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\begin{document}

\title{A Novel Bridging Strategy Using Central Extracorporeal Membrane
Oxygenation in Post-Myocardial Infarction Ventricular Septal Defect}



\author[1]{Stephanie Nguyen}%
\author[1]{Lucas Witer}%
\author[2]{Yuji Kaku}%
\author[1]{David Blitzer}%
\author[1]{William Erwin}%
\author[3]{Koji Takeda}%
\affil[1]{NewYork-Presbyterian/Columbia University Medical Center}%
\affil[2]{Columbia University Irving Medical Center}%
\affil[3]{Columbia University Medical Center}%


\vspace{-1em}



  
  \date{May 26, 2024}


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\selectlanguage{english}
\begin{abstract}
Ventricular septal defect (VSD) is a fatal mechanical complication of
acute myocardial infarction (MI). The outcome of conventional surgery in
post-MI VSD patients complicated by cardiogenic shock is extremely poor.
We report two cases of a post-MI VSD stabilized with extracorporeal
membrane oxygenation support followed by successful patch repair.%
\end{abstract}%



\sloppy


\textbf{Introduction}

With improvements in coronary revascularization, ventricular septal
defect (VSD) has become a rare mechanical complication of myocardial
infarction (MI). Mortality with conservative management remains over
94\%, emphasizing the need for surgery\textsuperscript{1}. The most
important determinant of survival is surgical timing, as there is a
graded decline in mortality with time and myocardial healing. Operative
mortality of VSD repair within 7 days of MI is 54.1\% versus 18.4\% if
surgery is performed after 7 days. When repair is delayed by over 21
days, mortality is reduced to 10\%\textsuperscript{2}. Strategies that
enable patient stabilization, allowing for optimal surgical timing are
necessary. We report two cases of post-MI VSD managed with a novel
approach using central extracorporeal membrane
oxygenation\textsuperscript{3} followed by patch repair.

\textbf{Case 1}

A 53-year-old male presented to an outside hospital with a 3-hour
history of chest pain. Electrocardiogram showed an inferior ST-elevation
MI. Coronary angiography revealed 100\% mid-right coronary artery
occlusion and a single drug-eluting stent (DES) was placed, as flow
could not be restored distally. Given good collateral flow with
preserved ejection fraction (EF 50\%), he was discharged after 2 days.
He developed recurrent chest pain and was readmitted 3 days later in
cardiogenic shock. Coronary angiography was unchanged with patent DES.
Transthoracic echocardiography (TTE) revealed normal left ventricular
function, severely depressed right ventricular function, hypokinetic
inferolateral wall, and a 2cm VSD at the inferior mid-septum with
left-to-right shunting (Figure 1A). Given his worsening cardiogenic
shock, femoral venoarterial extracorporeal membrane oxygenation
(VA-ECMO) was initiated prior to transfer to our institution.

The patient arrived intubated with minimal pulsatility and a non-opening
aortic valve with root stasis, requiring urgent conversion to central
ECMO. Intraoperative transesophageal echocardiography (TEE) demonstrated
a posterior VSD and aortic root thrombus (Figure 1B). The ascending
aorta and right atrium were exposed through a right anterior
mini-thoracotomy at the second intercostal space and the LV apex was
exposed through a left anterior mini-thoracotomy at the fifth
intercostal space (Figure 2). The ascending aorta and right atrium were
cannulated with a 21-Fr arterial and 24-Fr venous cannula, respectively.
Both cannulas were tunneled and exteriorized at the right upper chest.
The LV apex was cannulated with a 24-Fr venous cannula and tunneled out
to the left upper abdomen. LV apex and right atrial cannulas were
connected with a Y-connector as inflows. All cannulas were connected to
the CentriMag (Abbott Laboratories, Abbott Park, IL) and an oxygenator
was spliced into the circuit. The femoral cannulas were removed. He was
extubated on postoperative day 1 and participated in ambulatory
rehabilitation. The patient remained on CentriMag support for 20 days
with improving end-organ function before undergoing VSD closure.

