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\begin{document}

\title{SURGICAL TREATMENT OF ATRIAL FIBRILLATION IN ELDERLY PATIENTS UNDERGOING
HIGH RISK CARDIAC SURGERY}



\author[1]{Mohsin Uzzaman}%
\author[2]{Imthiaz Manoly}%
\author[2]{Mohini Panikkar}%
\author[2]{Maciej Matuszewski}%
\author[1]{Nicolas Nikolaidis}%
\author[2]{John Billing}%
\affil[1]{Affiliation not available}%
\affil[2]{New Cross Hospital}%


\vspace{-1em}



  
  \date{May 16, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
BACKGROUND/AIM To evaluate outcomes of concurrent Cox-Maze procedures in
elderly patients undergoing high-risk cardiac surgery. MEHODS We
retrospectively identified patients aged over 70 years with Atrial
Fibrillation (AF) from 2011 to 2017 who had two or more other cardiac
procedures. They were subdivided into two groups: 1. Cox-Maze IV AF
ablation 2. No-Surgical AF treatment. Patients requiring redo procedures
or those who had isolated PVI or LAAO were excluded. Heart rhythm
assessed from Holter reports or 12-lead ECG. Follow-up data collected
through telephone consultations and medical records. RESULTS There were
239 patients. Median follow up was 61 months. 70 patients had Cox-Maze
IV procedures (29.3\%). Demographic, intra- and post-operative outcomes
were similar between groups although duration of pre-operative AF was
shorter in Cox-Maze group (p=0.001). One (1.4\%) patient in Cox maze
group with 30-day mortality compared to 14 (8.2\%) the control group
(p=0.05). Sinus rhythm at annual and latest follow-up was 84.9\% and
80.0\% respectively in Maze group - significantly better than
No-Surgical AF treatment groups (P\textless{}0.001). 160 patients
(66.9\%) were alive at long-term follow-up with better survival curves
in Cox Maze group compared to No-Surgical treatment group (p=0.02).
There was significantly higher proportion of patients in NYHA 1 status
in Cox-Maze group (p=0.009). No differences observed in freedom from
stroke (p=0.80) or permanent pacemaker (p=0.33). CONCLUSIONS. Surgical
ablation is beneficial in elderly patients undergoing high-risk surgery
- promoting excellent long-term freedom from AF and
symptomatic/prognostic benefits. Therefore, surgical risk need not be
reason to deny benefits of concomitant AF-ablation.%
\end{abstract}%



\sloppy


\emph{TITLE PAGE}

\emph{SURGICAL TREATMENT OF ATRIAL FIBRILLATION IN ELDERLY PATIENTS
UNDERGOING HIGH RISK CARDIAC SURGERY}

\emph{Short Running title: High Risk Ablation Surgery}

\emph{Authors}

\begin{enumerate}
\tightlist
\item
  \textbf{Mohammed M Uzzaman\textsuperscript{1} - MRCS, MSc, BSc}
\item
  \textbf{Imthiaz Manoly\textsuperscript{1} -- FRCS, MD}
\item
  \textbf{Mohini Pannikkar\textsuperscript{1} -- MBChB}
\item
  \textbf{Maciej Matuszewski\textsuperscript{1} -- FRCS, MD}
\item
  \textbf{Nicolas Nikolaidis\textsuperscript{1} -- FRCS, MD}
\item
  \textbf{Stephen Billing\textsuperscript{1} -- DPhil, FRCS}
\end{enumerate}

\emph{Institution}

\textsuperscript{\textbf{1}}\textbf{Department Of Cardiothoracic
Surgery, New Cross Hospital, Wolverhampton, UK} .

