compared with this strategy, the authors wanted to assess the feasibility, acceptability, and safety of recruiting for such a trial.
Pilot and feasibility study of full trial protocol.
Two university tertiary-care hospitals.
A total of 160 individuals undergoing first-time elective isolated coronary artery bypass grafting.
Randomization (1:1) to protocols aiming to maintain serum potassium at either ≥3.6 mEq/L or ≥4.5 mEq/L after arrival in the postoperative care facility and for 120 hours or until discharge from the hospital or AFACS occurred, whichever happened first.
Primary outcomes: (1) whether it was possible to recruit and randomize 160 patients for six months (estimated 20% of those eligible); (2) maintaining supplementation protocol violation rate ≤10% (defined as potassium supplementation being inappropriately administered or withheld according to treatment allocation after a serum potassium measurement); and (3) retaining 28-day follow-up rates ≥90% after surgery. Between August 2017 and April 2018, 723 patients were screened and 160 (22%) were recruited. Potassium protocol violation rate = 9.8%. Follow-up rate at 28 days = 94.3%. Data on planned outcomes for the full trial also were collected.
It is feasible to recruit and randomize patients to a study assessing the impact of maintaining serum potassium concentrations at either ≥3.6 mEq/L or ≥4.5 mEq/L on the incidence of AFACS.
More Pumps Better?
2020, Journal of Cardiothoracic and Vascular Anesthesia
Gene signatures of postoperative atrial fibrillation in atrial tissue after coronary artery bypass grafting surgery in patients receiving β-blockers
2016, Journal of Molecular and Cellular Cardiology
Atrial tissue gene expression profiling may help to determine how differentially expressed genes in the human atrium before cardiopulmonary bypass (CPB) are related to subsequent biologic pathway activation patterns, and whether specific expression profiles are associated with an increased risk for postoperative atrial fibrillation (AF) or altered response to β-blocker (BB) therapy after coronary artery bypass grafting (CABG) surgery. Right atrial appendage (RAA) samples were collected from 45 patients who were receiving perioperative BB treatment, and underwent CABG surgery. The isolated RNA samples were used for microarray gene expression analysis, to identify probes that were expressed differently in patients with and without postoperative AF. Gene expression analysis was performed to identify probes that were expressed differently in patients with and without postoperative AF. Gene set enrichment analysis (GSEA) was performed to determine how sets of genes might be systematically altered in patients with postoperative AF. Of the 45 patients studied, genomic DNA from 42 patients was used for target sequencing of 66 candidate genes potentially associated with AF, and 2,144 single-nucleotide polymorphisms (SNPs) were identified. We then performed expression quantitative trait loci (eQTL) analysis to determine the correlation between SNPs identified in the genotyped patients, and RAA expression. Probes that met a false discovery rate < 0.25 were selected for eQTL analysis. Of the 17,678 gene expression probes analyzed, 2 probes met our prespecified significance threshold of false discovery rate < 0.25. The most significant probe corresponded to vesicular overexpressed in cancer – prosurvival protein 1 gene (VOPP1; 1.83 fold change; P = 3.47 × 10^− 7), and was up-regulated in patients with postoperative AF, whereas the second most significant probe, which corresponded to the LOC389286 gene (0.49 fold change; P = 1.54 × 10^− 5), was down-regulated in patients with postoperative AF. GSEA highlighted the role of VOPP1 in pathways with biologic relevance to myocardial homeostasis, and oxidative stress and redox modulation. Candidate gene eQTL showed a trans-acting association between variants of G protein-coupled receptor kinase 5 gene, previously linked to altered BB response, and high expression of VOPP1. In patients undergoing CABG surgery, RAA gene expression profiling, and pathway and eQTL analysis suggested that VOPP1 plays a novel etiological role in postoperative AF despite perioperative BB therapy.
Genome-wide association study of new-onset atrial fibrillation after coronary artery bypass grafting surgery
2015, American Heart Journal