After institution of cardiopulmonary bypass with bicaval cannulation,
CentriMag flow was terminated and the existing cannulas removed. A
double patch VSD closure was performed via the right
ventricle\textsuperscript{4}. The right ventriculotomy was made 1.5cm
from the mid-posterior descending artery and the VSD was identified,
surrounded by firm fibrotic tissue (Figure 3). Two patches of bovine
pericardium were tailored to the defect. The right ventriculotomy was
closed and the patient came off bypass with inotropic support. TEE
revealed EF 30-35\%, mildly decreased RV function, and no residual
shunt. The postoperative course was uncomplicated and he was discharged
home on postoperative day 12 with good functional status.

\textbf{Case 2}

A 73-year-old female presented with a 4-hour history of chest pain.
Electrocardiogram showed an anterolateral ST-elevation MI. Coronary
angiogram demonstrated complete occlusion of the mid-anterior descending
artery and 60\% stenosis of the obtuse marginal branch. Thrombectomy and
DES deployment were performed with excellent angiographic results. TTE
revealed global biventricular hypokinesis (EF 30\%), apical septal
akinesis, and a large mid-septal VSD with multiple left-to-right jets
(Figure 1C). The patient rapidly developed cardiogenic shock with rising
lactate (3.0 mmol/L) and underwent placement of an intra-aortic balloon
pump (IABP) and femoral VA-ECMO. Three days later, TTE showed minimal
aortic valve opening and root stasis, thus she was switched to central
cannulation.

The patient underwent IABP removal and conversion to central ECMO with
an LV apical vent (18-Fr aorta, 24-Fr RA, 22-Fr LV apex), as in Case 1.
She was extubated on postoperative day 3 and participated in ambulatory
rehabilitation. She remained hemodynamically stable with normalizing
end-organ function for 22 days before undergoing definitive repair.

After establishment of cardiopulmonary bypass and regular cardiac
arrest, CentriMag flow was terminated and the three existing cannulas
were removed. Saphenous vein graft was used to bypass the obtuse
marginal branch. A longitudinal right ventriculotomy was made 1 cm from
the LAD and the 2cm anterior VSD was identified in the mid-septum,
surrounded by firm fibrotic tissue. We proceeded with a double patch VSD
closure via the right ventricle, as in Case 1\textsuperscript{4}. No
residual VSD was seen on intraoperative TEE. The postoperative course
was uncomplicated and the patient was extubated on postoperative day 4.
She was discharged to a rehabilitation facility on postoperative day 20
with improving functional status.

\textbf{Comment}

These cases illustrate employment of a unique central ECMO strategy to
delay repair of post-MI VSD complicated by cardiogenic shock. Given the
high mortality and low likelihood of successful repair in the immediate
post-infarction period, both patients were stabilized with central ECMO
for 3 weeks, granting time for recovery from cardiogenic shock and
myocardial healing for successful patch closure.

Many mechanical circulatory support strategies have been used to
stabilize patients before VSD repair\textsuperscript{5,6}; however, each
has its limitations. Percutaneous devices (i.e. IABP, Impella,
TandemHeart) are readily placed and augment LV unloading and myocardial
and peripheral tissue perfusion. However, such devices are limited by
flow capability and inadequate support for biventricular failure, a
common feature of post-MI VSD. Femoral VA-ECMO provides additional
support but is limited by increased afterload and root stasis as seen in
our cases. Furthermore, it limits ambulation, leading to progressive
deconditioning. An axillary-jugular VA-ECMO configuration may also be
used; however, flow is limited by arterial size and may lead to
hyperperfusion of the arm and significant nerve injury if prolonged
support is required.

Alternatively, a temporary external VAD may provide sufficient
biventricular support in cardiogenic shock; however, insertion requires
a sternotomy and cardiopulmonary bypass. Our approach addresses each of
these limitations. Firstly, it facilitates biventricular unloading while
providing full cardiopulmonary support with antegrade oxygenated flow.
Additionally, it allows preservation of a virgin chest, with very
minimal intrapericardial adhesions noted, for the planned VSD closure
and permits ambulatory therapy prior to surgical repair.