\emph{Corresponding author}

\textbf{Mohammed Mohsin Uzzaman}

\textbf{Apartment 211, St Martin's Gate, 5 Worcester Street, Birmingham
B24BB}

E-mail: \textbf{mohsinuzzaman@yahoo.co.uk}

Telephone: \textbf{+44(0)7962234393}

\emph{Meeting Presentation:}

\textbf{Oral Presentation at European Association Of Cardiothoracic
Surgery (EACTS). Virtual Meeting. Oct 8-10. 2020.}

\textbf{AATS Surgical Treatment For Arrhythmias and rhythm disorders. A
Virtual Learning Experience. Virtual Poster. (Oct 30-31 2020).}

\emph{WORD COUNT:} \textbf{4495 words}

\emph{Ethics and Integrity Policies}

\begin{enumerate}
\tightlist
\item
  Data availability -- Nil required
\item
  Funding statement -- Self-funded
\item
  Conflicts of Interest -- Mr Billing is consultant for AtriCure Inc
\item
  Institutional Review Board or waiver -- Not required due to
  retrospective study
\item
  Patient consent statement -- Not required
\item
  Permission to produce material from other sources -- Not required
\item
  Clinical trial registration -- Not required
\end{enumerate}

\emph{ORCID ID:} https://orcid.org/0000-0002-7918-1136

\textbf{ABSTRACT}

BACKGROUND AND AIM OF STUDY

To evaluate outcomes of concurrent Cox-Maze procedures in elderly
patients undergoing high-risk cardiac surgery.

MEHODS

We retrospectively identified patients aged over 70 years with Atrial
Fibrillation (AF) from 2011 to 2017 who had two or more other cardiac
procedures. They were subdivided into two groups:

1. Cox-Maze IV AF ablation

2. No-Surgical AF treatment.

Patients requiring redo procedures or those who had isolated PVI or LAAO
were excluded. Heart rhythm was assessed from Holter reports or 12-lead
ECG. Follow-up data collected through telephone consultations and
medical records.

RESULTS

There were 239 patients. Median follow up was 61 months. 70 patients had
Cox-Maze IV procedures (29.3\%). Demographic, intra- and post-operative
outcomes were similar between the groups although duration of
pre-operative AF was shorter in Cox-Maze group (p=0.001). One (1.4\%)
patient in Cox maze group with 30-day mortality compared to 14 (8.2\%)
the control group (p=0.05). Sinus rhythm at annual and latest follow-up
was 84.9\% and 80.0\% respectively in Maze group - significantly better
than No-Surgical AF treatment groups (P\textless{}0.001). 160 patients
(66.9\%) were alive at long-term follow-up with better survival curves
in Cox Maze group compared to No-Surgical treatment group (p=0.02).
There were a significantly higher proportion of patients in NYHA 1
status in Cox-Maze group (p=0.009). No differences observed in freedom
from stroke (p=0.80) or permanent pacemaker (p=0.33).

CONCLUSIONS.

Surgical ablation is beneficial in elderly patients undergoing high-risk
surgery - promoting excellent long-term freedom from AF and
symptomatic/prognostic benefits. Therefore, surgical risk need not be a
reason to deny benefits of concomitant AF-ablation.

\textbf{KEYWORDS}

\begin{enumerate}
\tightlist
\item
  Atrial Fibrillation
\item
  Cox-Maze IV
\item
  Ablation
\item
  Elderly
\item
  Outcomes
\item
  Long-term
\end{enumerate}

\emph{Introduction}

Atrial fibrillation (AF) is the most common cardiac arrhythmia, with a
prevalence of 2.1\% in people aged more than 65 years, with the highest
prevalence in people aged more than 80 years {[}1{]}. The prevalence of
AF is expected to double by 2050 {[}2{]}. The occurrence of AF is
associated with age, sex, and, most importantly, cardiac disease. Fifty
percent of patients undergoing mitral valve surgery present with AF
{[}3{]}, as do 1\% to 6\% of patients undergoing coronary artery bypass
grafting or aortic valve surgery {[}4{]}.

