[Atrial Fibrillation After Coronary Artery Bypass Surgery: Risk Factors, Prevention and Treatment]

Predictors of Atrial Fibrillation Developing in Hospital Stage After Coronary Artery Bypass Surgery

Aim    To identify independent predictors associated with in-hospital atrial fibrillation (AF) following coronary artery bypass grafting (CABG).Material and methods     The study included 80 patients (88.75 % men) who had elective CABG surgery at the Sklifosovsky Research Institute of Emergency Medicine. Based on the development of AF during the hospital stage of treatment (up to 10 days after CABG surgery), patients were divided into two groups. The group with AF consisted of 19 patients, and the group without AF consisted of 61 patients. All patients underwent electrocardiography (ECG), transthoracic echocardiography (EchoCG) with calculation of the left ventricular (LV) geometry type, and assessment of operational indexes. During surgery, biopsy of a part of the right atrial (RA) appendage was taken from 61 patients to verify the severity of myocardial fibrosis on a four-score scale where 0 is no interstitial fibrosis, 1 is slight fibrosis, 2 is moderate fibrosis, and 3 is severe fibrosis.Results    All included patients had a low risk of developing postoperative complications according to the EuroSCORE II scale. According to EchoCG data, patients with AF had significantly higher ratios of left ventricular myocardial mass to body surface area (LVMM / BSA) (p = 0.0006) and of left atrial volume to body surface area (LA volume / BSA), p = 0.008). The distribution of patients by type of LV geometry was as follows: in the group with AF, 52.63 % (n=10) of patients were diagnosed with concentric LV hypertrophy (LVH) whereas in the group without AF, the majority of patients (83.60 %, n=51) had normal LV geometry and concentric LV remodeling (LVR) (p<0.0001). According to the results of histological study, patients of the AF group more frequently had moderate and severe interstitial fibrosis in the AF appendage (p = 0.003). After multivariate regression and ROC analysis, the predictive value remained for concentric LVH (p=0.002), LVMM / BSA ratio ≥97 g / m2 (p=0.006), LA volume / BSA ratio ≥ 34.4 ml / m2 (p=0.04), and for RA appendage interstitial fibrosis score ≥2 (p=0.004). Based on the identified predictors, a regression model was developed to predict the development of AF at the hospital stage after CABG (p<0.0001). The sensitivity and specificity of the model were 86.67 % and 78.26 %, respectively.Conclusion    In patients at low perioperative risk, the LVMM / BSA ratio ≥97 g / m2, the LA volume ratio / BSA ≥34.4 ml / m2, a RA appendage interstitial fibrosis score ≥2, and the presence of LVH were independent predictors of the development of AF at the hospital stage after CABG operation.Conclusion In patients at low perioperative risk, a LVMM / BSA ratio ≥97 g / m2, a LA volume / BSA ratio ≥34.4 ml / m2, a RA appendage interstitial fibrosis score ≥2, and the presence of LVH were independent predictors of the development of AF at the hospital stage after CABG.

Inflammatory continuum in the pathogenesis of atrial fibrillation after coronary bypass surgery

Atrial fibrillation (AF) after coronary bypass surgery is recorded in 20- 60% of patients and increase the early and long-term postoperative mortality. The aim of the review is to analyze the studies on causal relationships between damaging factors and the development of myocardial inflammation at each stage of surgical treatment in patients with multivessel coronary artery disease. In the review, myocardial inflammation is considered from the point of view of a continuum  — a chronic process that originates from the coronary endothelium damage and continuously proceeds within the AF pathogenesis after coronary bypass surgery. For the first time, the concept of inflammatory continuum for postoperative AF is introduced. The review discusses the main and latest laboratory and instrumental markers of local and systemic inflammatory response, which are informative in terms of severity and promising for improving approaches to the diagnosis and prevention of postoperative AF. The review was prepared using available materials from Russian and foreign library databases (PubMed, Medline, Web of Science and Cochrane Library). The search depth was >25 years since 1996. Based on the analysis of available studies, we concluded that inflammation is not just evidence of AF, but plays a causal role in its pathogenesis at each stage of surgical myocardial revascularization.

[The role of atherosclerotic coronary arteries lesions in development of new-onset atrial fibrillation after coronary artery bypass surgery]

Aim    To study the relationship between the type of circulation, severity and localization of atherosclerotic damage of coronary arteries, results of laboratory and instrumental tests, and historical data in patients with multivascular coronary lesions and atrial fibrillation (AF) that developed after coronary bypass surgery.Material and methods    This was a novel, retrospective study of data of patients after elective coronary bypass surgery at the Cardiac Surgery Department #1 of the N.V. Sklifosofsky Research Institute of Emergency Care from December, 2018 through December, 2020. The study included 100 patients. The main group consisted of 20 patients whose early postoperative period (first 7 days after surgery) was complicated with postoperative atrial fibrillation (POAF) (mean age, 65.15±9.7 years). The comparison group included 80 patients without the POAF complication during the early postoperative period (mean age, 62.0±9.16 years). Prior to the coronary bypass surgery, all patients underwent clinical, laboratory, and instrumental examination. Based on data of selective coronary angiography, localization, severity of coronary atherosclerotic damage (according to angiographic classification), number of affected arteries, and the type of circulation were taken into account.Results    Intergroup differences in the incidence and localization of myocardial infarctions in history, severity of arterial hypertension in history, class of chronic heart failure (according to the New York Heart Association, NYHA, classification), and heart rate were absent. 100 % of patients had left atrial (LA) dilatation not correlated with the development of AF in the early postoperative period. According to data of coronary angiography, there was no statistically significant association between the type of circulation and the development of POAF. The right type of myocardial blood supply prevailed in patients of both groups. There was no correlation between the severity and localization of coronary atherosclerotic lesions and the development of AF in the early postoperative period.Conclusion    The development of AF following coronary bypass surgery was not associated with features of coronary atherosclerotic lesions, which may indicate active development of inter- and intra-systemic anastomoses in patients with long-term history of chronic coronary atherosclerosis.