VSD closure was performed using a double-patch repair through a right
ventriculotomy. In this novel technique, two patches are anchored to the
VSD margin using interrupted horizontal mattress sutures placed
transeptally or transmurally from the LV (via the VSD) to the RV cavity
or LV wall, creating a ``sandwich'' closure. There are many advantages
to this approach, including preservation of contractile function by
avoiding a left ventriculotomy and reproducibility for anterior and
posterior defects.

In conclusion, our approach is a feasible bridge strategy in the
management of post-MI VSD with cardiogenic shock. Further experience
with this modality is required.

\textbf{Author Contributions}

Stephanie N. Nguyen, MD: concept/design, drafting article, critical
revision of article, Lucas J. Witer, MD: critical revision of article,
approval of article

Yuji Kaku, MD: critical revision of article,

David Blitzer, MD: drafting article, critical revision of article

William C. Erwin, MD: critical revision of article

Koji Takeda, MD: concept/design, drafting article, critical revision of
article, approval of article

\textbf{References}

Crenshaw BS, Granger CB, Birnbaum Y, et al. Risk Factors, Angiographic
Patterns, and Outcomes in Patients With Ventricular Septal Defect
Complicating Acute Myocardial Infarction. \emph{Circulation} .
2000;101(1):27-32.

Arnaoutakis GJ, Zhao Y, George TJ, et al. Surgical Repair of Ventricular
Septal Defect After Myocardial Infarction: Outcomes From The Society of
Thoracic Surgeons National Database. \emph{The Annals of Thoracic
Surgery} . 2012;94(2):436-444.

\begin{enumerate}
\tightlist
\item
  Takeda K, Garan AR, Topkara VK, et al. Novel minimally invasive
  surgical approach using an external ventricular assist device and
  extracorporeal membrane oxygenation in refractory cardiogenic
  shock.\emph{European Journal of Cardio-Thoracic Surgery} . June 2016.
\item
  Asai T, Hosoba S, Suzuki T, et al. Postinfarction ventricular septal
  defect: right ventricular approach---the extended ``Sandwich''
  patch.\emph{Seminars in Thoracic and Cardiovascular Surgery} .
  2012;24(1):59--62.
\item
  Patan\selectlanguage{ngerman}è F, Grassi R, Zucchetti MC, et al. The use of Impella Recover in
  the treatment of post-infarction ventricular septal defect: A new case
  report. \emph{International Journal of Cardiology} .
  2010;144(2):313-315.
\item
  Gregoric ID, Kar B, Mesar T, et al. Perioperative Use of TandemHeart
  Percutaneous Ventricular Assist Device in Surgical Repair of
  Postinfarction Ventricular Septal Defect. \emph{ASAIO Journal} .
  2014;60(5):529-532.
\end{enumerate}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

\textbf{Figure 1.} A) Intraoperative TEE 3D reconstruction demonstrating
posterior apical VSD. B) Intraoperative TEE demonstrating aortic root
thrombus C) Anterior VSD with left-to-right shunting seen on
preoperative TTE

\emph{TEE = transesophageal echocardiography; TTE = transthoracic
echocardiography; VSD = ventricular septal defect}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image2/image2}

\end{center}
\end{figure}

\textbf{Figure 2.} Central VA-ECMO with LV vent configuration. Inflow =
right atrium and left ventricular apex; outflow = ascending aorta.
Femoral cannulas are clamped for decannulation.

\emph{VA-ECMO = venoarterial extracorporeal membrane oxygenation}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image3/image3}

\end{center}
\end{figure}

\textbf{s}

\textbf{Figure 3.} Posterior ventricular septal defect (blue arrow)
visualized through an inferior right ventriculotomy.\selectlanguage{english}
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\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Fig-1-JCS/Fig-1-JCS}

\end{center}
\end{figure}\selectlanguage{english}
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\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Figure-2-JCS/Figure-2-JCS}

\end{center}
\end{figure}\selectlanguage{english}
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\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Figure-3-copy/Figure-3-copy}

\end{center}
\end{figure}

\selectlanguage{english}
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