Several large studies, including the Framingham study, have shown that
AF is associated with an increased risk for mortality and morbidity
{[}5,6{]}. In the past decade, studies have suggested that patients who
present for cardiac surgery with a significant history of AF have
reduced survival over time if AF is left untreated {[}4,7{]}. Other
studies have also found that patients who present with AF have worse
perioperative outcomes, including a higher incidence of thomboembolic
events like stroke and congestive heart failure {[}8-10{]}.

The Cox maze procedure was originally designed in 1987 as a concomitant
procedure for the treatment of AF in patients undergoing MVS {[}11{]}.
After several iterations, the Cox-Maze IV procedure was introduced in
2002 {[}12{]}. The Cox Maze IV simplified the original procedure by
replacing most of the ``cut and sew'' atrial incisions of the lesion set
with linear lines of ablation, making the operation technically easier
and faster to perform. Despite the proven success of the Cox-Maze
procedure, referring physicians and cardiac surgeons remain somewhat
reluctant to adopt the procedure for surgical ablation of AF. Gammie and
colleagues published a study based on the Society of Thoracic Surgeons'
database, which demonstrated that only 38\textbf{\%} of patients
presenting for cardiac surgery while experiencing AF underwent any type
of corrective surgical ablation concomitantly with a valve or coronary
bypass surgery {[}13{]}. The surgical complexity and predicted operative
risk are major variables in the decision of whether to perform surgical
ablation for AF at the time of other cardiac procedures, because there
is a general perception that surgical ablation significantly increases
the complexity, operating times and therefore risks for perioperative
complications. Currently, no risk models are available for concomitant
arrhythmia surgery; thus, the extent of the additional associated risk
has been poorly defined. In addition the level of training required to
perform surgical ablation and a lack of recognition of the clinical
importance of AF may also contribute to the relatively low uptake of the
procedure in clinical practice.

The treatment of elderly patients with AF remains a challenge due to
concurrent morbidities and age-related physiological changes.
Anticoagulation therapies recommended to prevent the thromboembolic
events associated with AF also have a greater risk of major bleeding
complications in elderly patients. The number of elderly patients is
increasing and this is reflected in surgical practice with more patients
undergoing cardiac surgery in the last 15 years {[}14{]}. Very few
studies have examined the efficacy of surgical AF ablation in elderly
patients. As a result, the purpose of this study was to evaluate the
outcomes of concurrent Cox maze procedures in elderly patients
(aged\textbf{[?]} 70 years) who undergo high risk cardiac surgery (i.e.
more than 2 additional concomitant procedures). We hypothesized that a
concurrent Cox maze procedure does not worsen outcomes in elderly
patients undergoing high-risk cardiac surgery.

\emph{MATERIAL AND METHODS}

This was a single-center cohort study in which all data were collected
prospectively for surgery occurring between January 2011 and December
2017. Patients with pre-operative AF, who were above 70 years and
underwent 2 cardiac procedures with or without additional AF procedures
were included in the study. Patients were divided into two groups based
on how the AF was addressed: (1) Cox-maze IV procedure (2) Nil surgical
AF treatment group. Patients undergoing redo procedures or who had
isolated Pulmonary vein isolation (PVI) or left atrial appendage
occlusion (LAAO) to address their AF were excluded from the study.
History of preoperative atrial fibrillation was determined through our
local database and type of atrial fibrillation was determined according
to Heart Rhythm Society guidelines. The database was also used to gain
additional preoperative characteristics and perioperative outcomes.
Detailed follow-up data was collected for patients through telephone
consultations and medical record review. In addition, reports from
primary care physicians and cardiologists from referring centres were
obtained if required. Rhythm status for patients who underwent a
surgical ablation procedure was determined according to the Heart Rhythm
Society guidelines and verified by electrocardiogram and Holter monitor.
The Heart Rhythm Society definition of success (ie, all documented
atrial Arrhythmias \textbf{\textgreater{}} 30 seconds are considered a
failure) was used to determine the return to sinus rhythm rate at first
follow (usually 6 weeks), annual follow and long-term follow-up
{[}15{]}. Anticoagulation status was also collected at the follow-up
time points. Operative mortality was defined as death occurring within
30 days of operation or at any time point during the index
hospitalization.

