\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[ngerman,english]{babel}



\usepackage{float}








\begin{document}

\title{Protecting the Esophagus During Catheter Ablation: Evaluation of a Novel
Vacuum Suction-Based Retractor}



\author[1]{Mohamad El Moheb}%
\author[2]{Marwan Refaat}%
\affil[1]{Massachusetts General Hospital}%
\affil[2]{American University of Beirut Medical Center}%


\vspace{-1em}



  
  \date{May 17, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
N/A%
\end{abstract}%



\sloppy


\par\null

Catheter ablation is the current standard of care for the management of
symptomatic atrial fibrillation (AFib) refractory to pharmacological
therapy. One of the complications of this procedure is thermal injury to
the esophagus due to its anatomical proximity to the posterior wall of
the left atrium (1). Rarely (\textless{}1\%), an atrioesophageal fistula
can form connecting the lumen of damaged esophagus to the atrial chamber
(2). This complication is almost always fatal and can result in
exsanguination, air embolism, and sepsis (3, 4). With a growing number
of catheter ablations being performed each year, the rate of
atrioesophageal fistulas is only expected to rise (5). Other more
frequent complications include esophageal wall erosions and ulcers
(47\%), and thermal injury to the vagus nerve plexus leading to
esophageal dysmotility and gastroparesis (17\%) (6, 7). Therefore,
protecting the esophagus from thermal injuries is paramount in ablative
procedures and several strategies have been devised to help mitigate
this risk. Many physicians monitor the luminal esophageal temperature
(LET) {[} as a surrogate for intramural esophageal tissue temperature{]}
with a single sensor or multisensor temperature probe and interrupt
energy delivery when LET reaches 38\selectlanguage{ngerman}°C or 39°C during radiofrequency
ablation. However, this technique significantly impacts the procedural
workflow due to the waiting periods for LET to return to baseline.
Alternative strategies involve cooling of the esophagus with ice water
or reducing the ablation lesion power, contact force and/or duration but
this strategy may increase the chances for pulmonary vein reconnection
(8). To that end, there has been a growing interest in mechanical
devices capable of deflecting the esophagus away from the atrium
protecting it from thermal injury.

In the current issue of the Journal of Cardiovascular Electrophysiology,
Houmsse et al. introduce a novel device capable of mobilizing the
esophagus laterally to protect it from injury when performing catheter
ablation for AFib. Although other devices have been developed and/or
used for this purpose (such as the transesophageal echocardiography
probe, endotracheal stylet, Esosure stylet and DV8 shaped balloon
retractor), this is the only one to operate using vacuum suction
allowing it to latch onto the esophageal wall. The device consists of
four main components: outer extrusion, inner stacking plates, deflecting
arm and control handle. The outer extrusion is inserted via a trochanter
or a bougie into the esophagus and is the only portion of the retractor
that comes in contact with the surrounding tissues. Small perforations
at the distal end allow for vacuum suction to adhere to the esophagus
and for a radiocontrast agent to be delivered to delineate the
esophageal contour. The inner stacking plates are then introduced
through the outer extrusion and are designed to allow movement of the
deflecting arm in the medio-lateral plane only. The deflecting arm is
connected to the distal end of the stacking plates through a pivot point
and can be steered using the control handle. The authors have evaluated
the effectiveness and safety of the device on canine and swine animal
models by measuring the distance and direction of displacement of the
esophagus, examining the cellular architecture after prolonged suction,
measuring the LET, and assessing compatibility of device with
electroanatomical mapping systems. A total of 68 deviations were
performed on four canine models. The average rightward deflection was
equal to 26.6 ± 2.5mm compared to 18.7 ± 2.3mm for the direct leftward
deflection (p\textless{}0.001), and 96\% of deviations did not have an
esophageal trailing edge. With the exception of one study, the average
distance displaced using the suction retractor was superior to other
devices (9-13). The substantial distance of deflection and the minimal
esophageal trailing edge significantly decreased the rise in LET from
baseline (mean increase of 0.2°C vs 2.5°C without deflection).
Examination of the esophageal tissue integrity following one hour of
continuous suctioning revealed no change in the esophageal cellular
architecture, and only minimal circular areas of hyperemia in mucosa due
to the suction ports without injury to the muscularis layer. Finally,
the retractor did not interfere with the electroanatomical mapping
systems used (CARTO and EnSite).

Despite its interesting findings, this study has several limitations
that should be acknowledged. First, the study was performed on swine and
canine animal models, which are known to have an anatomy close to
humans; however, the safety profile of the device and its effectiveness
in displacing the esophagus may not translate in humans. Second,
subjects may exhibit symptoms secondary to extreme deviation of the
esophagus in the absence of distortion of the cellular architecture.
Clinical studies are needed to assess the safety profile and side
effects of this esophageal retractor. Third, it is unclear whether these
results would be reproducible under monitored anesthesia care. Finally,
the fluoroscopic equipment tools lacked electronic caliper capabilities,
and the measurements were performed using radiopaque rulers.

