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\begin{document}

\title{Is coronary artery transfer still the jugular for the arterial switch
operation?}



\author[1]{Sandeep Sainathan}%
\author[1]{Leonardo Mulinari }%
\affil[1]{University of Miami Miller School of Medicine}%


\vspace{-1em}



  
  \date{June 10, 2024}


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\selectlanguage{english}
\begin{abstract}
The outcomes of the arterial switch operation have improved over a
period of time with the elimination of coronary artery anatomy as a risk
factor for operative mortality in some series. However, cumulatively,
when all the series published so far are analyzed, two coronary
variations, namely the single sinus coronary artery origin and
intramural type, persist as risk factors for an adverse operative
outcome.%
\end{abstract}%



\sloppy


\textbf{Title:} Is coronary artery transfer still the jugular for the
arterial switch operation?

\textbf{Running Head} : Transposition of the great arteries and arterial
switch operation

\textbf{Authors} : Sandeep Sainathan, MD\textsuperscript{1}, and
Leonardo Mullinari, MD\textsuperscript{1}.

\textbf{Author Affiliations} : Division of cardiothoracic surgery,
University of Miami\textsuperscript{1},

Corresponding Author:

Sandeep Sainathan, MD

90 SW 3rd street

Suite 2006.

Miami, FL 33130

sainathans@outlook.com

Since its first successful application by Jatene {[}1{]}, the arterial
switch operation has become the procedure of choice for transposition of
the great arteries over the atrial switch operation when both operations
are applicable. The shift in momentum towards the arterial switch was
due to increased experience with safe coronary transfer techniques and
an early application of the operation before regression of the
morphological left ventricle, leading to improved outcomes {[}2{]}.
While some single institution series have reported no operative
mortality directly attributable to coronary artery variation and
transfer technique {[}3{]}, Chowdhury and colleagues, in their expert
review, have synthesized a cumulative impact of coronary artery
variation on the short and long-term outcomes of the arterial switch
operation from previously published studies {[}4{]}.

Fundamental to a successful coronary artery reimplantation is an
understanding of distorting forces acting on the coronary button and
specific variations in the coronary artery pattern limiting the
application of conventional techniques of coronary artery transfer. The
goal is to have a coronary implant without tension, kinking, or torsion.

The coronary button can be subject to distortion in three principal
directions:

\begin{enumerate}
\tightlist
\item
  \emph{Rotation} along its long axis. Excessive rotation can lead to
  torsional obstruction of the implanted coronary artery. In order to
  minimize this, the button is implanted with a slight oblique medial
  tilt to the long axis of the great vessel.
\item
  An \emph{upward or downward pitch} perpendicular to its longitudinal
  axis. Implantation low in the sinus will lead to a downward pitch, and
  kinking and high in the sinus can lead to an upward pitch and create
  tension in the implant.
\item
  A \emph{medial or lateral movement} along its short axis. Usually, the
  button is subject to an excessive medial movement which is minimized
  by using a medially based trapdoor incision in the implanting sinus.
\end{enumerate}

Certain coronary variations such as a looping coronary course, single
sinus origin of the coronary arteries, and an intramural course of the
coronary are considered high risk for a coronary artery transfer as they
can further exacerbate the distorting forces. Several modifications have
been developed to address these coronary patterns, such as an easier
siting of the coronary button reimplantation site by constructing the
neoaortic root first as proposed initially by Jatene {[}3{]}, using the
``medial trap door'' technique, and siting the button high at or above
the neoaortic suture line. With the adoption of these techniques, a
looping course, unless associated with a single sinus origin of the
coronary arteries, is no longer considered a risk factor for a safe
coronary artery transfer, at least in the short term {[}5{]}. However,
despite these techniques, the single sinus origin of the coronary
arteries and an intramural course are still considered high-risk
variants and deserve further attention during coronary reimplantation.

Single sinus origin coronary artery type can have a single orifice or
multiple orifices for each major coronary artery in close proximity.
They are invariably associated with a looping course of one of the
coronary arteries. Alternatively, the arteries can have an interarterial
course with a possibility of an intramural and a juxta commissural
course. The coronary button is usually harvested as a single button, or
the button can be split into two buttons if there is enough separation
between the left and right coronary arteries orifices(\textgreater{} 2
mm){[}5{]}. The harvested single button may be reimplanted with a
conventional technique but minimizing medial rotation using a medially
based trapdoor with or without augmentation by patch material or by a
``bay window'' technique as described by Yamagishi {[}5{]}. However,
sometimes it is impossible to rotate a single button without kinking one
of the arteries. In such a case, if the button is not harvested yet, the
coronary artery is rerouted to the neoaorta using an aortopulmonary
window somewhat akin to a Takeuchi repair {[}5{]}. However, with this
technique there is risk for neopulmonary valve obstruction particularly
if the coronary ostium is deep within the sinus. If the button has been
harvested, a variation of the inverted button technique as described by
Yacoub is used {[}6{]}. Alternatively, conventional implantation
techniques may be used if the single button can be safely split. As the
authors have pointed out in the review, a single sinus origin,
particularly with a looping arterial course, remains a risk factor for a
safe coronary artery transfer leading to a 3-fold increase in early
mortality and continues to have a long-term mortality risk, albeit at a
much lower rate.

A coronary artery with an intramural course is another risk factor for a
safe transfer and, as detailed in the review, carries a 28\% risk for an
early mortality. The coronary artery is at risk for injury during
transection of the aortic root and during harvesting of the coronary
button if the intramural nature of the course is not appreciated. An
intramural course may be associated with a juxtacommisural course and
will require the takedown of the commissure to facilitate a harvest of
the coronary button. The intramural segment may be stenotic and require
an additional unroofing procedure. An intramural course can be
associated with a single sinus origin of the coronary arteries, further
compounding the risk. As pointed out by the authors in the review, there
is also a risk for long-term stenosis due to intimal fibrosis.

In conclusion, outcomes of the arterial switch operation have improved
over a period of time with the elimination of coronary artery anatomy as
a risk factor for operative mortality in some series. However,
cumulatively, when all the published series so far are analyzed, two
coronary variations, namely the single sinus coronary artery origin and
intramural type, persist as risk factors for an adverse operative
outcome.

\textbf{References:}

\begin{enumerate}
\tightlist
\item
  Jatene AD, Fontes VF, Paulista PP, et al. Anatomic correction of
  transposition of the great vessels. J Thorac Cardiovasc Surg. 1976
  Sep;72(3):364-70.
\item
  Quaegebeur JM, Rohmer J, Ottenkamp J, et al. The arterial switch
  operation. An eight-year experience. J Thorac Cardiovasc Surg. 1986
  Sep;92(3 Pt 1):361-84
\item
  Qamar ZA, Goldberg CS, Devaney EJ, et al. Current risk factors and
  outcomes for the arterial switch operation. Ann Thorac Surg. 2007
  Sep;84(3):871-8
\item
  Chowdhury UK, Anderson RH, Spicer DE, et al. Techniques and Pitfalls
  of Coronary Arterial Reimplantation in Anatomical Correction of
  Transposition. Journal of Cardiac Surgery. In press
\item
  Suzuki T. Modification of the arterial switch operation for
  transposition of the great arteries with complex coronary artery
  patterns. Gen Thorac Cardiovasc Surg. 2009 Jun;57(6):281-92.
\item
  Yacoub MH, Radley-Smith R. Anatomy of the coronary arteries in
  transposition of the great arteries and methods for their transfer in
  anatomical correction. Thorax. 1978 Aug;33(4):418-24
\end{enumerate}

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