Operative Approach

Multiple surgeons performed the complete Cox-maze IV lesion set in a
standard fashion as described previously. This consisted of a bilateral
PVI, roof and connecting lesions between the right and left pulmonary
veins, lesion to the left atrial appendage, mitral isthmus lesion, right
intercaval lesion, right appendage lesion, right free wall lesion to the
tricuspid annulus lesion and the coronary sinus lesion. The energy
source used was cryothermia and bipolar radiofrequency (Medtronic,
Minneapolis, Minn; AtriCure Inc, West Chester, Ohio). The left atrial
appendage was occluded in all patients who had Cox-Maze IV. This was
performed using the Atriclip device (AtriCure Inc, West Chester, Ohio).
The patients in the ``Nil procedure'' group only had two cardiac
procedures and served as our primary control group. The decision of
whether to add the Cox Maze procedure to a specific surgical procedure
was left to the discretion of the surgeon.

Statistical Analysis

Continuous data are presented as mean +/- standard deviation or Median
+/- Interquartile range. Categorical data is presented as frequency
(+/-percent) unless otherwise noted. Patient groups were compared
using\textbf{c} 2 or Fisher exact test for preoperative and
postoperative categorical variables and student independent samples t
test or Mann-Whitney U test for continuous measures as appropriate based
on parametric test assumptions. Statistical significance was considered
p \textless{} 0.05, 2-tailed. Kaplan-Meier analysis was used to compare
the groups on cumulative survival, freedom from AF, NYHA 1 status,
freedom from permanent pacemaker insertion and freedom from stroke.
Gehan-Behan-Wilcoxon test was used to assess significance of these
survival analyses. All analyses were conducted using SPSS version 17.0
(SPSS Inc, Chicago, Ill) or GraphPad Prism, Version 6.00 for Mac
(GraphPad Software, La Jolla, CA, USA).

\emph{RESULTS}

\textbf{Patient details}

Between Jan 2011 and Dec 2017, there were 239 patients who were aged
over 70 years with pre-operative AF who underwent two cardiac procedures
(with or without any additional AF procedures). These were divided into
the following groups depending on whether they had procedures to address
their AF (Figure 1). After exclusion of patients described above, 70
patients (29.2\%) had Cox-Maze IV and 169 patients (70.8\%) had No
Surgical-AF treatment (Figure 1).

The mean age of the whole cohort was 76.6+/-4.1 years. The demographic
data of the four groups are summarized in table 1. The logistic
Euroscore was slightly lower in the Cox Maze group (10.0 +/-8.6)
compared to the No Surgical AF treatment (13.0+/-8.9) (p=0.04). There
were no differences in the NYHA 1 status (p=0.10) or NYHA 4 status
(p=0.74) between the groups. There were a higher number of patients with
pulmonary hypertension in the No Surgical AF treatment group (15.4\%)
compared to the AF ablation group (p=0.02). Echocardiogram findings were
comparable between the groups with respects to left atrial size (p=0.48)
and left ventricular function (p=0.11). There was a significantly
shorter duration of AF in the Cox-Maze group (19.9+/-22.3 months)
compared to the No Surgical AF treatment group (94.2+/-113.7 months)
(p=0.001). There were a significantly higher proportion of patients with
PAF in the Cox-Maze group (22.9\%) compared to No Surgical AF treatment
groups (p=0.00001).

