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\begin{document}

\title{Multiple replacements for recurrent stuck mechanical valve in a patient
with Fontan circulationtech}



\author[1]{Kota Agematsu}%
\author[2]{Mitsugi Nagashima}%
\author[2]{Yoshiharu Nishimura}%
\affil[1]{Wakayama Medical University}%
\affil[2]{Wakayama Kenritsu Ika Daigaku}%


\vspace{-1em}



  
  \date{May 19, 2024}


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\selectlanguage{english}
\begin{abstract}
Significant atrioventricular valve insufficiency is associated with
increased mortality and morbidity in patients with a single-ventricle
because of the congestion associated with single-ventricle circulation.
Treatment of atrioventricular valve insufficiency is mandatory for
completing Fontan circulation. Although valve repair is a favorable
procedure for the lesion because it preserves the valve leaflet and
ventricular motion, replacement of the atrioventricular valve is the
last option of treatment. The choice of a mechanical valve is often made
for atrioventricular valve replacement in children. However, because
children's small body size, mechanical valve implantation can cause
early and late complications, including thromboembolic or hemorrhagic
events, the artificial valve leaflet becoming stuck, and ventricular
dysfunction. Because of these complications, valve replacement can be
performed several times, and repeat surgical intervention can induce
technical difficulties of artificial valve implantation as well. We
present a patient who received multiple mechanical valve replacements
due to repeat valve leaflet stuck after first palliation of pulmonary
artery banding followed by Glenn anastomosis and Fontan completion. To
overcome surgical difficulty, some technical modification was required
during the repeat valve replacement.%
\end{abstract}%



\sloppy


Title page

Multiple replacements for recurrent stuck mechanical valve in a patient
with Fontan circulation

Kota Agematsu, Mitsugi Nagashima, Yoshiharu Nishimura

Department of Cardiovascular Surgery, Wakayama Medical University

The data that support the findings of this case report are available on
request from corresponding author {[}K.A{]}

This case report has been approved by the institutional review board of
our university.

Informed consent was obtained from the patient for publication of this
case report.

Funding: none

Conflict of interest: none

Corresponding author: Kota Agematsu, Department of Cardiovascular
Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama city,
641-8510, Japan (E-mail:\emph{agematsukouta@yahoo.co.jp})

Abstract

Significant atrioventricular valve insufficiency is associated with
increased mortality and morbidity in patients with a single-ventricle
because of the congestion associated with single-ventricle circulation.
Treatment of atrioventricular valve insufficiency is mandatory for
completing Fontan circulation. Although valve repair is a favorable
procedure for the lesion because it preserves the valve leaflet and
ventricular motion, replacement of the atrioventricular valve is the
last option of treatment. The choice of a mechanical valve is often made
for atrioventricular valve replacement in children. However, because
children's small body size, mechanical valve implantation can cause
early and late complications, including thromboembolic or hemorrhagic
events, the artificial valve leaflet becoming stuck, and ventricular
dysfunction. Because of these complications, valve replacement can be
performed several times, and repeat surgical intervention can induce
technical difficulties of artificial valve implantation as well. We
present a patient who received multiple mechanical valve replacements
due to repeat valve leaflet stuck after first palliation of pulmonary
artery banding followed by Glenn anastomosis and Fontan completion. To
overcome surgical difficulty, some technical modification was required
during the repeat valve replacement.

\textbf{Introduction}

Significant atrioventricular valve (AVV) insufficiency, which has been
reported in up to 37\% of patients with single-ventricle {[}1,2{]}, is
one of the major drawbacks of the completion of Fontan circulation.
Congestion in the atrium resulting from atrioventricular regurgitation
should be reduced before and after completion of single-ventricle
circulation. Valve repair is preferable for surgical intervention to the
lesion, because valve and ventricle function can be preserved, and the
risk of complications related to anticoagulant therapy after mechanical
valve implantation might be reduced. Furthermore, an artificial valve
frame fixes the AVV annulus without expected annulus growth after
implantation, which results in the need for repeat artificial valve
replacement depending on the body growth of the patient. Valve
replacement is frequently associated with a moderately high mortality
and various complications, including the need for permanent pacemaker
implantation and repeat valve replacement {[}3{]}. However, valve
replacement is often used as treatment for irreparable valve lesions.