Postoperative atrial fibrillation (AF) is a potentially life-threatening complication after coronary artery bypass graft (CABG) surgery. Genetic predisposition may predict risk for developing postoperative AF.
Study subjects underwent CABG surgery with cardiopulmonary bypass at Duke University Medical Center. In a discovery cohort of 877 individuals from the Perioperative Genetics and Safety Outcomes Study, we performed a genome-wide association study using a logistic regression model with a covariate adjustment for AF risk index. Single-nucleotide polymorphisms (SNPs) that met a P < 5 × 10⁻⁵ were further tested using a replication dataset of 304 individuals from the CATHeterization GENetics biorepository, followed by meta-analysis. Potential pathways related to postoperative AF were identified through gene enrichment analysis using the top genome-wide association study SNPs (P < 10⁻⁴).
Nineteen SNPs met the a priori defined discovery threshold for replication, but only 3 met nominal significance (P < .05) in the CATHeterization GENetics group, with only one—rs10504554, in the intronic region in lymphocyte antigen 96 (LY96)—showing the same direction of the effect for postoperative AF (odds ratio [OR] 0.48, 95% CI 0.34-0.68, P = 2.9 × 10⁻⁵ vs OR 0.55, 95% CI 0.31-0.99, P = .046) and strong overall association by meta-analysis (meta-P = 4.0 × 10⁻⁶). Gene enrichment analysis highlighted the role of LY96 in pathways of biologic relevance to activation and modulation of innate immune responses. Our analysis also showed potential association between LY96 and nuclear factor κ-B interaction and postoperative AF through their relevance to inflammatory signaling pathways.
In patients undergoing CABG surgery, we found genetic polymorphisms in LY96 associated with decreased risk of postoperative AF.
Postoperative atrial fibrillation significantly increases mortality, hospital readmission, and hospital costs
2014, Annals of Thoracic Surgery
New-onset postoperative atrial fibrillation (POAF) is the most common complication following cardiac surgery. However, the magnitude of POAF on length of stay, resource utilization, and readmission rates remains an area of clinical interest. The purpose of this study was to examine the risk-adjusted impact of POAF on measures of mortality, hospital resources, and costs among multiple centers.
A total of 49,264 patient records from a multi-institutional Society of Thoracic Surgeons (STS) certified database for cardiac operations (2001 to 2012) were extracted and stratified by the presence of POAF (19%) versus non-POAF (81%). The influence of POAF on outcomes was assessed by hierarchic regression modeling, adjusted for calculated STS predictive risk indices.
Mean age was 64 ± 11 years, and median STS predicted risk of mortality for patients who developed POAF were incrementally higher (2% vs 1%, p < 0.001) compared with non-POAF patients. The rate of POAF was highest among those undergoing aortic valve replacement + coronary artery bypass grafting, aortic valve, and mitral valve replacement operations. The POAF patients had a higher unadjusted incidence of mortality, morbidity, hospital readmission, longer intensive care unit (ICU) and postoperative length of stay, and higher hospital costs. After risk adjustment, POAF was associated with a twofold increase in the odds of mortality (adjusted odds ratio = 2.04, p < 0.001), greater hospital resource utilization, and increased costs; POAF was associated with 48 additional ICU hours (p < 0.001), 3 additional hospital days (p < 0.001), and $3,000 (p < 0.001) and $9,000 (p < 0.001) of increased ICU and total hospital-related costs, respectively.
New onset POAF is associated with increased risk-adjusted mortality, hospital costs, and readmission rates. Protocols to reduce the incidence of POAF have the potential to significantly impact patient outcomes and the delivery of high-quality, cost-effective patient care.

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: Supported by a research grant from Hoechst Marion Roussell.

: Reprint requests: Steven Borzak, MD, Cardiovascular Division, Henry Ford Hospital, 2799 W Grand Blvd, Detroit, MI 48202

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Clinical Investigations: SurgeryAtrial Fibrillation After Bypass Surgery: Does the Arrhythmia or the Characteristics of the Patients Prolong Hospital Stay?