\textbf{Intra-operative factors}

The specific intra-operative factors are summarized in table 2. 194
patients (81.1\%) were performed in an elective setting, with no
difference between the groups (p=0.48). Unsurprisingly, the majority of
patients in the cohort had MVS (186 patients, 77.8\%) with no
significant difference between the groups (p=0.17). There were 105
patients (43.9\%) who had concomitant CABG with a lower number in the
Cox-Maze group (27.1\%, p=0.003). The CPB times in the Cox-Maze group
was 165.7+/-64.9 minutes which was comparable to the No Surgical AF
treatment group (p=0.77). Similarly, the X-clamp times for the Cox-Maze
group (135.1+/-40.6 minutes) was not any higher (p=0.91). 9 patients
required IABP at the end of the case (3.8\%) with no difference between
the groups (p=0.67).

\textbf{Perioperative outcomes}

The perioperative outcomes are summarized in table 3. \emph{The overall
30-day mortality was 6.3\% (15 patients) with no difference observed
between the groups (p=0.05). There was one peri-operative death (1.70\%)
observed in the Cox-Maze Group compared to 14 patients (8.2\%) in the
No-surgical AF treatment group. There were 3 cases of stroke in the
entire cohort (1.2\%) which were observed in the No Surgical AF
treatment group (p=0.21). No patients in the Cox-Maze group suffered a
peri-operative stroke.} There was no difference in return to theatre
(p=0.42) between the groups. There were 46 patients (19.2\%) who
developed respiratory complications with no significant difference
between the groups (p=0.06). 32 (13.4\%) patients developed AKI
requiring temporary filtration/dialysis with no difference between the
groups (p=0.16). There were 7 patients (2.9\%) with significant GI
complications (p=0.50). There were 10 patients (4.2\%) who required in
hospital-PPM with 3 cases (4.3\%) in the Cox-Maze group (p=0.96). The
duration of ITU stay (p=0.25) and overall hospital stay (p=0.30) was
comparable between the groups.

\textbf{Long-term outcomes}

The median follow-up was 58.9 +/-26.4 months. Freedom from AF is shown
in Figure 2. At 12 months 84.9\% of the Cox Maze group were in SR. These
benefits persisted until latest follow-up (80\%) and were significantly
superior to the No surgical AF treatment group (P\textless{}0.00001).

There were 79 mortalities (33.1\%) during the follow-up period. There
was a clear survival advantage of the Cox-Maze group (p=0.02) over the
No Surgical AF treatment group (figure 4). It should be mentioned that
all patients were over 70 years of age at the time of surgery.

There were 74 patients (31.0\%) who remained in NYHA 1 on long-term
follow-up. There were clear functional benefits in the Cox-Maze
(p=0.009) compared to No Surgical AF treatment groups (figure 5). On
follow-up echocardiography, the LVF was improved marginally in the
Cox-Maze group compared to the pre-operative LVF (1.0+/-2.2\%).
Conversely, the LVF worsened slightly in the control groups. Overall,
the post-operative LVF was not significantly higher in the Cox-Maze
group (55.2+/-8.3\%) compared to the No Surgical AF treatment group
(51.1+/-9.6\%).

There were 11 cases of stroke in the overall cohort on long-term
follow-up (4.6\%). There were 2 patients in the Cox-Maze group (2.9\%)
compared to 9 patients in the No Surgical AF treatment group (5.3\%).
There were no significant differences (p=0.80) in the long-term freedom
from stroke between the groups.

There were 19 patients who required PPM at long-term follow-up (7.9\%).
5 patients in the Cox-Maze group (7.1\%) compared to 14 in the No
Surgical AF treatment group (8.3\%). There were no significant
differences (p=0.33) in long-term freedom from PPM between the groups.
Only 15 patients in the entire cohort (6.3\%) stopped taking oral
anticoagulation at long-term follow-up with no comparable difference
between the groups (p=0.06).