Overall, the authors should be commended on their efforts to introduce
and evaluate an inexpensive and innovative tool for esophageal
protection during AFib ablation. This retractor addresses the
limitations of other products that serve a similar purpose. In fact, the
suctioning power of the product minimizes the trailing edge of the
esophagus that could not be managed with other devices which left
esophageal tissue in the ablation field (10, 13). In addition, the
control handle offers significant flexibility in device manipulation
allowing physicians to choose the site of angulation and the angle of
deflection depending on the patient's anatomy. Future studies should
focus on evaluating the safety and effectiveness of this device in
humans. Given the growing number of esophageal retracting devices,
studies should also aim to determine the device that produces the best
esophageal protection and most desirable outcomes of ablation.

REFERENCES

1. Chung MK, Refaat M, Shen WK, Kutyifa V, Cha YM, Di Biase L, Baranchuk
A, Lampert R, Natale A, Fisher J, Lakkireddy DR. Atrial Fibrillation:
JACC Council Perspectives. J Am Coll Cardiol. Apr 2020; 75 (14):
1689-1713.

2. D'Avila A, Ptaszek LM, Yu PB, Walker JD, Wright C, Noseworthy PA,
Myers A, Refaat M, Ruskin JN. Left Atrial-Esophageal Fistula After
Pulmonary Vein Isolation. Circulation May 2007; 115(17): e432-3.

3. Aryana A, Arthur A, O' Neill PG, D'Avila A. Catastrophic
manifestations of air embolism in a patient with atrioesophageal fistula
following minimally invasive surgical ablation of atrial fibrillation.
Journal of cardiovascular electrophysiology. 2013;24(8):933-4.

4. Stöckigt F, Schrickel JW, Andrié R, Lickfett L. Atrioesophageal
fistula after cryoballoon pulmonary vein isolation. Journal of
cardiovascular electrophysiology. 2012;23(11):1254-7.

5. Oral H, Siontis KC. Prevention of Atrioesophageal Fistula After
Catheter Ablation: If the Esophagus Cannot Stand the Heat (Cold), Can It
Be Moved to the Sidelines? : JACC: Clinical Electrophysiology; 2017.

6. Shah D, Dumonceau J-M, Burri H, Sunthorn H, Schroft A, Gentil-Baron
P, et al. Acute pyloric spasm and gastric hypomotility: an extracardiac
adverse effect of percutaneous radiofrequency ablation for atrial
fibrillation. Journal of the American College of Cardiology.
2005;46(2):327-30.

7. Schmidt M, Nölker G, Marschang H, Gutleben K-J, Schibgilla V, Rittger
H, et al. Incidence of oesophageal wall injury post-pulmonary vein
antrum isolation for treatment of patients with atrial fibrillation.
Europace. 2008;10(2):205-9.

8. Tran VN, Kusa S, Smietana J, Tsai W-C, Bhasin K, Teh A, et al. The
relationship between oesophageal heating during left atrial posterior
wall ablation and the durability of pulmonary vein isolation. Ep
Europace. 2017;19(10):1664-9.

9. Mateos JCP, Mateos EIP, Peña TGS, Lobo TJ, Mateos JCP, Vargas RNA, et
al. Simplified method for esophagus protection during radiofrequency
catheter ablation of atrial fibrillation-prospective study of 704 cases.
Brazilian Journal of Cardiovascular Surgery. 2015;30(2):139-47.

10. Bhardwaj R, Naniwadekar A, Whang W, Mittnacht AJ, Palaniswamy C,
Koruth JS, et al. Esophageal Deviation During Atrial Fibrillation
Ablation: Clinical Experience With a Dedicated Esophageal Balloon
Retractor. JACC Clin Electrophysiol. 2018;4(8):1020-30.

11. Herweg B, Johnson N, Postler G, Curtis AB, Barold SS, Ilercil A.
Mechanical esophageal deflection during ablation of atrial fibrillation.
Pacing and clinical electrophysiology. 2006;29(9):957-61.

12. Palaniswamy C, Koruth JS, Mittnacht AJ, Miller MA, Choudry S,
Bhardwaj R, et al. The extent of mechanical esophageal deviation to
avoid esophageal heating during catheter ablation of atrial
fibrillation. JACC: Clinical Electrophysiology. 2017;3(10):1146-54.

13. Parikh V, Swarup V, Hantla J, Vuddanda V, Dar T, Yarlagadda B, et
al. Feasibility, safety, and efficacy of a novel preshaped nitinol
esophageal deviator to successfully deflect the esophagus and ablate
left atrium without esophageal temperature rise during atrial
fibrillation ablation: The DEFLECT GUT study. Heart Rhythm.
2018;15(9):1321-7.

\selectlanguage{english}
\FloatBarrier
\end{document}

