ABSTRACT
Background : Although epicardial adipose tissue (EAT) has been
proved be associated with atrial fibrillation (AF) and post-ablation AF
recurrence, the relationship between EAT and AF after cardiac surgery
(AFACS) is not evident, yet.
Objective : In the study,
we
aim to perform a systematic review and meta-analysis to assess the
association between EAT and AFACS and whether it is independent of the
measurement methods.
Methods : Systematic reach was implemented until May, 30, 2020,
which “atrial fibrillation” and “epicardial adipose tissue” were as
the main items in electronic databases. Analysis was stratified by EAT
measurement methods into three pooled meta-analyses on 1) total EAT
volume, 2) left atrium (LA)-EAT volume and 3) EAT thickness between two
groups with and without AFACS, estimating standardized mean difference
(SMD) with a random effect model.
Results: Eight articles with ten studies (546 patients) were
included. Accordingly, the results of meta-analysis showed that EAT was
higher in AFACS subjects, regardless of the methods of EAT
measurement.[ total EAT volume: SMD = 0.56 ml; 95% confidence
interval (CI) = 0.56-1.10ml, I2 = 0.90, P=0.04; EAT
thickness: SMD = 0.85mm; 95% CI = 0.04-1.65mm, I2 =
0.90, P=0.04; LA-EAT volume: SMD = 0.57ml, 95% CI = 0.23-0.92ml,
I2 = 0.00, P=0.001.] And there was no evidence of
publication bias.
Conclusion : EAT may be a
potential marker and therapeutic target for AFACS. However, larger scale
studies are still required, and evaluation is needed to for further
estimation.
Keywords:Atrial
fibrillation; epicardial adipose tissue; cardiac surgery; meta-analysis;
echocardiography.
1.Background
Atrial
fibrillation (AF) is the most common arrhythmia with an increasing rate
of morbidity and mortality 1. AF after an cardiac
surgery
(AFACS)
is the most frequent postoperative complication of cardiac surgical
procedures, and occurs in up to 30% patients 2.
Although cardiac surgery-associated morbidity and mortality reduced, the
incidence of AFACS was almost unchanged 3,4. AFACS may
have a negative influence on post-operative results in the long term. It
can result in a two-fold increase in all-cause 30-day and 6-month
mortality after surgery compared to patients with sinus rhythm5.
Recently, more attention has been drawn to the relationship between
epicardial adipose tissue (EAT) and AF because of its inflammatory and
endocrine properties 6. EAT is an ectopic adipose
tissue, which includes fat depots located between the myocardium and the
visceral pericardium, such as pericardial fat, perivascular fat and
myocardial steatosis. According to the location, it is easy to
understand that the
physiological
functions of epicardial adipose tissue, including the storage of lipids
as an energy supply for cardiomyocytes, protection of autonomic ganglia
and nerve tissue, as well as regulation in the diameter and flow of
coronary vessels7. Therefore, we speculate that EAT
may play a central role in the pathogenesis of cardiovascular disease. A
number of studies have shown an increasing relationship between EAT and
coronary artery disease, atherosclerosis and the progression of coronary
plaque burden 8-10, major adverse cardiovascular
events 11 and AF12-15.
The relationship between EAT and AFACS was firstly described by
Charilaos et al. 16 in 2014, while more than ten
studies have been undergone investigation thus far. However, these
studies have been conducted in different populations, operations
(Coronary Artery Bypass Grafting or valve replacement), with a variety
of EAT measurement methods [computed tomography (CT) or
echocardiography], and diverse intervals of follow-up7,16-22. This study was the first attempt to prove the
association between AFACS and EAT, via conducting a systemic review and
meta-analysis in patients with and without AF occurrence after cardiac
surgery.