\emph{DISCUSSION}

A substantial increase in arrhythmia surgery has occurred in recent
years owing to both the increase in AF frequency in our ageing
population and the introduction of ablative technologies that have made
AF correction procedures easier to perform. The Cox-Maze IV remains the
most effective surgical treatment for AF and is the only surgical
procedure to receive an indication from the Food and Drug Administration
for the treatment of AF {[}16,17{]}. Since its introduction in 2002, the
Cox-Maze IV has shown excellent success rates with low morbidity and
mortality rates. However, the efficacy of the Cox-Maze IV at late
follow-up in elderly patients has remained poorly defined. This study
evaluated the efficacy and safety of the Cox-Maze IV in high risk
cardiac surgery in those patients aged above 70 years.

This study showed that surgical ablation was highly effective in the
treatment of AF with 84.9\% at annual follow-up and 80.0\% at long-term
follow-up. As expected, these results were far superior to the
No-surgical AF treatment procedure groups. Our results confirm previous
studies assessing long-term outcomes in elderly patients. Macgregor et
al showed the freedom from atrial tachyarrhythmia on or off
anti-arrhythmic drugs was 80\% and 61\% at 1 and 5 year follow-up
respectively in elderly cohort aged \textgreater{}75 years who had had
Cox Maze IV {[}17{]}. In another study, Ad and Colleagues showed freedom
from atrial tachyarrhythmia after Cox-Maze IV in patients \textgreater{}
75 years was 90\%, 85\% and 60\% at 6 months, 1 and 2 years respectively
{[}18{]}. Our results were also favorable compared to catheter ablation
studies in elderly patients. Bunch et al showed that 46 patients aged
\textgreater{}80 years reported freedom from AF on or off anti-arrythmic
drugs of 75\% and under 30\% at 1 and 5 year follow-up after catheter
ablation {[}19{]}.

It is clear that surgical ablation is under-utilized in current
practice. One of the reasons is the perception that a concomitant
procedure will increase the complexity and operating times of the
procedure and thereby lead to higher peri-operative complications. This
concern is likely to be accentuated in the elderly patients undergoing
high risk surgery with multiple cardiac procedures. Our study clearly
demonstrates that surgical ablation can be performed safely with low
peri-operative complications in elderly patients undergoing 2 or more
procedures. Operating times as reflected in CPB and X-Clamp times were
not significantly increased by concomitant surgical ablation. No patient
who had Cox-Maze IV or PVI had a post-operative stroke which is an
important finding given the known morbidity and mortality associated
with this complication.

Additionally, elderly patients in our study did not experience an
increase in renal failure requiring dialysis, reoperation for bleeding,
respiratory complications or longer ICU/hospital stay. These findings
are similar to those previously published by Ad et al {[}18{]}, as well
as complication rates documented in other studies examining
catheter-based ablation of AF in elderly patients {[}19{]}. On the basis
of their findings, Ad et al, advocated that age should not be the only
discriminatory factor in deciding whether to perform a concurrent Cox
Maze procedure {[}18{]}.

There were 3 patients requiring a PPM post-operatively after Cox Maze
procedure (4.3\%) which is comparable to the other groups in our study.
These rates are acceptable as elderly patients experience a greater rate
of post-operative PPM compared with younger patients as demonstrated by
a recent study by Macgregor et al {[}17{]}. Electrophysiological changes
in atrial tissue due to increasing age may impair sinus node function
and increase the risk of failed sinus node recovery. Despite this, our
long-term need for PPM in the entire cohort was relatively low (7.9\%)
and as a result, we were unable to capture any significant difference
between the groups during long-term follow-up.

The rate of death within the normal population for patients
\textgreater{}70 years old carries significance when trying to interpret
survival over time. Despite this, our study showed survival advantages
of the Cox-Maze IV compared to the group that had no intervention. Of
course, the patients receiving surgical ablation were selected and the
survival difference may merely reflect the preoperative condition.
Nonetheless, the sustained maintenance of SR following ablation may
confer survival benefits in the Cox-Maze group. This is clearly
demonstrated in previous studies that have shown patients who have
surgery without concomitant AF ablation have poorer short and long-term
outcomes than patients that come to surgery and are in SR {[}20,21{]}.
In addition, AF was found to be an independent significant predictor of
long-term mortality {[}22{]}. Ngaage et al demonstrated that
pre-operative AF on patients undergoing cardiac surgery was associated
with increased morbidity and decreased survival if not corrected
{[}23-25{]}. Despite the inherent selection bias, our study adds to the
evidence that even elderly patients undergoing high risk surgery will
achieve mortality benefits with concomitant Cox-Maze IV procedures.