\textbf{Case description}

The patient was diagnosed with a single right ventricle and mitral
atresia and received pulmonary artery banding (PAB) during the infantile
period for reduction of pulmonary blood flow and ventricle preload.
Moderate AVV regurgitation was already observed at that time. Almost one
month after PAB, replacement of the AVV with a mechanical valve
(diameter 18 mm) was required for uncontrollable AVV regurgitation.
After Glenn anastomosis as second-stage palliation followed by pulmonary
artery augmentation with the e-PTFE patch, Fontan circulation was
completed (age 2 years 5 months). Two years and 5 months after Fontan
operation (age 4 years 10 months), repeat valve replacement was
performed using a mechanical valve with a 21-mm diameter because of a
stuck valve leaflet. One month after this repeat valve replacement, a
stuck valve was again observed, another valve replacement was needed.
During the same hospitalization, the stuck valve was observed yet again,
and yet another valve replacement was performed using a mechanical valve
with a 21-mm diameter. Because the patient's ventricular structure
possibly caused the disturbance of the valve leaflet, the bottom of the
mechanical valve was raised with an artificial graft. Although repeated
valve leaflet stuck was observed, laboratory examination did not reveal
any coagulopathy. Repeated valve replacement resulted in severe
ventricular dysfunction, which might result in congestion of blood flow
through the valve leaflet. The patient was placed on much medication,
including diuretics and \selectlanguage{greek}β-\selectlanguage{english}blockers for severe heart failure. When the
patient was 6 years 5 months old, a stuck valve was again observed, and
rather than valve replacement, fibrous tissue around the stuck valve
leaflet was removed, which resulted in recovery of motion of the valve
leaflet. Because of the patient's severe ventricular dysfunction, it was
believed that it would be hard for the patient to be removed from
cardiopulmonary bypass after AVV replacement (AVVR) and AVVR was not
indicated then. However, one month after the operation, re-re-re-re
valve replacement was needed because of a stuck valve during the same
hospitalization. During the operation, an e-PTFE graft of the Fontan
route was transected to obtain the surgical field for valve
implantation, and then a bottom-raised mechanical valve with a 19-mm
diameter implanted. Because of the excessive fibrous tissue observed on
the AVV annulus, which could have hindered the valve leaflet motion, the
same-size valve could hardly be implanted. The left atrial (LA) space
was too small for the bottom-raised valve, and thus the LA wall was
augmented with an e-PTFE patch. To increase cardiac output, right atrium
to LA communication was created. On the 45th postoperative day, the
patient was discharged from the hospital on warfarin potassium to
maintain a prothrombin time--international normalized ratio between 2.5
and 3.0.

\textbf{Discussion}

Artificial valve implantation in small children with a single-ventricle
is associated with an increased risk of mortality {[}4{]}. The rigid
frame of the artificial valve disturbs the motion of the ventricle and
prevents the growth of the AVV annulus. In the small ventricle space,
the leaflet motion can be hindered by the ventricular structure, such as
chordae, and in the small atrial space, the bloodstream through the
valve leaflet is also obstructed. Considering the growth of children, it
might be preferable to select a larger size valve for implantation to
secure an adequate valve orifice area. However, this strategy could
result in valve dysfunction caused by bloodstream obstruction and a
stuck leaflet. In addition to these drawbacks, implanting a large
artificial valve could result in restriction of ventricle motion due to
the rigid frame of the valve followed by ventricle dysfunction.
Ventricle dysfunction may cause congestion of blood stream, which result
in artificial valve leaflet stuck as well. Implantation of a larger size
artificial valve in smaller children is a major risk factor for
mortality {[}4{]} for these reasons.

We also encountered much technical difficulty in removing the old valve
and implanting the new one because the direction of the cardiac apex
could not be changed to enable a good surgical field due to severe
adhesion caused by repeat heart surgery and after the multiple insertion
of an artificial valve, a thickening of the AVV annulus can often be
observed, which results in difficult insertion of a new valve on the
annulus.

In our case, a severe thickening of the AVV annulus and small LA space
were noted; thus, a smaller size valve with a diameter of 19 mm was
selected and implanted in the supra AVV annulus position. We were
concerned that the structure in the ventricle could hinder the opening
of the artificial valve leaflet. To reduce the chance of valve leaflet
dysfunction, the bottom of the mechanical valve was raised with an
e-PTFE graft. The LA wall was augmented with an e-PTFE patch because the
artificial valve was projected into the LA space. Various technical
modifications in mechanical valve implantation are necessary for the
case who had received repeated valve procedure.

Reference

1 Imai Y, Takanashi Y, Hoshino S, Terada M, Aoki M, Ohta J. Modified
Fontan procedure in ninety-nine cases of atrioventricular valve
regurgitation.

J Thorac Cardiovasc Surg 1997;113:262-- 8.

2 Knott-Craig CJ, Danielson GK, Schaff HV, Puga FJ, Weaver AL, Driscoll
DD. The modified Fontan operation. An analysis of risk factors for early
postoperative death or takedown in 702 consecutive patients from one
institution.

J Thorac Cardiovasc Surg 1995;109:1237-- 43.

3 Sughimoto K, Hirata Y, Hirahara N, et al: Mid-term result of
atrioventricular valve replacement in patients with a single ventricle.

Interact Cardiovasc Thorac Surg 27:895--900, 2018

4 Nakata T, Hoashi T, Shimada M, Ichikawa H, et al: Systemic
atrioventricular valve replacement in patients with functional single
ventricle.

Semin Thoracic Surg 31:526-34, 2019

\textbf{Figure legend}

Figure 1

(A) Artificial graft of the Fontan route (inferior vena cava to
pulmonary artery) was transected to obtain an adequate surgical field
for the valve replacement.

(B, C) The atrial wall was augmented with an e-PTFE patch, and the
transected artificial graft of the Fontan route was interposed with
another artificial graft.\selectlanguage{english}
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