The performance of the Cox Maze procedure, the high rate and maintanence
of SR and exclusion of the left atrial appendage may have an important
effect on risk reduction of thromboembolic and bleeding events. Although
the Kaplan-Meyer curve does not show a significantly lower rate of
stroke in the Cox Maze group, the number of patients in the study was
relatively small and most of our patients in all groups continued to
remain on long-term anticoagulation. There are recent evidence
suggesting that anticoagulation can be safely minimized 3-6 months after
successful Cox-Maze procedure without increasing the risk of stroke or
associated mortality {[}26{]}, and this would be another advantage of
successful ablation.

We are pleased with the finding that suggests reduced symptoms following
the Cox-Maze procedure. This is demonstrated by a significantly higher
number of patients who were in NYHA 1 status in the Cox-Maze group
compared to the other group. The assessment of symptoms and quality of
life is challenging, especially in this subgroup of elderly patients who
underwent a concomitant surgical procedure due to valvular or coronary
disease. As a result, part of their symptom benefits can be related to
the functional improvement as a result of their main cardiac procedure.
However, several studies have shown that the return and maintenance of
SR for patients with pre-operative AF conveyed a significant increase in
quality of life {[}18,27,28{]}. Ad et al also demonstrated improved
quality of life through SF-12 and AF-specific questionnaire in the
elderly cohort \textgreater{} 75 years who had concomitant Cox-Maze IV
{[}18{]}. Gu et al showed patients who were restored to SR
post-operatively had significantly better NYHA status compared to those
in AF {[}29{]}. They also demonstrated significantly improved LVF and
decreased size of LA and RA {[}29{]}. Our study did not show that the
LVF was significantly improved in the Cox-Maze group but it decreased in
the other group. However, we feel the reverse remodelling effect and
prevention of heart failure could contribute to the improvement in
symptoms in these patients in SR.

LIMITATIONS

This study is a retrospective and non-randomized study. This means there
is interval censoring as well as selection bias of the Cox-Maze group
leading to better symptomatic and prognostic benefits in this selected
group. Another potential limitation is that the cause of death was not
available for all patients. Knowing if the cause of death was cardiac in
origin would be of interest as many of these elderly patients carry
several cormorbid diagnoses as highlighted by the very high Euroscore in
the study cohort. Finally, incomplete follow-up for some of the patients
may lead to the study suffering attrition and cause reporting biases.

\emph{CONCLUSION}

The outcome of this study suggests that the concomitant Cox Maze
procedure in patients \textgreater{}70 years undergoing multiple cardiac
procedures is an excellent procedure for sinus rhythm conversion without
increased surgical risks. Our study also demonstrates a significant
symptomatic and prognostic benefit of surgical ablation in elderly
patients. Ultimately, we feel that age and complexity of surgery should
not be contraindications to performing the Cox-Maze procedure.

\textbf{Acknowledgment}

Nil

\textbf{Author contributions}

Mohammed Mohsin Uzzaman: Conceptualization; Data curation;
Investigation; Visualization; Writing---original draft. Imthiaz Manoly:
Data curation; Investigation; Visualization; Writing---original draft.
Mohini Pannikkar: Conceptualization; Data curation; Investigation.
Maciej Matuszewski: Data curation; Investigation; Writing---review \&
editing. Nikolas Nikolaidis: Data curation; Investigation;
Writing---review \& editing. Steve Billing: Conceptualization; Formal
analysis; Investigation; Methodology, Writing---original draft.
Writing---review \& editing.

\textbf{Figure Legends}

Figure 1. Breakdown of cases

Figure 2. Freedom from AF between the two group

Figure 3. Survival curve between the two group

Figure 4. NYHA 1 status between two group

\textbf{TABLES}\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
& COX MAZE (n=70) & NIL(n=169) & p-value\tabularnewline
\midrule
\endhead
AGE & 76.1+/- 3.7 & 77.2+/-4.3 & 0.26\tabularnewline
GENDER & M 33 F 37 & M 89 F 80 & 0.78\tabularnewline
DIABETES & 8 & 39 & 0.13\tabularnewline
COPD & 14 & 27 & 0.74\tabularnewline
BMI & 26.4+/-5.0 & 27.8+/-4.7 & 0.22\tabularnewline
CR Cl & 59.3+/-20.0 & 61.6+/-21.2 & 0.51\tabularnewline
Recent MI & 4 & 6 & 0.11\tabularnewline
Smoking History & 23 & 85 & 0.48\tabularnewline
HTN & 41 & 106 & 0.31\tabularnewline
Previous CVA/TIA & 7 & 23 & 0.79\tabularnewline
NYHA 1 & 2 & 7 & 0.10\tabularnewline
NYHA IV & 18 & 47 & 0.74\tabularnewline
Pulmonary HTN & 3 & 26 & \textbf{0.02}\tabularnewline
LVF & 54.8+/-5.8 & 52.3+/-8.4 & 0.11\tabularnewline
LA Size & 4.8+/-1.4 & 5.1+/-1.1 & 0.48\tabularnewline
AF Duration & 19.9+/-22.3 & 94.2+/-113.7 & \textbf{0.001}\tabularnewline
PAF (\%) & 16 (22.9) & 12 (7.1\%) & \textbf{0.00001}\tabularnewline
\bottomrule
\end{longtable}

Table 1. Demographic data for the two study groups

Table 2. Intra-operative parameters in the two groups\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
& COX MAZE (n=70) & NIL(n=169) & P-VALUE\tabularnewline
\midrule
\endhead
ELECTIVE & 60 & 134 & 0.48\tabularnewline
X-Clamp (min) & 135.1+/-40.6 & 130.7+/-86.3 & 0.91\tabularnewline
CPB (min) & 165.7+/-64.9 & 160.4+/-58.9 & 0.77\tabularnewline
CABG & 19 & 86 & \textbf{0.001}\tabularnewline
Mitral Surgery & 51 & 135 & 0.23\tabularnewline
IABP Intra-op & 2 & 7 & 0.67\tabularnewline
\bottomrule
\end{longtable}

\textbf{Table 3. Peri-operative outcomes between the two groups}\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
& COX MAZE (n=70) & NIL(n=169) & P-VALUE\tabularnewline
\midrule
\endhead
HOSP MORTALITY & 1 & 14 & 0.05\tabularnewline
STROKE & 0 & 3 & 0.21\tabularnewline
Return to theatre & 7 & 22 & 0.42\tabularnewline
AKI -- FILTER & 6 & 26 & 0.16\tabularnewline
PPM & 3 & 7 & 0.96\tabularnewline
Respiratory Complication & 18 & 28 & 0.06\tabularnewline
GI complications & 2 & 5 & 0.50\tabularnewline
ITU stay (Median, IQR) & 3 (2-6) & 3 (2-7) & 0.25\tabularnewline
POST-OP HOSP STAY (MEDIAN, IQR) & 11 (8-17) & 8 (7-16) &
0.30\tabularnewline
\bottomrule
\end{longtable}

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\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Figure!-Groups/Figure!-Groups}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/AF/AF}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Survival-AF/Survival-AF}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/NYHA/NYHA}

\end{center}
\end{figure}

\selectlanguage{english}
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\end{document}

